181. Potential Benefit of Masking and other COVID-19 Infection Prevention Measures on Late-Onset Infections in the NICU

Background

Incidence of blood stream infections (BSI) among NICU admissions remains high, with associated mortality and morbidity. Due to COVID-19, there are increased infection prevention (IP) measures in NICUs including universal masking for all healthcare workers and families, social distancing, visitation restrictions, and increased attention to hand hygiene. These measures may also affect late-onset infection rates and offer understanding of novel interventions for prevention.

Methods

We examined infection rates during the 24 months prior to implementation of COVID-19 IP measures (PRE-period) compared to the months after implementation from April 2020 (POST-period). Late-onset infections were defined as culture-confirmed infection of the blood, urine, or identification of respiratory viral pathogens. An interrupted time series analysis of infection per 1000 patient days was performed based on a change-point Poisson regression with a lagged dependent variable and the number of patient days used as offsets. Each month was treated as independent with additional analysis using an observation-driven model to account for serial dependence.

Results

Multicenter analysis to date included all infants cared for at three centers (Level 3 and 4) from 2018-2020. Monthly BSI rates decreased in the POST-period at the three centers (Figure 1). At all centers actual BSI rate was lower than the expected rate in the POST-period (Figure 2). The combined BSI rate per 1000 patient days was 41% lower compared to the rate prior to implementation (95% CI, 0.42 to 0.84, P=0.004) (Table 1). In subgroup analysis by birthweight, infants< 1000g had a 39% reduction in BSI (P=0.023), for1000-1500g patients there was a 44% reduction (P=0.292) and in those > 1500g there was a 53% reduction (0.083).

Figure 1. PRE and POST MASKING and other COVID Infection Prevention Measures and Monthly BSI Rates.

Figure 2. PRE and POST MASKING and other COVID infection prevention measures and BSI Trends.

At all centers actual BSI rate was lower than the expected rate for that center in the POST period. UVA and Duke showed a baseline decrease and Pennsylvania Hospital showed a downward trend in infection rates. There was an approximate decrease in expected bloodstream infection events at Pennsylvania Hospital by 7 events, at UVA by 22 events and at Duke by 23 events. Overall, all three centers saw a decrease in their expected infections after COVID-19 infection prevention measures were implemented.

Table 1. Percent reduction in Bloodstream Infection at each center.

Conclusion

In this preliminary analysis, we found a reduction of BSI after the implementation of COVID-19 infection prevention measures. Additionally, there were fewer viral infections, though there were a limited number of episodes. Further analyses of multicenter data and a larger number of patients will elucidate the significance of these findings and the role some of these IP measures such as universal masking may have in infection prevention in the NICU.

Disclosures

All Authors: No reported disclosures

Olivine-rich achondrites from Vesta and the missing mantle problem

Mantles of rocky planets are dominantly composed of olivine and its high-pressure polymorphs, according to seismic data of Earth's interior, the mineralogy of natural samples, and modelling results. The missing mantle problem represents the paucity of olivine-rich material among meteorite samples and remote observation of asteroids, given how common differentiated planetesimals were in the early Solar System. Here we report the discovery of new olivine-rich meteorites that have asteroidal origins and are related to V-type asteroids or vestoids. Northwest Africa 12217, 12319, and 12562 are dunites and lherzolite cumulates that have siderophile element abundances consistent with origins on highly differentiated asteroidal bodies that experienced core formation, and with trace element and oxygen and chromium isotopic compositions associated with the howardite-eucrite-diogenite meteorites. These meteorites represent a step towards the end of the shortage of olivine-rich material, allowing for full examination of differentiation processes acting on planetesimals in the earliest epoch of the Solar System.

The impact and recovery of asteroid 2018 LA

The June 2, 2018, impact of asteroid 2018 LA over Botswana is only the second asteroid detected in space prior to impacting over land. Here, we report on the successful recovery of meteorites. Additional astrometric data refine the approach orbit and define the spin period and shape of the asteroid. Video observations of the fireball constrain the asteroid's position in its orbit and were used to triangulate the location of the fireball's main flare over the Central Kalahari Game Reserve. 23 meteorites were recovered. A consortium study of eight of these classifies Motopi Pan as a HED polymict breccia derived from howardite, cumulate and basaltic eucrite, and diogenite lithologies. Before impact, 2018 LA was a solid rock of ~156 cm diameter with high bulk density ~2.85 g/cm³, a relatively low albedo pv ~ 0.25, no significant opposition effect on the asteroid brightness, and an impact kinetic energy of ~0.2 kt. The orbit of 2018 LA is consistent with an origin at Vesta (or its Vestoids) and delivery into an Earth-impacting orbit via the v₆ resonance. The impact that ejected 2018 LA in an orbit towards Earth occurred 22.8 ± 3.8 Ma ago. Zircons record a concordant U-Pb age of 4563 ± 11 Ma and a consistent ²⁰⁷Pb/²⁰⁶Pb age of 4563 ± 6 Ma. A much younger Pb-Pb phosphate resetting age of 4234 ± 41 Ma was found. From this impact chronology, we discuss what is the possible source crater of Motopi Pan and the age of Vesta's Veneneia impact basin.

The fall, recovery, classification, and initial characterization of the Hamburg, Michigan H4 chondrite

The Hamburg meteorite fell on January 16, 2018, near Hamburg, Michigan, after a fireball event widely observed in the U.S. Midwest and in Ontario, Canada. Several fragments fell onto frozen surfaces of lakes and, thanks to weather radar data, were recovered days after the fall. The studied rock fragments show no or little signs of terrestrial weathering. Here, we present the initial results from an international consortium study to describe the fall, characterize the meteorite, and probe the collision history of Hamburg. About 1 kg of recovered meteorites was initially reported. Petrology, mineral chemistry, trace element and organic chemistry, and O and Cr isotopic compositions are characteristic of H4 chondrites. Cosmic ray exposure ages based on cosmogenic ³He, ²¹Ne, and ³⁸Ar are ~12 Ma, and roughly agree with each other. Noble gas data as well as the cosmogenic ¹⁰Be concentration point to a small 40-60 cm diameter meteoroid. An ⁴⁰Ar-³⁹Ar age of 4532 ± 24 Ma indicates no major impact event occurring later in its evolutionary history, consistent with data of other H4 chondrites. Microanalyses of phosphates with LA-ICPMS give an average Pb-Pb age of 4549 ± 36 Ma. This is in good agreement with the average SIMS Pb-Pb phosphate age of 4535.3 ± 9.5 Ma and U-Pb Concordia age of 4535 ± 10 Ma. The weighted average age of 4541.6 ± 9.5 Ma reflects the metamorphic phosphate crystallization age after parent body formation in the early solar system.

Short Note on the Density of States in 3D Weyl Semimetals

The average density of states in a disordered three-dimensional Weyl system is discussed in the case of a continuous distribution of random scattering. Our results clearly indicate that the average density of states does not vanish, reflecting the absence of a critical point for a metal-insulator transition. This calculation supports recent suggestions of an avoided quantum critical point in the disordered three-dimensional Weyl semimetal. However, the effective density of states can be very small such that the saddle-approximation with a vanishing density of states might be valid for practical cases.

Silica-rich volcanism in the early solar system dated at 4.565 Ga

The ranges in chemical composition of ancient achondrite meteorites are key to understanding the diversity and geochemical evolution of planetary building blocks. These achondrites record the first episodes of volcanism and crust formation, the majority of which are basaltic. Here we report data on recently discovered volcanic meteorite Northwest Africa (NWA) 11119, which represents the first, and oldest, silica-rich (andesitic to dacitic) porphyritic extrusive crustal rock with an Al-Mg age of 4564.8 ± 0.3 Ma. This unique rock contains mm-sized vesicles/cavities and phenocrysts that are surrounded by quench melt. Additionally, it possesses the highest modal abundance (30 vol%) of free silica (i.e., tridymite) compared to all known meteorites. NWA 11119 substantially widens the range of volcanic rock compositions produced within the first 2.5-3.5 million years of Solar System history, and provides direct evidence that chemically evolved crustal rocks were forming on planetesimals prior to the assembly of the terrestrial planets.

Diagnose und Therapie von Festination und Freezing

Motorische Blockaden während des Gehens sind als eine episodisch auftretende Störung der Ganginitiierung und des Lokomotionserhalts bei Parkinsonsyndromen und zentralen Gangstörungen definiert. Phänomenologisch werden Festination, trembling-in-place und total akinesia als Freezing-Formen unterschieden. Fünf differente Gangsituationen wurden als klassische Provokatoren für Freezing-Episoden benannt. Um eine Testung durch einen Beobachter klinisch einfach und aussagekräftig durchführen zu können, haben wir ein neues Testinstrument, den Freezing-ofgait-Score (FOG-Score) entwickelt, der im klinischen Alltag erprobt wird. Freezing bei Parkinsonpatienten ist meist dopasensitiv, kann aber auch im On-Zustand des Patienten auftreten und ist dann schwer zu therapieren.Wir diskutieren standardisierte Therapieschemata für Patienten mit On-Freezing, die wir an unserem Zentrum entwickelt haben.

Myeloid protein tyrosine phosphatase 1B (PTP1B) deficiency protects against atherosclerotic plaque formation in the ApoE-/- mouse model of atherosclerosis with alterations in IL10/AMPKα pathway

Objective

Cardiovascular disease (CVD) is the most prevalent cause of mortality among patients with Type 1 or Type 2 diabetes, due to accelerated atherosclerosis. Recent evidence suggests a strong link between atherosclerosis and insulin resistance due to impaired insulin receptor (IR) signaling. Moreover, inflammatory cells, in particular macrophages, play a key role in pathogenesis of atherosclerosis and insulin resistance in humans. We hypothesized that inhibiting the activity of protein tyrosine phosphatase 1B (PTP1B), the major negative regulator of the IR, specifically in macrophages, would have beneficial anti-inflammatory effects and lead to protection against atherosclerosis and CVD.

Methods

We generated novel macrophage-specific PTP1B knockout mice on atherogenic background (ApoE^−/−/LysM-PTP1B). Mice were fed standard or pro-atherogenic diet, and body weight, adiposity (echoMRI), glucose homeostasis, atherosclerotic plaque development, and molecular, biochemical and targeted lipidomic eicosanoid analyses were performed.

Results

Myeloid-PTP1B knockout mice on atherogenic background (ApoE^−/−/LysM-PTP1B) exhibited a striking improvement in glucose homeostasis, decreased circulating lipids and decreased atherosclerotic plaque lesions, in the absence of body weight/adiposity differences. This was associated with enhanced phosphorylation of aortic Akt, AMPKα and increased secretion of circulating anti-inflammatory cytokine interleukin-10 (IL-10) and prostaglandin E2 (PGE₂), without measurable alterations in IR phosphorylation, suggesting a direct beneficial effect of myeloid-PTP1B targeting.

Conclusions

Here we demonstrate that inhibiting the activity of PTP1B specifically in myeloid lineage cells protects against atherosclerotic plaque formation, under atherogenic conditions, in an ApoE^−/− mouse model of atherosclerosis. Our findings suggest for the first time that macrophage PTP1B targeting could be a therapeutic target for atherosclerosis treatment and reduction of CVD risk.

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PTP1B inhibition as therapy for atherosclerosis/cardiovascular disease is proposed.

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Myeloid-PTP1B mice on ApoE^−/− background (ApoE^−/−/LysM-PTP1B) were generated.

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ApoE^−/−/LysM-PTP1B had improved glucose homeostasis with no body weight differences.

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ApoE^−/−/LysM-PTP1B had lower lipids and protection against atherosclerotic plaques.

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Protection was via a PGE₂/IL-10/AMPKα mechanism.

Superior functional outcome after femoral derotation osteotomy according to gait analysis in cerebral palsy

The femoral derotation osteotomy (FDO) is seen as the golden standard treatment in children with cerebral palsy and internal rotation gait. Variable outcomes with cases of over- and undercorrection mainly in the less involved patients have been reported. The determination of the amount of derotation is still inconsistent. 138 patients (age: 11 (± 3.3) years) with cerebral palsy and internal rotation gait were examined pre- and 1 year postoperatively after distal or proximal FDO, using standardized clinical examination and 3D gait analysis. Three groups were defined retrospectively depending on the amount of derotation in relation to the mean hip rotation in stance (MHR) during gait analysis: Group A (derotation angle > MHR + 10°), Group B (derotation angle = MHR ± 10°), Group C (derotation angle <MHR-10°), and compared according to their postoperative mean hip rotation. ANOVA with Bonferroni post hoc test was used for statistics (p < 0.05). Group B had the greatest benefit with the highest rate (86%) of good results (postoperative MHR = ± 15°). In contrast there were 14% cases of overcorrection and 5% cases of deterioration in Group A with only 81% good results and only 79% good results in Group C. It can be concluded, that it is less likely to have unsatisfactory outcomes if the amount of FDO is defined according to the findings of gait analysis compared with clinical examination.

Chelyabinsk airburst, damage assessment, meteorite recovery, and characterization

The asteroid impact near the Russian city of Chelyabinsk on 15 February 2013 was the largest airburst on Earth since the 1908 Tunguska event, causing a natural disaster in an area with a population exceeding one million. Because it occurred in an era with modern consumer electronics, field sensors, and laboratory techniques, unprecedented measurements were made of the impact event and the meteoroid that caused it. Here, we document the account of what happened, as understood now, using comprehensive data obtained from astronomy, planetary science, geophysics, meteorology, meteoritics, and cosmochemistry and from social science surveys. A good understanding of the Chelyabinsk incident provides an opportunity to calibrate the event, with implications for the study of near-Earth objects and developing hazard mitigation strategies for planetary protection.

Transitional Care Partners: a hospital-to-home support for older adults and their caregivers

PURPOSE

To describe the development, implementation, and preliminary results of the Transitional Care (TLC) Partners, a clinical demonstration program that supports the transition from hospital to home of older veterans.

DATA SOURCES

Hospital records of TLC patients to track their hospital and emergency department visits before and after the TLC Partners enrollment. Caregivers of patients completed Preparedness in Caregiving and the Short Form Zarit Burden Scale during the first week of the TLC Partners enrollment and on the week when the services ended.

CONCLUSIONS

The proportion of patients with one or more emergency department visits and rehospitalization is consistently lower among TLC patients compared to non-TLC patients at 30 and 60 days of hospital discharge. The mean preparedness and burden scores before and after the program essentially remained the same.

IMPLICATIONS FOR PRACTICE

The description of the implementation of the TLC Partners offers an example of how nurse practitioner-led interprofessional care models can be adapted to the needs of specific healthcare systems, and how they can be monitored to evaluate their reach, effectiveness, and fidelity to the core components of proved care models.

Mobile stroke unit for diagnosis-based triage of persons with suspected stroke

BACKGROUND

In this feasibility study, we tested whether prehospital diagnostic stroke workup enables rational decision-making regarding treatment and the target hospital in persons with suspected stroke.

METHODS

A mobile stroke unit that delivers imaging (including multimodal brain imaging with CT angiography and CT perfusion), point-of-care-laboratory analysis, and neurologic expertise directly at the emergency site was analyzed for its use in prehospital diagnosis-based triage of suspected stroke patients.

RESULTS

We present 4 complementary cases with suspected stroke who underwent prehospital diagnostic workup that enabled direct diagnosis-based treatment decisions and reliable triage regarding the most appropriate medical facility for that individual, e.g., a primary hospital vs specialized centers of a tertiary hospital.

CONCLUSIONS

This preliminary report demonstrates the feasibility of prehospital diagnostic stroke workup for immediate etiology-specific decision-making regarding the necessary time-sensitive stroke treatment and the most appropriate target hospital.

Tunable band gap in hydrogenated quasi-free-standing graphene

We show by angle-resolved photoemission spectroscopy that a tunable gap in quasi-free-standing monolayer graphene on Au can be induced by hydrogenation. The size of the gap can be controlled via hydrogen loading and reaches approximately 1.0 eV for a hydrogen coverage of 8%. The local rehybridization from sp(2) to sp(3) in the chemical bonding is observed by X-ray photoelectron spectroscopy and X-ray absorption and allows for a determination of the amount of chemisorbed hydrogen. The hydrogen induced gap formation is completely reversible by annealing without damaging the graphene. Calculations of the hydrogen loading dependent core level binding energies and the spectral function of graphene are in excellent agreement with photoemission experiments. Hydrogenation of graphene gives access to tunable electronic and optical properties and thereby provides a model system to study hydrogen storage in carbon materials.

Whole blood-derived miRNA profiles as potential new tools for ovarian cancer screening

BACKGROUND

Screening is an unsolved problem for ovarian cancer (OvCA). As late detection is equivalent to poor prognosis, we analysed whether OvCA patients show diagnostically meaningful microRNA (miRNA) patterns in blood cells.

METHODS

Blood-borne whole miRNome profiles from 24 patients with OvCA and 15 age- and sex-matched healthy controls were biostatistically evaluated.

RESULTS

Student's t-test revealed 147 significantly deregulated miRNAs before and 4 after Benjamini-Hochberg adjustment. Although these included miRNAs already linked to OvCA (e.g., miR-16, miR-155), others had never before been connected to specific diseases. A bioinformatically calculated miRNA profile allowed for discrimination between blood samples of OvCA patients and healthy controls with an accuracy of >76%. When only cancers of the serous subtype were considered and compared with an extended control group (n=39), accuracy, specificity and sensitivity all increased to >85%.

CONCLUSION

Our proof-of-principle study strengthens the hypothesis that neoplastic diseases generate characteristic miRNA fingerprints in blood cells. Still, the obtained OvCA-associated miRNA pattern is not yet sensitive and specific enough to permit the monitoring of disease progression or even preventive screening. Microarray-based miRNA profiling from peripheral blood could thus be combined with other markers to improve the notoriously difficult but important screening for OvCA.

Occurrence of biogenic amine-forming lactic acid bacteria in wine and cider

A collection of 810 lactic acid bacteria (LAB) strains isolated from wine and cider was screened for potential biogenic amine (BA) producers by combining molecular and phenotypic approaches. A newly developed multiplex PCR method allowed for the simultaneous detection of four genes involved in the production of histamine (histidine decarboxylase, hdc), tyramine (tyrosine decarboxylase, tyrdc) and putrescine (via either ornithine decarboxylase, odc, or agmatine deiminase, agdi) while TLC and HPLC analysis allowed for BA-production determination. One hundred and fifty-eight LAB strains were monitored by the molecular/phenotypic double approach and revealed a good correlation between genotypic and phenotypic data. Eighteen per cent of the tested strains were positive for at least one BA target gene with up to three detected simultaneously, in particular amongst Lactobacillus brevis and Lactobacillus hilgardii isolates for the tyrdc and agdi genes. The most frequent gene corresponded to the agdi gene detected in 112 strains (14% of all LAB strains) of 10 different LAB species. The tyrdc gene was detected in 67 strains represented by 7 different LAB species (8% overall), especially those isolated from wine. Lower levels of hdc(+) (2% of strains) and especially odc(+) (0.5% of strains) strains were observed. Interestingly, species that have never been described to carry BA-producing pathway genes were identified in this study. Furthermore, only one cadaverine-producer was detected and corresponded to Lactobacillus 30a, a collection strain not found in fermented beverages, although cadaverine is commonly detected in wines.

Random-gap model for graphene and graphene bilayers

The effect of a randomly fluctuating gap, created by a random staggered potential, is studied in a monolayer and a bilayer of graphene. The density of states, the one-particle scattering rate, and the transport properties (diffusion coefficient and conductivity) are calculated at the neutrality point. All of these quantities vanish at a critical value of the average staggered potential, signaling a continuous transition to an insulating behavior. Transport quantities are directly linked to the one-particle scattering rate. Although the behavior is qualitatively the same in mono- and bilayers, the effect of disorder is much stronger in the latter.

Nonlinear electromagnetic response of graphene: frequency multiplication and the self-consistent-field effects

Graphene is a recently discovered carbon-based material with unique physical properties. This is a monolayer of graphite, and the two-dimensional electrons and holes in it are described by the effective Dirac equation with a vanishing effective mass. As a consequence, the electromagnetic response of graphene is predicted to be strongly nonlinear. We develop a quasi-classical kinetic theory of the nonlinear electromagnetic response of graphene, taking into account the self-consistent-field effects. The response of the system to both harmonic and pulse excitation is considered. The frequency multiplication effect, resulting from the nonlinearity of the electromagnetic response, is studied under realistic experimental conditions. The frequency upconversion efficiency is analyzed as a function of the applied electric field and parameters of the samples. Possible applications of graphene in terahertz electronics are discussed.

Suppression of magnetotransport in strongly disordered graphene

A tight-binding model with randomly fluctuating atomic positions is studied to discuss the effect of strong disorder in graphene. We employ a strong-disorder expansion for the transport quantities and find a diffusive behavior, where the conductivity is decreasing with increasing disorder. For sufficiently strong disorder the magnetic field drops out of the diffusion coefficient and the conductivity. This signals a strong suppression of magnetotransport effects, a result which is consistent with recent experimental observations by Morozov et al.

New electromagnetic mode in graphene

A new, weakly damped, transverse electromagnetic mode is predicted in graphene. The mode frequency omega lies in the window 1.667<[see text]omega/micro < 2, where micro is the chemical potential, and can be tuned from radio waves to the infrared by changing the density of charge carriers through a gate voltage.

Second interims analysis of the ARA Plus study: Breast Cancer (BC) adjuvant chemotherapy (CT) with and without darbepoetin- alpha, analysis of serious adverse events

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Background: TAC is one of the most effective regimens. It‘s associated with higher frequency of anemia and chemotherapy-induced neutropenia (CIN). The erythropoiesis stimulating factor (ESF) support of chemotherapy, its complications and survival effect remain unclear. Erythropoetins do prevent chemotherapy-associated anemia (CAA) and subsequent fatigue syndrome but their potential influence on survival is still unclear. One aim of this analysis is to investigate the correlation between CT, growth factor support and toxicity (SAE‘s). Methods: This ARA Plus phase III trial compare chemotherapy ±ARA in breast cancer patients >18 years old, with positive lymph nodes and with M0 disease. Pts get six cycles of of 5-fluoro-uracile 500mg/m2, epirubicine 100mg/m2 and cyclophosphamide 500mg/m2, (FEC, Bonneterre), 3-weekly or six cycles of docetaxcel 75mg/m2, adriamycin 50mg/m2 and cyclophosphamide 500mg/m2, (TAC, BCIRG) and are randomized to ARA 500μg q3w if Hb<13 g/dl or standard support care. Here arte the results. of SAE‘S. Results: A total of 756 pts (373 + ARA/383 -ARA) from 53 sites were enrolled since January 2004, there are 1234 pts. planned up to January 2008. 185 serious adverse events (SAE) are reported. Of these 185 SAE’s 100 (54%) had an ARA-therapy. Most frequent SAE’s were: leucopenia, febrile neutropenia, thrombosis and infections. In 9 (31%) out of the 29 febrile neuropenia SAE’s, ARA was given. 30 thromboses were reported (23+ARA/7-ARA s.) but only 10 at the verty time ARA was given. In 31 severe infections 16 (51,6%; n.s.) were reported in patients receiving ARA Therapy. From 43 patients with intestinal SAE‘s like Diarrhea/Mucositis/Nausea to 30 pts. (69,8 %) ARA eas given. Conclusions: The combination of CT and ARA is safe concerning febrile neutropenia and furthermore appears to be protective factor of this SAE when combined with TAC. There seem to be more SAE‘s concerning thrombosis and intestinal difficulties.These results allow to hypothesize that ARA therapy is associated with higher toxicity concerning thrombosis which could make the use of heparin necessary but on the other side it shows significant reduced neutropenia.

No significant financial relationships to disclose.

Robust transport properties in graphene

Two-dimensional Dirac fermions are used to discuss quasiparticles in graphene in the presence of impurity scattering. Transport properties are completely dominated by diffusion. This may explain why recent experiments did not find weak localization in graphene. The diffusion coefficient of the quasiparticles decreases strongly with increasing strength of disorder. Using the Kubo formalism, however, we find a robust minimal conductivity that is independent of disorder. This is a consequence of the fact that the change of the diffusion coefficient is fully compensated by a change of the number of delocalized quasiparticle states.

Isotopic compositions of cometary matter returned by Stardust

Hydrogen, carbon, nitrogen, and oxygen isotopic compositions are heterogeneous among comet 81P/Wild 2 particle fragments; however, extreme isotopic anomalies are rare, indicating that the comet is not a pristine aggregate of presolar materials. Nonterrestrial nitrogen and neon isotope ratios suggest that indigenous organic matter and highly volatile materials were successfully collected. Except for a single (17)O-enriched circumstellar stardust grain, silicate and oxide minerals have oxygen isotopic compositions consistent with solar system origin. One refractory grain is (16)O-enriched, like refractory inclusions in meteorites, suggesting that Wild 2 contains material formed at high temperature in the inner solar system and transported to the Kuiper belt before comet accretion.

Comet 81P/Wild 2 Under a Microscope

The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains an abundance of silicate grains that are much larger than predictions of interstellar grain models, and many of these are high-temperature minerals that appear to have formed in the inner regions of the solar nebula. Their presence in a comet proves that the formation of the solar system included mixing on the grandest scales.

Reduced Cellular Toxicity of a New Silver-Containing Antimicrobial Dressing and Clinical Performance in Non-Healing Wounds

Bacterial colonisation of wounds may delay wound healing. Modern silver-containing dressings are antimicrobial, yet cellular toxicity is a serious side-effect. We provide data for a newly formulated silver-containing ointment dressing, Atrauman Ag, for antimicrobial activity and cytotoxicity. Atrauman Ag effectively killed a panel of commensal skin as well as pathogenic bacterial strains while cytotoxicity for HaCaT keratinocytes was only around 10%. With these favourable in vitro tests, Atrauman Ag was analysed in 86 patients with traumatic and non-healing wounds of different aetiologies. The wound state was evaluated for 3 subsequent dressing changes. The slough score was reduced from 59.2 to 35.8%, granulation tissue increased from 27 to 40% and epithelialisation went up from 12.1 to 24%. We conclude that Atrauman Ag has a superior profile of antimicrobial activity over cellular toxicity and the low silver ion release rate may prevent interference with wound-healing mechanisms.