Search

Planetary protection guidance for martian exploration has become a notable point of discussion over the last decade. This is due to increased scientific interest in the habitability of the red planet with updated techniques, missions becoming more attainable by smaller space agencies, and both the private sector and governments engaging in activities to facilitate commercial opportunities and human-crewed missions. The international standards for planetary protection have been developed through consultation with the scientific community and the space agencies by the Committee on Space Research's (COSPAR) Panel on Planetary Protection, which provides guidance for compliance with the Outer Space Treaty of 1967. In 2021, the Panel evaluated recent scientific data and literature regarding the planetary protection requirements for Mars and the implications of this on the guidelines. In this paper, we discuss the COSPAR Planetary Protection Policy for Mars, review the new scientific findings and discuss the next steps required to enable the next generation of robotic missions to Mars.

Objective This investigation compared the biomechanical properties of a 2.0 mm locking compression notched head T-plate (NHTP) and 2.0 mm straight locking compression plate (LCP), in a simple transverse juxta-articular fracture model. Study Design Two different screw configurations were compared for the NHTP and LCP, modelling short (configuration 1) and long working length (configuration 2). Constructs were tested in compression, perpendicular and tension non-destructive four point bending and torsion. Plate surface strain was measured at 12 regions of interest (ROI) using three-dimensional digital image correlation. Stiffness and strain were compared between screw configurations within and between each plate. Results The LCP was stiffer than the NHTP in all three planes of bending and torsion (p Conclusion In this experimental model, a 2.0 mm LCP with two screws in the short fragment was significantly stiffer and had lower plate strain than a 2.0 mm NHTP with three screws in the short fragment. Extending the working length significantly reduced construct stiffness and increased plate strain. These findings may guide construct selection.

Objective This investigation compared the biomechanical properties of a 2.0 mm locking compression notched head T-plate (NHTP) and 2.0 mm straight locking compression plate (LCP), in a compressed, short, juxta-articular fragment fracture model. Methods Two different screw configurations were compared for the NHTP and LCP, modelling short (configuration 1) and long working length (configuration 2). Constructs were tested in compression, perpendicular and tension four-point bending and torsion. Plate surface strain was measured at 12 regions of interest using three-dimensional digital image correlation. Stiffness and strain were compared. Results The LCP was stiffer than the NHTP in all three planes of bending (p Conclusion In this experimental model of a compressed transverse fracture with a juxta-articular 9 mm fragment, a 2.0 mm LCP with two hybrid screws in the short fragment was stiffer than a 2.0 mm NHTP with three locking screws in the short fragment in three planes of bending but not torsion. Extending the working length of each construct reduced construct stiffness and increased plate strain.

Aseptic loosening is reported as the leading cause of revision total knee arthroplasty on the Australian National Joint Replacement Registry. Loosening of cemented tibial baseplates has been correlated with type of cement used, cementing technique, and cement contamination with biological material. The aim of this study was to evaluate the effect of cementing application and techniques including surface contamination and cement viscosity on fixation strength of tibia baseplates/cement interface.Mechanical assessment of the fixation strength of tibia baseplates/cement interface was tested using a pull-out test on a material testing system. Different tibial baseplate design, cementing techniques, cement viscosity and contamination of the implant/cement interface with bone marrow were assessed to determine if they influenced force required to disrupt the cement/implant interface (pull-out strength).The model with contamination of the cement prosthesis interface demonstrated a lower pull-out strength (p 0.001). The model with the keel and baseplate cemented showed a higher pull-out strength compared to cementing the baseplate alone (p 0.001). The use of low-viscosity cement resulted in a significantly higher failure force (p = 0.002) compared to high-viscosity cement when cementing the baseplate alone.Biomechanical testing demonstrated improved fixation with cementing the tibial keel and keeping surfaces free from contamination during the cementation process.

Objectives: To investigate the mechanical properties of cephalomedullary nailing of intertrochanteric OTA/AO 31-A3.1 (reverse oblique) fractures and to test the hypothesis that anatomical reduction and augmentation with cerclage wire produces a more stable construct. Methods: A standardized fracture model in composite saw bone was created to stimulate an intertrochaneric 31-A3.1 fracture, using a 3D printed cutting guide. Simulated osteosynthesis was performed with 12 femurs divided into anatomically reduced and varus malreduced groups. Each femur was tested with and without cerclage wire augmentation. All femurs were fixed with a 215 mm, 130 degree, 11.5 mm nail. An Instron 8874 biaxial materials testing machine was used to assess the axial stiffness. Cyclic loading consisted of 5000 cycles of sinusoidal combined axial-torsion loading at 3 Hz. Axial load was 100 N to 2000 N and torsion −4.5 Nm to +4.5 Nm. Stiffness was measured before and after cyclic loading. Results: Reduced constructs were stiffer than residual varus constructs. The mean overall fracture stiffness was 508.7 N/mm for reduced constructs and 379.2 N/mm for varus constructs. Removing the cables significantly decreased the fracture stiffness for both constructs (mean difference 60.0 N/mm, 95% CI 7.7–112.3, P = .032). Conclusions: Anatomical reduction has a dominant effect on facture stiffness. Anatomically reduced fractures are stiffer than varus malreduced fractures. A cerclage wire further improves construct stiffness if anatomical reduction is achieved. Cerclage wiring is less effective if anatomical reduction is not achieved.

Reverse total shoulder arthroplasty (RTSA) is being performed more frequently and indications for surgery have expanded to now include osteoarthritis with severe glenoid bone deformity and glenoid bone deficiency from previous failed arthroplasty surgery.

Background Anterior hip pain after total hip replacement (THR) can be caused by iliopsoas impingement (IPI). Validation of CT measured cup version is well published; however quantification of the anterior cup prominence has not been validated. Therefore, we did an in vitro study aiming to: 1) assess the accuracy of the current method of measuring the prominence of the acetabular component using a dry bone model, 2) develop a CT protocol based on bony anatomical landmarks that improves the accuracy of these measurements. Hypothesis We hypothesise that utilising reproducible anatomical landmarks on the acetabulum will improve the accuracy of measurement of anterior prominence at the psoas valley. Methods A dry bone pelvic model was implanted with bilateral acetabular cups. The cup was manipulated into ten different combinations of inclination and version, and anterior prominence directly measured in relation to the acetabular rim. A CT scan was performed for each position. Anterior prominence was then measured by two radiologists, first using standard methods (axial slice at level of center of femoral head) and then again using a novel protocol (based on the position of the psoas valley in relation to the inferior medial acetabular notch). Results Mean errors between direct measurement of anterior prominence and radiologist reported measurements using standard protocol were 6.94 mm ± 5.24 (SD) (95%Confidence Interval: 3.25–4.27) and 5.14 mm ± 3.07 (95%CI: 1.9-2.5) with a tendency towards overestimation of prominence. Using an anatomical landmark based protocol, mean error was reduced to 3.0 mm ± 1.9 (95%CI: 1.16–1.53) and 4.3 mm ± 4.3 (95%CI: 2.67–351) on the first attempt, and to 1.7 mm ± 1.9 (95%CI: 1.15–1.52) and 2.1 mm ± 1.4 (95%CI: 0.87–1.15) on the second attempt. Concordance correlation improved from 0.43 (95% CI: 0.19–0.68) and 0.59 (95% CI: 0.44–0.79) using the standard protocol, to 0.88 (95%CI: 0.61–0.91) and 0.9 (95%CI: 0.56 - 0.92) using the novel protocol. Conclusions There is a difference in mean error and reliability between radiologically measured values for anterior prominence and values measured directly with present methods. The use of our novel protocol based on bony acetabular landmarks, significantly improves the accuracy of measurement. This protocol may improve reproducibility and the accuracy of this measurement and aid in the decision between tenotomy or revision of the acetabular component. Level of evidence III, in vitro study comparing diagnostic tools.

Tendons are soft tissues of the musculoskeletal system that are designed to facilitate joint movement. Tendons exhibit a wide range of mechanical properties matched to their functions and, as a result, have been of interest to researchers for many decades. Dimensions are an important aspect of tendon properties. Change in the dimensions of tissues is often seen as a sign of injury and degeneration, as it may suggest inflammation or general disorder of the tissue. Dimensions are also important for determining the mechanical properties and behaviours of materials, particularly the stress, strain, and elastic modulus. This makes the dimensions significant in the context of a mechanical study of degenerated tendons. Additionally, tendon dimensions are useful in planning harvesting for tendon transfer and joint reconstruction purposes. Historically, many methods have been used in an attempt to accurately measure the dimensions of soft tissue, since improper measurement can lead to large errors in the calculated properties. These methods can be categorised as destructive (by approximation), contact, and non-contact and can be considered in terms of in vivo and ex vivo.

Background Anterior hip pain after total hip replacement (THR) can be caused by iliopsoas impingement (IPI). Validation of CT measured cup version is well published; however quantification of the anterior cup prominence has not been validated. Therefore, we did an in vitro study aiming to: (1) assess the accuracy of the current method of measuring the prominence of the acetabular component using a dry bone model; (2) develop a CT protocol based on bony anatomical landmarks that improves the accuracy of these measurements. Hypothesis We hypothesise that utilising reproducible anatomical landmarks on the acetabulum will improve the accuracy of measurement of anterior prominence at the psoas valley. Methods A dry bone pelvic model was implanted with bilateral acetabular cups. The cup was manipulated into ten different combinations of inclination and version, and anterior prominence directly measured in relation to the acetabular rim. A CT scan was performed for each position. Anterior prominence was then measured by two radiologists, first using standard methods (axial slice at level of centre of femoral head) and then again using a novel protocol (based on the position of the psoas valley in relation to the inferior medial acetabular notch). Results Mean errors between direct measurement of anterior prominence and radiologist reported measurements using standard protocol were 6.94 mm ± 5.24 (SD) (95%Confidence Interval: 3.25–4.27) and 5.14 mm ± 3.07 (95%CI: 1.9–2.5) with a tendency towards overestimation of prominence. Using an anatomical landmark based protocol; mean error was reduced to 3.0 mm ± 1.9 (95%CI: 1.16–1.53) and 4.3 mm ± 4.3 (95%CI: 2.67–351) on the first attempt, and to 1.7 mm ± 1.9 (95%CI: 1.15-1.52) and 2.1 mm ± 1.4 (95%CI: 0.87–1.15) on the second attempt. Concordance correlation improved from 0.43 (95% CI: 0.19–0.68) and 0.59 (95% CI: 0.44–0.79) using the standard protocol, to 0.88 (95%CI: 0.61–0.91) and 0.9 (95%CI: 0.56–0.92) using the novel protocol. Conclusions There is a difference in mean error and reliability between radiologically measured values for anterior prominence and values measured directly with present methods. The use of our novel protocol based on bony acetabular landmarks, significantly improves the accuracy of measurement. This protocol may improve reproducibility and the accuracy of this measurement and aid in the decision between tenotomy or revision of the acetabular component. Level of evidence III, in vitro study comparing diagnostic tools.

Background Intraoperative femur fractures are a common complication of revision hip arthroplasty. This study examined the use of a prophylactic cable in stopping a crack from propagating beyond the cable. Methods Seventy sheep femora were prepared. A 5-mm vertical incision was performed. Using a force-controlled materials testing machine, a Wagner shaft was advanced until a crack occurred. Cracks were visualized with green ink. In the first part, the control group without any cable (n = 10) was compared with polyethylene (n = 15) and single CoCr cable (n = 15) groups. The cables were positioned 15 mm distal to the osteotomy. In the second part, three different CoCr configurations were compared, single-wrapped (n = 15), double-wrapped (n = 125), and two separate cables at 10 and 15 mm distal to the osteotomy (n = 15). Results The polyethylene cable stopped only 3 of 15 cracks (20%), whereas the CoCr cable stopped 11 of 15 cracks (73%) (P = .009). The force needed to initiate the crack between the different groups was not significant. Twelve (80%) of 15 cracks were stopped at the level of the cable with two separate CoCr cables and 15 (100%) of 15 cracks with a double-wrapped cable (P = .11). Conclusion This study demonstrated that an elastic cable is not suitable for preventive cabling. The force required to form a crack is not improved with the use of a prophylactic cable placed 10-15 mm below the osteotomy. While the results on the different configurations were not conclusive, the double-wrapped cable was able to stop all cracks from progressing distally.

Background Different methods have been described for the reconstruction of cranial defects and orbital defects. The complex contouring between the orbital roof and frontal bone creates significant design challenges for prefabricated cranio-orbital reconstructions. In describing the first reported patient of combined skull and orbital roof reconstruction with a single-piece titanium plate cranioplasty, the authors present a new method of combined complex cranio-orbital reconstruction. Methods A 63-year-old lady presented with a large, right-sided frontal en-plaque meningioma involving the right orbit and sphenoid wing. Complete resection would require reconstruction of both the skull and the orbital roof. Surgical preplanning involved marking resection margins on a three-dimensional (3D) printed acrylonitrile-butadiene-styrene model. This margin was used to virtually resect the tumor and generate a repaired surface. A titanium plate was then fabricated using hydrostatic pressing into a 3D-printed mold and the orbital roof portion (a reentrant surface) was hand-finished. Lateral canthus and temporalis muscle suspension holes were prefabricated into the cranioplasty plate. Results The patient underwent hemicraniectomy and tumor resection guided by a custom-made 3D-printed cutting guide. The surgical defect was reconstructed with the prefabricated titanium plate achieving a good functional and cosmetic result. Conclusion Single-piece titanium plate cranioplasty is an effective novel reconstruction method for complex cranio-orbital defects.

This report describes the surgical reconstruction of a traumatic medial orbital wall blow-out fracture using an autologous calvarial bone graft modeled intraoperatively using a three-dimensional (3-D) fused deposition model of the fracture defect. Previous case reports have demonstrated the use of 3-D models in planning the surgical approach, selecting and fashioning the desired implant in the perioperative period, and even using models with sterile coverings intraoperatively to mold synthetic implants. This is an individually unique application of 3-D printing for the surgical repair of pure medical wall blow-out fracture.

Over 200,000 tourists per year visit Cape Breton Highlands National Park, Nova Scotia, Canada. The forests within the park are home to many rare epiphytic lichens, the species diversity of which has declined in some areas. The primary motivation for this study was to gain insight into the concentrations and potential local and long range sources of air pollution, but its association with lichen species diversity was also examined. Ogawa passive diffusion samplers were used to measure nitrogen dioxide (NO2) and sulfur dioxide (SO2) in the park at 19 sites in the winter and 20 sites in the summer of 2011. An improvement in the sensitivity of the sampler analytical protocol was developed. The mean concentrations in the park of winter and summer NO2 (0.81 and 0.16 ppb) and SO2 (0.24 and 0.21 ppb) are not at levels known to be phytotoxic to lichen. The NO2 concentrations in winter were significantly (p = 0.001) higher than those in summer whilst the SO2 concentrations did not differ significantly between winter and summer (p = 0.429). Highest NO2 concentrations in both seasons were observed in the Grand Anse Valley, presumably due to the steep road, emissions from the Pleasant Bay community at the foot of the valley and the enclosed topography of this area reducing dispersion of primary emissions. The SO2 concentrations in the park tended to be greater at elevated sites than valley sites, consistent with dispersion from long-range, rather than local, sources for this pollutant. Significant predictors in a multilinear regression for an index of air purity (lichen based measure of air quality) were lichen species number (p = 0.009), forest old growth index (p = 0.001) and distance from roads (p < 0.001) (model R2 = 0.8, model p = 0.004). The study suggests that local sources of pollution (roads emissions) are adversely associated with lichen species diversity in this National Park, compared with long-range transport, and that monitoring programs such as a lichen based ‘index of air purity’ can reveal locations where ambient air pollution, although low, is nevertheless at a level that may cause ecological detriment. The implications from this work could be applicable to national parks elsewhere.

Background The cross-sectional area (CSA) of a material is used to calculate stress under load. The mechanical behaviour of soft tissue is of clinical interest in the management of injury; however, measuring CSA of soft tissue is challenging as samples are geometrically irregular and may deform during measurement. This study presents a simple method, using structured light scanning (SLS), to acquire a 3D model of rabbit Achilles tendon in vitro for measuring CSA of a tendon. Method The Artec Spider™ 3D scanner uses structured light and stereophotogrammetry technologies to acquire shape data and reconstruct a 3D model of an object. In this study, the 3D scanner was integrated with a custom mechanical rig, permitting 360-degree acquisition of the morphology of six New Zealand White rabbit Achilles tendons. The reconstructed 3D model was then used to measure CSA of the tendon. SLS, together with callipers and micro-CT, was used to measure CSA of objects with a regular or complex shape, such as a drill flute and human cervical vertebra, for validating the accuracy and repeatability of the technique. Results CSA of six tendons was measured with a coefficient of variation of less than 2%. The mean CSA was 9.9±1.0 mm 2 , comparable with those reported by other researchers. Scanning of phantoms demonstrated similar results to μCT. Conclusion The technique developed in this study offers a simple and accurate method for effectively measuring CSA of soft tissue such as tendons. This allows for localised calculation of stress along the length, assisting in the understanding of the function, injury mechanisms and rehabilitation of tissue.

Voriconazole-related periostitis has been increasingly described in the literature over the last several years as a recognizable disease entity, especially in lung transplant patients. This relationship should be considered when approaching immunosuppressed patients presenting with diffuse bone pain and imaging findings of periostitis. We present a case of voriconazole-associated periostitis, capsular and enthesial ossification and glenuhumeral capsulitis in a patient with a hematologic malignancy. To the authors’ knowledge, soft tissue ossification associated with voriconazole has not been described in the radiology literature.

Mars' Atmosphere from Curiosity The Sample Analysis at Mars (SAM) instrument on the Curiosity rover that landed on Mars in August last year is designed to study the chemical and isotopic composition of the martian atmosphere. Mahaffy et al. (p. 263 ) present volume-mixing ratios of Mars' five major atmospheric constituents (CO 2 , Ar, N 2 , O 2 , and CO) and isotope measurements of 40 Ar/ 36 Ar and C and O in CO 2 , based on data from one of SAM's instruments, obtained between 31 August and 21 November 2012. Webster et al. (p. 260 ) used data from another of SAM's instruments obtained around the same period to determine isotope ratios of H, C, and O in atmospheric CO 2 and H 2 O. Agreement between the isotopic ratios measured by SAM with those of martian meteorites, measured in laboratories on Earth, confirms the origin of these meteorites and implies that the current atmospheric reservoirs of CO 2 and H 2 O were largely established after the period of early atmospheric loss some 4 billion years ago.

50% (and t value >3) of the peak t-value in the VOI. Average normalized FDG counts (NFC) were extracted. AD and MCI NFC obtained with the 2 approaches were compared to NCo NFC mean values. Cutoff points sensitivity and specificity, post-test likelihood ratios and p-values were assessed. Results: We studied 49 AD, 19 MCI, 9 NCo (no significant demographic difference found between groups). As compared to NCo, ANOVA of anatomical VOIs showed bilaterally reduced CG, pCu and IPC NFC in AD (P

We aimed to establish normal values on MDCT images for the atlantoaxial relationships including the atlantoaxial interval and lateral atlantodens interval (ADI) that could be used to detect atlantoaxial ligamentous injuries in adults and children.One hundred seventy-eight healthy adult patients between 20 and 40 years old and 112 pediatric patients between 2 months and 10 years old underwent cervical spine MDCT with multiplanar reconstructions. The width of the joint space between the lateral mass of C1 and the lateral mass of C2 was measured at three equidistant points on both the left and right sides on coronal reformatted images to determine the atlantoaxial interval. The distance between the lateral surface of the dens and the medial surface of the lateral mass of C1 was measured in the coronal plane to determine the lateral ADI bilaterally.The upper limit of the normal range of values for the atlantoaxial interval in adults was 3.34 mm on the right and 3.39 mm on the left. The upper limit of normal for the lateral ADI was 4.67 mm on the right and 5.6 mm on the left. More than 95% of the pediatric population was found to have an atlantoaxial interval of less than 3.9 mm on either side, a right lateral ADI of less than 7.4 mm, and a left lateral ADI of less than 8.0 mm.We propose that the obtained normal values be considered as the upper limits of the normal range for the atlantoaxial interval in adult and pediatric populations on MDCT images.

BACKGROUND There has been a significant reduction in the number of people with severe mental illness who spend extended periods in long-stay hospitals. Psychiatric and social services, both statutory and voluntary, aim to assist these people to stay in their local community. District health authorities, local authorities, housing associations and voluntary organisations are jointly expected to provide support for people with severe mental disorder/s. This 'support' may well involve some sort of special housing. OBJECTIVES To determine the effects of supported housing schemes compared with outreach support schemes or 'standard care' for people with severe mental disorder/s living in the community. SEARCH STRATEGY Cochrane Schizophrenia Group's Register of trials (February 2001) and the Cochrane Library (Issue 1, 2001) were searched using relevant phrases. These databases are compiled by methodical searches of BIOSIS, CINAHL, Dissertation abstracts, EMBASE, LILACS, MEDLINE, PSYNDEX, PsycINFO, RUSSMED, Sociofile, supplemented with hand searching of relevant journals and numerous conference proceedings. Reference list screening of relevant papers was performed. SELECTION CRITERIA Relevant randomised, or quasi-randomised, trials dealing with people with 'severe mental disorder/s' allocated to supported housing, outreach support schemes or standard care focusing on outcomes of service utilisation, mental state, satisfaction with care, social functioning, quality of life, and economic data, were sought. DATA COLLECTION AND ANALYSIS Studies were reliably selected, quality rated and data extracted. For dichotomous data, relative risks (RR) would have been estimated, with the 95% confidence intervals (CI). Where possible, the number needed to treat statistic (NNT) was to have been calculated. Analysis would have been by intention-to-treat. Normal continuous data were to have been summated using the weighted mean difference (WMD). Scale data were to have been presented for only those tools that had attained pre-specified levels of quality. Tests of heterogeneity and for publication bias were to have been undertaken. MAIN RESULTS No studies met the inclusion criteria although 139 citations were acquired from the searches. REVIEWER'S CONCLUSIONS Dedicated schemes whereby people with severe mental illness are located within one site or building with assistance from professional workers have potential for great benefit as they provide a 'safe haven' for people in need of stability and support. This, however, may be at the risk of increasing dependence on professionals and prolonging exclusion from the community. Whether or not the benefits outweigh the risks can only be a matter of opinion in the absence of reliable evidence. There is an urgent need to investigate the effects of supported housing on people with severe mental illness within a randomised trial.

Objective To evaluate the effect of tibial plateau levelling osteotomy on stifle extensor mechanism load in an ex vivo cruciate-intact canine cadaveric model. Study Design Ex vivo mechanical testing study. Animals Cadaveric canine pelvic limbs (n = 6). Materials and Methods A 21-mm tibial radial osteotomy was performed on pelvic limbs (n = 6) prior to being mounted into a load-bearing limb press. The proximal tibial segment was incrementally rotated until the anatomical tibial plateau angle had been rotated to at least 1°. The proportional change in stifle extensor mechanism load between the anatomical tibial plateau angle and the neutralized (∼6.5 degrees) and over-rotated (∼1°) tibial plateau angle was analysed using a one-sample t-test against a null hypothesis of no change. A p-value ≤0.05 was considered significant. Results There was no significant change in the stifle extensor mechanism load from the anatomical tibial plateau angle (308 N [261–355 N]) to the neutralized tibial plateau angle (313 N [254–372 N]; p =.81), or from the anatomical tibial plateau angle to the over-rotated tibial plateau angle (303 N [254–352 N; p = 0.67). Conclusion Tibial plateau levelling osteotomy does not significantly alter stifle extensor mechanism load at either a neutralized or over-rotated tibial plateau angle in our cruciate-intact model.