Set Of Beads Research Articles

Material taxonomies and beads on the East African coast, seventh-fifteenth centuries AD

ABSTRACT Beads found in assemblages from the coast of East Africa have received significant archaeological attention. Glass beads were imported in large numbers to coastal sites from Indian Ocean trade networks from at least the seventh century AD; they give an important indication of the volume and direction of trade. Beads produced locally from materials such as shell have normally been understood in the same ways, seen as objects of trade for partners within and beyond Africa. In this paper, bead evidence is instead considered as an index of local values and uses. Beads of different materials are reviewed and a more flexible approach to taxonomy is suggested, highlighting local categories of object that do not entirely align with archaeological taxonomies based on raw materials and technology. A set of skeuomorphic beads from the Tanzanian sites of Kilwa Kisiwani and Songo Mnara is considered as an example of how local categories might transcend materials-based taxonomic systems.

Screening of Methyl-β-cyclodextrins as an Antifading Agent for Cyanine Dye-Labeled Streptavidin to Improve the Performance of Genotyping Chips.

As a photostabilizing agent for cyanine dye, methyl-β-cyclodextrin (MβCD) was investigated as a possible antifading agent for cyanine dye-labeled proteins. Cyanine-3 (Cy3)-labeled streptavidin (SA-Cy3) solutions containing MβCD exhibited improved resistance against photobleaching. Further research revealed that MβCD can be used as a coating material on the surface of gene chips. Chips loaded with cyanine dye (Cy3 and Cyanine-5 (Cy5))-conjugated model microbeads exhibited resistance against photobleaching with MβCD coatings. MβCD coatings improved the imaging quality of model chips and resulted in higher discrimination ratios (DR) of single base recognition by a set of control beads (NP68). In a whole genome genotyping assay for human samples, the MβCD-coated samples were found to have a better clustering performance than the noncoated ones for a group of randomly picked single nucleotide polymorphisms (SNPs).

Crafting illusions: Human-made composite coating used to simulate amber beads in prehistoric Iberia

The discovery of a set of beads, comprising both Sicilian amber and resin-coated beads in the Middle Bronze Age burial site of Cova del Gegant (Sitges, Barcelona, Spain), has sparked inquiries into whether the coating was intended for imitation or counterfeiting of amber. We assert that human-made materials, such as bead coatings, are intentionally conceived, designed, and crafted to fulfill specific functions. Thus, for an object to effectively fulfill its intended purpose, it must meet particular performance criteria influenced by situational factors.This paper aims to construct an empirically grounded narrative elucidating the development and function of resin-coated bead technology. Our methodology includes a comprehensive quantitative analysis of the coating and beads, an exploration of the interplay between technical choices and situational factors, and an investigation into whether the simulation of sensory performance characteristics played a pivotal role in the concept and design of resin-coated beads. Additionally, we synthesize data to unveil broader patterns related to the crafting and utilization of resin-coated and amber beads across time and space.We have documented resin-coated beads in the Iberian Peninsula from the Neolithic period (5th to 3rd millennia BCE) until at least the Middle Bronze Age (first half of the 2nd millennium BCE), where they coexisted with amber beads. Analysis employing ATR-FTIR and μ-CT imaging has revealed a composite coating comprising pine resin, beeswax, and carotene, adhered to shell beads with bone glue. This composite material represents the earliest known development in human history, unique to the Iberian Peninsula and without parallel in Prehistoric Europe.Our examination of the performance characteristics and functional roles of resin-coated beads suggests their potential as substitutes for amber beads, particularly in regions where amber was scarce or inaccessible. Despite being crafted from commonplace materials, these coated beads exhibit intentional design choices likely aimed at simulating the visual performance characteristics of amber. This deliberate effort, alongside their widespread distribution across time and space, indicates that composite-coated beads held symbolic and social significance akin to amber beads.

The Spondylus beads from El Molino (Puerta de Corral Quemado, Catamarca, Argentina): Analysis and implications for the study of local power in Inka times

The purpose of this paper is to present the analysis of a set of Spondylus beads found in El Molino (Puerta de Corral Quemado, Dept. of Belén, province of Catamarca, Argentina) –3000 km south of Tumbes–, a local residential pre-Inka site, with evidence of Inka influence during the 15th century CE. Given that the presence of objects manufactured in Spondylus in Chile and Argentina is nearly restricted to the capacochas −Inka burial ceremonies of children and young maidens dressed in fine textiles at the top of the snow-capped peaks of the Andes−, the discovery of these beads in El Molino acquires special relevance. We present the description of the raw material, the reconstruction of possible manufacturing techniques, the analysis of the morphometry and the comparison with other sets of beads. The implications of this discovery at a local and regional scale, taking into account the symbolic and strategic importance of this resource for the Inka expansive policy, are discussed. It is proposed that the site could have been a space of local power, where an elite group, that organized the manufacture of prestigious goods, was benefited by the mechanisms of hierarchization and legitimation of political power promoted by the state.

Brownian dynamics simulations of bottlebrush polymers in dilute solution under simple shear and uniaxial extensional flows.

We study the dynamics of bottlebrush polymer molecules in dilute solutions subjected to shear and uniaxial extensional flows using Brownian dynamics simulations with hydrodynamic interaction (HI). Bottlebrush polymers are modeled using a coarse-grained representation, consisting of a set of beads interacting pairwise via a purely repulsive potential and connected by finitely extensible nonlinear springs. We present the results for molecular stretching, stress, and solution viscosity during the startup of flow as well as under steady state as a function of side chain length while keeping the backbone length fixed. In extensional flow, the backbone fractional extension and the first normal stress difference decrease with an increase in side chain length at a fixed Weissenberg number (Wi). Using simulation results both in the presence of and in the absence of HI, we show that this is primarily a consequence of steric interaction resulting from the dense grafting of side chains. In shear flow, we observe a shear-thinning behavior in all cases, although it becomes less pronounced with increasing side chain length. Furthermore, nonmonotonicity in the backbone fractional extension is observed under shear, particularly at high Wi. We contextualize our simulation results for bottlebrush polymers with respect to existing studies in the literature for linear polymers and show that the unique dynamical features characterizing bottlebrush polymers arise on account of their additional molecular thickness due to the presence of densely grafted side chains.

Research on nondestructive detection of pine nut quality based on terahertz imaging

ObjectivePine nuts are of great nutritional and medicinal value, but they cannot avoid such defects as mildew and insect-eating during storage. Because of their hard shells, the internal quality detection of pine nuts is a major problem for industrial sorting. For this reason, it is of great significance to carry out rapid nondestructive detection of the internal quality of pine nuts. MethodsIn this paper, a rapid and nondestructive detection of pine nuts for mildew and plumpness based on terahertz transmission imaging technology was carried out. Firstly, the terahertz transmission images of pine nut samples were acquired and the terahertz spectral signals of four different regions of interest were extracted for analysis. Secondly, in order to reduce the interference of external environment on the acquisition of terahertz spectra, the terahertz spectra were pre-processedby several methods, such as ALS, AirPLS, BEADS and SNV + Detrending, and then three qualitative discriminant models, namely, Linear Discriminant Analysis (LDA), Support Vector Machine (SVM) and XGBoost integration learning, were established respectively to explore the optimal qualitative discriminant model for the detection of pine nut quality. Finally, the terahertz transmission image of pine nuts was subjected to image processing. The main feature gamut extraction combined with channel separation strategy were adopted. and then the automatic threshold segmentation algorithm was applied to perform binary threshold segmentation on the separated image, thus the plumpness of the pine nuts was calculated by calculating the ratio of the pixel points of the shell and the kernel. ResultsThe prediction set of BEADS + XGBoost model was established after data preprocessing with the optimal effect and the accuracy of 98.61%. The acquired terahertz images of pine nuts were extracted by the main feature gamut and the images of channel B were extracted by using channel separation. Finally, the automatic threshold segmentation of channel B was performed by using the maximum one-dimensional entropy, which can well realize the visual detection of the inner shell kernel of pine nuts. ConclusionTerahertz imaging technology can achieve rapid and nondestructive detection of pine mildew as well as pine nut plumpness. This study provides a new rapid and nondestructive effective method for pine nut quality detection, which can provide technical reference for other shelled nut quality detection and has significant practical value.

The hoard of the Early Iron Age at the settlement of Dianovo-II (Belozersk district of the Kurgan region)

In 2016, in the area of Dianovo village of the Belozersk district of the Kurgan region (West Siberia), a hoard of the Early Iron Age artifacts was found. While examining the area for the identification of structures of the Civil War period, a round-bottomed vessel was accidentally discovered. Inside the container, there was a massive rectangular bronze plate, glass beads, and fragments of jewelry, including bronze strings, bronze plaques in the shape of fish and four-petal plaques strung on leather cords, all wrapped in organic material (felt?). In total, the Dianovo treasure contains 370 ob-jects made of bronze and glass, assembled within a single set, classified as women’s. At present, this is one of very few elements of the women’s costume of the Early Iron Age that have been best preserved in the Southern Trans-Urals. These finds were transferred to the archaeological laboratory of the Kurgan State University, and later the archaeologi-cal survey was carried out at the discovery location by I.A. Spiridonov. The purpose of this research is a typological description of the contents of the hoard, its chronological analysis, and a possible reconstruction of the bronze orna-ment. The main research materials are the container in which the treasure was found — a ceramic round-bottomed vessel, a set of bronze objects that piece together a female (breast?) adornment, a set of glass beads of three types (rounded blue, black (square and rounded) with festoon-like white and yellow pattern), and a massive bronze plate with traces of manufacturing, which probably had the purpose of an ingot. Based on the analysis of the materials, it has been established that the hoard was most likely left by the population of the Gorokhovskaya Culture. This conclusion was made on the basis of the shape and features of the ceramic vessel. This is also supported by the location of the treasure and the general dating of individual items: glass beads of the Black Sea origin have numerous similarities in the sites and are quite clearly dated by these analogues to the 4th–3rd c. BC. The dating of other items of the hoard — elements of the bronze ornament and a bronze ingot-plate is complicated due to the lack of clearly dated analogues or chronological duration of their use. Judging by the composition and carefulness of packing of the items, this hoard ap-parently was of a situational (possibly in the event of an attack) and returnable character.

Chemistry and Production Technology of Hallstatt Period Glass Beads from Bohemia.

The presented study evaluated a set of beads primarily originating from the Hallstatt period (800–400 BC) and uncovered in the region of Bohemia. Utilizing an SEM/EDS method, the chemical composition of the glass samples was determined and their homogeneity measured. Owing to the presence of opaque glass, Raman spectroscopy was applied, enabling the definition of the phases causing the opacity of the glass, as well as its coloring. This article discusses opacifying agents, including the possible ways in which they entered the artefacts. In addition, the techniques used to produce the glass beads are described, for both the single-colored beads, as well as the so-called eye beads that are present in a significant amount in the set. The majority of the beads examined were found to be made of the LMG glass type (low-magnesium soda-lime glass). An unexpected result was the identification of glass with a high content of K2O not corresponding to the mixed alkali type (LMHK), which is frequently discussed in the literature. The glass type in question most likely does not come from the traditional area of glass production: the eastern Mediterranean territory.

Two types of humoral response in acute myocardial infraction

BackgroundAtherothrombosis and myocardial infarction are accompanied by the development of an inflammatory reaction. The severity of the immune reaction and its role in the acute myocardial infarction (AMI) remain contradictory to date.PurposeThe objective of this study was to analyze 39 cytokines and chemokines in the serum of patients hospitalized with AMI compared to the healthy volunteers.MethodsAll patients included in the study were COVID-19 negative. Patients' blood was collected within 1–2 days after hospitalization in the cardiology department. Cytokine and chemokine detection in the serum of patients (n=20) and donors (n=20) was performed using a 39-plex set of cytometric beads.ResultsAmong all factors analyzed TGFa, IL-17A, IL-1b, 3, 5, 9 were not detected both in patient and donor sera. Three groups of factors were identified in the normal serum: housekeeping chemokines and vascular factors (F1) ranged from 1000 to 22000 pg/mL (Fig. a); sentinel innate immunity factors F2 (Fig. b), 30–200 pg/mL; and acute phase factors F3 (Fig. c, d), 0–30 pg/mL, detected only in 0–30% of donors but in all AMI patients. Severe imbalance was found in AMI sera at all three levels including chemokine, growth factors, and cytokines. Among AMI patients 65% (Gr1) demonstrated 2–4 times increased level (Fig. a, grey brackets) while 35% (Gr2) had a decreased level of F1 factors in a comparison with donor sera. There was not significant difference between clinical features of the patients in Gr1 and Gr2. GRO, PDGF-AA, and sCD40L levels decreased 35, 15, and 10 times accordingly. Gr1 and Gr2 also differed in F2 and some F3 concentrations: Gr1 had 3–5 times increased level of multiple factors (Fig, b), among them – IL-6, IL-8, and IL-10 were increased 5, 6, and 14 times. At the same time Gr2 had a normal level of these factors (Fig, b, blue brackets). Finally, multiple cytokines and growth factors F3 were significantly increased in both AMI groups (Fig, b, d, red brackets). Of note, IL-12, IFN-g, IL-15, GM-CSF, FLT-3T were increased 8, 6, 5, 5, 5 times accordingly in pooled Gr1+Gr2. There were no correlations found between cytokine profiles in Gr1 and Gr2 and their clinical parameters.ConclusionsTwo types of humoral response in AMI patients were identified which differed in the levels of GRO, PDGF-AA, and sCD40L. IL-6 as well as TNF-a can not serve as master cytokines because their levels were increased only in Gr1 patients. These data show that Th1 cytokine increase is specific for AMI. Further studies are needed to identify groups of patients who may be exposed to new therapeutic targets.Funding AcknowledgementType of funding sources: None.

A chrono-cultural reassessment of levels III-V from El Cuco rock-shelter: a new sequence for the late Middle Palaeolithic – early Upper Palaeolithic boundary in the Cantabrian region (northern Iberia)

The Iberian Peninsula is one of the key areas for studying the last populations of Neanderthals and the arrival in Europe of the first anatomically modern humans. In the Cantabrian region, this process can be traced in just a few sites with levels dating to the final stages of the Middle Palaeolithic and the earliest phases of the Upper Palaeolithic. One of these singular enclaves is El Cuco rock-shelter, where the sequence was initially dated by 14C only to the early Upper Palaeolithic sensu lato. However, new studies and datings now place this archaeological sequence in the late Mousterian and the Aurignacian. In this article we present a chrono-cultural reassessment of the upper levels of El Cuco (III-V), including a study of the large mammals. Levels Vc and Vb (>43.5-40.5 ky uncal BP) date from the late Mousterian, whereas levels Va, IV and III (c. 36.5-30 ky uncal BP) cover an interval extending at least from the Early Aurignacian to the Evolved Aurignacian. Particularly noteworthy is the discovery in level Va of a set of decorative beads made from marine shells in a context of possible symbolic behaviour.

Characterization of Glass, Shell, and Fishbone Beads on Ibo Island (Northern Mozambique) in the Context of the Indian Ocean Trade

A set of beads made of glass, gastropod mollusk shell, and fishbone from a Swahili occupation level on Ibo Island (northern Mozambique) is dated to the eleventh and twelfth centuries AD. The chemical composition of the glass beads and their chromophores, and the shell and fishbone materials, are studied to understand the local and trading provenance of these items. Representative samples of each material, including two flat glass shards, were characterized using optical microscopy, field emission scanning electron microscopy (FESEM) with energy dispersive X-ray (EDS) microanalysis attached, UV-Vis-NIR spectrophotometry, and X-ray diffraction (XRD). Glass beads represent 60% of the bead assemblage. The shell and fishbone beads are 38.75% and 1.25%, respectively. Three groups of glasses were identified: (1) mineral-soda alumina glass beads associated with the recently identified m-Na-Al 6 group that come from Western India; (2) vegetal-soda alumina, represented by one flat glass shard probably from the Middle East, and beads of v-Na-Al glass of type A that came from Central Asia; and (3) conventional soda-lime silicate glasses, of modern chronology and probable European origin. Groups 1 and 2 show a variety of chromophores, both ionic and colloidal. A ruby-color bead was also identified as belonging to the Na2O-ZnO-SiO2 system and colored with cadmium sulfoselenide colloids, but this was of modern chronology. Shell beads were made from Lambis lambis gastropod mollusk shells and were locally produced. The fishbone beads may have been from a cartilaginous fish of the Chondrichthyes class, but it is difficult to specify the taxonomical level. The results of the analysis suggest that Ibo Island was integrated very early into the Swahili trade networks of the Indian Ocean.

Ab initio determination of the shape of membrane proteins in a nanodisc

New software, called Marbles, is introduced that employs SAXS intensities to predict the shape of membrane proteins embedded into membrane nanodiscs. To gain computational speed and efficient convergence, the strategy is based on a hybrid approach that allows one to account for the contribution of the nanodisc to the SAXS intensity through a semi-analytical model, while the embedded membrane protein is treated as a set of beads, similarly to as in well known ab initio methods. The reliability and flexibility of this approach is proved by benchmarking the code, implemented in C++ with a Python interface, on a toy model and two proteins with very different geometry and size.

Automatic Detection and Location of Weld Beads With Deep Convolutional Neural Networks

Welding quality detection is a critical link in modern manufacturing, and the weld bead location is a prerequisite for the high-precision assessment of welding quality. It is generally necessary for weld bead detection to be accomplished in the context of complex industrial environments. However, conventional detection and location methods based on specific detection conditions or prior knowledge lack accuracy and adaptability. To precisely detect and locate the weld beads in real industrial environments, a novel weld bead detection and location algorithm is proposed based on deep convolutional neural networks. Because there is no open data set of weld beads and the samples in real industrial applications are insufficient for effective model training of the deep convolutional neural network, a novel data augmentation method based on a deep semantic segmentation network is proposed to increase the sample diversity and enlarge the data set. Then, a dynamic sample updating strategy is put forward to cover more welding situations. Finally, faced with the weak-feature and weak-texture characteristics of weld beads, a simplified YOLOV3 model is proposed to realize end-to-end weld bead location. Experiments demonstrate that the proposed method could effectively satisfy the robustness and precision requirements for weld bead detection and location combined with a deep semantic segmentation network and simplified YOLOV3 model.

Synthesis and characterization of polyvinyl alcohol/corn starch/linseed polyol-based hydrogel loaded with biosynthesized silver nanoparticles

Nanocomposite hydrogel film was prepared from Polyvinyl alcohol [PVA], Corn Starch [CS], Linseed oil polyol [LP], and silver nanoparticles [NP]. LP was prepared by epoxidation and hydration of Linseed oil [LO]. IR and NMR supported the insertion of hydroxyl groups in LP by epoxide ring opening reaction at epoxidized LO. Silver NP were biosynthesized using aqueous leaves' extract from locally grown Ocimum forsskaolii Benth [LEO] plant. FTIR, XRD, UV and TEM confirmed the synthesis of NP (size 30 to 39 nm). Transparent and foldable hydrogel film resulted by blending the constituents (PVA, CS, LP and NP), crosslinking by glutaraldehyde, at room temperature, and showed expansion in water, different pH solutions, biodegradation and good antibacterial and antifungal activity against tested microbes. Linseed polyol influenced the structure, morphology, hydrophilicity, improved swelling ability and thermal stability and accelerated biodegradation of hydrogel films. NP were well adhered to LP globules that were embedded in PVA/CS matrix as strung set of beads (LP globules) decorated with black pearls (spherical NP). Silver NP conferred antimicrobial behavior to hydrogel film as observed by antimicrobial screening on different microbes. The results were encouraging and showed that such hydrogel films may find prospective applications in antimicrobial packaging.

Fluorescence calibration standards made from broadband emitters encapsulated in polymer beads for fluorescence microscopy and flow cytometry

We present here the design and characterization of a set of spectral calibration beads. These calibration beads are intended for the determination and regular control of the spectral characteristics of fluorescence microscopes and other fluorescence measuring devices for the readout of bead-based assays. This set consists of micrometer-sized polymer beads loaded with dyes from the liquid Calibration Kit Spectral Fluorescence Standards developed and certified by BAM for the wavelength-dependent determination of the spectral responsivity of fluorescence measuring devices like spectrofluorometers. To cover the wavelength region from 400 to 800 nm, two new near-infrared emissive dyes were included, which were spectroscopically characterized in solution and encapsulated in the beads. The resulting set of beads presents the first step towards a new platform of spectral calibration beads for the determination of the spectral characteristics of fluorescence instruments like fluorescence microscopes, FCM setups, and microtiter plate readers, thereby meeting the increasing demand for reliable and comparable fluorescence data especially in strongly regulated areas, e.g., medical diagnostics. This will eventually provide the basis for standardized calibration procedures for imaging systems as an alternative to microchannel slides containing dye solutions previously reported by us.Graphical abstract

Iron to Gas: Versatile Multiport Flow-Column Revealed Extremely High Corrosion Potential by Methanogen-Induced Microbiologically Influenced Corrosion (Mi-MIC).

Currently, sulfate-reducing bacteria (SRB) is regarded as the main culprit of microbiologically influenced corrosion (MIC), mainly due to the low reported corrosion rates of other microorganisms. For example, the highest reported corrosion rate for methanogens is 0.065 mm/yr. However, by investigating methanogen-induced microbiologically influenced corrosion (Mi-MIC) using an in-house developed versatile multiport flow test column, extremely high corrosion rates were observed. We analyzed a large set of carbon steel beads, which were sectionally embedded into the test columns as substrates for iron-utilizing methanogen Methanobacterium IM1. After 14 days of operation using glass beads as fillers for section separation, the highest average corrosion rate of Methanobacterium IM1 was 0.2 mm/yr, which doubled that of Desulfovibrio ferrophilus IS5 and Desulfovibrio alaskensis 16109 investigated at the same conditions. At the most corroded region, nearly 80% of the beads lost 1% of their initial weight (fast-corrosion), resulting in an average corrosion rate of 0.2 mm/yr for Methanobacterium IM1-treated columns. When sand was used as filler material to mimic sediment conditions, average corrosion rates for Methanobacterium IM1 increased to 0.3 mm/yr (maximum 0.52 mm/yr) with over 83% of the beads having corrosion rates above 0.3 mm/yr. Scanning electron images of metal coupons extracted from the column showed methanogenic cells were clustered close to the metal surface. Methanobacterium IM1 is a hydrogenotrophic methanogen with higher affinity to metal than H2. Unlike SRB, Methanobacterium IM1 is not restricted to the availability of sulfate concentration in the environment. Thus, the use of the multiport flow column provided a new insight on the corrosion potential of methanogens, particularly in dynamic conditions, that offers new opportunities for monitoring and development of mitigation strategies. Overall, this study shows (1) under certain conditions methanogenic archaea can cause higher corrosion than SRB, (2) specific quantifications, i.e., maximum, average, and minimum corrosion rates can be determined, and (3) that spatial statistical evaluations of MIC can be carried out.

Two-step magnetic bead-based (2MBB) techniques for immunocapture of extracellular vesicles and quantification of microRNAs for cardiovascular diseases: A pilot study.

Extracellular vesicles (EVs) have attracted increasing attention because of their potential roles in various biological processes and medical applications. However, isolation of EVs is technically challenging mainly due to their small and heterogeneous size and contaminants that are often co-isolated. We have thus designed a two-step magnetic bead-based (2MBB) method for isolation a subset of EVs as well as their microRNAs from samples of a limited amount. The process involves utilizing magnetic beads coated with capture molecules that recognize EV surface markers, such as CD63. Captured EVs could be eluted from beads or lyzed directly for subsequent analysis. In this study, we used a second set of magnetic beads coated with complementary oligonucleotides to isolate EV-associated microRNAs (EV-miRNAs). The efficiencies of 2MBB processes were assessed by reverse transcription-polymerase chain reaction (RT-PCR) with spiked-in exogenous cel-miR-238 molecules. Experimental results demonstrated the high efficiency in EV enrichment (74 ± 7%, n = 4) and miRNA extraction (91 ± 4%, n = 4). Transmission electron micrographs (TEM) and nanoparticle tracking analysis (NTA) show that captured EVs enriched by 2MBB method could be released and achieved a higher purity than the differential ultracentrifugation (DUC) method (p < 0.001, n = 3). As a pilot study, EV-miR126-3p and total circulating cell-free miR126-3p (cf-miR126-3p) in eight clinical plasma samples were measured and compared with the level of protein markers. Compared to cf-miR126-3p, a significant increase in correlations between EV-miR126-3p and cardiac troponin I (cTnI) and N-terminal propeptide of B-type natriuretic peptide (NT-proBNP) was detected. Furthermore, EV-miR126-3p levels in plasma samples from healthy volunteers (n = 18) and high-risk cardiovascular disease (CVD) patients (n = 10) were significantly different (p = 0.006), suggesting EV-miR126 may be a potential biomarker for cardiovascular diseases. 2MBB technique is easy, versatile, and provides an efficient means for enriching EVs and EV-associated nucleic acid molecules.

Abstract 1391: Development of in vitro multiplex colorectal cancer associated mutation detection assay powered with xenonucleic acid

Abstract Precise detection of cancer associated mutations have many advantages including diagnosis and monitoring of the disease and monitoring development of drug resistance. However, unlike germline mutations, somatic mutations in cancer are found at a much lower frequency. For this reason it remains a challenge especially when trying to detect mutations from limited amount of patient tissue biopsy or liquid samples. Currently, detection and genotyping of these mutations is heavily dependent on deep NGS methods. These procedures, however, are costly and time consuming. Here, we developed an alternative high-throughput method that combines DiaCarta’s proprietary xenonucleic acid (XNA) technology that allows target enrichment, and Luminex MAGPIX platform technology that enables simultaneous detection of up to 50 mutation targets. Briefly, multiplex PCR amplification of cancer associated genes is conducted in the presence of XNA. In this reaction, XNA specifically suppresses the wild-type DNA from being amplified and thus, only generates amplicons from the genes that carry mutations. The amplicons are then hybridized in a single tube that contains a set of magnetic beads. Each bead is uniquely color-coded for identification, and each corresponds to a single mutation of interest. The beads are analyzed on Luminex platform for genotyping of the mutations. Using this method, we compared conditions with or without XNA for target amplification. Our preliminary data show that when we tested the cancer oncogene KRAS exon 2 mutation variations, we find that 100% correct allele call was made with XNA for all 7 reference mutations genes. However, in conditions without XNA, the PCR product was composed of mostly wild-type sequences, and thus, only two correct allele calls (28.6%) were made. Consequently we have showed a clear advantage of XNA technology for efficient mutant target enrichment, followed by Luminex MAGPIX platform technology for simultaneous detection of multiple genetic targets. Multiplex capacity of both PCR and Luminex MAGPIX platform allows a significant reduction in the total amount of patient samples needed for precise mutation detection from each assay, especially for the mutations with low allelic frequency. Further development on this assay will provide a more reliable, sensitive and quick method for simultaneously detecting mutations associated with cancer in a single reaction. Citation Format: Michael Y. Sha, Anna J. Lee, Michael J. Powell, Aiguo Zhang. Development of in vitro multiplex colorectal cancer associated mutation detection assay powered with xenonucleic acid [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1391.

Estimation of online particle size distribution of a particle mixture in free fall with acoustic emission

For many powder processes, the particle size distribution (PSD) is a key quality attribute of the flow properties of the process powders. This paper presents a method for estimating the PSD with acoustic emissions (AE) by implementing a time domain-based threshold approach followed by the extraction of the amplitude mean from each set threshold and correlation to particle size. The experiments were carried out using a powder-free fall experimental rig, and a set of glass beads, while the acquired data were analyzed with a designed signal analysis method. The results of the experiments showed that the PSD of the particle mixtures being investigated could be identified with an average absolute error of 10%. The main advantage of the designed signal analysis method was identified as the requirement for a low hardware complexity due to a simpler algorithm than its predecessors. In an attempt to benchmark the performance of the system, the performance of the designed approach was compared to a wavelet-based analysis designed by Ren et al. From this it was seen that the approach used by Ren et al. is reliant on a tuning process to aid the algorithm in making the size estimation, suggesting that Ren’s approach would prove to be inefficient in a process where powder segregation occurred due to poor mixing.

Investigating beads from Chalcolithic funerary cremation contexts of Perdigões, Portugal

A set of beads was studied to investigate their nature. They come from a funerary feature used for the secondary deposition of cremated remains of more than a hundred individuals. The pit is located in the centre of Perdigões (Évora, Portugal) ditched enclosures (Valera et al., 2014a) and is dated from the third quarter of the 3rd millennium BC. The beads were also burned and were part of the funerary votive assemblages, also composed by arrowheads ivory figurines, marble idols and pots, phalanx idols, copper awls, Pecten shells and pottery sherds. These beads have a diameter between 5 and 10.5 mm, with a central perforation up to 5 mm and maximum thickness of 3 mm, they are dark grey or black and were of unknown nature.This study shows that these beads were made from shells and submitted to heating processes. The study demonstrates the ability of neutron and X-ray methods to determine the nature of the material even being very calcium rich.Chemical results show that they have high contents of calcium, and that the surface is more contaminated with soil particles due to high Si, Fe and K contents, and phosphorous was found in higher proportion, certainly originated from the bones. FTIR patterns show that the major part of the beads is calcium carbonate crystallized in calcite form, contaminated with silicates and calcium phosphate, pointing to shells as raw materials. The ToF-ND results also indicate the crystal lattice structure of calcite, and aragonite, a polymorph formed in the biomineralisation process of shells, was not detected, indicating a total phase transformation to calcite probably due to heating processes during funerary practices. The SEM-EDS results confirm the shell nature of beads. The results were of wider significance for the archaeological discussion, especially deciphering the nature of the beads, contributing to the debate of interaction in the Chalcolithic of Southern Iberia.