Intrinsic Contamination Research Articles

Systematic review of healthcare-associated Burkholderia cepacia complex outbreaks: presentation, causes and outbreak control

SummaryBackgroundOver the past decades, the Burkholderia cepacia complex (BCC) has been linked to multiple healthcare-associated outbreaks. No systematic analysis of these outbreaks has been carried out to date. The aim of this study was to conduct a systematic review of reports on nosocomial BCC outbreaks.MethodsPublished studies from 1971 until 9/12/2019 presenting nosocomial BCC outbreaks were identified using Embase, Pubmed and abstracts from professional meetings.ResultsWe identified a total of 111 outbreak reports. Thirty-two percent of the affected institutions were academic hospitals and 43.8% community hospitals. The average outbreak duration was 198.6 ± 604.4 days. A total of 240 deaths (10% of the 2390 case patients) were reported but only 28 (1.2% of the 2390 case patients and 11.7% of the 240 deaths) were directly attributable to BCC. The source could be identified in 73.9% of the outbreaks; 53.2% were caused by contaminated medical solutions and medications, 12% were due to a contaminated disinfectant. In 28.2% of the outbreaks intrinsic product contamination was reported. Multidrug resistance was noted in 26.1% of the BCC strains. PFGE was the most frequently used typing method (43.2%) in the context of outbreak work-up.ConclusionMedical products are the most frequent source of BCC outbreaks, representing over half of the identified sources, with 12% of the outbreaks caused by disinfectant products. Intrinsic product contamination was detected frequently, suggesting a need for stricter regulation. While BCC-related mortality was low, our systematic review revealed significant heterogeneity in both investigations and reporting of BCC outbreaks.

The risk of infectious pathogens in breast-feeding, donated human milk and breast milk substitutes.

This review collates the published reports that focus on microbial and viral illnesses that can be transmitted by breast milk, donor milk and powdered infant formula (PIF). In this context, we attempt to define a risk framework encompassing those hazards, exposure scenarios, vulnerability and protective factors. A literature search was performed for reported cases of morbidity and mortality associated with different infant feeding modes. Exclusive breast-feeding is the recommended for infant feeding under 6 months, or failing that, provision of donated human milk. However, the use of PIF remains high despite its intrinsic and extrinsic risk of microbial contamination, as well as the potential for adverse physiological effects, including infant gut dysbiosis. Viable pathogen transmission via breast-feeding or donor milk (pasteurised and unpasteurised) is rare. However, transmission of HIV and human T-cell lymphotropic virus-1 is a concern for breast-feeding mothers, particularly for mothers undertaking a mixed feeding mode (PIF and breast-feeding). In PIF, intrinsic and extrinsic microbial contamination, such as Cronobacter and Salmonella, remain significant identifiable causes of infant morbidity and mortality. Disease transmission through breast-feeding or donor human milk is rare, most likely owing to its complex intrinsically protective composition of human milk and protection of the infant gut lining. Contamination of PIF and the morbidity associated with this is likely underappreciated in terms of community risk. A better system of safe donor milk sharing that also establishes security of supply for non-hospitalised healthy infants in need of breast milk would reduce the reliance on PIF.

Electrocatalytic Metallic Nanostructures Prepared By Electrorefining and Cathodic Corrosion

Metallic nanostructures (NS) due to their unique properties are often used as electrocatalytic electrode materials in energy conversion and storage as well as in sensing applications. Their common methods of preparation involve homogeneous synthesis and electrodeposition from solutions containing appropriate precursor and often reducing agent and capping agent (surfactant). The main drawbacks of these methods are restricted yield, waste production and often intrinsic contamination of the surface of obtained NS. Moreover, surface capping ligands affect electrocatalytic activity by hindrance of reactant access to the active sites.We propose a versatile method of preparation of bare (non-capped) mono- and multi-metallic (Au,1 Cu,2 Ag, Fe) NS by localized electrorefining of polycrystalline raw metals at high efficiency in a controlled manner. Catalytic activities of obtained NS towards oxygen reduction reaction (ORR) in alkaline media, hydrogen evolution (HER) and carbon dioxide reduction (CO2RR) to easily electrooxidizable fuels (formic acid and carbon monooxide) were analyzed by feedback mode scanning electrochemical microscopy (SECM). The morphology and specific activity of obtained NS depend on used support material (indium tin oxide (ITO) and glassy carbon) and other electrorefining parameters such as electrodeposition potential, source velocity and the composition of the electrolyte. The last parameter determines stoichiometry of Faradaic processes. Both gold and copper electrooxidation and electroreduction can follow one electron stoichiometry. ORR in alkaline media and CO2RR occur effectively on NS with highly developed surfaces, containing large number of defects, corners and edges, whereas HER occurs efficiently at crystallographic Cu facets. Bare gold NS also exhibit outstanding plasmonic properties. They were applied as support for surface-enhanced Raman spectroscopy (SERS) of single molecules providing enhancement factor >106.1 Another method of preparation of metallic nanostructures is cathodic corrosion. This approach for platinum was studied by Koper group.3 We used this procedure for platinum ultramicroelectrode treatment. Obtained Pt NS exhibit unique catalytic properties towards electrooxidation of glucose.

An EFT description of galaxy intrinsic alignments

We present a general perturbative effective field theory (EFT) description of galaxy shape correlations, which are commonly known as intrinsic alignments. This rigorous approach extends current analytical modelling strategies in that it only relies on the equivalence principle. We present our results in terms of three-dimensional statistics for two- and three-point functions of both galaxy shapes and number counts. In case of the two-point function, we recover the well-known linear alignment result at leading order, but also present the full next-to-leading order expressions. In case of the three-point function we present leading order results for all the auto- and cross-correlations of galaxy shapes and densities. We use a spherical tensor basis to decompose the tensor perturbations in different helicity modes, which allows us to make use of isotropy and parity properties in the correlators. Combined with the results on projection presented in a forthcoming companion paper, our framework is directly applicable to accounting for intrinsic alignment contamination in weak lensing surveys, and to extracting cosmological information from intrinsic alignments.

Sulfur contaminations inhibit depolymerization of Kraft lignin

Softwood Kraft lignin (s-KL) and methanol-fractionated extracted Kraft lignin (ex-KL) samples were thermally depolymerized via fractional (step-wise) pyrolysis at temperatures from 175 °C to 700 °C in an isothermal System for Thermal Diagnostic Studies (STDS) reactor. Major pyrolysis products include guaiacols, vanillins, phenols, syringols, and sulfur-containing compounds. Sulfur-containing compounds, as intrinsic contaminants (both adsorbed and covalently bound to KL matrixes), strongly inhibited the formation of pyrolysis products. The lesser the sulfur content in the KL matrix, the higher the yields of major pyrolysis products. The high yields and early release of tar components from pyrolysis of ex-KL were attributed to the initial pretreatment of s-KL (Soxhlet extraction in methanol) causing a decrease in sulfur content from 3.61% (s-KL) to 2.91% (ex-KL). Mechanistic explanations for the absence of sulfur-containing bio-oil products, inhibitory effect of sulfur-containing compounds, and the relatively high char content in depolymerization of both lignin substrates, are developed.

Clean Graphene Surfaces: A Force‐Engineered Lint Roller for Superclean Graphene (Adv. Mater. 43/2019)

A new approach to clean the surface of graphene is reported by Hailin Peng, Zhongfan Liu, and co-workers in article number 1902978, who use a force-engineered “lint roller” to selectively removing the graphene's intrinsic surface contaminants. The as-obtained super-clean graphene can be transferred to dielectric substrates with significantly reduced polymer residues, and it exhibits superior electronic and optical properties such as ultrahigh carrier mobility and low contact resistance.

Large-Area Synthesis of Superclean Graphene via Selective Etching of Amorphous Carbon with Carbon Dioxide.

Contamination commonly observed on the graphene surface is detrimental to its excellent properties and strongly hinders its application. It is still a great challenge to produce large-area clean graphene film in a low-cost manner. Herein, we demonstrate a facile and scalable chemical vapor deposition approach to synthesize meter-sized samples of superclean graphene with an average cleanness of 99 %, relying on the weak oxidizing ability of CO2 to etch away the intrinsic contamination, i.e., amorphous carbon. Remarkably, the elimination of amorphous carbon enables a significant reduction of polymer residues in the transfer of graphene films and the fabrication of graphene-based devices and promises strongly enhanced electrical and optical properties of graphene. The facile synthesis of large-area superclean graphene would open the pathway for both fundamental research and industrial applications of graphene, where a clean surface is highly needed.

Large‐Area Synthesis of Superclean Graphene via Selective Etching of Amorphous Carbon with Carbon Dioxide

AbstractContamination commonly observed on the graphene surface is detrimental to its excellent properties and strongly hinders its application. It is still a great challenge to produce large‐area clean graphene film in a low‐cost manner. Herein, we demonstrate a facile and scalable chemical vapor deposition approach to synthesize meter‐sized samples of superclean graphene with an average cleanness of 99 %, relying on the weak oxidizing ability of CO2 to etch away the intrinsic contamination, i.e., amorphous carbon. Remarkably, the elimination of amorphous carbon enables a significant reduction of polymer residues in the transfer of graphene films and the fabrication of graphene‐based devices and promises strongly enhanced electrical and optical properties of graphene. The facile synthesis of large‐area superclean graphene would open the pathway for both fundamental research and industrial applications of graphene, where a clean surface is highly needed.

Plastic-derived contaminants in sediments from the coastal zone of the southern Baltic Sea

Plastics may leach out harmful chemicals, such as plastic additives and monomers, to the environment. This study focused on three intrinsic plastic-derived contaminants, viz. bis(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), and styrene, based on surface (0–5 cm) sediment samples taken from transition areas located in the human-impacted coastal zone of the southern Baltic Sea. The concentrations of DEHP in the sediments from the Gulf of Gdańsk and the Szczecin Lagoon ranged from 38 to 228 ng/g d.w. and from 494 to 807 ng/g d.w., respectively. The levels of sedimentary BPA varied from <1 to 32 ng/g d.w., whereas styrene was not detected in any of the samples studied. Compared to worldwide data, the levels of plastic-derived contaminants in the sediments from the Gulf of Gdańsk and the Szczecin Lagoon were generally not high. However, according to sediment quality guidelines, some adverse environmental effects are probable.

Li-self doping effect on the LiAl5O8 luminescent properties

The influence of Li self-doping effect on the structural and optical properties of LiAl5O8 was investigated. X-ray diffraction (XRD) results indicated the samples present high crystalliny degree and single crystalline phase. Scanning Electron Microscopy (SEM) images showed nanosized particles disposed in agglomerates. X-ray Absorption Near Edge Spectroscopy (XANES) indicated that the Al local geometry is similar for both sets of samples, independent on the Li excess. X-ray Fluorescence (XRF) mapped intrinsic contaminants (Fe and Cr) from the precursors. Photoluminescence (PL) and X-ray Excited Optical Luminescence (XEOL) emission spectra presented broad bands and transitions associated with Fe3+, Cr3+ and defects from the host. XEOL excitation spectra presented positive edge and luminescent grow tendency with the increase of the excitation energy around the Al K-edge. The observed optical transitions by the excitation with X-rays, ultraviolet and visible were more expressive in the red/near infrared range.

Absolute Dating of Early Iron Objects from the Ancient Orient: Radiocarbon Dating of Luristan Iron Mask Swords

ABSTRACTLuristan Iron Mask Swords have been recovered mostly from illegal diggings in the 1920s. The about 90 known objects are characterized by a disk-shaped pommel on the top of the handle with two mounted bearded heads on two sides. According to the similarity in form and radiocarbon (14C) measurements on two swords from museum collections, an overall short production period was assumed around 1000 BC (Moorey 1991; Rehder 1991). Here we present the results of metallurgical analysis and 14C measurements for three newly acquired Luristan swords, which were donated to the Royal Museums of Art &amp; History, Brussels. Metallurgical analysis indicates an iron production via the bloomary furnace technique. Analyzed samples show large slag inclusions (Fayalite, Wüstite, glass) within a mostly ferritic and pearlitic iron. The carbon contents varied between 0.2 wt% to around 0.8 wt%). 14C measurements on thermally extracted carbon give 14C ages between 2800 BP–3360 BP (calibrated ∼1745 BC–900 BC). The reliability of the 14C measurements are discussed with respect to external (contamination during handling) and intrinsic contamination (e.g. fossil carbon sources during manufacture).

KiDS+GAMA: Intrinsic alignment model constraints for current and future weak lensing cosmology

We directly constrain the non-linear alignment (NLA) model of intrinsic galaxy alignments, analysing the most representative and complete flux-limited sample of spectroscopic galaxies available for cosmic shear surveys. We measure the projected galaxy position-intrinsic shear correlations and the projected galaxy clustering signal using high-resolution imaging from the Kilo Degree Survey (KiDS) overlapping with the GAMA spectroscopic survey, and data from the Sloan Digital Sky Survey. Separating samples by colour, we make no significant detection of blue galaxy alignments, constraining the blue galaxy NLA amplitude AIAB = 0.21−0.36+0.37 to be consistent with zero. We make robust detections (∼9σ) for red galaxies, with AIAR = 3.18−0.46+0.47, corresponding to a net radial alignment with the galaxy density field, and we find no evidence for any scaling of alignments with galaxy luminosity. We provide informative priors for current and future weak lensing surveys, an improvement over de facto wide priors that allow for unrealistic levels of intrinsic alignment contamination. For a colour-split cosmic shear analysis of the final KiDS survey area, we forecast that our priors will improve the constraining power on S8 and the dark energy equation of state w0, by up to 62% and 51%, respectively. Our results indicate, however, that the modelling of red/blue-split galaxy alignments may be insufficient to describe samples with variable central/satellite galaxy fractions.

A photoelectron study of annealing induced changes to workfunction and majority carrier type in pulsed laser deposited few layer WS2 films

Annealing few layer pulsed laser deposited WS2 films in sulfur increased the S/W ratio from 1.3 to 2.2, improved the mobility from 0.5 to 28 cm2 V−1 s−1, and switched the conductivity from n to p-type. The annealing induced n to p-type switch was confirmed by ultraviolet photoelectron spectroscopy which revealed a workfunction increase from 3.36 to 4.52 eV, a corresponding change in the Fermi level separation from the valence band edge, and a shift of the tungsten X-ray photoelectron spectrum to lower binding energy by ~ 1 eV. Current-voltage measurements indicated that charge injection from ohmic contacts was independent of the interfacial energy barrier, and was governed instead by tunneling from gap states associated with intrinsic point defects and surface contamination. The increased mobility with annealing is ascribed to improved stoichiometry and reduced incoherent scattering from point defects. The p-type conductivity is possibly due to excess sulfur in the form of interstitial ions.

Outbreak of fungemias by Sarocladium kiliense in eight public hospitals per intrinsic contamination of ondansetron intravenous

Sarocladium kiliense is a saprophyte fungus that can cause opportunistic infections associated to invasive procedures. We report a multi-hospital nosocomial outbreak of fungemias due to this agent. Patients with positive blood culture to this agent were studied after six bloodstream infections identified in three Chilean hospitals in July 2013 were reported to Ministry of Health National Infection and Prevention Control Program. In general, there were mild clinical manifestations, without deaths attributable to the infection. Epidemiological and micro-biological study identified 65 cases in 8 hospitals, mostly pediatric patients in chemotherapy. Initial studies of 94 different drugs and medical devices had negative results, until a second analysis of specific blisters and their pharmaceutical matrix selected by epidemiological criteria identified an intrinsic contamination of ondansetron blisters from a specific producer used in all the patients. A recall of contaminated ondansetron blisters was performed in all the country, after which the outbreak was contained. Surveillance and response of local and national infection prevention and control programs and laboratory support were key to control of a national multi-hospital common source outbreak due to contamination of a drug by an unusual fungus.

230 - Investigating and responding to contamination and sterility failures of cell-based therapies

Cell-based therapies and especially autologous therapy processing begin will the starting raw material, often by leukapheresis cell collection. Therefore it is known that intrinsic contamination at the beginning of processing batch is a real risk that must be adequately assessed. The rate or percentage of product contamination events may be similar to that found in the blood or platelet transfusion industry, or perhaps even higher such as in some peripheral blood progenitor stem cell processes. Therefore, process contamination in the manufacturing stream will likely be realized at some frequency requiring an investigation and response in the form of a deviation report with appropriate corrective and preventative action (CAPA). Sometimes the process contamination may stay hidden at undetectable or unobservable levels throughout early processing until after cell culture incubation phases. Proliferation of microbial contaminants that were previously at low-levels become significantly elevated raising additional risks for cross-contamination of other processes, and risks for patient safety, especially if the product is fresh with a short shelf-life. These factors plus risks for extrinsic contamination from the facility environment and operators involved in open processing results in a final cell product that may at times fail the sterility test specification. Therefore a robust, systematic procedure for investigation of, and responding to contamination events, including thorough and repeatable root cause analysis system, is a vital quality system element that should be in place.

Selection of electron (anti-)neutrinos at the T2K near detector ND280

The intrinsic electron neutrino contamination of the T2K neutrino beam provides the single largest background in the measurement of electron neutrino appearance in T2K. These electron neutrinos can be measured directly in the T2K near detector ND280. Measurements of the intrinsic electron (anti-)neutrino backgrounds from the anti-neutrino running are shown, including details on the event selections and rejection of the large background of muons, photons, protons and pions. The νe and beam compositions are then extracted and the rescaling parameters of the expected rate of νe and events are f(νe) = 1.250 ± 0.135(stats.) ± 0.122(syst.) and respectively.

Assessment of intrinsic vulnerability to the contamination of karst aquifer using the COP method in the Carste Lagoa Santa Environmental Protection Unit, Brazil

This study addresses the intrinsic groundwater vulnerability by using the COP method index and GIS technology on the karst-fissured aquifer of the Carste Lagoa Santa Protection Unit, located in the state of Minas Gerais, Brazil. This area has a great importance due to its rich paleontology, archeology and speleology. The region is groundwater dependent, and it has been suffering pressure by economic development. Therefore, it is important to identify vulnerable areas in which infiltration of contaminants is likely to happen. The main goal of this study was to create an intrinsic groundwater contamination vulnerability map (scale 1:50.000), which will be used to assist the implantation of groundwater monitoring net project in the area. The index vulnerability was evaluated by analyzing COP model parameters through geoprocessing techniques. However, in order to adapt the method to the studied area conditions, changes in frame and values of input parameter weights (lithology and slope/vegetation) were necessary. The outcomes showed five categories of groundwater contamination vulnerable zones: high to the highest vulnerability level (10.95%), moderated (58.77%) and low to the lowest vulnerability (30.28%). Despite the low percentage of high to the highest vulnerably level area, they must be considered by environmental managers due to strong relationship between superficial and groundwater in the area.

Methodological approach to assessment of groundwater contamination risk in an agricultural area

Water contamination by nitrates of agricultural origin is a major problem in Sardinia (Italy) where Nitrate Vulnerable Zones (NVZs) has been identified in the Arborea reclamation area (W. Sardinia), where intensive agriculture and farming are the mainstays of the local economy. Agricultural practices have seen an increase in the use of animal and chemical fertilizers for enhancing soil productivity. This, accompanied by the intensive use of groundwater resources for irrigation has led to the deterioration of groundwater quality, in areas particularly vulnerable to nitrate contamination. In the test area, the intrinsic nitrate contamination risk from agricultural sources has been evaluated through the combined application of the parametric methods, SINTACS, SI and IPNOA. Risk assessment, using vulnerability and hazard mapping, is considered a fundamental aspect of sustainable groundwater management. All parameters used in this risk assessment were prepared, classified, weighted and integrated in a GIS environment. Results show that nitrate concentrations are located in those areas where agricultural and livestock farming are concentrated. These results could, consequently, be interesting for future development and long term planning of groundwater protection management. The risk methods adopted, verified by comparing the distribution of nitrates in the groundwater with the different vulnerability classes, proved to be a valid tool. In fact the areas with nitrate concentration of more than 100mg/l coincide well with those at high risk identified by the model and the areas with nitrate concentration of less than 25mg/l closely match those areas with low and moderate risk.

Understanding and Controlling Cu-Catalyzed Graphene Nucleation: The Role of Impurities, Roughness, and Oxygen Scavenging.

The mechanism by which Cu catalyst pretreatments control graphene nucleation density in scalable chemical vapor deposition (CVD) is systematically explored. The intrinsic and extrinsic carbon contamination in the Cu foil is identified by time-of-flight secondary ion mass spectrometry as a major factor influencing graphene nucleation and growth. By selectively oxidizing the backside of the Cu foil prior to graphene growth, a drastic reduction of the graphene nucleation density by 6 orders of magnitude can be obtained. This approach decouples surface roughness effects and at the same time allows us to trace the scavenging effect of oxygen on deleterious carbon impurities as it permeates through the Cu bulk. Parallels to well-known processes in Cu metallurgy are discussed. We also put into context the relative effectiveness and underlying mechanisms of the most widely used Cu pretreatments, including wet etching and electropolishing, allowing a rationalization of current literature and determination of the relevant parameter space for graphene growth. Taking into account the wider CVD growth parameter space, guidelines are discussed for high-throughput manufacturing of “electronic-quality” monolayer graphene films with domain size exceeding 1 mm, suitable for emerging industrial applications, such as electronics and photonics.

Cosmology constraints from shear peak statistics in Dark Energy Survey Science Verification data

Shear peak statistics has gained a lot of attention recently as a practical alternative to the two point statistics for constraining cosmological parameters. We perform a shear peak statistics analysis of the Dark Energy Survey (DES) Science Verification (SV) data, using weak gravitational lensing measurements from a 139 deg$^2$ field. We measure the abundance of peaks identified in aperture mass maps, as a function of their signal-to-noise ratio, in the signal-to-noise range $0<\mathcal S / \mathcal N<4$. To predict the peak counts as a function of cosmological parameters we use a suite of $N$-body simulations spanning 158 models with varying $\Omega_{\rm m}$ and $\sigma_8$, fixing $w = -1$, $\Omega_{\rm b} = 0.04$, $h = 0.7$ and $n_s=1$, to which we have applied the DES SV mask and redshift distribution. In our fiducial analysis we measure $\sigma_{8}(\Omega_{\rm m}/0.3)^{0.6}=0.77 \pm 0.07$, after marginalising over the shear multiplicative bias and the error on the mean redshift of the galaxy sample. We introduce models of intrinsic alignments, blending, and source contamination by cluster members. These models indicate that peaks with $\mathcal S / \mathcal N>4$ would require significant corrections, which is why we do not include them in our analysis. We compare our results to the cosmological constraints from the two point analysis on the SV field and find them to be in good agreement in both the central value and its uncertainty. We discuss prospects for future peak statistics analysis with upcoming DES data.