Non-absorbing Surfaces Research Articles

Preliminary Investigation of a Potential Optical Biosensor Using the Diamond™ Nucleic Acid Dye Applied to DNA and Friction Ridge Analysis from Fingerprint Traces

Developments in science and technology lead to an increasing use of scientific evidence in litigation. Interdisciplinary research can improve current procedures and introduce new ones for the disclosure and examination of evidence. The dactyloscopic trace is used for personal identification by matching minutiae (the minimum required may vary by country) or for extracting DNA material from the trace under investigation. The research presented in this article aims to propose the merging of two currently used personal identification methods, DNA analysis and dactyloscopic trace analysis, which are currently treated as separate forensic traces found at a crime scene. Namely, the forensic trace to be analyzed is the dactyloscopic trace containing DNA, and both sources of information needed for identification are examined as one. Promega’s Diamond™ Nucleic Acid Dye, presented as a safe alternative to ethidium bromide, works by binding to single- and double-stranded DNA and is used to visualize the separation of material in a gel and to detect DNA in forensic samples. Spectroscopic studies as absorption and emission spectra and fluorescence microscopy observations presented in our research confirm that Diamond™ Nucleic Acid Dye can also be used to visualize fingerprints on non-absorbent surfaces and that combining the two methods into one can significantly increase the evidential value and contribute to the design of an innovative fast-acting optical biosensor.

Nanostructured assessment of copper oxide for latent fingerprint recognition

Nanotechnology has revolutionized the different fields of forensic science, particularly in the efficient examination of evidence. In this study, we report scalable synthesis of copper oxide (CuO) nanosheets by using hydrothermal method and its exploration in the forensic examination of latent fingerprints. The identification and structural characterization of CuO nanoparticles were carried out using advanced spectroscopic methods such as powder X-ray diffraction (PXRD), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The stabilization of CuO nanosheets in monoclinic symmetry (space group C2/c) was confirmed through Le Bail refinements. Morphological studies based on scanning electron microscopy (SEM) revealed that the CuO nanosheets exhibit, a rectangular, thin plate like morphology.The applicability of these nanosheets was tested for examining and developing fresh and aged (7 days old) latent fingerprints on dry, non-absorbent substrates using the powder dusting method. The formulation successfully developed sharp and clear fingerprints on various substrates, allowing the second-level details of the fingerprints to be viewed without any background interference. Additionally, these nanosheets are non-hazardous and cost-effective, making them a suitable fingerprint developing agent for a wide range of dry, non-absorbent surfaces recovered from crime scenes.

Improving printed products manufacturing technology using 3D printing

The aim of the paper is to analyze the state of the printing industry in the current conditions, learn reproduction technologies on non-absorbent surfaces, and study modern technological processes of obtaining products based on 3D printing, which is the research object. The problem lies in the lack of general recommendations for using the above technology to produce printed products or their elements. The main factors affecting the quality of finished products have been determined. The criterion to compare possible options for creating printed products was selected, namely, the examination method was considered. After processing the expert group summary, the consistency degree of opinions was determined using Kendall’s concordance coefficient. The most significant factor was identified, and further research is focused on it. Layer-by-layer deposition modeling was chosen as the technology for creating the test. Test fragments were developed, and materials and equipment to run the experiment were selected. A quantitative and qualitative assessment of the quality of 3D printing was carried out. Following the conducted research, the shortcomings were taken into account, and a number of recommendations for further creation of the forthcoming high-quality product were made. Those recommendations refer to the optimal line width (1.5 points and more), typeface origin and font size (20 points and above) for the reproduction of text information, and thickness of the element base of printed products (minimum 2.5–3 mm). The above recommendations allow a 3D printing product and its elements to achieve a remarkable quality level and visual appeal, as well as enable enterprises to use it as the basis of technological instructions for applying modern technologies.

Experimental Study of the Effect of Tack Coats on Interlayer Bond Strength of Pavement

The performance and lifetime of the flexible asphalt pavement are mainly dependent on the interfacial bond strength between layer courses. To enhance the bond between layers, adhesive materials, such as tack coats, are used. The tack coat itself is a bituminous material, which is applied on an existing relatively non-absorbent surface to ensure a strong bond between the old and newly paved layer. The primary objective of this study was to evaluate the effects of various types of tack coat materials on interlayer bond strength and to determine the optimal application rate for each type. The tack coat types used in this paper were RC-70, RC-250, and CSS-1h. Both laboratory-prepared and field-constructed hot mix asphalt concrete pavements using the tack coats were tested for the binding strength between the layers. A direct shear test was used for the testing. The results obtained from the study showed that the optimum application rate for RC-70 was 0.1 L/m2, and for RC-250, it was 0.2 L/m2, while the optimum application rate for CSS-1h was 0.1 L/m2. From the field test, the optimum application rate of the RC-250 tack coat was 0.1 L/m2.

Estimating the modelling of polymer materials’ optical density rate

Mathematical representation of reality is one of the variants of a model as a system, the study of which allows obtaining information about some other system. The mathematical model, in particular, is designed to predict the behavior of a real object. All natural and social sciences that use the mathematical apparatus, in fact, are engaged in mathematical modeling: they replace the object of study with its mathematical model and then study the latter. With the help of mathematical methods, as a rule, an ideal object or process is described, built at the stage of meaningful modeling. The connection of a mathematical model with reality is carried out with the help of a chain of empirical laws, hypotheses, idealizations and simplifications. A mathematical regression model has been developed that takes into account the influence of the speed of printing equipment and pressure on the optical density of the print when printing on non-absorbent surfaces using the gravure printing method.

A versatile approach towards development of easy-to-clean transparent nanocoating systems with pronounced anti-static properties for various substrates

<abstract> <p>Sol-gel is a widely applied method for the development of hydrophobic anti-soiling coatings. Most of them however suffer from serious drawbacks which restrict their generic applicability, especially on surfaces with limited number of hydroxyl groups. This study aims to propose a facile and straightforward strategy for the development of an "one-fits-all" anti-soiling coating with strong adhesion to a variety of hard, non-absorbent surfaces. The structure of the proposed composition is based on a two-component coating system consisting of an organopolysilazane primer and an alkoxysilane topcoat, based on a quaternarized ammonium silane. Morphology and microstructure were systematically studied, while hydrophobicity, adhesion, stability, abrasion and chemical resistance were determined on aluminum and PC substrates. The anti-soiling behavior of the proposed coating system was also evaluated. It was found that the polysilazane primer provided mechanical and chemical robustness regardless of substrate type, while the quaternarized silane offered pronounced easy-to-clean and anti-static attributes. The combination of such attributes within a single sol-gel coating system is highly beneficial for numerous applications.</p> </abstract>

An Advanced Tape-Stripping Approach for High-Efficiency Sampling on Non-Absorbent Surfaces.

Surface sampling is a frequent task in laboratory work and field studies. Simple methods usually have low efficiency in collecting target substances from surfaces. This study developed an advanced tape-stripping approach for efficient sampling on non-absorbent surfaces. A film-forming solution, prepared using polyvinyl alcohol, is applied to the target surface, where it covers and engulfs the surface deposits and then solidifies into an elastic membrane as it is exposed to air. The deposits are collected by stripping off the membrane and re-dissolving it in water. This new approach exhibited an efficiency of 100% in collecting uniform-size microspheres from glass surfaces and extremely high efficiencies (>96.6%) in detecting selected target DNA materials from glass and stainless steel surfaces. In comparison, the common swab-rinse method exhibited an efficiency of 72.6% under similar measuring conditions. The viability of S. aureus during sampling using the new approach decreased as the ethanol concentration in the applied solution increased. Using a solution with a mass ratio of ethanol of 17.6% balanced the effects of multiplication and degradation of the S. aureus on glass surfaces during sampling. Overall, the proposed approach exhibits high efficiency in collecting living and abiotic matter from non-absorbent surfaces, complementing existing sampling methods.

Proposing a sustainable strategy for the fabrication of robust anti-soiling coatings with enhanced antibacterial attributes for non-absorbent substrates

In this paper, we propose a convenient methodology for fabricating a generic structure toward developing a robust, easy-to-clean transparent coating with inherent antibacterial properties for smooth, non-absorbent surfaces, such as glass and plastics. A two-step coating comprising an organopolysilazane primer and an alkoxysilane topcoat, based on positively charged quaternary ammonium silanes, is proposed. The topcoat is co-condensed with the primer to provide a hybrid structure with high wear strength even on surfaces that lack surface hydroxyl groups. Surfaces examined included glass and PMMA. The coated samples were studied in terms of abrasion resistance as well as anti-soiling and antimicrobial performance. It was found that the quaternary silane compound could covalently graft onto the primer acting both as an antibacterial, anti fungicidal, and hydrophobizing agent. The utility of amphoteric surfactants within the coating’s solution was also examined. The resulting structure was transparent and exhibited pronounced self-disinfecting properties with remarkable sustainability. These attributes suggested a dual functionality of the coating, i.e., both anti-soiling and antimicrobial, thus rendering it a potential candidate for numerous industrial and commercial applications.

Experimental study of how far blood spatter stains on fabrics can be found from the blood source, and relevance to crime scene reconstruction

For investigative purposes, the bloodstain pattern analyst might have to estimate whether a given stain on fabric could have originated from a specific location. A wide range of values of the maximum distance that a blood drop can travel have been reported based on experiments, ranging from less than 1 m to more than 10 m. It is also known that stains on porous materials such as fabrics are more difficult to interpret than stains on non-absorbing surfaces, because of wicking. Here, we perform several fluid dynamic spatter experiments and formulate a fluid dynamics model to describe the trajectories of the blood drops. The experiments are performed with swine blood, the properties of which are well understood. The main parameters screened are the drop size, initial velocity, the launch angle, and the orientation of the fabric. A large number of blood drops are produced by impact events. The resulting stains on knitted white T-shirt fabric are digitally measured. Their position relative to the source and size is reported. Trajectories are simulated accounting for the influence of gravity and drag forces. A simple relation between drop size and stain size is established based on extensive experiments on a specific fabric. Results of the trajectory simulations are then searched and mined for parameters directly measurable on a crime scene, such as the stain size on fabric and the relative location of the fabric with respect to the blood source. The experimental results are compared and found in agreement with the numerical predictions. The results are presented in one chart relevant to crime scene reconstruction. The chart is easy to use and only requires minimum knowledge of fluid dynamics.

Drip stains formed on ice and snow: an observational study

When a crime is committed in colder climates, there is potential for bloodshed to occur in areas covered in ice and/or snow. In this work, we investigate drip stain formation on ice and snow surfaces. We examine the effects of dripping height and surface type on bloodstain size, shape and distribution. Seventy-five drip stains were created from droplets generated perpendicular to the surface across five different dripping heights and three surface types (new snow, powder snow and crust). Digital images of each bloodstain were collected and were analyzed using FIJI. Additionally, high-speed videos were taken of drip stains forming on three types of natural snow surfaces. The bloodstains observed in this study exhibited irregular characteristics compared to those seen in bloodstains on hard, non-porous and non-absorbent surfaces created in ambient laboratory conditions. The type of surface was observed to affect the diameter, circularity and distribution of satellite stains; however, dripping height did not affect these characteristics. While the estimated roughness of the snow surfaces may have influenced the formation of the bloodstains, we suggest that it is not the only surface property involved in bloodstain appearance. Our findings, while preliminary, support future investigation of bloodstain formation on cold complex surfaces.

Viral load could be an important determinant for fomites based transmission of viral infections.

Background and Objective:Fomites are common sources of transmission of certain infections. Infectious pathogens, such as viruses known to cause respiratory tract infections, are common examples of being transmitted by fomites. However, the load of the particular pathogen on these inanimate surfaces is a crucial factor for the transmission. The current study aims at investigating the load of one such viral pathogen on the surfaces of commonly used materials.Methods:Based on the cycle threshold (Ct) values in the diagnostic system using gene amplification for the considered viral pathogen, we categorized the positive samples for high (17 to < 24), moderate (24 to < 31), or mild (31 to < 38) viral load. Five randomly selected samples from each of these category were smeared on commonly used cardboard surface (absorbent surface) and stainless steel (non-absorbent surface). After an observation duration of 90 min, samples from the surfaces were analyzed again for gene amplification using RT-PCR.Results:Viral load/titter positively correlated with the viral material on either of these investigated surfaces post-observation duration. Higher viral load (low Ct) samples exhibited higher probability of being detected on the surfaces than those samples with lower/moderate (high Ct) viral load.Interpretation and Conclusion:Common inanimate surfaces are potential source of the viral transmission, however the viral load on these surfaces are key determinant of such transmission.

Prevalence of Hepatitis B Virus among Febrile Patient in General Hospital Okigwe, Imo State, Nigeria

Introduction: Hepatitis B virus (HBV) infection is a major cause of prenatal death worldwide. Chronic hepatitis B (CHB) infection is associated with an increased risk of cirrhosis, hepatic decomposition, and hepatocellular carcinoma (HCC). Objective: This project work surveyed the prevalence of hepatitis B among febrile patients as well as to detect hepatitis B virus in the blood and the stage of the infection of hepatitis B on the affected patients and carrier stage or state of immunity of the affected patients. Methodology: A well-designed questionnaire/checklist was used to gather information regarding age, HIV-Status, and sex from 50 febrile patients. 2 ml of blood sample was obtained by venin-puncture using a sterile hypodermic syringe and emptied into a clean dry tube (without anticoagulant) observing the necessary aseptic techniques. The blood was centrifuged and the sera obtained and stored at 2 - 8 c for HBsAg screening. Hepatitis B virus was tested using an in-vitro diagnostic kit called HBsAg one-step rapid test strip. The HBsAg one-step rapid test is a lateral flow chromatographic immunoassay based on the principle of the double antibody-sandwich technique. The membrane is pre-coated with anti-HBsAg antibodies on the test line region of the test. During testing, the serum specimen reacts with the particle coated with anti-HBsAg antibody. The serum moves up with capillary action to react with the coated antibody on the membrane. Then, the colored line (positive) will be generated which shows the presence of the virus. But negative shows absence of the virus. The blood in the test tube was spun using a centrifuge to separate the red cells from the serum. The test pouch, serum, and control were allowed to equilibrate to room temperature before testing. The test strip was removed from the sealed pouch and used immediately. The test strip was immersed vertically into the serum with the arrows pointing towards the serum for about 10 - 15 seconds, without exceeding the maximum line on the test strip. The strip was placed on a non-absorbent flat surface. The time was set and the result read after 15 minutes and recorded. The procedure was repeated for each sample and the results were recorded accordingly. The test is positive when two red lines appear on the test region (T) and control region (C) only. The result is said to be invalid when one line appears on the test region (T) and non on the control region (C) and also when no line appears on both the test region (T) and control region (C). Results: After interpretation of the result of the test on fifty patients, Table 1 shows the age range of the population. The total distribution of subjects concerning age was as follows: 4 out of 50 populations (8%) were observed for the age range of 0 - 10; 7 out of 50 (14%) were observed of the age range of 11 - 20; 28 out of 50 (56%) were observed for a range of 21 - 30; 9 out of 50 (18%) were observed for the age range of 31 - 40; 2 out of 50 (4%) were observed at the age range of 21 - 30 with percentage seroprevalence of 4%. There is no significant correlation in the age group concerning percentage seroprevalence (P = 0.05). Also, the sex of the study population as seen in Table 2 shows that 21 were males and 29 were females. Out of the 21 males population, 3 (14.24%) were positive. In the female population, 5 out of 29 (17.24%) were positive. The prevalence of the population concerning their sex was tested using Pearson’s chi-square and it was concluded that there is no significant relationship between sex and seroprevalence of hepatitis B. Table 3 shows the HIV of the study population and it shows that 6 out of 14 HIV positive patients (42.56%) were positive and 3 out of 36 HIV-negative patients (4.55%)) were positive. The prevalence of the population concerning HIV status was tested using Pearson’s chi-square and it was concluded that there is a significant association between HIV status and seroprevalence of hepatitis B. Conclusion: In conclusion, this study shows that there is a low prevalence of hepatitis B among febrile patients at the study area, hence limiting fever as a major determinant of hepatitis B infection. Considering the high risk of HBV in HIV co-infected patients, there is a need for the screening of HIV-infected patients for hepatitis B and appropriate therapy followed up on possible HBV-HIV co-infected patients. Appropriate preventive measures especially vaccination against hepatitis B virus should be encouraged among the susceptible population.

All-Natural Smart Mycelium Surface with Tunable Wettability

A naturally occurring smart mycelium surface with tunable wettability is demonstrated. The commercially produced mycelium foam shows a natural hydrophobic and nonabsorbent surface with water contac...

Interactions between Colloidal Particles Mediated by Nonadsorbing Polymers: Casimir and Anti-Casimir Effects

We examined a simple model system of homopolymer solutions in 3D confined between two parallel and nonabsorbing surfaces and in equilibrium with a bulk solution and accurately calculated the effective interaction between the two surfaces using both lattice Monte Carlo (MC) simulations and self-consistent field (SCF) calculations. Our results here, when compared with those in 2D (Zhang, P.; Wang, Q., Macromolecules 2019, 52, 5777), quantitatively revealed that the fluctuation-induced intermediate-range repulsion between the two surfaces (i.e., the anti-Casimir effect) is about 1 order of magnitude stronger than the repulsion due solely to the finite chain length given by the SCF theory, is weaker but occurs over a broader range of surface separation in 3D than in 2D, and decreases with decreasing solvent quality. We also found for the first time a long-range attraction between the two surfaces (i.e., the Casimir effect) near the critical point of the bulk solution in both MC simulations and SCF calculations.

The double-swab technique versus single swabs for human DNA recovery from various surfaces

Most crime scene DNA evidence is retrieved using cotton swabs. Since the late 90’s, the double-swab technique has been favoured by many practitioners throughout the world. However, the superiority of double-swabbing over applying single wet swabs has not been broadly verified. Here we set out to evaluate the need for the second dry swab for various surfaces, aiming at mimicking the range of surfaces encountered at crime scenes: flat and ridged, absorbing and non-absorbing. For the tested non-absorbing surfaces, i.e., window glass, steel, brass, synthetic leather and ridged plastic, the first wet swabs gave at least 16 times higher DNA yields compared to the second dry swabs. In addition, second wet swabs gave more DNA than second dry ones, opposing the common notion that the purpose of the second swab is to absorb excess liquid. When ten experienced staff members sampled saliva stains on a window glass surface the variation between persons was considerable, with mean DNA yields for the first wet swabs ranging from 0.045 ± 0.022 to 0.13 ± 0.024 ng/μL. The first wet swabs gave 4–162 times more DNA than the second dry swabs, with higher DNA amounts on second swabs coinciding with lower amounts for first swabs. We show that for non-absorbing surfaces, the first wet swab takes up most of the cells in dried stains, making it less valuable to apply a second dry swab. The differences in DNA recovery between first and second swabs were notable also for absorbing surfaces. Double-swabbing may be preferable for some complex surfaces, but focusing on efficient sampling technique with single wet swabs is likely a better general approach.

Metabolomic profiling of bloodstains on various absorbent and non-absorbent surfaces.

Bloodstains found at crime scenes contain immense information about the crime; thus, studies involving analysis of small molecules in bloodstains have been conducted. However, most of these studies have not accounted for the difference in the results of small molecule analysis due to the surface of bloodstains. To evaluate the "surface effect," we prepared bloodstains on seven surfaces, including both absorbent and non-absorbent surfaces, and performed global small molecule analysis by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). We used three indicators: (1) count recovery rate (%) of molecular features (MFs), (2) the number of MFs extracted from the surface without bloodstains, and (3) difference in abundance recovery rate (%) of MFs, to determine the ranking of the seven surfaces in the order of their similarity with blood. We also confirmed the correlation between each surface and blood through multivariate analysis. We found that the non-absorbent surfaces ranked better than the absorbent surfaces; wooden flooring was ranked as the most efficient surface, followed by stainless, vinyl flooring, glass, tile, filter paper, and mixed cotton. This study will help in the selection of the most efficient surface for collection of bloodstains for small molecule analysis from a crime scene. This is the first study to identify the effects of surface on extraction of global small molecules from bloodstains; it will help forensic scientists in obtaining more accurate information from small molecules present in the bloodstains collected at the field. Graphical abstract.

Wet Powder White – zawiesina proszku nie tylko na klejące strony taśm samoprzylepnych

The article presents new possibilities of revealing fingerprints on non-absorbent surfaces by using Wet Powder White, known and used in Polish dactyloscopy. Powder suspension based on titanium dioxide has been successfully used to reveal fingerprints on the adhesive sides of non-porous tapes, as well as on the inner surfaces of rubber gloves. So far, however, the broader application of Wet Powder White has not been known in Polish dactyloscopic practice. Foreign publications quoted in the article, research conducted and the use of white suspension powder in dactyloscopic opinions dedicated to the visualization of traces unequivocally confirm the high effectiveness of Wet Powder White in revealing fingerprints on non-absorbent surfaces, especially on plastic packaging and areas that have been or could have been previously wetted or subjected to high humidity.

Dermanyssus gallinae eradication approach – application of inert compounds and integral animal health protection

The generally accepted approach to D. gallinae control is based on the control of infestations. The reduction of D. gallinae infection to an acceptable level can temporarily prevent its harmful effects on the health status ofpoultry. However, the reduced number of D. gallinae continues to persist in poultry environment resulting in an intensive increase of infestation rate and consequent transmission of infectious and contagious diseases. Contrary to suppression, the eradication approach completely eliminates D. gallinae thus improving general health status of the flock and providing the control of infectious and contagious diseases associated with this organismand eliminating other adverse effects. Biological efficiency and selection of inert compounds was performed in laboratory conditions. The previous experience with application of SiO2 formulations in practice confirmed thepossibility of successful eradication in 8 cases (combined application of liquid and powdered form). New generation of inert compounds (P 547/17) showed a range of superior properties as compared with SiO2 formulations,especially in view of high and long-lasting residual effects on non-absorbent surfaces. In laboratory conditions, after 7 months, the layer formed by a 20% working emulsion on a metal substrate exhibited efficiency of 92%after 1-hour exposure. In clinical conditions, the presence of mites was not detected even after 6.5 months of the settlement of the flock. Clinical tests of inert oils are still ongoing, but their high potential for the eradication of D.gallinae The eradication of D. gallinae is highly complex procedure, which cannot be performed at all times and in all conditions. The conditions for the eradication of D. gallinae using inert compounds include adequate hygienic preparation of the facilities while still empty, adequate application of selected compounds, and then adequate ambient temperatures which leads to increase of mites activity. The program of D. gallinae control includesprocedures for the preparation, implementation, eradication checks, and prevention of re-infestation

Experimental investigation of mortar mechanical properties for glass brick masonry

The main advantage of solid bricks over hollow blocks is substantially higher compressive strength. On the other hand, solid bricks have much higher thermal conductivity, which would lead to major heat loss when used for exterior walls. Masonry pillars and walls are usually loaded in compression and/or bending resulting from the eccentricity of vertical load or wind load. In case of solid glass bricks, compressive strength is about ten times higher than tension strength therefore the limiting factor of the glass masonry is tensile stress resulting from the bending. Whether compared to ceramic or concrete bricks masonry, the glass bricks have a smooth and non-absorbent surface and the adhesion of the mortar to the glass surface is the critical parameter. Presented paper is focused on the experimental investigation of mortar applicable for glass brick masonry with regard to use for load bearing brick walls or columns. Shear, compression and tension tests have been recently performed. Shear and tension resistance and failure modes of brick bed joint were determined during series of tests using various mortar composition, two types of surface treatment and different thickness of the mortar joint. Significant influence of the joint thickness on the resistance was found. The compression tests were performed on two small pillars to determine the compression resistance and failure mode of glass bricks walls and pillars. In parallel to these tests, several small-scale tests have been performed to determine flexural and compressive strength of hardened mortar.

Investigation of Polyaniline and a Functionalised Derivative as Antimicrobial Additives to Create Contamination Resistant Surfaces.

Antimicrobial surfaces can be applied to break transmission pathways in hospitals. Polyaniline (PANI) and poly(3-aminobenzoic acid) (P3ABA) are novel antimicrobial agents with potential as non-leaching additives to provide contamination resistant surfaces. The activity of PANI and P3ABA were investigated in suspension and as part of absorbent and non-absorbent surfaces. The effect of inoculum size and the presence of organic matter on surface activity was determined. PANI and P3ABA both demonstrated bactericidal activity against Escherichia coli and Staphylococcus aureus in suspension and as part of an absorbent surface. Only P3ABA showed antimicrobial activity in non-absorbent films. The results that are presented in this work support the use of P3ABA to create contamination resistant surfaces.