First Set Of Samples Research Articles

Thermal fluctuations on the corrosion behaviour of 17-4PH stainless steel alloys fabricated via material extrusion additive manufacturing technique

Herein, the influence of fluctuating thermal conditions on the corrosion behaviour of 17-4PH stainless steel alloys manufactured via fused filament fabrication is reported. The printed samples were sintered and then exposed to different temperature-fluctuating conditions to simulate the application environment of such alloys. The first set of samples (A) was studied as-sintered, the second set of samples (B) was aged at 480°C for 3 h followed by quenching in water, the third set (C) was exposed to conditions of B followed by aging at 360°C for 3 h and quenching in water and the final set of samples (D) was exposed to conditions of C followed by aging at 200°C for 3 h, quenching in water, aging at 400°C for 3 h, and finally quenching in water. The surface roughness evolved with the temperature conditions. The optical microscopy revealed that sample B had a fine and homogenous distribution of precipitates. Sample B had the highest microhardness values followed by C, D, and A in that order. XRD analysis revealed the presence of retained FCC austenitic phases within the microstructure whose peaks became stronger with the increased thermal fluctuations. The potentiodynamic polarisation studies revealed a distinct linear Tafel region on the cathodic region and a dual-slope inflection point on the anodic region of the polarisation curves. Sample D exhibited the highest corrosion rate whereas sample B revealed the lowest. As such, exposing fused filament fabricated 17-4 PH SS to fluctuating temperature conditions leads to degradation of mechanical strength and corrosion resistance.

Evaluation of early African swine fever virus detection using CP204L gene encoding the p30 protein using quantitative polymerase chain reaction.

The African swine fever virus (ASFV), spanning 170-193 kb, contains over 200 proteins, including p72 and p30, which play crucial roles in the virus's entry and expression. This study investigated the capability of detecting ASFV early through the analysis of genes B646L and CP204L, encoding p72 and p30 antigen proteins, by employing ASFV, diagnosis, immunohistochemistry (IHC), quantitative polymerase chain reaction (qPCR), and IHC techniques. Samples were taken from both experimentally and field-infected pigs to evaluate the effectiveness of qPCR and IHC in detecting ASFV. Twenty-two infected pigs were necropsied at 3-, 5-, 7-, and 9-day post-infection to obtain the first set of samples, collecting anticoagulated blood and tissues each time. The thymus, spleen, and lymph nodes were processed by fixing in 10% formalin, paraffin-blocking, and undergoing IHC staining. Forty anticoagulated blood samples were collected from clinically infected sows at a pig farm for the second batch of samples. Based on the lowest Ct values, three blood samples were diluted fivefold for qPCR DNA testing, and their tissues were used for both qPCR and IHC analyses. At 1-day post-infection, p30-qPCR identified more ASFV-positive pigs and measured lower Ct values compared to p72-qPCR. At later time points, both methods showed similar levels of detection. ASFV was detected earlier and with lower Ct values in lymphoid tissues using p30-qPCR compared to p72-qPCR, particularly in the spleen and lymph nodes. In a field outbreak study, p30-qPCR demonstrated superior sensitivity and lower Ct values when detecting ASFV in blood samples compared to p72-qPCR. The early detection of the CP204L gene encoding p30 and its corresponding antigenic protein in ASFV diagnosis compared to the gene encoding p72 suggests that CP204L and p30 are promising candidates for the development of more effective antigen and antibody testing methods.

Antibacterial activity of 3D printed thermoplastic elastomers doped with carbon quantum dots for biomedical applications

3D printing provides a lot of varieties for the manufacturing of personalized biomedical devices. Incorporation of the nanoparticles with potential antibacterial activity to the printed materials is another added value. One example of such nanoparticles are hydrophobic carbon quantum dots (hCQDs), which are zero-dimensional redox-active materials with high chemical stability and low production costs. They produce singlet oxygen only when activated by a specific wavelength of visible blue light which allows for controlled antibacterial action and minimizes the chances of bacterial resistance emergence. We prepared and characterized polymer composites based on thermoplastic elastomers (TPE) doped with hCQDs (TPE/hCQDs). The composites were 3D printed using fused deposition modeling method. In the first set of samples, a filament of pure TPE was immersed in a solution of hCQDs (0.5 mg/mL), then 3D printed, and compared with unmodified TPE filament. The mechanical properties, swelling behavior, hardness, and thermal stability of TPE/hCQDs were compared with the pure TPE printed samples. The production of singlet oxygen was confirmed by the electron paramagnetic resonance method. The antibacterial activity of the samples was tested according to ISO 22196 against Staphylococcus aureus and Escherichia coli after one hour of exposure to blue light, which completely inhibited bacterial growth. Besides, the cytotoxicity of samples was evaluated by MTT assay, and no significant effect of the materials on cell viability was observed. 3D printed materials with antibacterial activity represent a perspective for the future, especially in the field of personalized medicine, as well as in products for other industries.

Enhancement of Filtration Performance Characteristics of Glass Fiber-Based Filter Media, Part 1: Mechanical Modification with Electrospun Nanofibers.

Various modifications of standard glass fiber filtration media using electrospun PA66 nanofibers are described. PA66 were selected because they were readily available from commercial sources. Other polymers, such as PP, PET and PBT, could also be used. The first set of samples was prepared by mixing the nanofibers at two, three and five weight percent with glass fibers, and the second by laying the same proportion of the nanofibers directly onto the downstream side of the substrate. The aim of these modifications was to improve the three most basic functionalities of filter media, the separation efficiency, the differential pressure (ΔP) and the dirt holding capacity (DHC). The modified media samples were evaluated with the standard textile characterization techniques and filtration performance evaluation procedures. The results showed differences in the several tens of percentage points achieved with the two modification methods. Moreover, additional differences in performance were observed depending on the percentage of nanofibers admixed to the substrate. These differences were most apparent in the filtration efficiency and the DHC, both by several percentage points, with no apparent effect on the ∆P. The results strongly suggest that the preparation of new filter media by incorporating nanofibers directly into the matrix can result in significant improvements in filtration performance characteristics.

The Impacts of Abattoir Wastes on Soil Quality at Ukwunwangwu, Uturu, Abia State, Nigeria

This study investigated the impact of abattoir waste on the soil quality in Ukwunwangwu, Uturu, Abia State. The aim of this study was to assess the impact of abattoir wastes on soil quality at Ukwunwangwu, Uturu, Abia State. Experimental research design was used and it was carried out at Uturu, Abia State, Nigeria. Three sampling locations were chosen, the bone, dung and slurry sections respectively and two control points labeled A and B respectively. The first set of samples were collected in the morning to ensure freshness and the second set of samples were collected after two weeks making it a total of eight samples used for this study. These samples were collected at different sections so as to know the variations in concentrations of the following important physico-chemical parameters: pH, Temperature, Moisture Content, Soil Organic Carbon, Cation Exchangeable Capacity and Soil Exchangeable Acidity. The temperature was taken in-situ using a mercury-in-glass thermometer. Results of analyses revealed that UK3A had the highest temperature of 35.00C in the first week and also 35.20C after two weeks, control A had the highest pH value of 8.2mg/l in the first week while UK2B had the highest pH of 8.5mg/l after two weeks. Control A had the higher moisture content value of 58.08% in the first week while UK3B had the highest value of 54.81% after two weeks. UK1A had the highest soil organic carbon 30.5 in the first week and also after two weeks. UK3A had the highest soil exchangeable capacity of 0.6 in the first week while UK3B had the highest value of 0.5 after two weeks. UK3A had the highest cation exchangeable capacity of 5.0 in the first week while UK2B had the highest value of 4.8 after two weeks. The correlation between the results was done using the Pearsons Correlation Moment. The experiment will help reduce the impact of abattoir waste on the environment by reducing the effect of global Climate Change and other environmental hazards. The study therefore recommended that strict environmental laws that can help curb the effects of abattoir wastes on the environment be enforced.

Trace element evidence for diverse origins of superheavy pyrite in Neoproterozoic sedimentary strata

Sedimentary pyrite has long been used as an archive of marine environments in Earth history. To capture reliable paleoenvironmental signals, however, we need to first evaluate pyrite in sedimentary strata as it can be altered and masked by later diagenetic and/or hydrothermal processes. Here, we trained two supervised machine learning algorithms on a large LA-ICP-MS pyrite trace element database to distinguish pyrite of different origins. The analysis validates that two models built on the co-behavior of 12 trace elements (Co, Ni, Cu, Zn, As, Mo, Ag, Sb, Te, Au, Tl, and Pb) can be used to accurately predict pyrite origins. Further statistical analysis suggests four trace element clusters behaving differently among sedimentary (syngenetic and early diagenetic), synsedimentary hydrothermal (syngenetic hydrothermal), and post-sedimentary hydrothermal (epigenetic hydrothermal) pyrite, which is probably driven by chemical and physical properties of source fluids, interactions between elements, competition among coprecipitating minerals, and pyrite growth rate. Armed with this initial success and aided by new LA-ICP-MS trace element data from 9 samples, we then demonstrated the efficacy of this approach in identifying the origins of pyrite from two Neoproterozoic sedimentary successions in South China. The first set of samples contain isotopically superheavy pyrite (i.e., whose bulk-sample δ34S values greater than those of contemporaneous seawater sulfate and whose origins remain controversial) from the Cryogenian Tiesi’ao and Datangpo formations. The second set of samples contain pyritic rims (associated with fossiliferous chert nodules and thought to be critical in exceptional fossil preservation) from the Ediacaran Doushantuo Formation. For the superheavy pyrite, the models consistently show high confidence levels (mostly > 80 % probability) in identifying its genesis type, and three out of four samples were given sedimentary origins. For the pyritic nodule rims, the models suggest that early diagenetic pyrite was subsequently altered by hydrothermal fluids and therefore shows mixed signals. The study highlights the importance of pyrite trace elements in deciphering and distinguishing the origins of pyrite in sedimentary strata.

B-014 Impact of Centrifugation Time Reduction in Laboratory Automation System

Abstract Background The centrifugation of specimens is an important preanalytical process which will be impact the most on turnaround time of the laboratory results. To verify the automation systems, we tested different combinations of tube and centrifugation settings to determine the most efficient for routine chemistry procedure. The outcomes of each combination were then compared to the benchmark to find out the best setting to reduce turnaround time for laboratory results. Methods In this study, we evaluated a total of 40 leftover blood samples that were collected on 4 mL plastic Vacutainer® (Becton Dickinson) lithium heparin tubes and 2 mL plastic Vacuette® (Greiner bio-one) lithium heparin tubes. All tubes were centrifuged on Abbott Automation GLP systems. The first set of samples was centrifuged according to the manufacturer’s guideline (10 min at 1300 × g, room temperature for Vacutainer® tubes and 10 min at 2200 × g, room temperature for Vacuette® tubes). The second set was centrifuged 7 min at 2700 × g, room temperature. And the third set was centrifuged 5 min at 2700 × g, room temperature. Then, analyzed all samples with 22 routine chemistry parameters on Alinity ci analyzers. The allowable total error and correlation coefficient (R) were used to determine the significance of the differences between 3 protocols of the centrifugation time. Results The study showed that the centrifugation times of 7 min and 5 min were not significantly different from the manufacturer’s protocol (10 min) after testing with 22 routine chemistry parameters (albumin, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, direct bilirubin, total bilirubin, calcium, chloride, cholesterol, creatinine, low-density lipoprotein-cholesterol, iron, potassium, lactate dehydrogenase, sodium, phosphorus, total protein, triglycerides, unsaturated iron-binding capacity, high-density lipoprotein-cholesterol, urea nitrogen and uric acid) in both 4 mL plastic Vacutainer® lithium heparin tubes and 2 mL plastic Vacuette® lithium heparin tubes. Overall, the results of the study indicate that shorter centrifugation times of 7 min and 5 min at 2700 × g able to use for routine chemistry. Conclusion The study concluded that the centrifugation time did not affect the analytical results of 22 routine chemistry parameters. This suggests that shorter centrifugation times able to use with no impact on accuracy or reliability. The results of the study will support laboratory to have efficiency improvements by shorten the turnaround time on the results release.

Development of Multiplex Polymerase Chain Reaction (PCR)-Based MSA Assay for Bladder Cancer Detection.

Several studies have shown that microsatellite changes can be profiled in the urine to detect bladder cancer. Microsatellite analysis (MSA) of bladder cancer detection requires a comprehensive analysis of up to 15-20 markers based on amplifying and interpreting many individual MSA markers, which can be technically challenging. To develop fast, efficient, standardized, and less costly MSA to detect bladder cancer, we developed three multiplex polymerase chain reaction (PCR) based MSA assays, all of which were analyzed by a genetic analyzer. First, we selected 16 MSA markers based on nine publications. We developed MSA assays based on triplet or three-tube-based multiplex PCR (Triplet MSA assay) using samples from Johns Hopkins University (JHU Sample, first set of samples). In the second set of samples (samples from six cancer patients and fourteen healthy individuals), our Triplet Assay with 15 MSA markers correctly predicted all 6/6 cancer samples to be cancerous and 14/14 healthy samples to be healthy. Although we could improve our report with more clinical information from patient samples and an increased number of cancer patients, our overall results suggest that our Triplet MSA Assay combined with a genetic analyzer is a potentially time- and cost-effective genetic assay for bladder cancer detection and has potential use as a dependable assay in patient care.

Comprehensive testing and rapid dissemination of local drug supply surveillance data in Rhode Island.

The North American overdose crisis has continued at unprecedented rates with more than 100,000 overdose deaths estimated to have occurred in the United States in 2022. Regional variations in overdose rates signify differences in local drug supplies. State-level drug supply surveillance systems have been limited in their ability to document and communicate the rapidly changing drug supplies which can hinder harm reduction efforts at the community level. We sought to address by piloting a two-year, community-engaged local drug supply surveillance program in Rhode Island (RI). The first set of samples (n=125) were collected from May 2022 to January 2023 across RI and included used paraphernalia (e.g., cookers), refuse (e.g., baggies), and product. Samples were tested using comprehensive toxicology testing approaches via liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Results were disseminated to participants and the broader public across platforms. Fentanyl was detected in 67.2% of all samples tested. 39.2% (n=49) of samples were expected to be fentanyl. Xylazine was detected in 41.6% of all samples-always in combination with fentanyl-and no samples were expected to contain xylazine. In expected stimulant samples (n=39), 10% contained fentanyl and/or analogues as major substances and 30.8% contained trace amounts of fentanyl and/or analogues. In expected stimulant samples, 15.4% contained xylazine with fentanyl. No opioids or benzodiazepines were detected in expected hallucinogen or dissociative samples (n=7). In expected benzodiazepine samples (n=8), no opioids were detected. Our results describe part of the local drug supply in Rhode Island, including a presence of NPS and adulterants (e.g., designer benzodiazepines, xylazine). Importantly, our findings underscore the feasibility of developing a community-driven drug supply surveillance database. Expanding drug supply surveillance initiatives is imperative for improving the health and safety of people who use drugs and informing public health approaches to addressing the overdose crisis.

Mechanical properties of structured copper and printed silver hybrid stretchable electronic systems

Stretchable electronics can be realized using different manufacturing methods and hybrids thereof. An example of the latter is the combination of stretchable circuit boards with screen-printing, which will be discussed in this work. The hybrid stretchable electronics structures are based on photolithographically structured and rigid copper islands and screen-printed silver ink interconnections. This enables the assembly of components with a high number of contacts onto the copper islands and deformable silver ink lines between islands. The transition area between islands and lines is critical due to local stress concentration. The effect and potential mitigations were studied by measuring the electrical resistance of test interconnections under mechanical loading. The first set of samples was elongated up to 30% in tensile tests. The second set of samples was elongated 10%, 20%, and 30% in cyclic tests up to 10 000 cycles. After the tests, extensive failure analysis, e.g. scanning electron microscope, and finite element analysis were conducted. In tensile tests at maximum load, the interconnections either snap apart or their resistance increases by 640% in the transition area. Adding protective structures around the transition area, the resistance increase can be reduced to 12%. Stress concentration in the transition area can be controlled with the layout of the structures, as shown in the cyclic tests. Depending on a layout, the structures protect interconnections in the transition area (resistance <4 Ω at 10% and 20% throughout 10 000 cycles, and up to 5000 cycles at 30% elongation), or with particular designs, cause fatal damage of the circuitry and fail early. The identified failure mechanism is typically fatigue damage caused by the repeated bending of the protective structure. The observed resistance increase at the interface was closely related to the crack propagation phase in the protective structures.

Effect of Substratum Structural Complexity of Coral Seedlings on the Settlement and Post-Settlement Survivorship of Coral Settlers

The substratum structure is critical for facilitating settlement and increasing the survivorship of coral settlers. However, knowledge about its structural complexity is largely lacking. In this study, we examined the effect of complexity on the settlement and post-settlement survivorship of coral settlers using four types of structures: groove, using a CSD (Coral Settlement Device, 4.5 cm φ × 2.5 cm H, top-shaped ceramic); flat, using a CP (Ceramic Plate, 29.5 cm L × 3.1 cm W × 0.9 cm H, unglazed ceramic plate); linear, using a CN (Coral Net, mesh size 19 mm, biodegradable plastic net); and wrinkle, using a SS (Scallop Shell, 11.0 cm in shell length). The complexity was obtained from the ratio of the surface area to the vertically projected area of the substratum. The substratum sets were installed in the coral reef around the Ryukyu Islands every May from 2012 to 2014. After about 2 or 6 months of spawning, a certain number of substratum types were sampled, and the number of coral spats that settled on them was counted by taxa classified into Acropora, Pocilloporidae, Millepora, and Others. The larval settlement rate in the first set of samples and the survivorship of coral spats in the second set of samples were estimated. The mean settlement rate was, in order, the CSD; SS; CN; and CP, and the mean survivorship was, in order, the CSD; CP; SS; and CN, over three years. A positive correlation was found between the structural complexity, mean settlement rate, and mean survivorship. Our results show that the structural complexity of coral seedlings affects the settlement of coral larvae and the survivorship of coral spats.

Absorption Performances of PLA-Montmorillonite Nanocomposites Thin Films in Salisbury and Rozanov Configurations: Influence of Aging and Mechanical Recycling.

The present paper aims to address the crucial concern of pollution induced by growing plastic waste and electromagnetic interference (EMI). Nanocomposites combining poly(lactic acid) (PLA) and organo-modified montmorillonite (OMMT) are synthesized and compression molded into thin films. A first set of samples, referred as virgin, was kept as is, while a second set of samples were photochemically, thermally and hydrolytically aged before mechanical recycling via extruding and second compression molding, resulting in the so-called recycled composite. The electromagnetic (EM) properties with a focus on microwave absorption performances of virgin and recycled samples are compared for various thicknesses and weight concentrations of OMMT in PLA matrix. The EM performances are gauges by Rozanov and Salisbury structures that consist in one- and two-layer stacks of composite films back-coated by a metal foil. Characterization in Rozanov configuration shows an average absorption index over the Ka band of 29.3% and 21.1% for, respectively, virgin and recycled PLA reinforced with 4 wt.% OMMT. An optimization of the film thickness is proposed; up to 61.85% and 80% of absorption with a thickness of 1.4 mm and 3.75 mm, respectively, is reached with a metal back-coated rPLA-4%OMMT film. Characterization in Salisbury configuration gives advantage to the recycled structure with an average absorption of 49.6% for a total thickness of 1.4 mm. The requirements of EMI shielding are met by PLA-OMMT composites with a certain benefit of recycling process on EM performance.

Triple Blending Effect of Fly Ash, Silica Fume and Steel Fibers on Performance of High Strength Concrete

Abstract: Compressive strength is an integral property of concrete that play a key role in the construction industry. The present works investigates the effect of triple blend of fly ash, silica fume and steel fibers on the compressive, split tensile and flexural strength of concrete. Fly ash (FA) and silica fume (SF) are introduced as a partial replacement for cement for various additions of steel fibers by volume of concrete. A replacement level of 0% FA with 0 %, 5%, 10%, 15% SF in place of cement for 0% addition of steel fibers by volume of concrete is used for the preparation of first set of samples. Second set of samples were prepared with the change in fly ash proportion to 20%, keeping replacement levels of SF unchanged for 0% inclusion of steel fibers and the last set of samples were prepared with 40% FA replacement percentage without any change in the replacements of SF for the same 0% steel fibers. Likewise, the same combinations of FA and SF were repeated for 0.5% and 1% steel fibers and tested for various strength results after 28 days curing. Later, it is seen that an optimum mix of 20% FA with 10% SF for 1% inclusion of steel fibers, produced the maximum compressive strength of 81.20 N/mm2 and maximum flexural strength of 8.40 N/mm2. Keywords: Fly ash (FA), Silica Fume (SF), Steel fibers, compressive strength, flexural strength

Effect of quercetin or butylated hydroxytoluene on cooled or frozen-thawed ram sperm quality

Cooling and freezing processes cause physical and chemical damage to sperm by cold shock and oxidative stress. This study aimed to evaluate the effect of two antioxidants on sperm parameters of cooled and frozen-thawed ram semen diluted in an egg yolk-based extender. Semen was collected from 30 rams and processed in two consecutive experiments to test the inclusion of different concentrations of quercetin and butylated hydroxytoluene (BHT) in an egg yolk-based semen extender. Dimethyl sulfoxide (DMSO) was added as a solvent to the semen extender in a ratio of 1 mL DMSO for 90 mg of quercetin and 1 mL DMSO for 880 mg of BHT. After collection, semen was diluted at 200 × 106 motile sperm/mL (control) and split into different groups in each experiment. In experiment 1, semen was diluted with the extender containing quercetin (Q5, 5 μg/mL; Q10, 10 μg/mL; Q15, 15 μg/mL) or DMSO alone (DMSO1, 0.055 μL DMSO per mL; DMSO2, 0.165 μL DMSO per mL). In experiment 2, semen was diluted with the extender with BHT (BHT1, 0.5 μg/mL; BHT2, 1 μg/mL; BHT3, 1.5 μg/mL) or DMSO alone (DMSO3, 0.375 μL DMSO per mL; DMSO4, 1.125 μL DMSO per mL). After dilution, the semen was divided into two aliquots. Treated ram sperm samples were also subjected to different storage methods. The first set of samples was cooled at 5 °C for 24 h, whereas the second set of samples was frozen-thawed. Sperm motility parameters and plasma membrane integrity (PMI) were evaluated immediately after dilution (0h) and 24 h after cooling and in the frozen-thawed samples via computer-assisted sperm analysis and epifluorescence microscopy, respectively. The inclusion of quercetin or BHT did not affect sperm motility parameters or PMI of fresh, cooled, or frozen-thawed sperm in this study (P &lt; 0.05). However, further studies are needed to test the effects of these antioxidants on the fertility of cryopreserved ram semen.

Analysis of heat treatment parameters on the properties of selected tool steels M390 and M398 produced with powder metallurgy

This paper deals with the comparison of two tool steels M390 and M398 produced by powder metallurgy of the MICROCLEAN type. The primary use of steel is in the plastics industry to produce screws for injection moulding machines. The main purpose of the paper is to analyze the hardness after different stages of heat treatment. The first part of the article evaluates the hardness of steels after hardening, which was performed using a hardening dilatometer DIL805A. A total of 8 different controlled cooling measurements were performed, for both types of powdered tool steels, from a maximum rate of 100 °C/s to a minimum of 0.01 ° C/s. Based on the results of the first set of samples from the hardening dilatometer, the optimal cooling time is evaluated to achieve the highest hardness of both materials. This rate was used to heat treat a second set of samples that had undergone a quenching process from which a selected group was quenched to -78 °C. Freezing was performed to reduce the amount of residual austenite. Before measuring the hardness, the samples were tempered at temperatures of 200, 400, 600 °C for 2x2h. The measured hardness values were then compared with data from the manufacturer BÖHLER.

Experimental study of bulletproof concrete

This paper focuses on the study of composite concrete specimen’s resistance under an impact of AK-47 bullet with an estimated projectile’s speed of 715 m/s, and energy of 2019 J. Two sets of samples (a total of nine samples) are fabricated and tested from mortar with 1 cm steel fibers or 1 cm carbon fibers respectively. Tensile and compression tests are applied for the first set of samples, to investigate the effect of steel and carbon fibers on the strength of the specimens. Two ratios (1% and 2%) of fibers per mortar mass are also experienced before assessing the bullet resistance. For the second set of samples, three different composite sandwich configurations are tested with a rear impact test. An Armox-® 500 T plate is applied in front of mortar panels for two configurations. Results show that the addition of carbon and steel fibers to concrete panels enhances the impact resistance of concrete by keeping the panels coherent and preventing them from breaking into fragments, reducing crater diameters and detached mass. The three proposed configurations of sandwiches panels stopped the full perforation of the bullet.

Evolution of the interface microstructure of short-period Cr/Ti multilayers with increase in number of bi-layers

Evolution of interface microstructure with addition of more number of layers has been investigated on Cr/Ti multilayer which is important for application as a mirror or monochromator in the “water window” soft X-ray spectral regime. Two sets of Cr/Ti multilayers at moderate and low bi-layer thickness regime have been prepared for this purpose using Ion Beam Sputtering technique. In one set, Cr/Ti multilayer with 25, 50, 60 and 100 numbers of bilayers with moderate bi-layer thickness of 3.8 nm have been deposited. In another set, four samples each having low bilayer thickness of 2.4 nm with 25, 50, 75 and 100 number of bi-layers have been prepared and the multilayers have subsequently been characterized with Specular X-ray reflectivity and diffuse X-ray scattering measurements at grazing incidence with hard X-rays. It is observed that cumulative effect of interface imperfections became more pronounced with increasing number of bilayers resulting in continuous increase in the interface width in both the thickness regimes; however, its evolution is not exactly same for the two sets of samples. Diffuse X-ray scattering result reveals that for the first set of samples, interface imperfections are dominated by interface roughness with no change in the interface diffusion with increase in number of layers, while for the second set, both interface roughness as well as interface diffusion contribute towards the cumulative accumulation of interface imperfections which is also confirmed by cross-sectional Transmission Electron Microscopy. Finally, performance of the multilayers in water window regime has been checked by soft X-ray reflectivity measurements using synchrotron radiation. The above results have direct implication in utilisation of these multilayers over a wide bi-layer thickness regime required to cover the full ‘water-window’ spectrum.

An Approach to Mechano-Electrochemistry on a Stainless-Steel Alloy

Galvanic couples play an important role in atmospheric corrosion, and tools enabling greater understanding of their mechanisms can better inform the development of corrosion models. This work employs UNS S13800 in a simulated atmospheric corrosion environment to explore the influence of mechanical stress on cathodic reaction kinetics. The electrochemical response of this material was measured, using electrochemical impedance spectroscopy and polarization experiments, while mechanically loaded and in the unstressed state. All samples were exposed to thin electrolyte films with elevated chloride concentrations that had equilibrated to the chamber’s temperature and relative humidity. The first set of samples was cathodically polarized to different static potentials while elastic load cycles were performed at different rates. The second set of samples were similarly polarized but the applies stresses induce plastic deformation in the samples while the load cycling was performed. The time-varying ORR rates were used to monitor the mechanical influence on electrochemical kinetics.

An alarming high prevalence of resistance-associated mutations to macrolides and fluoroquinolones in Mycoplasma genitalium in Belgium: results from samples collected between 2015 and 2018

ObjectivesThe number of reported cases of multiresistant Mycoplasma genitalium (MG) is increasing globally. The aim of this study was to estimate the prevalence of macrolide and possible fluoroquinolone resistance-associated mutations...

Stability and validity of intact parathyroid hormone levels in different sample types and storage conditions.

BackgroundSeveral pre‐analytical factors can affect the measurement of intact Parathyroid Hormone (IPTH). In this study, we have investigated the effects of using different types of tubes, time elapsed before separation, and storage conditions over time on the measured values of IPTH.MethodBlood samples from 30 subjects were collected into plain, SST, and EDTA tubes. All serum and plasma were separated immediately (first set) and after 2 hrs delay (second set). The first set of samples were aliquoted and stored at RT (25°C), at fridge (4°C), and freezer (−20°C). IPTH was measured in all the stored aliquots at 2,4, and 8 days after collection using Architect analyzer.ResultsPaired T test and ANOVA repeated measures showed no significant difference between IPTH levels in all tubes. The second set of serum and plasma were significantly lower (3.8% and 7.4%, p < 0.001, respectively) when compared to samples measured initially. Serum samples stored at RT were significantly lower (by 45%,59%, and 77%) on days 2,4, and 8 when compared to the initial time (p < 0.001 in all cases). Plasma samples stored at RT, were significantly lower on day 8 after collection, by 30.8% (p < 0.001). These differences would be clinically important.ConclusionPlasma IPTH can be stored at RT for up to four days. Both plasma and serum IPTH are not affected by a delay in the separation of up to two h and they can be stored for up to 8 days in a fridge or freezer without any clinically significant changes in their values.