Waxy Materials Research Articles

Multi-stimulus Response Behavior of Biomimetic Autocrine Waxy Materials for Potential Self-Constructing Surface Microstructures.

Many functions of terrestrial plant leaves rely on the regenerable epidermal wax layer. Biomimetic autocrine waxy materials (AWMs) inspired by renewable epidermal waxes are attracting increasing attention. However, the growth properties of the wax layer remain unclear, limiting the development of this promising material. This work focuses on the stimulated growth characteristics and microstructural regulation methods of the waxy layers. It is found that the wax layers exhibit a corresponding behavior of changing their surface micromorphology under force, heat, solvents, and other stimuli during the self-growth process, and as a result of which, various types of fine surface microstructures such as grids, rings, stripes, pattern copying, and printing can be self-built on their surfaces. The composition of the surface autocrine wax layer changes with the autocrine time, and this finding may be useful for the separation and purification of alkane mixtures. In addition, the surface wax layer possesses the ability to self-heal and strengthen itself at the damage site after being stimulated by injury, similar to the damage-response behavior of a bark surface. Such multi-stimulus response behavior described here provides a platform for the discovery of more functional materials and microstructural self-construction techniques and can also serve as a basis for their applications.

Experimentation on enhancement of solar still performance

This work presents new results from controlled experiments using well-designed and constructed single-inclination solar stills. The aim of these experiments is to explore methods for enhancing still performance by studying the individual effects of three types of methods. Specifically, the experiments investigate the actual effects of still basin water depth, the use of a sensible heat storage medium, and the treatment of the inner glass surface with waxy substances. The main distinction in this work is the use of solar stills that can achieve thermal efficiencies in excess of 40% under favourable weather conditions without any modification. This high efficiency level allows for meaningful analysis of the impact of modifications on still performance. The results indicate that still yield, productivity, and thermal efficiency decrease significantly when the water depth in the basin exceeds 6 cm. additionally, introducing black gravel in excess of a 2% gravel to water mass ratio in the still basin does not produce a significant change in still thermal efficiency. Treatment of the still inner glass surface with two types of waxy materials resulted in large drop in still performance.

Preparation and evaluation of lipid matrix microencapsulation for drug delivery of azilsartan kamedoxomil

The aim of the work is to consolidate azilsartan-kamedoxomil (AZM) into lipid matrix controlled-release microparticles to enhance its permeability because AZM belongs to Biopharmaceutical classification (BCS) IV which characterized by poor permeability and to protect AZM from light and humidity and execute a prolonged release profile.
 Materials and methods. A reversed-phase HPLC method was created and validated to estimate the drug. AZM microparticles formulations were invented using melt dispersion technique and waxy materials such as carnuba wax, beeswax, stearic acid in the ratio of waxy-substance: drug ranging from 0.25: 1 to 1:1 and stabilizer namely; tween 80 and Poloxamer 407 in ratio of stabilizer: drug ranging from 0.5:1 to 1:1. Azilsartan formulations were assessed for azilsartan-medoxomil content, loading, entrapment efficiency, the zeta potential,the particle size, the morphology by scanning electronic microscopy (SEM), and in-vitro release profile.
 Results. Zeta potential results for microparticle formulations using beeswax and carnuba range from -21.1 mV to -26.6 mV and -20.6 mV to -26.7 mV, respectively. This difference indicates that the azilsartan microparticles containing stearic acid are better stabilized with zeta potential of 25.3 - 29.7 mV. Furthermore, the release from azilsartan microparticle formulations containing stearic acid exceeded 80 % after 8 h and remained for 24 h while release from beeswax did not exceed 65 % after the same period and less than 60 % in case of carnuba formulations
 Conclusions. The formulation (AZSP4) exhibited the highest zeta potential and released exceeding 80 % of AZM over the course of 8 hours and remained over a day. AZSP4 microparticles formulation containing, poloxamer 407, in a 0.8:0.8:1 drug: stearic acid: poloxamer ratio proved the ability of stearic acid microencapsulation employing poloxamer as stabilizer in a certain ratio can prolong the release of AZM

Experimental simulation of volumetric compacts formation from spherical waxy elements

The growth in metal intensity of industrial production and the volume of consumption of finished metal products determine the relevance of development and research of energy efficient technological processes aimed at reducing costs by reducing the number of operations while maintaining product performance. In mechanical engineering, the problem of obtaining blanks with increased dimensional and geometric accuracy and complex configuration is solved by using a common method of investment casting. Expansion of the use of such technological approach to produce blanks in mechanical engineering is hindered by a number of physical phenomena associated with the thermal expansion of investment and ceramic materials, which leads to an increase in the product final cost. A significant number of defect-forming factors can be eliminated by applying an innovative solution consisting in the formation of porous removable models by compacting mixtures based on waxy materials. This solves the problem of material shrinkage and increases the crack resistance of ceramic molds, which significantly reduces the share of machining in the overall volume of technological operations. Technical tests of the new method have revealed the reason why the machining of castings cannot be completely eliminated at present. The problem mainly lies in elastic response of compacted material of the model mixture, which, in some cases, affects the increase in the compacts size. This paper considers the effect of initial packing of spherical-shaped elements simulating one- and two-component model mixtures on the stress-strain state of a powder body subjected to unilateral compaction in a rigid cylindrical matrix to technologically justified density values. The results of the experiment are presented in the form of stress-strain relations. Preferable conditions of compact formation with minimal values of elastic response of the compacted material are considered.

Evaluation of cosmetic lipsticks for hazardous heavy metals and determination of antimicrobial potency

Background: Lipstick, a cosmetic product containing pigment, wax materials, oils and emollient that apply color, is the most widely used cosmetic make-up to enhance the beauty of lips. Consciously or unconsciously, lipsticks have cast a spell over cultures for years and its possible health implications on the consistent wearer's remain a subject of controversy. This study evaluated commercial lipsticks purchased from selected beauticians' shops in Ibadan for antimicrobial potency and hazardous heavymetals. Methods: One gram (1g) of representative lipsticks samples was weighed on analytical weighing balance and dissolve in 10 mL of acetone. A stock concentration of 100mg/mL was prepared using 50% acetone as diluents. Thereafter, 5mL of the stock was pipette in to 5mls of 5% acetone to make a concentration of 50mg/mL . A quantity of 0.8g of each representative samples were weighed and 8mL of HNO3: HCl (1:3) were added to the samples in each beaker. The samples were heated and the preparation was allowed to cool and filtered to removed undissolved waxy materials, while the digested solutions were made up to mark 40 ml with sterile distilled water. The sample solutions were analyzed for Cr, Pb, Cd, Mn, Fe and Zn using FlameAtomicAbsorption Spectrophotometer. Culture of E. coli, S. aureus, K. pneumonia, Streptococcus sp, and Pseudomonas aeruginosa seeded in moltenMueller Hinton agar were challenged with (100mg/mL and 50mg/mL) concentrations of selected acetone dissolved lipsticks samples using agar well diffusion technique. Results: Lead was found in varied concentrations in all the 15 samples examined, while Cadmium, Magnesium, Zinc and Iron were found in 7 of the 15 samples, Chromium was found in 3 of the total samples examined. Thirteen (13) of the 15 samples of lipsticks examined exhibited antimicrobial property against Escherichia coli, Staphylococcus aureus and Klebsiella spp at either 100 mg/mLand/or 50mg/mL. Conclusion: The degree of heavy metals detected from the samples examined could be inimical to user's health coupled with the susceptibility of some of the lipsticks sample to bacteria of clinical potential. There is therefore a need for extensive testing to assess and assure the efficacy of lipsticks regularly before delivery to markets.

Importance of char-volatiles interactions during co-pyrolysis of polypropylene and biomass components

This study reports the importance of plastic volatiles on char-volatiles interactions during co-pyrolysis of polypropylene (PP) and biomass components under non-catalytic conditions in a two-stage reactor. PP-volatiles were generated and interacted with biochar from cellulose and lignin downstream at different temperatures. Different experiment configurations were designed in order to explore the contribution of the tarry and waxy materials in PP-volatiles to the char-volatiles interactions. Experimental results showed that the char-volatiles interactions altered the yield and the chemical structure of PP-oil and biochar. The O-containing and aromatic species in biochar acted as active sites during interactions. Large aromatic rings in the biochar were predominant during the cracking of the tarry materials in PP-volatiles, while the O-containing species dominated during the recombination and polymerization of the waxy material in PP-volatiles. At higher temperatures, waxy and tarry materials released H-radicals inside the cellulose-char matrix, and strengthened the ring aromatic condensation reactions, while waxy and tarry materials were involved in heavier aromatic structures in lignin-char, leading to the fragmentation of lignin. In addition, even at low temperatures (e.g. 500 °C), waxy material can provide hydrogen and slightly enhance the condensation of the aromatic ring systems in lignin-char.

Formulations of sustained release matrix tablets of Furosemide using natural and synthetic polymers

The primary benefit of a sustained release dosage form compared to a conventional dosage form, is the consistent drug plasma concentration and consequently uniform therapeutic effect. Matrix system are preferential because of their ease, patient compliance etc, than traditional drug delivery which have several drawbacks like reiterated administration, variation in blood concentration level etc. The aim of the present research study was to develop and evaluate sustained release matrix tablets of furosemide using direct compression method using natural gummy and waxy materials (Xanthan gum, bees wax) and synthetic polymers (HPMC K4M). The matrix tablet formulations were prepared by using different drug: polymer ratios (1:1, 1:2 and 1:3). All formulations were assessed using micromeritics studies of powder blend and diverse physicochemical tests. All the physicochemical characters of the formulated tablets were within acceptable limits. The release pattern of the drug was viewed over a period of 12 hours and determined the amount of drug by the UV-Visible spectroscopic method. Dissolution data demonstrated that the formulated tablets with Xanthan gum and hydroxyl propyl methylcellulose (HPMC) provided sustained release of the drug up to 12 hrs. Therefore inexpensively it may be appropriate for the pharmaceutical industries to employ this kind of simple technologies for the expansion of advanced formulations. Hence, we conclude that the purpose of this study was to formulate a sustained release matrix tablet of furosemide using diverse polymers and their dissimilar proportions have been attained.
 Keywords: Furosemide, Direct compression, Natural, Synthetic polymers, Sustained release tablets.

USING LIPASE ENZYME IN CLEANING OF ARCHAEOLOGICAL GLASS: AN EXPERIMENTAL APPLIED STUDY

The main objective of this research paper is to study the effect oflipase enzyme on the waxy materials mixed with the carbon particlesresulting from the burning of the candles, which were difficult toremove in one of the archaeological glass candle stands in the CopticMuseum, Cairo, Egypt. The paper is divided into an experimentalstudy for the use of the lipase enzyme in glass cleaning and anapplied study on cleaning an archaeological glass candle stand.The experimental samples were cleaned using lipase enzymefrom Burkholderia sp. X-Ray Fluorescence (XRF) was used toidentify the components of the archaeological glass candle standin the colorless and colored parts. X-Ray Diffraction (XRD) andRaman spectroscopy analysis were used to identify the damagedproducts in the study sample. Then, the stereo microscope and USBdigital microscope were employed to find out the efficacy of thelipase enzymes in the cleaning of experimental samples and theapplied study. The results proved that there was a high efficacy inthe dissolution of waxy fatty layers and the dissociation of carboncalcifications. USB digital microscopic images showed that lipaseenzymes from Burkholderia sp. gave good results in cleaning thesurface of the archaeological candle stand. Moreover, the enzymewas inhibited with the use of ethyl alcohol.

Photoactive polyurethanes based on 2,2′-dihydroxyazobenzene fluorescent segments

This article presents the synthesis and structural, thermal and dynamic mechanical characterization of segmented polyurethane - PCLDHAB - based on poly(caprolactone)-diol (PCL-diol) as a flexible segment, and polyurethane-diol (PU-diol) as a rigid segment based on 2,2′-dihydroxyazobenzene (2,2′-DHAB). While the precursors PU-diol and PCL-diol are rigid and waxy materials, respectively, PCLDHAB is a flexible, semi-crystalline polymer, which has a heterogeneous amorphous phase. To better understand the absorption spectra of the polyurethanes, theoretical predictions by DFT and TD-DFT of a model molecule in DMF (implicitly added) were carried out. The model molecule was a fragment of the hard segment of the polyurethane’s chain, containing one 2,2′-DHAB and two 4′-isocyanate-4′-methylbenzene fragments, bonded to each other by carbamate bonds, the 4-isocyanate-4′-metylbenzene-alt-2,2′-dihydroxyazobenzene. Similar to 2,2′-DHAB, PU-diol and PCLDHAB do not show photoisomerization, however they emit fluorescence. 2,2′-DHAB segments in the polyurethane chains present different conformations with distinct spectroscopic characteristics. However, the conformer’s proportion in the polymer chains differs from the 2,2′-DHAB monomers in DMF solution. 2,2′-DHAB emits in two ranges in the UV–vis spectrum while its polyurethanes emit in three ranges, covering a broader wavelength range from ultraviolet to visible.

Preformulation Studies of Pralidoxime Chloride for Formulation Development of Microspheres

Microspheres are one of the novel drug delivery system which possess several applications and are made up of assorted polymers. Microspheres can be defined as solid, approximately spherical particles ranging in size from 1 to 1000 μm range in diameter having a core of drug and entirely outer layers of polymers as coating material. They are made up of polymeric, waxy or other protective materials i.e. biodegradable synthetic polymer and modified natural products such as starches, gums, proteins, fats and waxes. Preformulation is a group of studies that focus on the physicochemical properties of a new drug candidate that could affect the drug performance and the development of a dosage form. This couldprovide important information for formulation design or support the need for molecular modification. Every drug has intrinsic chemical and physical properties which has been consider before development of pharmaceutical formulation. This property provides the framework for drugs combination with pharmaceutical ingredients in the fabrication of dosage form. Objective of preformulation study is to develop the elegant, stable, effective and safe dosage form by establishing kinetic rate profile, compatibility with the other ingredients and establish Physico-chemical parameter of new drug substances. The purpose of the present study was to systematically investigate some of the important physicochemical properties of pralidoxime chloride for preparation of microspheres. The physicochemical properties such as solubility, pKa, dissolution, melting point, assay development, excipient compatibility etc. of pralidoxime chloride was carried out. Before selection of excipients, the Preformulation study of drug pralidoxime is completed for successful formulation of microspheres. The result of Preformulation studies shows good flow properties, excipient compatibility, solubility efficiency and melting point. From this study we concluded that pralidoximewith HPMC and EC can be used to formulate pralidoxime microspheres for modified release.
 Keywords: Microspheres, Preformulation, Pralidoxime chloride, Physico-chemical parameter.

A Review on Microsphere and it's Application

Microspheres are multiparticulate drug delivery systems which are prepared to obtain prolonged or controlled drug delivery to improve bioavailability, stability and to target the drug to specific site at a predetermined rate. They are made from polymeric waxy or other protective materials such as natural, semi synthetic and synthetic polymers. Microspheres are characteristically free flowing powders having particle size ranging from 1–1000 μm consisting of proteins or synthetic polymers. The range of techniques for the preparation of microspheres provides multiple options to control as drug administration aspects and to enhance the therapeutic efficacy of a given the drug. These delivery systems offer numerous advantages compared to conventional dosage forms, which include improved efficacy, reduced toxicity, improved patient compliance and convenience. Such systems often use macromolecules as carriers for the drugs. The present review highlights various types of microspheres, different methods of preparation, its applications and also various parameters to evaluate their efficiency.

Painting the Palace of Apries I: ancient binding media and coatings of the reliefs from the Palace of Apries, Lower Egypt

This study gives an account of the organic components (binders and coatings) found in the polychromy of some fragmented architectural reliefs from the Palace of Apries in Memphis, Egypt (26th Dynasty, ca. 589-568 BCE). A column capital and five relief fragments from the collections of the Ny Carlsberg Glyptotek in Copenhagen were chosen for examination, selected because of their well-preserved polychromy. Samples from the fragments were first investigated using Fourier transform infrared (FTIR) spectroscopy to screen for the presence of organic materials and to identify the chemical family to which these materials belong (proteinaceous, polysaccharides or lipid). Only the samples showing the potential presence of organic binder residues were further investigated using gas chromatography with mass spectrometry detection (GC–MS) targeting the analysis towards the detection and identification of compounds belonging to the chemical families identified by FTIR. The detection of polysaccharides in the paint layers on the capital and on two of the fragments indicates the use of plant gums as binding media. The interpretation of the sugar profiles was not straightforward so botanical classification was only possible for one fragment where the results of analysis seem to point to gum arabic. The sample from the same fragment was found to contain animal glue and a second protein material (possibly egg). While the presence of animal glue is probably ascribable to the binder used for the ground layer, the second protein indicates that either the paint layer was bound in a mixture of different binding materials or that the paint layer, bound in a plant gum, was then coated with a proteinaceous material. The surface of two of the investigated samples was partially covered by translucent waxy materials that were identified as a synthetic wax (applied during old conservation treatments) and as beeswax, respectively. It is possible that the beeswax is of ancient origin, selectively applied on yellow areas in order to create a certain glossiness or highlight specific elements.

Synthesis of Nano-Cellulose from Okra Fibre and FTIR as Well as Morphological Studies on It

Nano-cellulose was extracted from Okra fiber by various chemical treatment such as alkali treatment, bleaching and then by acid hydrolysis. The final products were characterized by means of Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). FTIR results showed that the hemicelluloses and lignin were removed from the extracted nano-cellulose. On the other hand, SEM analysis showed that the surface morphology of raw fiber, bleached fiber, alkali treated fiber and nano-cellulosic fiber. The surface of raw fiber was rough, not plain and smooth but the surface of Crystalline Nano Cellolose (CNC) became plain, smooth and not rough for the removing of lignin and fatty and waxy materials from it and simultaneously there is a honey comb structure appeared which will be very helpful for producing nano composites with polymeric materials. Size of the okra fiber was cellulose reduced into nano-sized particles.

FTIR characterization ans chemo-mechanical distinction of reted kenaf fibres

Inadequate information on the binding characteristics of kenaf biomass at the molecular level has adversely affected the modifications of its cellulose-hemicellulose-lignin structure. This study was undertaken to assess the characteristic features and chemo-mechanical properties of kenaf fibres retted under three different media namely: tank, stream and ribbon. Fourier transform infra-red (FTIR) spectra analysis as well as the ASTM standard for tensile tests were applied. The results showed that the broad bands occurred at the range of 3312- 3420 cm−1 for all the retted fibres were due to the presence of hydroxyl (–OH) group while the peaks were obtained at 1635.76, 1635.34, and 1730.69 cm−1 for stream, tank and ribbon retted fibres respectively. However, tank retted fibres had the most broad band intensity at 3419.78cm-1 while ribbon fibres had the highest absorption peak of 1730.69cm-1 corresponding to C=O stretching of the acetyl group in hemi-cellulose. Stream retted Kenaf fibres had the highest tensile strength followed by the tank retted fibres while ribbon fibres had the least. Furthermore, there was no significant difference between stream and tank retted Kenaf fibres in terms of tensile modulus and this was significantly higher than that of ribbon fibre. The α-cellulose content of stream retted fibres was slightly higher than that of ribbon fibres while tank retted fibres had the least. From the results, tank retted Kenaf fibre was ranked as ‘the best fibre’ with the most intensive broad bands and least in lignin and hemi-cellulose content which were regarded as the impurities, gummy and waxy materials, responsible for an easy deformation of the fibre cellular networks.

Extraction of green absolute from thyme using ultrasound and sunflower oil

Absolute is the plant aroma isolate mostly used in the food and fragrance sectors. The use of organic solvents constitutes the most commonly used method for obtaining this aroma. However, this technique may leave trace amounts of solvents which are considered undesirable for these industries. In this work, a new green extraction approach was implemented using ultrasound (US) with sunflower oil (SO) as a natural solvent to produce green absolute from thyme (Thymus vulgaris). US optimal conditions for absolute yield were investigated using response surface methodology (RSM) and compared to conventional SO (SO-CV) and hexane (Hex-CV) extractions. The absolutes were analyzed by GC–MS for their chemical composition and tested for their antioxidant activities (total phenols, DPPH and frying test). Optimized conditions obtained by RSM for absolute yield were T = 50 °C, t = 22 min, P = 98W. The US using SO as solvent offers important advantages: shorter extraction time, increase of 47% in absolute yield compared to SO-CV extraction. Although the absolute obtained by hexane extraction provided improved yield (8.64 g/100 g DW), it contained around 75% of waxy materials. GC–MS analysis showed no remarkable variation of the chemical composition of the absolutes compared to those obtained by hexane extraction. Moreover, the US extraction allowed the highest recovery of monoterpene phenols thymol and carvacrol (86.2%). The absolute obtained by SO-US was free from waxes and organic solvent residues and exerted the highest antioxidant activity. Results show that ultrasound extraction using SO is a good alternative. It suggests the possibility of the production of green absolutes on pilot and industrial scale.

Extraction of green absolute from thyme using ultrasound and sunflower oil

Abstract Absolute is the plant aroma isolate mostly used in the food and fragrance sectors. The use of organic solvents constitutes the most commonly used method for obtaining this aroma. However, this technique may leave trace amounts of solvents which are considered undesirable for these industries. In this work, a new green extraction approach was implemented using ultrasound (US) with sunflower oil (SO) as a natural solvent to produce green absolute from thyme ( Thymus vulgaris ). US optimal conditions for absolute yield were investigated using response surface methodology (RSM) and compared to conventional SO (SO-CV) and hexane (Hex-CV) extractions. The absolutes were analyzed by GC–MS for their chemical composition and tested for their antioxidant activities (total phenols, DPPH and frying test). Optimized conditions obtained by RSM for absolute yield were T = 50 °C, t = 22 min, P = 98 W. The US using SO as solvent offers important advantages: shorter extraction time, increase of 47% in absolute yield compared to SO-CV extraction. Although the absolute obtained by hexane extraction provided improved yield (8.64 g/100 g DW), it contained around 75% of waxy materials. GC–MS analysis showed no remarkable variation of the chemical composition of the absolutes compared to those obtained by hexane extraction. Moreover, the US extraction allowed the highest recovery of monoterpene phenols thymol and carvacrol (86.2%). The absolute obtained by SO-US was free from waxes and organic solvent residues and exerted the highest antioxidant activity. Results show that ultrasound extraction using SO is a good alternative. It suggests the possibility of the production of green absolutes on pilot and industrial scale.

Extraction and characterization of wax from sugarcane bagasse and the enzymatic hydrolysis of dewaxed sugarcane bagasse

ABSTRACTExtraction of high-value products from agricultural wastes is an important component for sustainable bioeconomy development. In this study, wax extraction from sugarcane bagasse was performed and the beneficial effect of dewaxing pretreatment on the enzymatic hydrolysis was investigated. About 1.2% (w/w) of crude sugarcane wax was obtained from the sugarcane bagasse using the mixture of petroleum ether and ethanol (mass ratio of 1:1) as the extraction agent. Results of Fourier-transform infrared characterization and gas chromatography–mass spectrometry qualitative analysis showed that the crude sugarcane wax consisted of fatty fractions (fatty acids, fatty aldehydes, hydrocarbons, and esters) and small amount of lignin derivatives. In addition, the effect of dewaxing pretreatment on the enzymatic hydrolysis of sugarcane bagasse was also investigated. The digestibilities of cellulose and xylan in dewaxed sugarcane bagasse were 18.7 and 10.3%, respectively, compared with those of 13.1 and 8.9% obtained from native sugarcane bagasse. The dewaxed sugarcane bagasse became more accessible to enzyme due to the disruption of the outermost layer of the waxy materials.

Enhancements in crystallinity, thermal stability, tensile modulus and strength of sisal fibres and their PP composites induced by the synergistic effects of alkali and high intensity ultrasound (HIU) treatments

In this investigation, sisal fibres were treated with the combination of alkali and high intensity ultrasound (HIU) and their effects on the morphology, thermal properties of fibres and mechanical properties of their reinforced PP composites were studied. FTIR and FE-SEM results confirmed the removal of amorphous materials such as hemicellulose, lignin and other waxy materials after the combined treatments of alkali and ultrasound. X-ray diffraction analysis revealed an increase in the crystallinity of sisal fibres with an increase in the concentration of alkali. Thermogravimetric results revealed that the thermal stability of sisal fibres obtained with the combination of both alkali and ultrasound treatment was increased by 38.5°C as compared to the untreated fibres. Morphology of sisal fibre reinforced composites showed good interfacial interaction between fibres and matrix after the combined treatment. Tensile properties were increased for the combined treated sisal fibres reinforced PP composites as compared to the untreated and pure PP. Tensile modulus and strength increased by more than 50% and 10% respectively as compared to the untreated sisal fibre reinforced composite. It has been found that the combined treatment of alkali and ultrasound is effective and useful to remove the amorphous materials and hence to improve the mechanical and thermal properties.

Evaluation and Examination of a Possible Shoe-polish Trace in a Hold-up Case

In this article, we show how the Bayesian framework can be applied to a hold-up case involving a possible shoe-polish trace according to one of the parties. This article highlights the importance of interpreting data from the beginning of the examination through the preassessment steps. Once a set of alternative propositions in agreement with the information provided by the parties is chosen, one can establish what is needed in the case. Here, limited data were available to assign factors such as transfer and rarity of the traces. Consequently, we showed how specific case-tailored experiments provide meaningful data for evaluation. In this case, the police had observed a trace on the jacket of a person who reported to have been pushed with the offender's gun during the hold-up attempt. When the jacket was submitted to our laboratory, the exact nature of the trace was unknown. Particles from this trace were collected and analyzed by stereomicroscopy, microscopy, and infrared spectroscopy. The obtained results supported that this trace was waxy material. The literature dealing with the analysis of waxy materials generally uses solvent extraction-based methods. Here, as our analytical sequence allowed a good discrimination of different waxy products of known origin, we considered that this methodology was adequate. Moreover, it did not involve any extraction step that could lead to undesired compounds from the substrate (e.g., dyes and additives). This article therefore suggests an alternative analytical sequence for the analysis of such material in casework.

Microsphere: A Brief Review

Microspheres are multiparticulate drug delivery systems which are prepared to obtain prolonged or controlled drug delivery to improve bioavailability, stability and to target the drug to specific site at a predetermined rate. They are made from polymeric waxy or other protective materials such as natural, semi synthetic and synthetic polymers. Microspheres are characteristically free flowing powders having particle size ranging from 1-1000 μm consisting of proteins or synthetic polymers. The range of techniques for the preparation of microspheres provides multiple options to control as drug administration aspects and to enhance the therapeutic efficacy of a given the drug. These delivery systems offer numerous advantages compared to conventional dosage forms, which include improved efficacy, reduced toxicity, improved patient compliance and convenience. Such systems often use macromolecules as carriers for the drugs. The present review highlights various types of microspheres, different methods of preparation, its applications and also various parameters to evaluate their efficiency. Microspheres are various types like Bioadhesive microspheres, Magnetic microspheres, Floating microspheres, Radioactive microspheres, Polymeric microspheres, Biodegradable polymeric microspheres, Synthetic polymeric microspheres and are prepared by methods like Spray Drying, Solvent Evaporation, Single emulsion technique, Double emulsion technique, Phase separation coacervation technique, Spray drying and spray congealing, Solvent extraction, Quassi emulsion solvent diffusion. Microspheres have wide range of applications because of controlled and sustained release.