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Over the past few decades, the topic of recycling has become increasingly prominent in the field of sustainable materials and circular economy. One significant challenge is the physical separation of different types of plastics to obtain recyclates of one plastic type as pure as possible with comparable quality and properties to those of virgin material. Given the substantial effort involved in such separation, small amounts of contamination from other plastics may be tolerated. However, these contaminations must be monitored to ensure high-level recyclate quality. In recent years, compact, low-cost ion mobility spectrometers (IMS) with high analytical performance have been developed, and have thus become widely used in a variety of sensing applications. Due to their high sensitivity, IMS are particularly suited for detecting lowest concentration levels of various compounds, as required for the detection of impurities in recyclate quality monitoring. When coupled to a miniature gas chromatograph (GC), GC-IMS reach even higher separation power while being still compact. To bring recyclate samples to the gas phase, pyrolysis (Py) is used in this work. A first feasibility study was conducted to assess the potential of such a pyrolysis–gas chromatography-ion mobility spectrometer (Py-GC-IMS) with the objective of detecting contaminations of polyethylene terephthalate (PET) in polyethylene (PE) recyclates. The study clearly demonstrates the ability to identify PET-related fingerprints while suppressing the PE background matrix by design so that Py-GC-IMS seems a promising approach for in-process monitoring PET contaminations in PE recyclates. [ABSTRACT FROM AUTHOR]

Purpose: The multifactorial nature of patellofemoral instability requires a comprehensive assessment of the affected patients. While an association between tibial tuberosity (TT) torsion and patellofemoral instability is known, its specific effect has not yet been investigated. This study investigated the effect of TT torsion on patellofemoral instability. Methods: This retrospective cohort study compared patients who underwent surgical intervention for patellofemoral instability and asymptomatic controls. TT torsion was measured in addition to other commonly assessed risk factors for patellofemoral instability using standardised computed tomography (CT) data of the lower extremities. The diagnostic performances of the assessed parameters were evaluated using receiver operating characteristic curve analysis and odds ratios (ORs) were calculated. Results: The patellofemoral instability group consisted of 79 knees, compared to 72 knees in the asymptomatic control group. Both groups differed significantly in all assessed parameters (p < 0.001), except for tibial torsion (n.s.). Among all parameters, TT torsion presented the best diagnostic performance for predicting patellar instability with an area under the curve of 0.95 (95% confidence interval [CI], 0.91–0.98; p < 0.001). A cut‐off value of 17.7° yielded a 0.87 sensitivity and 0.89 specificity to predict patellar instability (OR, 55.2; 95% CI, 20.5–148.6; p < 0.001). Conclusion: Among the evaluated risk factors, TT torsion had the highest predictive value for patellofemoral instability. Patients with TT torsions ≥ 17.7° showed a 55‐fold increased probability of patellofemoral instability. Therefore, TT torsion should be included in the assessment of patients with patellofemoral instability. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Purpose: Recent studies point toward a potential benefit of doxycycline use for post-exposure prophylaxis (PEP) or pre-exposure prophylaxis (PrEP) to prevent sexually transmitted infections (STIs). Although prescribing doxycycline in a prophylactic intention is not generally recommended yet, we noticed an increasing number of inquiries from individuals within the LGBTQ community for doxycycline prescriptions. Methods: We conducted an anonymous online survey to evaluate the current extent of doxycycline use for PEP or PrEP within the LGBTQ community using REDCap electronic data capture tools. Participants gained access to the online survey through a QR code on posters in the premises of our STI outpatient department and at LGBTQ community-related events in the south-western region of Germany. Additional access was provided by a direct link shared on social media profiles for men having sex with men (MSM), transgender, and queers. Results: 96 of 99 responses were eligible for analysis. Twenty-two participants (23%) indicated to have already used doxycycline for PEP and six participants (6%) used doxycycline for PrEP. The majority of participants used pills left over from previous doxycycline treatment. Forty percent of indicated modes of access were without a regular prescription, e.g., by provision from acquaintances (with or without healthcare profession) or by ordering online. Conclusion: Our study shows that the concept of doxycycline use for prevention of STIs is already well known and applied in the LGBTQ community. Further analysis, especially modeling studies, are needed to evaluate strategies aiming to reduce doxycycline intake (PEP/PrEP versus repeated targeted therapies) and improve sexual health outcomes within the community. [ABSTRACT FROM AUTHOR]

Functional and structural alterations of peritubular capillaries (PTCs) are a major determinant of chronic kidney disease (CKD). Using a software-based algorithm for semiautomatic segmentation and morphometric quantification, this study analyzes alterations of PTC shape associated with chronic tubulointerstitial injury in three mouse models and in human biopsies. In normal kidney tissue PTC shape was predominantly elongated, whereas the majority of PTCs associated with chronic tubulointerstitial injury had a rounder shape. This was reflected by significantly reduced PTC luminal area, perimeter and diameters as well as by significantly increased circularity and roundness. These morphological alterations were consistent in all mouse models and human kidney biopsies. The mean circularity of PTCs correlated significantly with categorized glomerular filtration rates and the degree of interstitial fibrosis and tubular atrophy (IFTA) and classified the presence of CKD or IFTA. 3D reconstruction of renal capillaries revealed not only a significant reduction, but more importantly a substantial simplification and reconfiguration of the renal microvasculature in mice with chronic tubulointerstitial injury. Computational modelling predicted that round PTCs can deliver oxygen more homogeneously to the surrounding tissue. Our findings indicate that alterations of PTC shape represent a common and uniform reaction to chronic tubulointerstitial injury independent of the underlying kidney disease. [ABSTRACT FROM AUTHOR]

Purpose: Recent data suggest that individual morphologic factors should be respected to restore preoperative patellofemoral alignment and thus reduce the likelihood of anterior knee pain. The goal of this study was to investigate the effect of excessive femoral torsion (FT) on clinical outcome of TKA. Methods: Patients who underwent TKA and complete preoperative radiographic evaluation including a long-leg radiograph and CT scan were included. 51 patients showed increased FT of > 20° and were matched for age/sex to 51 controls (FT < 20°). Thirteen patients were lost to follow-up. Thirty-eight matched pairs were compared after a 2 year follow-up clinically (Kujala and patellofemoral score for TKA) and radiographically (FT, frontal leg axis, TT-TG, patellar thickness, patellar tilt, and lateral displacement of patella). Functional alignment of TKA was performed (hybrid-technique). All patellae were denervated but no patella was resurfaced. Results: There was no significant difference between clinical scores two years after surgery between patients with normal and excessive FT (n.s.). Kujala score was 64.3 ± 16.7 versus 64.8 ± 14.4 (n.s.), and patellofemoral score for TKA was 74.3 ± 21 versus 78.5 ± 20.7 (n.s.) for increased FT group and control group, respectively. There was no correlation between preoperative FT and clinical scores. Other radiographic parameters were similar between both groups. No correlations between clinical outcomes and preoperative/postoperative frontal leg axis or total leg axis correction were found (n.s.). Conclusion: If the leg axis deformity is corrected to a roughly neutral alignment during cemented TKA, including patellar denervation, then excessive FT was not associated with patellofemoral pain or instability. Level of evidence.: Prospective comparative study, level II. [ABSTRACT FROM AUTHOR]

Purpose: Anterior knee pain (AKP) is common following total knee arthroplasty. The tibial tuberosity trochlear groove distance (TTTG) influences patellofemoral joint loading in the native knee. Increased TTTG may lead to maltracking of the patella and anterior knee pain. The purpose of this study was to investigate potential changes in TTTG following total knee arthroplasty (TKA). Methods: TTTG was measured on preoperative CT data on a consecutive series of patients scheduled to receive TKA with patient-specific instrumentation, and compared to a computer simulation of the postoperative TTTG. Preoperative TTTG was measured with a 3D planning software in 250 knees. The postoperative result was simulated and TTTG measured within the software. Three different groups were analysed: neutral (180° ± 3) (n = 50), valgus (> 190°) (n = 100), and varus (< 170°) (n = 100). Results: Median preoperative to simulated postoperative TTTG decreased from 15.0 [interquartile range (IQR) 6.0] mm to 6.5 (IQR 5.0) mm for all axes combined. A significant postoperative reduction of TTTG was found in each group (p < 0.001). The mean change in TTTG did not differ significantly between the groups [− 8.8 (IQR 5.5) mm neutral, − 8.3 (IQR 7.0) mm valgus, − 7.5 (IQR 5.8) mm varus, p = 0.223]. Conclusion: This computer-based study suggests that mechanically aligned TKA significantly decreases TTTG distance in neutral, valgus and varus knees, assuming that the postoperative result coincides with the preoperative planning. Further study is warranted to evaluate the clinical relevance of this finding. [ABSTRACT FROM AUTHOR]

The first High Kinetic Energy-Ion Mobility Spectrometry-Mass Spectrometry (HiKE-IMS-MS) studies involving six volatiles (acetone, acetonitrile, methanol, ethanol, 2-propanol, and 1-butanol) and their fully deuterated analogues are reported. The goal is to further our understanding of the ion–molecule chemistry occurring in the HiKE-IMS. This is needed for its full analytical potential to be reached. Product ions are identified as a function of the reduced electric field (30–115 Td) and the influence of sample air humidity in the reaction region on deuterium/hydrogen (D/H) exchange reactions is discussed. Reagent ions include H3O+(H2O)m (n = 0, 1, 2 or 3), NO+(H2O)n (m = 0 or 1) and O2+·. Reactions with H3O+(H2O)m lead to protonated monomers (through either proton transfer or ligand switching). Reactions with NO+ involve association with acetone and acetonitrile, hydride anion abstraction from ethanol, 2-propanol, and 1-butanol, and hydroxide abstraction from 2-propanol and 1-butanol. With the exception of acetonitrile, O2+· predominantly reacts with the volatiles via dissociative charge transfer. A number of sequential secondary ion-volatile processes occur leading to the formation of dimer and trimer-containing ion species, whose intensities depend on a volatile's concentration and the reduced electric field in the reaction region. Deuterium/hydrogen (D/H) exchange does not occur for product ions from acetone-d6 and acetonitrile-d3, owing to their inert methyl functional groups. For the deuterated alcohols, rapid D/H-exchange reaction at the hydroxy group is observed, the amount of which increased with the increasing humidity of the sample air and/or lowering of the reduced electric field. [ABSTRACT FROM AUTHOR]

Optimisation of microbiological diagnostics in primarily sterile body fluids is required. Our objective was to apply EUCAST's RAST on primarily sterile body fluids in blood culture bottles with total lab automation (TLA) and to compare results to our reference method Vitek2 in order to report susceptibility results earlier. Positive blood culture bottles (BACTEC™ Aerobic/Anaerobic/PEDS) inoculated with primarily sterile body fluids were semi-automatically subcultured onto Columbia 5% SB agar, chocolate agar, MacConkey agar, Schaedler/KV agar and Mueller-Hinton agar. On latter, cefoxitin, ampicillin, vancomycin, piperacillin/tazobactam, meropenem and ciprofloxacin were added. After 6 h, subcultures and RAST were imaged and MALDI-TOF MS was performed. Zone sizes were digitally measured and interpreted following RAST breakpoints for blood cultures. MIC values were determined using Vitek2 panels. During a 1-year period, 197 Staphylococcus aureus, 91 Enterococcus spp., 38 Escherichia coli, 11 Klebsiella pneumoniae and 8 Pseudomonas aeruginosa were found. Categorical agreement between RAST and MIC was 96.5%. Comparison showed no very major errors, 2/7 (28.6%) and 1/7 (14.3%) of major errors for P. aeruginosa and meropenem and ciprofloxacin, 1/9 (11.1%) for K. pneumoniae and ciprofloxacin, 4/69 (7.0%) and 3/43 (5.8%) for Enterococcus spp. and vancomycin and ampicillin, respectively. Minor errors for P. aeruginosa and meropenem (1/8; 12.8%) and for E. coli and ciprofloxacin (2/29; 6.5%) were found. 30/550 RAST measurements were within area of technical uncertainty. RAST is applicable and performs well for primarily sterile body fluids in blood culture bottles, partially better than blood-based RAST. Official EUCAST evaluation is needed. [ABSTRACT FROM AUTHOR]

Fusarium oxysporum is a plant pathogenic fungus leading to severe crop losses in agriculture every year. A sustainable way of combating this pathogen is the application of mycoparasites—fungi parasitizing other fungi. The filamentous fungus Trichoderma atroviride is such a mycoparasite that is able to antagonize phytopathogenic fungi. It is therefore frequently applied as a biological pest control agent in agriculture. Given that volatile metabolites play a crucial role in organismic interactions, the major aim of this study was to establish a method for on-line analysis of headspace microbial volatile organic compounds (MVOCs) during cultivation of different fungi. An ion mobility spectrometer with gas chromatographic pre-separation (GC-IMS) enables almost real-time information of volatile emissions with good selectivity. Here we illustrate the successful use of GC-IMS for monitoring the time- and light-dependent release of MVOCs by F. oxysporum and T. atroviride during axenic and co-cultivation. More than 50 spectral peaks were detected, which could be assigned to 14 volatile compounds with the help of parallel gas chromatography-mass spectrometric (GC-MS) measurements. The majority of identified compounds are alcohols, such as ethanol, 1-propanol, 2-methyl propanol, 2-methyl butanol, 3-methyl-1-butanol and 1-octen-3-ol. In addition to four ketones, namely acetone, 2-pentanone, 2-heptanone, 3-octanone, and 2-octanone; two esters, ethyl acetate and 1-butanol-3-methylacetate; and one aldehyde, 3-methyl butanal, showed characteristic profiles during cultivation depending on axenic or co-cultivation, exposure to light, and fungal species. Interestingly, 2-octanone was produced only in co-cultures of F. oxysporum and T. atroviride, but it was not detected in the headspace of their axenic cultures. The concentrations of the measured volatiles were predominantly in the low ppbv range; however, values above 100 ppbv were detected for several alcohols, including ethanol, 2-methylpropanol, 2-methyl butanol, 1- and 3-methyl butanol, and for the ketone 2-heptanone, depending on the cultivation conditions. Our results highlight that GC-IMS analysis can be used as a valuable analytical tool for identifying specific metabolite patterns for chemotaxonomic and metabolomic applications in near-to-real time and hence easily monitor temporal changes in volatile concentrations that take place in minutes. [ABSTRACT FROM AUTHOR]

Aims: Upon suspicion of infective endocarditis, the causative microorganism must be identified to optimize treatment. Blood cultures and culturing of removed valves are the mainstay of this diagnosis and should be complemented by growth-independent methods. We assessed the diagnostic benefit of examining removed endocarditis valves by broad-range bacterial PCR to detect causative bacteria in cases where culturing was not available, negative, or inconclusive because a skin commensal was detected, in patients from our clinical routine practice. Methods and results: Patients from Heidelberg University Hospital with suspicion of endocarditis, followed by valve replacement and analysis by 16S rDNA PCR, between 2015 and 2018, were evaluated. 146 patients with definite infective endocarditis, confirmed by the valve macroscopics and/or histology, were included. Valve PCRs were compared to corresponding blood and valve culture results. Overall, valve PCR yielded an additional diagnostic benefit in 34 of 146 cases (23%) and was found to be more sensitive than valve culture. In 19 of 38 patients with both negative blood and valve cultures, valve PCR was the only method rendering a pathogen. In 23 patients with positive blood cultures detecting skin commensals, 4 patients showed discordant valve PCR results, detecting a more plausible pathogen, and in 11 of 23 cases, valve PCR confirmed commensals in blood culture as true pathogens. Only the remaining 8 patients had negative valve PCRs. Conclusion: Valve PCR was found to be a valuable diagnostic tool in surgical endocarditis cases with negative blood cultures or positive blood cultures of unknown significance. Trial registration: S-440/2017 on 28.08.2017 retrospectively registered. Subdividing of all infective endocarditis patients in this study, showing that valve PCR yields valuable information for patients with skin commensals in blood cultures, which were either confirmed by the same detection in valve PCR or refuted by the detection of a different and typical pathogen in valve PCR. Additionally, benefit was determined in patients with negative or not available blood cultures and only positive detection in valve PCR. +: Positive; −: negative; n/a: not available results [ABSTRACT FROM AUTHOR]

Ion mobility spectrometers can detect gaseous compounds at atmospheric pressure in the range of parts per trillion within a second. Due to their fast response times, high sensitivity, and limited instrumental effort, they are used in a variety of applications, especially as mobile or hand-held devices. However, most real-life samples are gas mixtures, which can pose a challenge for IMS with atmospheric pressure chemical ionization mainly due to competing gas-phase ionization processes. Therefore, we present a miniaturized drift tube IMS coupled to a compact gas chromatograph for pre-separation, built of seven bundled standard GC columns (Rtx-Volatiles, Restek GmbH) with 250 μm ID and 1.07 m in length. Such pre-separation significantly reduces chemical cross sensitivities caused by competing gas-phase ionization processes and adds orthogonality. Our miniaturized GC-IMS system is characterized with alcohols, halocarbons, and ketones as model substances, reaching detection limits down to 70 pptv with IMS averaging times of just 125 ms. It separates test mixtures of ketones and halocarbons within 180 s and 50 s, respectively. The IMS has a short drift length of 40.6 mm and reaches a high resolving power of RP = 68. [ABSTRACT FROM AUTHOR]

The drift voltage required for operating ion mobility spectrometers implies high voltage isolation of either the ion source or the detector. Typically, the detector is grounded due to the sensitivity of the small ion currents to interferences and thus higher requirements for signal integrity than the ion source. However, for certain ion sources, such as non-radioactive electron emitters or electrospray ionization sources, or for coupling with other instruments, such as gas or liquid chromatographs, a grounded ion source is beneficial. In this paper, we present an isolated data acquisition interface using a 16 bit, 250 kilosamples per second analog to digital converter and fiber optic transmitters and receivers. All spectra recorded via this new data acquisition interface and with a grounded ion source show the same peak shapes and noise when compared with a grounded detector, allowing additional freedom in design. [ABSTRACT FROM AUTHOR]

Ion mobility spectrometers (IMS) are able to detect pptV-level concentrations of substances in gasses and in liquids within seconds. Due to the continuous increase in analytical performance and reduction of the instrument size, IMS are established nowadays in a variety of analytical field applications. In order to reduce the manufacturing effort and further enhance their widespread use, we have developed a simple manufacturing process for drift tubes based on a composite material. This composite material consists of alternating layers of metal sheets and insulator material, which are connected to each other in a mechanically stable and gastight manner. Furthermore, this approach allows the production of ion drift tubes in just a few steps from a single piece of material, thus reducing the manufacturing costs and efforts. Here, a drift tube ion mobility spectrometer based on such a composite material is presented. Although its outer dimensions are just 15 mm × 15 mm in cross section and 57 mm in length, it has high resolving power of Rp = 62 and detection limits in the pptV-range, demonstrated for ethanol and 1,2,3-trichloropropane. [ABSTRACT FROM AUTHOR]

Our objective was to evaluate EUCAST's 'rapid antimicrobial susceptibility testing' (RAST) directly from positive blood culture that delivers antimicrobial results within 6 h for Staphylococcus aureus, Enterococcus spp., Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, using total lab automation. Zone diameters from RAST were compared with MIC results. Furthermore, its influence on time to report was investigated. RAST was performed to all positive aerobic and anaerobic blood culture bottles by subculturing them, i.e. onto Mueller-Hinton agar and adding six antibiotic discs covering Gram-negative and Gram-positive therapy (cefoxitin, ampicillin, vancomycin, piperacillin/tazobactam, meropenem and ciprofloxacin). RAST was automatically imaged after 6 h. Zone sizes were measured using a TLA software tool and interpreted according to EUCAST clinical breakpoints. Bacteria were identified using MALDI-TOF MS and MIC results were determined using Vitek2 panels. Categorial agreement between agar diffusion and MIC results was investigated. Additionally, time to RAST and time to Vitek were compared for 100 isolates (20 per species). Between November 2018 and April 2019, 3313 positive mono-bacterial blood culture bottles were collected of which 894 bottles with RAST-validated species were investigated. Among these bottles, 2029 individual antibiotic measurements were compared with MIC results from Vitek2 and 14 very major, 28 major and 12 minor errors were found. A median reduction of 17:30 h in time to report was observed. Introduction of RAST with automatic TLA imaging function could reduce time to report by 17:30 h. Excellent accordance between zone diameter and MIC results, particularly for cefoxitin, vancomycin and meropenem, was observed, but drawbacks due to ATU were seen. [ABSTRACT FROM AUTHOR]

Syndromic panel-based molecular testing has been suggested to improve and accelerate microbiological diagnosis. We aimed to analyze workflow improvements when using the multiplex Seegene Allplex™ GI-Bacteria(I) assay as a first-line assay for bacterial diarrhea. Technical assay evaluation was done using spiked stool samples and stored patient samples. After implementation of the assay in the routine clinical workflow, an analysis of 5032 clinical samples analyzed by the Seegene assay and 4173 control samples examined by culture in a similar time period 1 year earlier was performed. Sensitivity of the assay was shown to be between 0.4 and 95.9 genome equivalents/PCR. For 159 positive patient samples with a composite reference of culture and/or a molecular assay, the sensitivity of the assay was 100% for Campylobacter, 92% for Salmonella, 89% for Aeromonas, and 83% for Shigella. Sensitivity for C. difficile toxin B detection was 93.9%. The comparison of clinical samples obtained in two 8-month periods showed increased detection rates for Aeromonas (2.90%vs. 0.34%), Campylobacter spp. (2.25% vs. 1.34%), Shigella spp. (0.42% vs. 0.05%) whereas detection of Salmonella was slightly decreased (0.46% vs. 0.67%) when using the Seegene assay. An analysis of the time-to-result showed that the median dropped from 52.7 to 26.4 h when using the molecular panel testing. The Seegene Allplex™ GI-Bacteria(I) assay allows accelerated, reliable detection of major gastrointestinal bacteria roughly within 1 day. Workload is reduced, specifically in a low-prevalence setting. [ABSTRACT FROM AUTHOR]

Single-cell dispensing for automated cell isolation of individual cells has gained increased attention in the biopharmaceutical industry, mainly for production of clonal cell lines. Here, machine learning for classification of cell images is applied for 'real-time' cell viability sorting on a single-cell printer. We show that an extremely shallow convolutional neural network (CNN) for classification of low-complexity cell images outperforms more complex architectures. Datasets with hundreds of cell images from four different samples were used for training and validation of the CNNs. The clone recovery, i.e. the fraction of single-cells that grow to clonal colonies, is predicted to increase for all the samples investigated. Finally, a trained CNN was deployed on a c.sight single-cell printer for 'real-time' sorting of a CHO-K1 cells. On a sample with artificially damaged cells the clone recovery could be increased from 27% to 73%, thereby resulting in a significantly faster and more efficient cloning. Depending on the classification threshold, the frequency at which viable cells are dispensed could be increased by up to 65%. This technology for image-based cell sorting is highly versatile and can be expected to enable cell sorting by computer vision with respect to different criteria in the future. [ABSTRACT FROM AUTHOR]

Introduction: Mesenchymal stem cells (MSCs) represent a very important cell source in the field of regenerative medicine and for bone and cartilage tissue engineering applications. Three-dimensional (3D) bioprinting has the potential to improve the classical tissue engineering concept as this technique allows the printing of cells with high spatial control of cell allocation within a 3D construct. In this study, we systematically compared different hydrogel blends for 3D bioprinting of MSCs by testing their cytocompatibility, ability to support osteogenic differentiation and their mechanical properties. In addition, we compared four different MSC populations isolated from different human tissues for their osteogenic differentiation capacity in combination with different hydrogels. The aim of this study was to identify the best MSC source and the most suitable hydrogel blend for extrusion-based bioprinting of 3D large-scaled osteogenic constructs. Materials and Methods: MSCs were isolated from different tissues (umbilical cord, adipose tissue, bone marrow). MSCs were seed onto or into different hydrogels and analyzed for cell viability, proliferation and osteogenic differentiation. In addition, viscoelastic properties of the hydrogels were determined. MSC-containing cubes with the size of 1 cm3 were printed by means of 3D extrusion-based bioprinting and analyzed by (immuno)histology for cell survival and production of a calcified extracellular matrix. Results: Adipose tissue derived MSCs (ASCs) showed the highest osteogenic differentiation potential. A complex hydrogel blend consisting of fibrin, gelatin, hyaluronic acid, glycerol (F/G/H/Gl), tuned with hydroxyapatite, showed the best viscoelastic properties in combination with an excellent biocompatibility towards ASCs. This cell/hydrogel combination was used to bioprint 3D cubes. The cubes showed good mechanical stability and the printed ASCs were viable and able to calcify the hydrogel after bioprinting. Conclusions: The combination of the HA-tuned F/G/H/Gl hydrogel blend along with ASCs can be considered as a very promising bioink for 3D bioprinting of artificial bone tissue equivalents for prospective applications in tissue engineering and regenerative medicine. [ABSTRACT FROM AUTHOR]

Outcome of patients with blood stream infections (BSI) depends on the rapid initiation of adequate antibiotic therapy, which relies on the fast and reliable identification of the underlying pathogen. Blood cultures (BC) using CO2-sensitive colorimetric indicators and subsequent microbiological culturing are the diagnostic gold standard but turnaround times range between 24 and 48 h. The detection of volatile organic compounds of microbial origin (mVOC) has been described as a feasible method for identifying microbial growth and to differentiate between several microbial species. In this study, we aimed to investigate the ability of mVOC analyses using a gas chromatograph coupled to an ion mobility spectrometer (GC-IMS) for the recognition of bacterial growth and bacterial differentiation in BCs. Therefore, samples of whole blood and diluted bacterial suspension were injected into aerobic and anaerobic BC bottles and incubated for 8 h. Headspace samples from cultures of Escherichia coli (DSM 25944), Staphylococcus aureus (DSM 13661), and Pseudomonas aeruginosa (DSM 1117) were investigated hourly and we determined at which point of time a differentiation between the bacteria was possible. We found specific mVOC signals in the headspace over growing BCs of all three bacterial species. GC-IMS headspace analyses allowed faster recognition of bacterial growth than the colorimetric indicator of the BCs. A differentiation between the three investigated species was possible after 6 h of incubation with a high reliability in the principal component analysis. We concluded that GC-IMS headspace analyses could be a helpful method for the rapid detection and identification of bacteria in BSI. [ABSTRACT FROM AUTHOR]

Determination of the capsule type of clinical isolates of Streptococcus pneumoniae is a prerequisite for epidemiological studies and further vaccine development. The Quellung reaction for serotyping is expensive and mostly done in reference centres. We wanted to evaluate whether Fourier-transformed infrared (FT-IR) spectroscopy is suitable for capsular type analysis and prediction of pneumococcal serotypes. We used the IR-Biotyper™ (Bruker) to create a database containing the spectra of 120 strains from invasive disease. The strains covered the 24 vaccine serotypes contained in the 13-valent conjugate vaccine (PCV13) and the 23-valent polysaccharide vaccine (PSV23). Hierarchical clustering analysis was performed. Finally, two different classification sets were created (PCV13 and PSV23). They were used to predict the serotype of 168 different challenge strains (invasive and non-invasive disease) covering 48 different serotypes (vaccine and non-vaccine types). FT-IR spectra from pneumococci (1300–800 cm−1) clustered along their serotype as determined by the Quellung reaction (120 strains, 24 different serotypes). Strains with unknown serotype fell within the cluster of the correct serotype, as long as the latter was represented in the database (168 strains, 48 different serotypes). Concordance between the Quellung reaction and FT-IR spectroscopy was excellent (kappa ≥ 0.75). FT-IR spectroscopy is a fast and cost-effective method to predict the capsular serotype of pneumococci. [ABSTRACT FROM AUTHOR]

Developing powerful hand-held drift tube ion mobility spectrometers (IMS) requires small, lightweight drift tubes with high analytical performance. In this work, we present an easy-to-manufacture, miniaturized drift tube ion mobility spectrometer, which is manufactured from polyether ether ketone, stainless steel foils and printed circuit boards. It is possible to operate the drift tube IMS with a radioactive 3H ionization source or a non-radioactive X-ray ionization source with 3 kV acceleration voltage. The drift tube design provides high resolving power of Rp = 63 at a drift length of just 40 mm, 15 mm × 15 mm in cross-section (outer dimensions) and a drift voltage of 2.5 kV. The limits of detection for less than one second of averaging are 40 pptv for dimethyl-methylphosphonate and 30 pptv for methyl salicylate. For demonstration, the miniaturized drift tube IMS is integrated into a stand-alone battery-powered mobile device, including a closed gas-loop, high performance driver electronics and wireless data transmission. In a proof-of-concept study, this device was tested in an international field evaluation exercise to detect the release of a volatile, hazardous substance inside a large entry hall. [ABSTRACT FROM AUTHOR]

With recent advances in ionization sources and instrumentation, ion mobility spectrometers (IMS) have transformed from a detector for chemical warfare agents and explosives to a widely used tool in analytical and bioanalytical applications. This increasing measurement task complexity requires higher and higher analytical performance and especially ultra-high resolution. In this review, we will discuss the currently used ion mobility spectrometers able to reach such ultra-high resolution, defined here as a resolving power greater than 200. These instruments are drift tube IMS, traveling wave IMS, trapped IMS, and field asymmetric or differential IMS. The basic operating principles and the resulting effects of experimental parameters on resolving power are explained and compared between the different instruments. This allows understanding the current limitations of resolving power and how ion mobility spectrometers may progress in the future. [ABSTRACT FROM AUTHOR]

Purpose: Despite antifungal prophylaxis following liver transplantation (LTX), patients are at risk for the development of subsequent opportunistic infections, such as an invasive fungal disease (IFD). However, culture-based diagnostic procedures are associated with relevant weaknesses. Methods: Culture and next-generation sequencing (NGS)-based fungal findings as well as corresponding plasma levels of ß-D-glucan (BDG), galactomannan (GM), interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-2, -4, -6, -10, -17A and mid-regional proadrenomedullin (MR-proADM) were evaluated in 93 patients at 6 consecutive time points within 28 days following LTX. Results: A NGS-based diagnostic approach was shown to be suitable for the early identification of fungal pathogens in patients following LTX. Moreover, MR-proADM and IL-17A in plasma proved suitable for the identification of patients with an IFD. Conclusion: Plasma measurements of MR-proADM and IL-17A as well as a NGS-based diagnostic approach were shown to be attractive methodologies to attenuate the weaknesses of routinely used culture-based diagnostic procedures for the determination of an IFD in patients following LTX. However, an additional confirmation within a larger multicenter trial needs to be recommended. Trial registration: German Clinical Trials Register: DRKS00005480. [ABSTRACT FROM AUTHOR]

In order to optimize an ion mobility spectrometer (IMS) with respect to resolving power and sensitivity, the exact spatial ion density distribution generated by the used ionization source is of major interest. In this work, we investigate the two-dimensional (2D) spatial ion density distribution generated by a 63Ni source and the three-dimensional (3D) spatial ion density distributions generated by a radioactive 3H electron source, our non-radioactive electron source and an X-ray source. Therefore, we used an experimental setup consisting of the ionization source under investigation, an ionization region, a 5 mm short drift tube and a PCB Faraday detector segmented into stripe electrodes to measure the ion current. Repeating this measurement for different detector angles, the resulting 3D spatial ion density distribution can be calculated by image reconstruction. Furthermore, we varied the kinetic electron energy of our non-radioactive electron source in order to validate the simulated ion density distribution shown in previous work. [ABSTRACT FROM AUTHOR]

Adoptive T cell therapy (ACT) is a safe and effective personalized cancer immunotherapy that can comprise naturally occurring ex vivo expanded cells (e.g., tumor-infiltrating lymphocytes [TIL]) or T cells genetically engineered to confer antigen specificity (T-cell receptor [TCR] or chimeric antigen receptor [CAR] engineered T cells) to mediate cancer rejection. In recent years, some ACTs have produced unprecedented breakthrough responses: TIL therapy has moved from melanoma to solid tumor applications, TCR-engineered cells are developed for hematologic and solid tumors, and CAR-engineered T cells have received Food and Drug Administration (FDA) approval for the treatment of patients with certain B-cell malignancies. Although results are encouraging, to date, only a small percentage of patients with advanced malignancies can benefit from ACT. Besides ACT availability and accessibility, treatment-related toxicities represent a major hurdle in the widespread implementation of this therapeutic modality. The large variety of observed toxicities is caused by the infused cell product or as side effects of accompanying medication and chemotherapy. Toxicities can occur immediately or can be delayed. In order to render those highly promising therapeutic approaches safe enough for a wider pool of patients outside of clinical trials, an international consensus for toxicity management needs to be established. [ABSTRACT FROM AUTHOR]

Objectives: To assess the value of pre-procedural computed tomography angiography (CTA) measurements of the suprahepatic inferior vena cava (IVC) to detect elevated central venous pressure (CVP) assessed by right heart catheterisation (RHC), and to predict post-procedural 1-year mortality in a cohort of patients undergoing transcatheter aortic valve implantation (TAVI).Methods: We retrospectively evaluated 408 consecutive patients undergoing CTA before TAVI between January 2011 and December 2014. Two hundred and five patients were included in the RHC cohort, who underwent RHC and CTA within ≤1 day prior to TAVI. Two hundred and three patients not fulfilling this requirement were included in the validation cohort. Measurements of the IVC were performed between diaphragm and right atrium on axial slices. Receiver operating characteristic (ROC) analyses, Kaplan-Meier analyses and Cox regression analyses were performed.Results: In the RHC cohort, ROC curve analyses for IVC area measurements indicated an AUC of 0.77 (p < 0.001) to detect CVP ≥10mmHg and an area under the ROC curve (AUC) of 0.72 (p < 0.001) to predict 1-year mortality. An IVC area cut-off of ≥665 mm2 predicted 1-year mortality with a specificity of 84% and a sensitivity of 63%. Kaplan-Meier analysis showed that patients with an IVC area ≥665 mm2 had a significantly higher post-procedural 1-year mortality (38% versus 7%, log-rank p < 0.001) with a hazard ratio of 5.5 (95% CI, 2.2-13.6; p < 0.001). Applying this cut-off value to the validation cohort confirmed a significantly higher 1-year mortality after TAVI (34% versus 11%; log-rank p = 0.004) for patients with an IVC area ≥665 mm2.Conclusions: Pre-procedural enlargement of the suprahepatic IVC is a predictor of post-procedural 1-year mortality in patients evaluated for TAVI.Key Points: • IVC measurements are moderate predictors of an elevated CVP in TAVI patients. • Pre-procedural IVC enlargement is a predictor of 1-year mortality after TAVI. • IVC enlargement is associated with right heart dysfunction in TAVI patients. [ABSTRACT FROM AUTHOR]

In 2016, the workflow for MRSA detection in nasal swabs was changed from a classic-manual workflow to an automated workflow using total lab automation (TLA; BD Kiestra). This change entailed a reduction of the incubation time from 2 days to 20 h and reading of plates on weekdays and weekends instead of weekdays only. The workflow alteration did not include the introduction of 24/7. We wanted to follow up on the consequences for the times to report (TTR). We compared the TTR of all nasal swabs, which were sent for MRSA detection from June until August in 2015 (workflow—classic-manual) and in 2016 (workflow—automated). We calculated median TTR and interquartile ranges for the three possible reporting outcomes (negative, MRSA-known, MRSA-new) per day and workflow. A multivariable linear regression modeled the exposure variables workflow, day, and reporting outcome on TTR including interaction variables. The quantity and reasons for a TTR longer than 3 days were analyzed. During both 3-month periods, a total of 16,111 reports were issued (2015:7620; 2016:8491). The median TTR for negative reports was 48:28 (hh:mm) in 2015 and 23:58 in 2016. In the linear regression, all exposure variables had a strong and highly significant (p < 0.001) influence on the TTR. The number of reports with a TTR longer than 3 days shrank from 2418 (2015) to 60 (2016). The workflow alteration halved the median TTR for negative reports and the number of reports with a TTR longer than 3 days was reduced by 97.5%. [ABSTRACT FROM AUTHOR]

Measuring a mixture of acetone and perdeuterated acetone (acetone-d6) with an ultra-high resolution drift time ion mobility spectrometer (resolving power of Rp = 235) and ultraviolet ionization (10.6 eV) at ambient pressure reveals three separated peaks. Two of the peaks can easily be associated with acetone and perdeuterated acetone. In a former publication several findings indicated an exchange of a methyl group and the formation of a H3COCD3 related peak. In this work the formed ion species were analyzed with a high resolution drift time ion mobility time of flight mass spectrometer. The mass spectra clearly show the formation of three proton-bound dimer peaks whereas the peak between acetone and acetone-d6 is a proton-bound mixed dimer consisting of one acetone and one acetone-d6 molecule. [ABSTRACT FROM AUTHOR]

While total laboratory automation (TLA) is well established in laboratory medicine, only a few microbiological laboratories are using TLA systems. Especially in terms of speed and accuracy, working with TLA is expected to be superior to conventional microbiology. We compared in total 35,564 microbiological urine cultures with and without incubation and processing with BD Kiestra TLA for a 6-month period each retrospectively. Sixteen thousand three hundred thirty-eight urine samples were analyzed in the pre-TLA period and 19,226 with TLA. Sixty-two percent (n = 10,101/16338) of the cultures processed without TLA and 68% (n = 13,102/19226) of the cultures processed with TLA showed growth. There were significantly more samples with two or more species per sample and with low numbers of colony forming units (CFU) after incubation with TLA. Regarding the type of bacteria, there were comparable amounts of Enterobacteriaceae in the samples, slightly less non-fermenting Gram-negative bacteria, but significantly more Gram-positive cocci, and Gram-positive rods. Especially Alloscardivia omnicolens, Gardnerella vaginalis, Actinomyces spp., and Actinotignum schaalii were significantly more abundant in the samples incubated and processed with TLA. The time to report was significantly lower in the TLA processed samples by 1.5 h. We provide the first report in Europe of a large number of urine samples processed with TLA. TLA showed enhanced growth of non-classical and rarely cultured bacteria from urine samples. Our findings suggest that previously underestimated bacteria may be relevant pathogens for urinary tract infections. Further studies are needed to confirm our findings. [ABSTRACT FROM AUTHOR]

The drift voltage is one of the key experimental parameters of any drift tube ion mobility spectrometer. In this work, we show that a universal relationship between optimum drift voltage and the resolving power reached at this point exists, governed only by temperature and ion charge state. With these two quantities known, the measured optimum drift voltage and resolving power combination can be used to estimate the ideality of the drift conditions inside a drift tube, since any deviation from the theoretical values must be caused by non-idealities in the ions' drift. Analyzing drift voltage sweeps from nine different ion mobility spectrometers, a continuous increase in drift tube ideality over the past is observed, reaching from less than 50% thirty years ago to 99% for a current design based on printed circuit boards. Furthermore, possible causes for the observed non-idealities are discussed. [ABSTRACT FROM AUTHOR]

Aims: Methanotrophic bacteria drive upland soil methane (CH) uptake. Land-use change often affects their activity, but the mechanisms involved are not well understood. We studied soil-atmosphere CH fluxes along a 120-year Norway spruce afforestation chronosequence on subalpine pasture, testing whether effects were related to shifts in the spatial niche of methanotrophs. Previous field data had shown that soil CH uptake increased with forest age, and that this effect was driven by decreased water filled pore space due to higher rainfall interception in the more developed canopies of older forest stands. Methods: The spatial distribution of methanotrophic activity was determined by CH-labelling followed by soil section preparation, aggregate size fractionation, aggregate erosion, and micro-autoradiographic imaging. Results: Uptake rates of CH measured in laboratory incubations of soil cores as well as their water contents largely followed the in situ measurements previously made in the field. CH assimilation was heterogeneously distributed, and occurred further down the soil profile in older forest that had a more developed organic layer that did not contribute to CH uptake. Assimilation was largest in 2-8 mm aggregates, and higher at the exterior than in the interior of aggregates. Conclusions: Our data indicates that differences in soil aggregation and related methanotrophic activities did not contribute substantially to higher CH uptake in older forest, mostly because aggregation did not change much with age. On a per mass basis, however, large aggregates contributed less to CH uptake due to their unfavorable surface to volume ratio. More generally, we argue that the (sub-)aggregate heterogeneity of soil microbial activity and diversity is underexplored, although it critically determines ecological interactions that drive ecosystem-level processes. [ABSTRACT FROM AUTHOR]

For the ionization of gas mixtures, several ionization sources can be coupled to an ion mobility spectrometer. Radioactive sources, e.g. beta radiators like Ni and H, are the most commonly used ionization sources. However, due to legal restrictions radioactive ionization sources are not applicable in certain applications. Non-radioactive alternatives are corona discharge ionization sources or photoionization sources. However, using an electron gun allows regulation of ion production rate, ionization time and recombination time by simply changing the operating parameters, which can be utilized to enhance the analytical performance of ion mobility spectrometers. In this work, the impact of an ionization source parameter variation on the ion mobility spectrum is demonstrated. Increasing the ion production rate, the amount of the generated ions increases leading to higher signal intensity while the noise remains constant. Thus, the signal to noise ratio can be increased, leading to better limits of detection. In a next step, the ion production rate is kept constant while the influence of ionization time on the ion mobility spectrum is investigated. It is shown, that varying the ionization time allows the determination of the reaction rate constants as additional information to the ion mobility. Furthermore, we show the prevention of discrimination processes by using short ionization times combined with an increased ion production rate. Thus, the limit of detection for benzene in presence of toluene is improved. Additionally, it is shown that using ion-ion recombination leads to the detection of the ion species with the highest proton affinity at higher recombination times while the low proton affine ions already recombined. Thus, the measurement of the ion mobility spectra at a defined recombination time allows a suppression of disturbing low proton affine substances. [ABSTRACT FROM AUTHOR]

Mass media frequently makes use of more than the visual image. With the exception of music, movie scores, and radio news however, media geographers have largely ignored the impact sound in media has on shaping and characterizing our experience of the world. We address this lack by showcasing two types of audio media: audio drama and audio-guided tours. The former will be explored with the help of the world's most successful audio drama series The Three Investigators to give a historical and theoretical introduction to the realm of sound within mass media. The latter will be illustrated using the example of the Austin Walking Tour as a representative production for city tourism. [ABSTRACT FROM AUTHOR]

One of the key experimental parameters of measurements using a drift tube ion mobility spectrometer is the drift voltage applied across its length, as it governs a multitude of processes during the ion drift. While the effect of the drift voltage on the resolving power has already been well-described, only little attention has been paid so far to developing an equally sophisticated model for the effect on the limits of detection. In this work, we extend our previous model for the resolving power and signal-to-noise-ratio of a drift tube ion mobility spectrometer operated at the resolving power optimal drift voltage to arbitrary drift voltages. It is shown that the deviation from this operating point can be completely described for any drift tube by using only the dimensionless factor β, which is defined as the ratio between the applied drift voltage and the resolving power optimal drift voltage. From these general equations, it can be shown that the signal-to-noise-ratio and therefore the limits of detection vary much more significantly with changing drift voltage than the resolving power. Thus, it is possible to apply a higher than resolving power optimal drift voltage to lower the limits of detection with only a slight loss of resolving power. E.g., a 47.5 % higher drift voltage is able to halve the limits of detection, but yields only 8 % resolving power loss. [ABSTRACT FROM AUTHOR]

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In numerous applications biomass or biochemically active substances, like pharmaceuticals, flavors or bio-ethanol, are produced in industrial-scale bioreactors. In order to ensure a constant and high quality and quantity of the particular product the biochemical environment within the reactor needs to be continuously controlled within narrow limits. Thus, sensitive sensor systems that allow continuous and preferably non-invasive monitoring of relevant parameters during the cultivation are required. In this work we present results of an analysis of exhaust gas of a bioprocess composed of growing phase and auto-inductive protein production phases of a recombinant Escherichia coli BL21 strain as model organism using a compact closed-loop ion mobility spectrometer (IMS) with gas chromatographic (GC) pre-separation. The used GC-IMS (in-house development) has a mobility resolution of about R = 90 (IMS drift time / peak width) and enables automatic sampling and analysis of the exhaust gas every 20 min. We compare the intensity of different IMS peaks with additional online and offline data like oxygen consumption, optical density or the fluorescence of a GFP-labeled protein which is produced by the organism after auto-induction. A great challenge in this context is to detect trace concentrations of possible precursors for a metabolic change or indicators for the efficiency of such a change in the presence of very high concentrations of water and compounds like acetone, ethanol and ammonia. Besides multiple peaks that show a significant and reproducible change during the cultivation we observe at least one peak that is assumed to be a precursor for the induction process. [ABSTRACT FROM AUTHOR]

Recently, we have published an analytical model describing the resolution and signal-to-noise-ratio of peaks present in an ion mobility spectrum acquired by a drift tube instrument. Based on this model, we designed a combination of a compact 10 cm long drift tube and a fast transimpedance amplifier achieving a resolution above 180. Here, we present results using an improved drift tube with slightly longer drift length of 15 cm and higher drift voltages, resulting in a resolution of R = 250 for the positive reactant ion peak and R = 230 for the negative reactant ion peak. By applying a deconvolution algorithm based on the Jansson method, a two- to three-fold separation improvement is possible in theory. However, as a larger resolution improvement than the initial resolution loss by diffusion may lead to erroneous results, we limited the resolution enhancement to 70 %, reaching a resolution of R = 425 for deconvolved spectra. [ABSTRACT FROM AUTHOR]

The development of novel effective immunotherapeutic agents and early clinical data hinting at significant activity in non-small cell lung cancer (NSCLC) has introduced yet another player in the field of management of advanced disease. At present, first-line cytotoxic chemotherapy is generally withheld pending results of molecular testing for any actionable genetic alteration that could lead to targeted treatment, and in their absence chemotherapy is prescribed as a default therapy. Phase III trials comparing head-to-head immune checkpoint inhibitors with standard platinum-based doublet chemotherapy are underway. Second-line chemotherapy is likewise being challenged in phase III trials, one of which having recently reported positive results in advanced squamous cell carcinoma. In tumors harboring actionable transforming genetic alterations such as EGFR mutations and ALK rearrangements, second- and third-generation inhibitors allow for multiple lines of targeted treatment beyond initial resistance, postponing the use of cytotoxic chemotherapy to very late lines of therapy. Chemotherapy as a longstanding but still present standard of care capable of prolonging survival, improving quality of life, and relieving symptoms sees its role increasingly restricted to clinical, immunological, and molecular subsets of patients where its activity and efficacy have never been tested prospectively. [ABSTRACT FROM AUTHOR]

A key component in the design of every drift tube ion mobility spectrometer (IMS) is the ion shutter which controls the injection of ions into the drift tube. Especially, compact drift tube IMS require very short injection pulses to achieve high resolution and therefore require fast ion shutters. Thus, it is important to find an ion shutter principle that can be readily scaled towards these short injection widths without causing major non-idealities in the injection process, such as drift field inhomogeneities, ion loss and ion discrimination by mobility. In this paper, we compare different ion shutter principles, foremost the Bradbury-Nielsen gate and a field switching design. It is shown through theoretical considerations and field simulations that the Bradbury-Nielsen shutter is more universally applicable and typically less complex for long injections widths but field inhomogeneities associated with its operating principle impede the scaling process. Thus, the currently less used field switching shutters will become the superior principle when very short injection widths are required, as this shutter principle allows for single digit microsecond widths. [ABSTRACT FROM AUTHOR]