Cosmic dust impacts on the Hubble Space Telescope

Exposure of the Hubble Space Telescope to space in low Earth orbit resulted in numerous hypervelocity impacts by cosmic dust (micrometeoroids) and anthropogenic particles (orbital debris) on the solar arrays and the radiator shield of the Wide Field and Planetary Camera 2, both subsequently returned to Earth. Solar cells preserve residues from smaller cosmic dust (and orbital debris) but give less reliable information from larger particles. Here, we present images and analyses from electron, ion and X-ray fluorescence microscopes for larger impact features (millimetre- to centimetre-scale) on the radiator shield. Validated by laboratory experiments, these allow interpretation of composition, probable origin and likely dimensions of the larger impactors. The majority (~90%) of impacts by grains greater than 50 μm in size were made by micrometeoroids, dominated by magnesium- and iron-rich silicates and iron sulfides, metallic iron-nickel and chromium-rich spinel similar to that in ordinary chondrite meteorites of asteroid origin. Our re-evaluation of the largest impact features shows substantially fewer large orbital debris impacts than reported by earlier authors. Mismatch to the NASA ORDEM and ESA MASTER models of particle populations in orbit may be partly due to model overestimation of orbital debris flux and underestimation of larger micrometeoroid numbers. This article is part of the theme issue 'Dust in the Solar System and beyond'.

A unique CO-like micrometeorite hosting an exotic Al-Cu-Fe-bearing assemblage - close affinities with the Khatyrka meteorite

We report the discovery of a unique micrometeorite, containing an exotic Al-Cu-Fe alloy composed of two intermixed phases: khatyrkite (CuAl₂) and stolperite (CuAl) and both containing minor Fe (<1.4 wt%). These phases are dendritic and rapidly co-crystallized at the binary system's peritectic (~550 °C). The host micrometeorite is an otherwise typical S-type micro-porphyritic cosmic spherule containing relict olivine (Fo76-90, Cr₂O₃: 0.01-0.56 wt%, MnO: 0.03-0.32 wt% and CaO: 0.09-0.22 wt%) and a cumulate layered texture. These properties suggest the micrometeorite is derived from a carbonaceous chondrite (best matched to a CO chondrite) and entered the atmosphere a high speed (~16 kms^-1), implying an origin from a highly eccentric orbit. This particle represents the second independent discovery of naturally occurring intermetallic Al-Cu-Fe alloys and is thus similar to the previously reported Khatyrka meteorite - a CV chondrite containing near-identical alloys and the only known natural quasicrystals. We did not observe quasicrystalline phases in this micrometeorite, likely due to the low amounts of Fe in the alloy, insufficient to stabilize quasicrystals. Our discovery confirms the existence of Al-Cu-Fe intermetallic alloys on chondritic parent bodies. These unusual phases require a currently unexplained formation process, we tentatively suggest this could represent the delivery of exotic interstellar material to the inner solar system via impact.

Clinicians' perceptions of the quality of outsourced radiology and actions taken around perceived imaging errors in practice

OBJECTIVES

Outsourcing of radiological reporting services has fundamentally altered communication between radiologists and clinicians in clinical decision making, which relies heavily on diagnostic imaging. The aim of this study was to understand clinicians' perspectives and experiences of interpretation of outsourced reports in clinical practice, if the author of imaging reports matters to clinicians, and actions taken to deal with perceived errors.

METHODS

A printed survey was distributed to a purposive sample of 50 of the 250 senior medical and surgical staff of a large National Health Service hospital in the UK who regularly engaged with the Radiology Department between May and October 2017, representing 20% of this hospital workforce. The survey consisted of ten questions examining clinicians' opinions on radiology reporting, with comment options to encourage respondents to give further detail. Participants were requested to return the survey to the study investigators.

RESULTS

The survey elicited a 100% response rate (n = 50). A constant comparative framework was used to guide analysis, revealing themes relevant to the ongoing inter-professional relationship between clinicians and radiologists. The disparity between in-house and externally sourced radiology reports and underlying issues of trust surrounding outsourced reports were the most significant themes identified.

CONCLUSIONS

This study found outsourcing of radiology reporting needs multi-disciplinary team availability regarding the interpretation and discussions around capacity for effective communication. It raises important issues around often under-acknowledged additional workloads imposed on in-house radiologists. There are financial and pragmatic clinical aspects in pathways of radiology practice which require further research and examination.

KEY POINTS

• Utilisation of outsourcing is increasing in practice in response to imaging demands. • Outsourcing increases departmental primary reporting capacity but may increase the workload of the local radiologist. • The development of strategies for outsourcing examinations may lessen demands on the in-house workforce.

The crystal structure of cesbronite, Cu3TeO4(OH)4: a novel sheet tellurate topology

The crystal structure of cesbronite has been determined using single-crystal X-ray diffraction and supported by electron-microprobe analysis, powder diffraction and Raman spectroscopy. Cesbronite is orthorhombic, space group Cmcm, with a = 2.93172 (16), b = 11.8414 (6), c = 8.6047 (4) Å and V = 298.72 (3) Å3. The chemical formula of cesbronite has been revised to CuII 3TeVIO4(OH)4 from CuII 5(TeIVO3)2(OH)6·2H2O. This change has been accepted by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, Proposal 17-C. The previously reported oxidation state of tellurium has been shown to be incorrect; the crystal structure, bond valence studies and charge balance clearly show tellurium to be hexavalent. The crystal structure of cesbronite is formed from corrugated sheets of edge-sharing CuO6 and (Cu0.5Te0.5)O6 octahedra. The structure determined here is an average structure that has underlying ordering of Cu and Te at one of the two metal sites, designated as M, which has an occupancy Cu0.5Te0.5. This averaging probably arises from an absence of correlation between adjacent polyhedral sheets, as there are two different hydrogen-bonding configurations linking sheets that are related by a ½a offset. Randomised stacking of these two configurations results in the superposition of Cu and Te and leads to the Cu0.5Te0.5 occupancy of the M site in the average structure. Bond-valence analysis is used to choose the most probable Cu/Te ordering scheme and also to identify protonation sites (OH). The chosen ordering scheme and its associated OH sites are shown to be consistent with the revised chemical formula.

Patient reported experiences of CT guided lung biopsy: a prospective cohort study

Background: CT guided lung biopsy is a commonly performed procedure to obtain tissue for a histological diagnosis in cases of suspected lung cancer. Methods: This is a prospective cohort study to obtain information directly from patients about their experiences of the biopsy procedure, thus obtaining a more accurate picture of complications compared with previously performed retrospective reviews. Patients participated in a post-procedure telephone interview and information was gathered about any procedural complications and personal experiences. We also compared the patient reported complications with those obtained from a retrospective review of hospital databases, analogous to previously performed retrospective studies. Results: In our patient group, reported procedural complication rates were 10% pneumothorax rate (4% requiring a chest drain) and 10% haemoptysis. Post-procedural pain and shortness of breath showed positive correlation, with one patient experiencing prolonged pain. No statistical difference was found between the patient reported complication rates and those obtained from retrospective review of the hospital database. Conclusions: Our study demonstrates CT guided lung biopsy is a safe procedure and is generally well tolerated. Some patients may experience significant and lasting pain and therefore should be counselled about this pre-procedure.

Patient reported experiences of CT guided lung biopsy: a prospective cohort study

Background

CT guided lung biopsy is a commonly performed procedure to obtain tissue for a histological diagnosis in cases of suspected lung cancer.

Methods

This is a prospective cohort study to obtain information directly from patients about their experiences of the biopsy procedure, thus obtaining a more accurate picture of complications compared with previously performed retrospective reviews. Patients participated in a post-procedure telephone interview and information was gathered about any procedural complications and personal experiences. We also compared the patient reported complications with those obtained from a retrospective review of hospital databases, analogous to previously performed retrospective studies.

Results

In our patient group, reported procedural complication rates were 10% pneumothorax rate (4% requiring a chest drain) and 10% haemoptysis. Post-procedural pain and shortness of breath showed positive correlation, with one patient experiencing prolonged pain. No statistical difference was found between the patient reported complication rates and those obtained from retrospective review of the hospital database.

Conclusions

Our study demonstrates CT guided lung biopsy is a safe procedure and is generally well tolerated. Some patients may experience significant and lasting pain and therefore should be counselled about this pre-procedure.

Familial aplasia of the inferior rectus muscles

PURPOSE

We describe inferior rectus aplasia in three members of a family. No family member showed signs of craniofacial dysostosis syndromes or neurofibromatosis.

PATIENTS AND FINDINGS

A woman with abnormal head posture, right exotropia, and right hypotropia presented to our clinic. She mentioned that her two children had similar problems. A provisional diagnosis of ocular fibrosis or atypical Duane syndrome was made and she underwent surgery. During surgery, the inferior rectus muscle could not be identified in either eye. Subsequently, her children were examined and orbital magnetic resonance imaging (MRI) was performed for all family members. MRI confirmed bilateral absence of the inferior rectus muscles in the mother and unilateral absence with atrophic and fibrotic contralateral inferior rectus muscles in the children.

CONCLUSION

This is the first report in the literature of a family with aplastic inferior rectus muscles with no signs of craniosynostosis or neurofibromatosis.

Crural laceration--diagnosis and management of an unusual penile injury

Crural laceration is a previously unreported variant of penile trauma. We present a case that was diagnosed using MRI and managed conservatively with a successful functional outcome.

Groin dissection

This review provides a brief history of groin dissection, including studies on anatomical considerations and technique. A groin dissection for complete ablation of the node-bearing areolar tissue in the inguinal and iliac regions and with negligible morbidity requires careful attention to the pathophysiology of cancer in lymphatics, pre- and postoperative care, and surgical technique, including coordinated use and general, plastic, vascular, and orthopedic surgical principles.

Groin dissection

This review provides a brief history of groin dissection, including studies on anatomical considerations and technique. A groin dissection for complete ablation of the node-bearing areolar tissue in the inguinal and iliac regions and with negligible morbidity requires careful attention to the pathophysiology of cancer in lymphatics, pre- and postoperative care, and surgical technique, including coordinated use and general, plastic, vascular, and orthopedic surgical principles.

Trypanosoma cruzi infection of free-ranging lion-tailed macaques (Macaca silenus) and ring-tailed lemurs (Lemur catta) on St. Catherine's Island, Georgia, USA

Free-ranging Old World primates released on St. Catherine's Island, Georgia (USA), were tested for infection with Trypanosoma cruzi as part of a study of the epizootiology of sylvatic T. cruzi in the southeastern USA. The parasite was observed in liver infusion tryptose medium cultures of blood from seven of 11 lion-tailed macaques (Macaca silenus) and one of 19 ring-tailed lemurs (Lemur catta). Cultures of blood from 10 black and white ruffed lemurs (Varecia variegata) were all negative. Analysis of small subunit ribosomal RNA gene polymorphisms detected using polymerase chain reaction techniques indicates that the parasites isolated from both the lion-tailed macaques and the ring-tailed lemur are probably the same as T. cruzi parasites isolated from raccoons (Procyon lotor) trapped on St. Catherine's Island and other locations in the southeastern USA. Foraging lion-tailed macaques were observed to handle and partially consume specimens of Triatoma sanguisuga, the triatomine bug thought to be a vector of T. cruzi in the southeastern USA. Oral transmission of the parasite may have occurred as a result of this behavior.

Vitamin E in cranes: reference ranges and nutrient interactions

Fat soluble vitamins E and A (quantified as alpha-tocopherol and all-trans retinol, respectively) were measured in plasma samples from 274 captive cranes from four institutions and five free-ranging birds. Ages ranged from 4 mo to 80 yr, and all 15 crane species were represented. Captive cranes had a mean +/- standard error (SE) of 6.57 +/- 0.82 micrograms/ml alpha-tocopherol; migrating greater sandhill cranes (Grus canadenis tabida) had a plasma concentration of 3.71 +/- 0.22 micrograms/ml. Sex and age differences were not significant, but crane species that evolved in temperate habitats had higher circulating levels of alpha-tocopherol than tropical or subtropical species. Mean +/- SE retinol values were 0.69 +/- 0.05 micrograms/ml in captive cranes, and 0.66 +/- 0.08 micrograms/ml in free-ranging cranes; values did not differ significantly by sex, age, or species. Dietary vitamin E concentrations were significantly correlated with plasma alpha-tocopherol levels in a logarithmic relationship. Dietary selenium at 0.5 mg/kg was associated with decreased circulating alpha-tocopherol concentrations.

Cancer of the colon: the influence of the no-touch isolation technic on survival rates

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