Extraction Step Research Articles

Microfactory Design for Valorization of E-Waste Plastics (Acrylonitrile-Butadiene-Styrene, Polycarbonate, and Polypropylene) on Additive Manufacturing Sector

Less than half of e-waste plastics are sorted worldwide, and this rate is likely to decline as major processing countries have banned importation of e-waste plastics. This forces the development of decentralized processing facilities, also known as microfactories. The present work investigates the recyclability of different grades of acrylonitrile-butadiene-styrene (ABS) copolymer, polycarbonate, and polypropylene, which were found to be very abundant in a recycling site in the UK. The determination of the matrix relied on the resin identification codes imprinted in the e-waste plastics and subsequent Fourier-transform infrared spectroscopy (FTIR). Melt-blend extrusion technology enabled the valorization of the wasted thermoplastics as 3D filament without significant degradation of the polymers. The recycled materials maintained the tensile strength at around 2.5 MPa in agreement with the specifications offered by virgin polymers. Further characterization was done by means of laser microscope, thermogravimetric analysis, and X-ray fluorescence to determine the commercial viability of the recycled filament. A modified solvent-based method was developed with acetone to remove the brominated flame retardants: 25 g/100 mL, 30 min of contact time, and 4 extraction steps. The FTIR results show that the degradation of the rubbery dispersed phase corresponding to the butadiene can be accumulated in the less soluble fraction of the extracted ABS.

Biopolymer manufacturing from pectin extraction of jackfruit waste to increase oil production in EOR

This research was conducted with the aim of making an alternative, nature-based biopolymer formed from the extraction of jackfruit peel pectin as a substitute for commercial polymers. The manufacture of this biopolymer is carried out by means of laboratory tests using conventional methods with a chemical extraction process on jackfruit skin. The raw material used is jackfruit skin (Artocarpus integer). Processing of jackfruit skin into pectin is carried out by several procedures such as extraction using citric acid, purification of pectin with 96% ethanol, FTIR characterization test, density test, viscosity test, shear rate test, and the effect of salinity. The FTIR test showed that pectin was formed after the extraction step, as evidenced by the structure of the pectin-forming groups which was similar to commercial pectin. The deposition of impurity particles contained in the pectin content is evidenced by the lack of optimal pectin to increase the viscosity of water. The increase in viscosity will occur as the concentration of pectin increases. Jackfruit pectin is able to survive in solutions that have high salinity, as evidenced by the higher the salinity of the solution, the thickening process continues.

Urban sewage sludge valorization to biodiesel production: Solvent-free lipid recovery through adsorption on used 3 Ply Safety Face Masks

The use of urban sewage sludge as the feedstock of lipids to produce biodiesel is a topic of great interest and potential. However, the extractive step, conventionally operated with organic solvents, makes this use unfeasible and with a high environmental impact. In this work, for the first time, the solvent-free recovery of lipids from sewage sludge was studied through adsorption onto non-polar polymeric materials (Spunbonded nonwoven Polypropylene (s-nwPP)). After being immersed in sedimented sewage sludge (TS: 6.9 wt%), s-nwPP sheets were easily separated, dried and analyzed: sewage sludge’s lipids were preferentially adsorbed onto the polymeric surface. Free fatty acids (FFAs) were the dominant species and were recovered from s-nwPP sheets through acidic methanol in a separated reactive washing step as fatty acid methyl esters (FAMEs) A crude product was obtained through this sequence of adsorption and reactive desorption operations, with a FAMEs content of over 55 wt%. After preliminary investigations on commercial s-nwPP sheets, 3 Ply Safety Face Masks were also positively tested. pH, weight ratio polymer/wet sludge (R) and temperature were the parameters optimized: operating at 343 K under acidic conditions (pH of sludge<2), with an R equal to 6%, a total FFAs recovery yield of 70% as FAMEs was already achieved after two adsorption cycles. A preliminary evaluation of the economic feasibility demonstrated that used PP surgical facial masks allow the recovery and generation of crude biodiesel from sewage sludge at a very reasonable price with minimal environmental impacts.

A comparison of feature extraction capabilities of advanced UHPLC-HRMS data analysis tools in plant metabolomics.

Data analysis of ultrahigh performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) is an essential and time-consuming step in plant metabolomics and feature extraction is the fundamental step for current tools. Various methods lead to different feature extraction results in practical applications, which may puzzle users for selecting adequate data analysis tools to deal with collected data. In this work, we provide a comprehensive method evaluation for some advanced UHPLC-HRMS data analysis tools in plant metabolomics, including MS-DIAL, XCMS, MZmine, AntDAS, Progenesis QI, and Compound Discoverer. Both mixtures of standards and various complex plant matrices were specifically designed for evaluating the performances of the involved method in analyzing both targeted and untargeted metabolomics. Results indicated that AntDAS provide the most acceptable feature extraction, compound identification, and quantification results in targeted compound analysis. Concerning the complex plant dataset, both MS-DIAL and AntDAS can provide more reliable results than the others. The method comparison is maybe useful for the selection of suitable data analysis tools for users.

Determination of eight cannabinoids in foods with enhanced matrix removal-lipid adsorbent by ultra performance liquid chromatography-tandem mass spectrometry

A novel method was developed for the simultaneous determination of eight cannabinoids in six types of food matrices, including chocolate, fondant, biscuit, beverage, cookie and baijiu, using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sample extraction and cleanup steps were optimized, and various purification methods were investigated to remove the oil matrix and glue in chocolate and fudge, respectively. Enhanced matrix removal-lipid adsorbent (EMR-Lipid) provided efficient, selective cleanup of the evaluated matrices. The sample was extracted using acetonitrile, followed by EMR-Lipid cleanup, and then dried using anhydrous sodium sulfate. The acetonitrile layer was concentrated by nitrogen to near-dry after 100 μL 10% glycerol in methanol was added to improve the recovery by reducing loss during concentration under the stream of nitrogen gas. Eight cannabinoids were separated using a Waters ACQUITY UPLC BEH Shield RP18 column (100 mm×3.0 mm, 1.7 μm). The responses of the cannabinoids in the positive and negative ionization modes were investigated and optimized, and the responses were superior in the negative ion mode compared to those in the positive ion mode. MS detection was performed in the multi-reaction monitoring (MRM) mode using an electrospray source in the negative ion mode. The cannabinoids were quantified using an external standard with matrix calibration curves to reduce the influences of the matrix effects on the quantitative results. The developed method was verified, and the conditions of sample pretreatment were also optimized. The calibration curves of tetrahydrocannabinol, cannabidivarin, tetrahydrocannabivarin, and cannabigerol and those of cannabidiol, cannabinol, cannabidiolic acid, and tetrahydrocannabinolic acid exhibited good linearities, with r>0.995, in the ranges of 2-200 and 0.4-40 ng/mL, respectively. The respective limits of detection (LODs, S/N=3) and quantification (LOQs, S/N=10) of tetrahydrocannabinol, cannabidivarin, tetrahydrocannabivarin, and cannabigerol were 4 and 10 μg/kg, and those of cannabidiol, cannabinol, cannabidiolic acid, and tetrahydrocannabinolic acid were 0.8 and 2 μg/kg. The average recoveries of the cannabinoids were 82.0%-114.9% under three spiked levels with corresponding relative standard deviations (RSDs) of <15% (n=6). EMR-Lipid provided efficient, selective cleanups of food matrices with good accuracy. The method is sensitive, rapid, accurate, simple to execute, and it is suitable for the determination of cannabinol compounds in typical food matrices.

Novel fully automated and parallel gas assisted dynamic accelerated solvent extractor and parallel solvent evaporator for analysis of solid and semi-solid samples

The extraction of non-volatile and semi-volatile analytes from solid and semisolid samples has been primarily carried out via heated and/or pressurized liquid extraction mechanisms. Although analyte extraction and concentration processes have significantly evolved and currently several automated solutions are commercially available, these two steps are carried out independently. To the best of our knowledge, human intervention is always required throughout the entire process for sample extract manipulation/transportation among instruments/processes. Expectedly, excessive sample handling throughout the analytical workflow contributes to an increase in the analysis cost, the loss of analyte (s), and numerous potential analytical errors. Herein, we present the first fully automated sample-to-vial solution for analysis of non-volatile and semi-volatile compounds from solid and semisolid samples. This technological development, which is based on gas assisted dynamic accelerated solvent extraction (GA-dASE) and an integrated level-sensing system that controls the endpoint of the evaporation step, allows for fully automated analyte extraction and analyte enrichment. As a proof of concept, we applied this fully automatic extraction and enrichment system towards the quantitative determination of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) in soil samples. Our results showed that GA-dASE not only matched the performance of the legacy accelerated solvent extraction (ASE), in terms of analyte recovery and reproducibility, but also delivered nearly 3-time reduction in labor per sample. Furthermore, our experiments demonstrated the capability of the instrument to perform fully automated extraction and evaporation steps without human intervention and with no impact on data quality (Relative Standard Deviation, RSD, ≤ 20%). In terms of interlaboratory reproducibility (n = 2), our results showed comparable results for the determination of PAHs using either 10- or 100-mL sample cells.

Robust Event Classification Using Imperfect Real-World PMU Data

This paper studies robust event classification using imperfect real-world phasor measurement unit (PMU) data. By analyzing the real-world PMU data, we find it is challenging to directly use this dataset for event classifiers due to the low data quality observed in PMU measurements and event logs. To address these challenges, we develop a novel machine learning framework for training robust event classifiers, which consists of three main steps: data preprocessing, fine-grained event data extraction, and feature engineering. Specifically, the data preprocessing step addresses the data quality issues of PMU measurements (e.g., bad data and missing data); in the fine-grained event data extraction step, a model-free event detection method is developed to accurately localize the events from the inaccurate event timestamps in the event logs; and the feature engineering step constructs the event features based on the patterns of different event types, in order to improve the performance and the interpretability of the event classifiers. Based on the proposed framework, we develop a workflow for event classification using the real-world PMU data streaming into the system in real time. Using the proposed framework, robust event classifiers can be efficiently trained based on many off-the-shelf lightweight machine learning models. Numerical experiments using the real-world dataset from the Western Interconnection of the U.S power transmission grid show that the event classifiers trained under the proposed framework can achieve high classification accuracy while being robust against low-quality data.

Conidia production of the entomopathogenic fungus Beauveria bassiana using packed-bed bioreactor: Effect of substrate biodegradability on conidia virulence

This work presents the scale-up of the conidia production of the entomopathogenic fungus Beauveria bassiana using two different wastes, coupled with concentration and virulence tests of the produced conidia against the pest Tenebrio molitor. Beauveria bassiana CECT 20374 was used in solid state fermentation (SSF) operating under batch strategy. Two substrates with different biodegradability (rice husk and beer draff) were tested, successfully scaling from 1.5 L to 22 L bioreactors. Higher conidia production was reached using beer draff as substrate (2.5 × 109 and 6.0 × 108 conidia g−1 dry matter in 1.5 and 22 L reactors respectively) highlighting air free porosity relevance as scale-up parameter. Concentration and dose-response tests against larvae and adult Tenebrio molitor were performed to compare strain CECT 20374 with control strain KVL 13–39 (a B. bassiana strain previously tested against T. molitor). Virulence effect of the 22 L fermentation product of strain CECT using rice husk or beer draff was tested against T. molitor adult stage. However, quality loses between conidia produced in agar plates and fermented products were observed (from 75 to 80% mortality in plates to 40% in rice husk and 50–60% in beer draff fermented products respectively). The differences between plate and fermented samples also indicated fermentation process, extraction and conservation steps as possible causes for quality losses, highlighting the need to optimize them to maximize virulence maintenance.

Implementation of Cloud Point Extraction Using Surfactants in the Recovery of Polyphenols from Apricot Cannery Waste

The objective of this study was to investigate the feasibility of using Cloud Point Extraction (CPE) to isolate natural antioxidants (polyphenols) from apricot cannery waste (ACW). Four different food-grade surfactants (Genapol X-080, PEG 8000, Tween 80, and Lecithin) were tested at varying concentrations to evaluate the effectiveness of the technique. It was observed that low concentrations of surfactants in one-step CPE resulted in less than 65% polyphenol recovery, which necessitated further extraction steps. However, high concentrations of surfactants were found to significantly improve polyphenol extraction from ACW for all surfactants tested. Among the four surfactants, PEG 8000 was found to be the most effective in most circumstances; specifically, adding only 2% of the surfactant per step in a two-step CPE was enough to effectively extract polyphenols with recovery rates better than 99%. When 10% w/v of PEG 8000 was used, recoveries greater than 92% were obtained. Since PEG 8000 is a reagent with low toxicity and the CPE method is simple, rapid, cheap, sensitive, and selective, the extracted organic compounds from ACW can be used as natural antioxidants in food technology. This has important implications for the development of natural and sustainable food additives.

Evaluation of the AdvanSure One-Stop COVID-19 Plus Kit for SARS-CoV-2 Detection Using a Streamlined RNA Extraction Method.

Real-time reverse transcription (rRT)-PCR, which is the reference standard for the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, generally involves a time-consuming and costly RNA extraction step prior to amplification. We evaluated the performance of the AdvanSure One-Stop COVID-19 Plus Kit (LG Chem, Seoul, Korea), a novel rRT-PCR assay that can detect SARS-CoV-2 within 90 minutes using a streamlined RNA extraction method. In total, 509 nasopharyngeal swab (NPS) specimens (SARS-CoV-2 positive: N=205; SARS-CoV-2 negative: N=304) previously tested using the PowerChek SARS-CoV-2 Real-time PCR Kit (Kogene Biotech, Seoul, Korea) were tested using the AdvanSure assay. The limit of detection (LOD) of the AdvanSure assay was determined using serially diluted inactivated SARS-CoV-2. The positive and negative percent agreements between the AdvanSure and PowerChek assays were 99.5% (204/205) and 99.3% (302/304), respectively. The LODs of the AdvanSure assay for SARS-CoV-2 nucleocapsid and spike/RNA-dependent RNA polymerase genes were 672 and 846 copies/mL, respectively. The results show that the performance of the AdvanSure assay is comparable to that of the PowerChek assay used for routine SARS-CoV-2 testing, suggesting that the AdvanSure assay is a useful diagnostic tool for rapid and accurate detection of SARS-CoV-2 infection.

Ozonation/extraction coupled non‐catalytic desulphurization of VGO/natural gas condensate

AbstractThe desulphurization of hydrocarbon fuels with high sulphur content and a wide variety of sulphur‐containing compounds brings significant challenges. In the present work, the non‐catalytic desulphurization of vacuum gas oil (VGO) and natural gas condensate mixed fuel has been investigated. In this regard, ozone was employed as the oxidant in a bubble column gas–liquid contactor, and an extraction step was further incorporated. The effects of the oxidation reactor scheme, ozonation time, and extraction with different solvents, applying pre‐ and post‐extraction strategies (i.e., ozonation/extraction/extraction and extraction/ozonation/extraction), have been studied. It was found that pre‐extraction of mixed fuel increases the oxidative desulphurization (ODS) efficiency due to the removal of light sulphur‐containing compounds (SCCs). N‐methyl‐2‐pyrrolidone (NMP) has been found to be the most effective extraction agent, removing 44% of sulphur by pure extraction and 77.4% by ozonation + extraction. However, in terms of fuel loss, dimethylformamide (DMF) performs better than NMP, and it has been shown to be the most appropriate solvent for achieving a 90% desulphurization ratio. Finally, it was found that the applied procedure could effectively remove the wide range of SCCs, especially refractive components such as benzothiophene (BT) and dibenzothiophene (DBT).

Discrete representation learning for handwritten text recognition

Handwritten text recognition, i.e., the conversion of scanned handwritten documents into machine-readable text, is a complex exercise due to the variability and complexity of handwriting. A common approach in handwritten text recognition consists of a feature extraction step followed by a recognizer. In this paper, we propose a novel DNN architecture for handwritten text recognition that extracts discrete representation from the input text-line image. The proposed model is constructed of an encoder–decoder network with an added quantization layer which applies a dictionary of representative vectors to discretize the latent variables. The dictionary and the network parameters are trained jointly through the k-means algorithm and back propagation, respectively. The performance of the suggested model is evaluated through conducting extensive experiments on five datasets, analyzing the effect of discrete representation on handwriting recognition. The results demonstrate that the use of feature discretization improves the performance of deep handwriting text recognition models when compared to the conventional DNN models with continuous representation. Specifically, the character error rate is decreased by 22% and 21.1% on IAM and ICFHR18 datasets, respectively.

Solid phase extraction of ocean dissolved organic matter with PPL cartridges: efficiency and selectivity

Our current knowledge of the chemical composition of ocean dissolved organic matter (DOM) is limited, mainly because of its extreme molecular diversity, low concentration of individual compounds and the elevated ionic strength of ocean waters. As a result, many analytical methods require a previous extraction step. The efficiency and selectivity of the extraction method defines the representativeness of the extracted DOM fraction. Nowadays, the most widespread procedure for concentrating DOM is solid phase extraction (SPE) using styrene divinyl benzene polymer cartridges (PPL). Here, we investigate the effect of SPE-PPL on DOM elemental and optical properties to assess the efficiency and selectivity of this extraction method on water samples from the main intermediate and deep water masses of Arctic, Mediterranean and Antarctic origin present in the Cape Vert Frontal Zone (CVFZ, NW Africa). Furthermore, North and South Atlantic Central waters converge in this area and coastal DOM is injected by the giant upwelling filament of Cape Blanc. On one side, the colored fraction of DOM (CDOM) presented extraction efficiencies comparable to that of the bulk dissolved organic carbon (DOC), but decreased significantly with increasing wavelength, suggesting an affinity of PPL cartridges for low molecular weight organic compounds. While the protein-like fluorescent fraction of DOM (FDOM) was also extracted with the same efficiency than DOC, the extraction efficiency of the humic-like fraction was comparatively much higher. On the other side, dissolved organic nitrogen (DON) extraction efficiencies were about half that of DOC. These contrasting extraction efficiencies of the different DOM pools indicated that the extracts were enriched in N-poor, low molecular weight and recalcitrant DOM, therefore showing less variability than the corresponding bulk DOM. Furthermore, DOC, DON, CDOM and FDOM extracted were not homogeneous through the water column but displayed certain significant differences among water masses in both efficiency and selectivity.

Rapid and Efficient SpPRE Approach: A Step Towards Meeting High Demand of Bioactive Swertiamarin

ABSTRACT Swertiamarin has a potential for treating metabolic illnesses, Parkinson’s disease, and its hepatoprotective and antiaging effects are evident. In spite of high yield in herb Enicostemma littorale Blume, the complexity of phytochemical makeup of extract presents difficulties in purification of swertiamarin due to a closely eluting flavonoid glycoside(s) and has an impact on the final output. At the laboratory scale, advanced techniques such as centrifugal partition and counter-current chromatography have been examined. However, feasibility of scaling up these strategies is limited. We developed a four-step SpPRE technique for enriching swertiamarin in the extract which includes optimization of Solvent for extraction, liquid-liquid partitioning, Precipitation, and Resin Enrichment step. This technique enabled enrichment of swertiamarin from 10.9% to 81.7% with reduction in extract weight by 91%. Subsequently, a single-step silica gel column chromatography resulted into 97% pure swertiamarin. The SpPRE methodology has resolved the problem of repeated column chromatography as well as the sample loading over to silica gel. To determine the concentration of the compound at each step, a validated HPLC method was employed. Furthermore, the current approach’s ability to isolate the target component in a high yield will increase swertiamarin’s market value and research prospects.

Sequential Solid-Phase Microextraction with Biocompatible Coating Materials to Address Displacement Effects in the Quantitative Analysis

Solid-phase microextraction (SPME) is a simple and effective sample-preparation technique for the analysis of complex samples. However, sample matrices containing high concentrations of nonpolar substances or spiked analytes in free form can cause swelling, saturation, and/or competition phenomena in the coating material. This results in a displacement effect wherein polar analytes with low affinities for the solid coating material are displaced by nonpolar substances in the matrix or spiked analytes with a high affinity. Therefore, the quantitative analysis of polar analytes can be challenging, as the displacement effect causes non-linearity in the calibration curves. This paper presents a comprehensive investigation of the conditions under which the displacement effect occurs and how it influences the quantitative analysis of polar analytes. To remedy this issue, a sequential SPME strategy using two SPME blades with different selectivities is applied. SPME blades offer a large surface area and coating volume─and thus, greater extraction capacity─which may mitigate the displacement effect. In addition, the biocompatible coatings on the SPME blades are comprised of small amounts of sorbent particles embedded by a polyacrylonitrile (PAN) binder, which allows them to be directly immersed into complex matrixes such as biological and food samples, as the PAN acts as a barrier that prevents the adsorption of large macromolecules (e.g., cells and proteins). As such, a C18/PAN-coated blade was applied for the first extraction step, which significantly decreased the concentrations of nonpolar compounds in the sample. In the second step, a hydrophilic-lipophilic balanced (HLB)/PAN-coated blade was employed to extract the polar analytes and any remaining nonpolar analytes. The proposed sequential SPME strategy successfully enabled the quantitative determination of polar and nonpolar drugs of abuse with log P values ranging from 0.16 to 4.98 in biological matrices while also providing good linearities.

Optimizing mycobacteria molecular diagnostics: No decontamination! Human DNA depletion? Greener storage at 4 °C!

Tuberculosis (TB) is an infectious disease caused by the group of bacterial pathogens Mycobacterium tuberculosis complex (MTBC) and is one of the leading causes of death worldwide. Timely diagnosis and treatment of drug-resistant TB is a key pillar of WHO's strategy to combat global TB. The time required to carry out drug susceptibility testing (DST) for MTBC via the classic culture method is in the range of weeks and such delays have a detrimental effect on treatment outcomes. Given that molecular testing is in the range of hours to 1 or 2 days its value in treating drug resistant TB cannot be overstated. When developing such tests, one wants to optimize each step so that tests are successful even when confronted with samples that have a low MTBC load or contain large amounts of host DNA. This could improve the performance of the popular rapid molecular tests, especially for samples with mycobacterial loads close to the limits of detection. Where optimizations could have a more significant impact is for tests based on targeted next generation sequencing (tNGS) which typically require higher quantities of DNA. This would be significant as tNGS can provide more comprehensive drug resistance profiles than the relatively limited resistance information provided by rapid tests. In this work we endeavor to optimize pre-treatment and extraction steps for molecular testing. We begin by choosing the best DNA extraction device by comparing the amount of DNA extracted by five commonly used devices from identical samples. Following this, the effect that decontamination and human DNA depletion have on extraction efficiency is explored. The best results were achieved (i.e., the lowest Ct values) when neither decontamination nor human DNA depletion were used. As expected, in all tested scenarios the addition of decontamination to our workflow substantially reduced the yield of DNA extracted. This illustrates that the standard TB laboratory practice of applying decontamination, although being vital for culture-based testing, can negatively impact the performance of molecular testing. As a complement to the above experiments, we also considered the best Mycobacterium tuberculosis DNA storage method to optimize molecular testing carried out in the near- to medium-term. Comparing Ct values following three-month storage at 4 °C and at -20 °C and showed little difference between the two. In summary, for molecular diagnostics aimed at mycobacteria this work highlights the importance of choosing the right DNA extraction device, indicates that decontamination causes significant loss of mycobacterial DNA, and shows that samples preserved for further molecular testing can be stored at 4 °C, just as well at -20 °C. Under our experimental settings, human DNA depletion gave no significant improvement in Ct values for the detection of MTBC.

Chinese Event Detection without Triggers Based on Dual Attention

In natural language processing, event detection is a critical step in event extraction, aiming to detect the occurrences of events and categorize them. Currently, the defects of Chinese event detection based on triggers include polysemous triggers and trigger-word mismatches, which reduce the accuracy of event detection models. Therefore, event detection without triggers based on dual attention (EDWTDA), a trigger-free model that can skip the trigger identification process and determine event types directly, is proposed to fix the problems mentioned above. EDWTDA adopts a dual attention mechanism, integrating local and global attention. Local attention captures key semantic information in sentences and simulates hidden event trigger words to solve the problem of trigger-word mismatch, while global attention digs for the context of documents, fixing the problem of polysemous triggers. Besides, event detection is transformed into a binary classification task to avoid problems caused by multiple tags. Meanwhile, the sample imbalance brought about by the transformation is settled with the application of the focal loss function. The experimental results on the ACE 2005 Chinese corpus show that, compared with the best baseline model, JMCEE, the accuracy rate, recall rate, and F1-score of the proposed model increased by 3.40%, 3.90%, and 3.67%, respectively.

The Socket-Plug Technique and Materials Comparison in Atraumatic Extractions - A Multiple-Case Study

It is confirmed that tooth extraction with spontaneous healing may lead to degrees of alveolar bone resorption due to the bone remodelling phase. Reconstructive materials are proposed to insert into the socket during the extraction procedure preventing the loss of alveolar bone dimension. The “Socket Plug” technique is an alveolar ridge preservation (ARP) method saving both operational time and is easy to apply in clinical routines. The technique includes steps of atraumatic extraction, flapless design, biomaterial placement, and suturing. Four clinical cases are reported using the socket-plug technique placing hemostatic gelatin sponges as spontaneous healing and collagen plug in sockets as ARP with or without interradicular septum.

Validation of an expanded, in-house library and an optimized preparation method for the identification of fungal isolates using MALDI-TOF mass spectrometry.

The goal of this study was to validate an optimized sample preparation method for filamentous fungal isolates coupled with the use of an in-house library for the identification of moulds using Matrix Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) in a multicenter context. For that purpose, three Spanish microbiology laboratories participated in the identification of 97 fungal isolates using MALDI-TOF MS coupled with the Filamentous Fungi library 3.0 (Bruker Daltonics) and an in-house library containing 314 unique fungal references. The isolates analyzed belonged to 25 species from the genus Aspergillus, Fusarium, Scedosporium/Lomentospora, the Mucorales order and the Dermatophytes group. MALDI-TOF MS identification was carried out from hyphae resuspended in water and ethanol. After a high-speed centrifugation step, the supernatant was discarded and the pellet submitted to a standard protein extraction step. The protein extract was analyzed with the MBT Smart MALDI Biotyper system (Bruker Daltonics). The rate of accurate, species-level identification obtained ranged between 84.5% and 94.8% and the score values were1.8 for 72.2-94.9% of the cases. Two laboratories failed to identify only one isolate of Syncephalastrum sp. and Trichophyton rubrum, respectively and three isolates could not be identified in the third center (F. proliferatum, n=1; T.interdigitale, n=2). In conclusion, the availability of an effective sample preparation method and an extended database allowed high rates of correct identification of fungal species using MALDI-TOF MS. Some species, such as Trichophyton spp. are still difficult to identify. Although further improvements are still required, the developed methodology allowed the reliable identification of most fungal species.

Purification and Characterization of a Novel D-Galactose Binding Lectin from Seeds of Meizotropis buteiformis.

The main aim of the present study is to find out the novelty and characteristics of a lectin purified from the plant Meizotropis buteiformis. Lectins are proteins that possess the ability to specifically bind glycans of glycoconjugates. Plants are considered rich sources of lectins and the determination of sugar specificity of a purified plant lectin is an important aspect in order to evaluate its potential area of application. In the present study, a novel D-Galactose specific lectin is purified from Meizotropis buteiformis through affinity chromatography and examined for its various physical and biochemical characteristics. The objective of the present study is to purify a novel lectin up to its homogeneity from the seeds of Meizotropis buteiformis and characterization of its various physical and biochemical properties. The lectin was purified by simple successive steps of lectin extraction, ammonium sulphate fractionation, and affinity chromatography. Activity of the purified lectin was determined by hemagglutination assay. Some physicochemical parameters of the purified protein were also determined along with identification of protein by LC-MS/MS and the spectra analysis using Mascot sequence matching software (Matrix Science) with the NCBI database. From the current investigation, it was found that the purified lectin has a native molecular weight of 75 kDa. Among the various sugars and sugar derivatives tested, lactose and D-galactose were found to be potent inhibitors of its activity. Its optimum pH range was found to be from 6.5 to 7.5 and also it exhibited full activity at a temperature from 0ºC to 50ºC. The purified lectin does not show any effects on its activities for metal ions tested. The protein view report of the LC-MS/MS result analysis showed a 50% sequence similarity with that of the lectin beta-chain of the Butea monosperma. In the present study, a novel D-Galactose specific lectin is purified from Meizotropis buteiformis by affinity chromatography using Sepharose 4B. The purified lectin is found to be heterodimeric and metal ion independent. The LC-MS/MS results suggested that the purified lectin has not been reported earlier.