Vector-apodizing phase plate coronagraph: design, current performance, and future development [Invited]

Over the last decade, the vector-apodizing phase plate (vAPP) coronagraph has been developed from concept to on-sky application in many high-contrast imaging systems on 8 m class telescopes. The vAPP is a geometric-phase patterned coronagraph that is inherently broadband, and its manufacturing is enabled only by direct-write technology for liquid-crystal patterns. The vAPP generates two coronagraphic point spread functions (PSFs) that cancel starlight on opposite sides of the PSF and have opposite circular polarization states. The efficiency, that is, the amount of light in these PSFs, depends on the retardance offset from a half-wave of the liquid-crystal retarder. Using different liquid-crystal recipes to tune the retardance, different vAPPs operate with high efficiencies (${\gt}96\%$) in the visible and thermal infrared (0.55 µm to 5 µm). Since 2015, seven vAPPs have been installed in a total of six different instruments, including Magellan/MagAO, Magellan/MagAO-X, Subaru/SCExAO, and LBT/LMIRcam. Using two integral field spectrographs installed on the latter two instruments, these vAPPs can provide low-resolution spectra (${\rm{R}} \sim 30$) between 1 µm and 5 µm. We review the design process, development, commissioning, on-sky performance, and first scientific results of all commissioned vAPPs. We report on the lessons learned and conclude with perspectives for future developments and applications.

Posterolateral plate fixation with Pantalarlock® is more stable than nail fixation in tibiotalocalcaneal arthrodesis in a biomechanical cadaver study

BACKGROUND

Despite the promising results of ankle joint arthroplasty, the tibiotalocalcaneal (TTC) arthrodesis remains an established procedure in treatment of combined pathology of the ankle and subtalar joint. Despite the promising results in biomechanical investigations, nonunion rates of up to 24% are described in recent studies. The objective of this work was a comparative study of the biomechanical properties of the posterolateral plate fixation with retrograde intramedullary nail fixation.

METHODS

Twenty four fresh-frozen human lower leg specimens (12 pairs) were used for the comparative biomechanical testing. Every specimen was preconditioned with 100 N over 200 cycles. After every 250 cycles the force was increased by 50 N from 200 to 600 N. This was followed by cyclic loading in dorsi-/plantiflexion with 800 N for 3000 cycles. All specimens were subjected to bone densitometry (DXA) and computed tomography.

RESULTS

Significantly higher number of spacimens with nails (4) failed during the cycling testing in dorsi-/plantarflexion and futher two during the cyclic testing with 800 N. Two specimens with plates failed during the cyclic testing with 800 N. Statistical analysis showed that the specimens with the plate were significantly more stable in each test direction. The Pearson correlation demonstrated for the specimens with plate a linear relationship between the stiffness and the determined bone density.

CONCLUSIONS

The results demonstrate a significantly superior stiffness of the Pantalarlock®-plate in all testing directions compared with the HAN nail. Probably the position of the plate on the tension side of the joint and the combination of locking and lag screws provide the higher stiffness of the plate system. The correlation of the stiffness with bone density leads to more predictable results of the plate arthrodesis. We hope for a reduction of the pseudarthrosis rate and shorten the postoperative treatment phase. The authors expect advantages in the treatment of high risk patients with severe deformity of the ankle, bone defects, neuropathic deformity, poor bone quality and osteoporosis.

Multi-phase volcanic resurfacing at Loki Patera on Io

The Jovian moon Io hosts the most powerful persistently active volcano in the Solar System, Loki Patera. The interior of this volcanic, caldera-like feature is composed of a warm, dark floor covering 21,500 square kilometres surrounding a much cooler central 'island'. The temperature gradient seen across areas of the patera indicates a systematic resurfacing process, which has been seen to occur typically every one to three years since the 1980s. Analysis of past data has indicated that the resurfacing progressed around the patera in an anti-clockwise direction at a rate of one to two kilometres per day, and that it is caused either by episodic eruptions that emplace voluminous lava flows or by a cyclically overturning lava lake contained within the patera. However, spacecraft and telescope observations have been unable to map the emission from the entire patera floor at sufficient spatial resolution to establish the physical processes at play. Here we report temperature and lava cooling age maps of the entire patera floor at a spatial sampling of about two kilometres, derived from ground-based interferometric imaging of thermal emission from Loki Patera obtained on 8 March 2015 ut as the limb of Europa occulted Io. Our results indicate that Loki Patera is resurfaced by a multi-phase process in which two waves propagate and converge around the central island. The different velocities and start times of the waves indicate a non-uniformity in the lava gas content and/or crust bulk density across the patera.

Acetabular Fractures in an Advanced Age - Current Knowledge and Treatment Options

The demographic change in industrial countries leads to an increasing population that sustains an acetabular fracture in an advanced age. Some authors predicted elderly individuals to be the most rapidly growing subgroup of patients currently sustaining acetabular fractures. Gold standard of treatment of acetabular fractures remains the open reduction and internal fixation. Relevant factors impeding surgical treatment include the significantly decreased bone stock and the incapability of the patients to partially weight bear following surgery. Therefore, special considerations should be performed when dealing with this patient group as surgical treatment is associated with several risks and often accompanied by poor outcomes. This review aims to summarize the current body of knowledge and to give a recommendation concerning a surgical treatment cascade.

Subinternship in Radiology - A Practical Start to the Specialization?

Purpose: To identify factors influencing medical students to choose radiology in the four-month clinical elective in the final year of medical school following radiology subinternships. Materials and Methods: A subsample of medical students in a nationwide German online survey evaluated a subinternship in radiology (19 items). They were divided into four groups: Students who could imagine doing a clinical elective in radiology in the practical year based on their experiences during the subinternship ("yes, based on subinternship"), students who could not ("no, based on subinternship") and students who had made this decision prior to the subinternship ("yes, prior to subinternship" and "no, prior to subinternship"). Results: 94 medical students evaluated a radiology subinternship (54.4 % females). Based on their experiences during the subinternship, 54 students (57.4 %) intended to do a final year clinical elective in radiology, 39 of them (41.5 %) being encouraged by the subinternship. 40 (42.6 %) reported having a negative attitude towards a clinical elective in radiology, 16 of them (17.0 %) having made this decision based on their subinternship experience. Groups did not differ regarding gender (p = 0.396) and age (p = 0.853). Students motivated to do a final year clinical elective in radiology experienced excellent academic teaching (p = 0.001) and practical involvement (p = 0.003), achieved their learning goals more often (p = 0.001), were better integrated into the team (p = 0.001), and acquired more practical skills (p = 0.003). Overall satisfaction was higher in these groups (p = 0.001). Conclusion: Satisfaction with a radiology subinternship is crucial for motivating medical students to do a final year clinical elective in radiology. A structured subinternship and continuous mentoring should be targeted to keep students connected to radiology. Key Points: • Radiology subinternships influence further interest in the specialization.• The quality and structure of teaching critically influence student satisfaction.• Team integration and practical involvement positively affect the attitude towards a specialization. Citation Format: • Kasch R, Wirkner J, Hosten N et al. Subinternship in Radiology - A Practical Start to the Specialization? Fortschr Röntgenstr 2016; 188: 1024 - 1030.

Fixation of acetabular fractures via the ilioinguinal versus pararectus approach

This study compared the quality of reduction and complication rate when using a standard ilioinguinal approach and the new pararectus approach when treating acetabular fractures surgically. All acetabular fractures that underwent fixation using either approach between February 2005 and September 2014 were retrospectively reviewed and the demographics of the patients, the surgical details and complications were recorded.

A total of 100 patients (69 men, 31 women; mean age 57 years, 18 to 93) who were consecutively treated were included for analysis. The quality of reduction was assessed using standardised measurement of the gaps and steps in the articular surface on pre- and post-operative CT-scans.

There were no significant differences in the demographics of the patients, the surgical details or the complications between the two approaches. A significantly better reduction of the gap, however, was achieved with the pararectus approach (axial: p = 0.025, coronal: p = 0.013, sagittal: p = 0.001).

These data suggest that the pararectus approach is at least equal to, or in the case of reduction of the articular gap, superior to the ilioinguinal approach.

This approach allows direct buttressing of the dome of the acetabulum and the quadrilateral plate, which is particularly favourable in geriatric fracture patterns.

Cite this article: Bone Joint J 2015;97-B:1271-8.

[Significance and prevention of post-operative wound complications]

Although surgical site infections (SSI) in dermatologic operative procedures are extremely rare, it is important to understand risks and etiological factors to initiate risk assessment and specific preventive measures. SSI commonly are associated with a complicated, long-term and expensive outcome. Typical wound pathogens of these infections include a variety of multiresistant organisms along with Staphylococcus aureus, Staphylococcus epidermidis, hemolytic streptococci and the gram-negative bacilli Escherichia coli and Pseudomonas aeruginosa. Effective hygienic measures as part of an adequate quality management system should consider the critical points in the development of SSI, particularly in the setting of an outpatient dermatologic unit, such as preparation of the operative area, preoperative skin antisepsis, hand hygiene, safe and skilled technique by surgeons, and barrier nursing to prevent spread of pathogens. The baseline infection incidence in dermatologic surgery inherently is low; nevertheless significant improvements can be achieved by implementation of risk-adapted infection control measures.

[Humeral fracture due to arm wrestling - an indirect fracture in a doped athlete]

BACKGROUND

Humeral shaft fractures due to recreational arm wrestling are reported from time to time.

CASE REPORT

We report the case of a 19 year old, anabolic steroids up taking, recreational arm wrestler who sustained a spiral fracture of the right humeral bone and secondary radial nerve palsy. We discuss the surgical treatment and the biomechanics of this rare injury mechanism.

CONCLUSION

Every professional or recreational arm wrestler has to be aware of dangerous sports injuries.

[Accidents, illness and injuries involved in road haulage : consequences for medical care and prevention]

This article reviews basic characteristics of road traffic crashes of heavy vehicles and the current health status of truck drivers. It summarises previous findings from research with a focus on orthopaedic diseases and injuries. These findings comprise a risky health behaviour and high prevalence of associated diseases which can be attributed to both the occupational framework and personal risk-taking behavioural patterns. These are of major importance given the increasing number of drivers and the consequences for acute care and prevention. On the other hand there is a substantial lack of medical care for the drivers on the road. Therefore this article presents the"DocStop Initiative" for medical care on the road, an initiative that runs an international network of care providers (http://www.docstop-online.eu).

Antiseptic efficacy and tolerance of tissue-tolerable plasma compared with two wound antiseptics on artificially bacterially contaminated eyes from commercially slaughtered pigs

AIM

To compare the tissue tolerance and efficacy of two wound antiseptics with tissue-tolerable plasma (TTP) on enucleated contaminated eyes from slaughtered pigs in order to draw consequences for the use of TTP on wounds.

METHOD

The corneas of extracted eyes were contaminated with Staphylococcus aureus or Pseudomonas aeruginosa. One and 10 min after application of 10% povidone (PVP)-iodine and 0.04% polyhexanide, respectively, the eyes were rinsed with inactivating solution. To test TTP, the plasma pen meandered over the eyes at a speed of 30 mm/s and a distance of 5 mm; the eyes were then rinsed with balanced salt solution. The reduction factor was calculated by the difference between the logarithm of colony-forming units in the rinse before and after antisepsis or TTP application.

RESULTS

The efficacy of TTP (reduction factor 2.4-2.9) was significantly higher (p < 0.001) than that of PVP-iodine and polyhexanide (reduction factor 1.7-2.1).

CONCLUSION

TTP is more effective than the tested wound antiseptics. The lack of histological damage to the eyes of slaughtered pigs would seem to make its use as a wound antiseptic a viable alternative. In contrast to antiseptics, it supplies additional energy in the form of heat, electric fields and radicals by TTP.

Oldie but goldie: Bristow-Latarjet procedure for anterior shoulder instability

PURPOSE

To analyse the functional and radiological outcomes of the Bristow-Latarjet procedure in patients with recurrent anterior glenohumeral instability.

METHODS

Records of 29 patients were reviewed retrospectively. Date of first dislocation, injury mechanism, and number of recurring dislocations before and after surgery were recorded. The overall function and stability of the shoulder was evaluated.

RESULTS

24 (83%) of the glenohumeral instabilities were caused by trauma. The mean number of recurring dislocations was 8 (95% confidence interval [CI], 0-18); one patient had had 40 recurrences. No dislocation ensued postoperatively. The overall functional outcome was good, with a mean Rowe score of 90 points (95% CI, 78-100). Scores of 17 (59%) of the patients were excellent, 7 (24%) were good, 3 (10%) were fair, and 2 (7%) were poor.

CONCLUSION

The Bristow-Latarjet procedure is a good surgical treatment for recurrent anterior-inferior instability of the glenohumeral joint.

[Retrospective analysis of march fractures in the german armed forces in the years 1998 to 2000]

AIM

The aim of this study was to determine the incidence/frequency of march fractures in the German Armed Forces in the years from 1998 to 2000. In particular, the age, length of service, distribution of the metatarsals and the occurrence of anthropometric risk factors were considered.

METHODS

At the Medicostatistical Institute of the German Armed Forces the records of soldiers, 191 cases with 204 fractures, with diagnosed "march fractures" were selected and analyzed.

RESULTS

82% of the affected soldiers were between 19 and 22 years old. More than 50% of the fractures occurred within the first eight weeks of service. In about 64% the 3rd metatarsal was affected, in 25% the 2nd metatarsal and in only 11% of all cases the 4th, 5th, and 1st metatarsals. Soldiers were exempted from duty for an average of 26.5 days. No specific anthropometric risk factors were found to be connected with the occurrence of march fractures.

CONCLUSION

March fractures in the German Armed Forces are non-predictable injuries of young and physically fit individuals; youth is not a protective factor. There is an increased risk for march fractures during the first weeks of military service. There appears to be no possibility for a screening.

Das solitäre Osteochondrom der Skapula

Solitary osteochondroma of the scapula is rare. Because of the atypical location with unspecific shoulder pain, the diagnosis is often made late. We present a 35 year old patient with a solitary ostochondroma of the scapula with unspecific pain of the shoulder-neck region over about 4 years. In a thorax x-ray 2 years ago, a tumor like lesion was found. CT and MRI scan led to suspicion of a solitary osteochondroma of the scapula. Because of progressive thoracic pressure pain, a wide excision was made. The problems of diagnosis and therapy are presented and the literature is discussed.

Two cases of severe sepsis due to Vibrio vulnificus wound infection acquired in the Baltic Sea

Two severe cases of Vibrio vulnificus wound infection with secondary septicemia occurred during 1 week in August 2003 on the German island of Usedom in the southwestern Baltic Sea. In both cases, pre-existing wounds were inoculated by wading in contaminated sea water. One of the patients died from septic multiorgan failure. To the best of our knowledge, this is the first fatality due to a V. vulnificus infection to have occurred in Germany. Microbiological analysis revealed high concentrations of V. vulnificus in sea water along the coastline, following a period when water temperature exceeded 20 degrees C for more than 2 weeks.

Aufklärung über die Heparin-induzierte Thrombozytopenie im Rahmen der Thromboseprophylaxe mit Heparin

BACKGROUND

The practicability and acceptance of written information about heparin thrombosis prophylaxis and the associated risk of heparin-induced thrombocytopenia (HIT) was evaluated in a pilot study.

PATIENTS AND METHODS

All patients consecutively admitted to the department of trauma- and reconstructive surgery at the Ernst-Moritz-Arndt-University, Greifswald, Germany, with an indication for heparin thrombosis prophylaxis were give written information about thrombosis prophylaxis and the undesired drug effect HIT. After this, acceptance was evaluated using a standardized questionnaire. Primary endpoint was refusal of heparin for thrombosis prophylaxis, secondary endpoint acceptance and comprehensibility of the information.

RESULTS

None of the 460 patients included in the study subsequently refused thrombosis prophylaxis with heparin. The majority welcomed the information and thought it should be given to all patients that are about to be treated with heparin. Only 0.9 % of patients judged comprehensibility of the information to be insufficient. Anticipation of imminent heparin therapy (good/very good in 90 %) and appreciation of the quality of care was not judged to be unacceptable by any patient.

CONCLUSIONS

The present study demonstrates that giving information about heparin-induced thrombocytopenia during explanation of the risks and benefits of heparin thrombosis prophylaxis is feasible. This information--given in writing in our pilot study--was judged by patients to be comprehensible and necessary and did not lead to refusal of treatment. Lower incidence of HIT with use of low molecular weight heparins should be considered in the choice of drug for thrombosis prophylaxis.

[Current recommendations for diagnosis and therapy of heparin-induced thrombocytopenia]

Thrombosis prophylaxis using heparins is mandatory in most trauma patients. However, heparins can induce heparin-induced thrombocytopenia (HIT), the most common and clinically important immune-mediated drug-dependent thrombocytopenia. Affected patients are at risk of developing new thromboembolic complications. HIT has to be considered if platelet counts decrease >50% between day 5-10 of heparin therapy that cannot be explained alternatively or if new thromboses occur in a sufficiently heparinised patient. Immediately changing the anticoagulant to danaparoid or lepirudin is most important. Proof of anti-platelet-factor-4/heparin antibodies secures the diagnosis, usually retrospectively. Diagnosis and therapy are demonstrated in a typical HIT patient. HIT usually occurs in the second week of heparin administration. Heparin-reexposure within 100 days can lead to HIT before day 5. For early recognition of HIT, platelet counts should be monitored regularly. Because of earlier discharge of patients to rehabilitation or outpatient care, the problem of HIT-diagnosis and therapy gains increasing relevance in these sectors.

Com yield increases relative to nonfumigant chemical control of nematodes

Corn yields were measured after application of nematicides in 16 experiments, mostly in medium-to-heavily textured soil, at 12 locations in Iowa during 1973-1976. The average maximum yield increase in plots treated with nematicides was 21% over yields in untreated plots. Yields were correlated negatively with nematode numbers or nematode biomass in nearly all comparisons. Correlations of nematode numbers in the soil with yield averaged -0.56 for Helicotylenchus pseudorobustus, -0.45 for Hoplolaimus galeatus, -0.51 for Pratylenchus spp., and -0.64 for Xiphinema americanum. Correlation coefficients for numbers of nematodes in the roots and yield averaged -0.63 for Pratylenchus spp. and -0.56 H. galeatus. Correlation coefficients for yield and total number of nematodes averaged -0.65 in roots and -0.55 in soils. Negative correlations also were greater for comparisons of yield with total parasitic-nematode biomass than with numbers of individual nematodes of a species or total numbers of parasitic nematodes.