Comparison of the Microstructural, Mechanical and Corrosion Resistance Properties of Ti6Al4V Samples Manufactured by LENS and Subjected to Various Heat Treatments

In this paper, the influences of two post-heat treatments on the structural, mechanical and corrosion resistance properties of additively manufactured Ti6Al4V alloys were discussed in detail. The materials were produced using the laser engineering net shaping (LENS) technique, and they were subjected to annealing without pressure and hot isostatic pressing (HIP) under a pressure of 300 MPa for 30 min at temperatures of 950 °C and 1050 °C. Annealing without pressure led to the formation of a thin plate structure, which was accompanied by decreasing mechanical properties and increasing elongation and corrosion resistance values. For the HIP process, the formation of a thick plate structure could be observed, resulting in the material exhibiting optimal mechanical properties and unusually high elongation. The best mechanical and corrosion resistance properties were obtained for the material subjected to HIP at 950 °C.

Properties of Padding Welds Made of CuAl2 Multiwire and CuAl7 Wire in TIG Process

This paper presents the influence of the Hot Isostatic Pressing (HIP) process on the structure, mechanical properties and corrosion resistance of padding welds made using the TIG method from aluminium bronzes-CuAl7 and CuAl2 (a composite bundled wire). The tested CuAl7 material was a commercial welding wire, while the CuAl2 composite was an experimental one (a prototype of the material produced in multiwire technology). The wire contains a bundle of component materials-in this case, copper in the form of a tube and aluminium in the form of rods. The padding welds were manufactured for both the CuAl7 wire and the CuAl2 multiwire. The prepared samples were subjected to the Hot Isostatic Pressing (HIP) process, chemical composition tests were performed, and then the samples were subjected to observations using light microscopy, Vickers hardness testing, electrical conductivity tests, and apparent density determination using Archimedes' Principle. Tribological tests (the 'pin on disc' method) and neutral salt spray corrosion tests were conducted. The padding weld made of CuAl2 multifiber material subjected to the HIP process is characterized by an improvement in density of 0.01 g/cm3; a homogenization of the hardness results across the sample was also observed. The average hardness of the sample after the HIP process decreased by about 15HV, however, the standard deviation also decreased by about 8HV. The electrical conductivity of the CuAl2 welded sample increased from 16.35 MS/m to 17.49 MS/m for the CuAl2 sample after the HIP process. As a result of this process, a visible increase in electrical conductivity was observed in the case of the wall made of the CuAl2 multiwire-an increase of 1.14 MS/m.

High Impact for Whom? A Qualitative Analysis of Organization Concerns About the Transition to High-Impact Prevention Policy

HIV represents a significant health burden in the United States. In 2012, the Centers for Disease Control and Prevention (CDC) stopped recommending many once-promoted interventions as part of a shift from one HIV intervention policy, Diffusion of Effective Behavioral Interventions (DEBI), to another, High Impact Prevention (HIP). Twenty-nine staff members from 10 organizations were interviewed to explore how organizations reacted to this shift. Three major themes emerged: (1) Personal experience, community assessment, and epidemiological evidence influenced organizations' perceptions of efficacy and preference for earlier interventions. (2) Organizations were concerned that HIP interventions were not a good fit for their priority populations. (3) Organizations were frustrated with the top-down approach by the CDC prioritizing HIP interventions over earlier interventions. These results indicate that organizations continue to see value in and provide DEBI interventions. In addition, a more participatory process incorporating qualitative evidence and organizations' experiences may be necessary to achieve widespread de-implementation of DEBI interventions.

Microstructure of TiAl Capsules Processed by Electron Beam Powder Bed Fusion Followed by Post-Hot Isostatic Pressing

The microstructures of intermetallic γ-titanium aluminide (TiAl) alloys are subjected to a certain degree of Al evaporation when processed by electron beam powder bed fusion (EB-PBF). The magnitude of the Al-loss is mainly correlated with the process parameters, and highly energetic parameters produce significant Al evaporation. The Al-loss leads to different microstructures, including the formation of inhomogeneous banded structures, thus negatively affecting its mechanical performance. For this reason, the current work deals with creating EB-PBFed TiAl capsules with the inner part produced using only the pre-heating step and melting parameters with low energetic parameters applying high beam speed from 5000 to 3000 mm/s. This approach is investigated to reduce the Al-loss and microstructure inhomogeneity after hot isostatic pressing (HIP). The results showed that the HIP treatment effectively densified the capsules obtaining a relative density of around 100%. After HIP, the capsules produced with the inner part melted at 3000 mm/s presented a lower area shrinkage (around 6.6%) compared to the capsules produced using only the pre-heating step in the core part (around 20.7%). The different magnitudes of shrinkage derived from different levels of residual porosity consolidated during the HIP process. The HIPed capsules exhibited the presence of previous particle boundaries (PPBs), covered by α2 phases. Notably, applying low energetic parameters to melt the core partially eliminates the particles' surface, thus reducing the PPBs formation. In this case, the capsules melted with low energetic parameters (3000 mm/s) exhibited α2 concentration of 3.5% and an average size of 13 µm compared to the capsules produced with the pre-heating step in the inner part with an α2 around 5.7% and an average size around 23 µm. Moreover, the Al-loss of the capsules was drastically limited, as determined by X-ray fluorescence (XRF) analysis. More in detail, the capsules produced with the pre-heating step reported an atomic percentage of Al of 48.75, while using low energetic melting parameters led to 48.36. This result was interesting, considering that the massive samples produced with standard parameters (so more energetic ones) revealed atomic Al percentage from 48.04 to 47.70. Finally, the recycled small particles showed a higher fraction of α2 phases with respect to the coarse particles, as determined by X-ray diffraction (XRD).

Influence of Different Build Orientations and Heat Treatments on the Creep Properties of Inconel 718 Produced by PBF-LB

Inconel 718 is a nickel-based superalloy with excellent creep properties and good tensile and fatigue strength. In the field of additive manufacturing, it is a versatile and widely used alloy due to its good processability in the powder bed fusion with laser beam (PBF-LB) process. The microstructure and mechanical properties of the alloy produced by PBF-LB have already been studied in detail. However, there are fewer studies on the creep resistance of additively manufactured Inconel 718, especially when the focus is on the build direction dependence and post-treatment by hot isostatic pressing (HIP). Creep resistance is a crucial mechanical property for high-temperature applications. In this study, the creep behavior of additively manufactured Inconel 718 was investigated in different build orientations and after two different heat treatments. The two heat treatment conditions are, first, solution annealing at 980 °C followed by aging and, second, HIP with rapid cooling followed by aging. The creep tests were performed at 760 °C and at four different stress levels between 130 MPa and 250 MPa. A slight influence of the build direction on the creep properties was detected, but a more significant influence was shown for the different heat treatments. The specimens after HIP heat treatment show much better creep resistance than the specimens subjected to solution annealing at 980 °C with subsequent aging.

The Effect of Postprocessing on the Fatigue Properties of Ti-5Al-5Mo-5V-1Cr-1Fe Produced Using Electron Beam Melting

Despite the significant potential advantages of processing Ti-5Al-5Mo-5V-1Cr-1Fe alloy (Ti-55511) using Electron Beam Melting (PBF-EB/M), when compared to conventional manufacturing technologies, the resulting internal defects are an important characteristic of such additive technologies and can highly decrease mechanical properties. One of the most dangerous defects formed during metal additive manufacturing processes are material discontinuities such as a lack of fusion. Defects of this type, due to their "flat" nature, are difficult to characterize. For cycle-loaded specimens, where the loading force acts perpendicular to the lack-of-fusion plane, defects of this type can significantly reduce fatigue properties. This paper presents the results of research aimed at improving the fatigue properties of Ti55511 alloy by reducing the influence of the lack-of-fusion defect on fatigue damage. The static and fatigue properties of specimens in the as-built state, as well as after hot isostatic pressing (HIP) treatment, were analyzed. The effect of HIP on both the reduction of pores and the degree of sphericity when using the X-ray computed tomography (XCT) system was presented. The change in the microstructure after HIP was analyzed in terms of the change in the size of individual phases, as well as the change in the phase ratio. This paper also contains a fractographic analysis of the samples after tensile and fatigue tests.

The influence of a large build area on the microstructure and mechanical properties of PBF-LB Ti-6Al-4 V alloy

This study investigated the print homogeneity of Ti-6Al-4 V alloy parts, when printed over a large build area of 250 × 250 × 170 mm³, using a production scale laser powder bed additive manufacturing system. The effect of part location across this large build area was investigated based on printed part porosity, microstructure, hardness, and tensile properties. In addition, a Hot Isostatic Pressing (HIP) treatment was carried out on the as-built parts, to evaluate its impact on the material properties. A small increase in part porosity from 0.01 to 0.09%, was observed with increasing distance from the argon gas flow inlet, which was located on one side of the build plate, during printing. This effect, which was found to be independent of height from the build plate, is likely to be associated with enhanced levels of condensate or spatter residue, being deposited at distances, further from the gas flow. Despite small differences in porosity, no significant differences were obtained for microstructural features such as prior β grain, α lath thickness, and phase fraction, over the entire build area. Due to this, mechanical performances such as hardness and tensile strengths were also found to be homogenous across the build area. Additionally, it was also observed based on the lattice constants that partial in-situ decomposition of α ' → α + β phases occurred during printing. Post HIP treatment result showed a decrease of 7 and 6%, in the yield strength (YS) and ultimate tensile strength (UTS), respectively, which was associated with a coarsening of α lath widths. The potential of the laser powder bed system for large area printing was successfully demonstrated based on the homogenous microstructure and mechanical properties of the Ti-6Al-4 V alloy parts.

Sliding Wear Behavior of Intermetallic Ti-45Al-2Nb-2Mn-(at%)-0.8vol%TiB2 Processed by Centrifugal Casting and Hot Isostatic Pressure: Influence of Microstructure

Intermetallic alloys such as titanium aluminides (TiAl) are potential materials for aerospace applications at elevated temperatures. TiAl intermetallics have low weight and improved efficiency under aggressive environments. However, there is limited information about wear behavior of these alloys and their microstructure. The present work aims to study the influence of the microstructure in the tribological behavior of TiAl intermetallic alloy (45Al-2Mn-2Nb(at%)-0.8 vol%TiB₂). Wear tests were performed on samples manufactured by centrifugal casting (CC) and hot isostatic pressure (HIP). Reciprocating sliding wear test was carried out for TiAl, it was combined with different loads and frequencies. Wear tracks were analyzed through opto-digital microscopy and electron microscopy (SEM). The results obtained reveal that CC intermetallics present the lowest volume wear lost, approximately 20% less than HIP intermetallics. This good behavior could be related to the high hardness material, associated with the main microstructure where CC intermetallic has nearly lamellar microstructure and HIP intermetallics present duplex microstructure.

Hyperglycemia in pregnancy - prevalence and perinatal outcomes. A retrospective multicenter cohort study in Poland

OBJECTIVES

Hyperglycemia in pregnancy (HIP) is one of the most common complications of pregnancy. Recently adopted new criteria for the diagnosis of HIP as well as the greater prevalence of risk factors could have a significant impact on HIP prevalence. The objective of the study was to assess the rates of HIP and the associated complications.

MATERIAL AND METHODS

This was a retrospective analysis of clinical records from pregnant women who delivered in eight tertiary hospitals in Poland in 2016.

RESULTS

The number of pregnant women with hyperglycemia totaled 1280 (7.25%), including gestational diabetes mellitus (GDM) in 1169 (6.62%) women and pregestational diabetes mellitus (PGDM) in 111 (0.63%). In addition to dietary modifications, 477 (41% of the GDM group) women received medical treatment (GDMG2). In women with PGDM multiple daily insulin injections (MDI) were used in 53 (47.7%) cases, continuous subcutaneous insulin infusions (CSII) in 57 (51.3%) cases and one woman was treated with metformin. The rate of cesarean sections was 69.4% and 62.9% for PGDM and GDM, respectively. Large-for-gestational-age (LGA) infants accounted for 38% and 21% of births in the PGDM and GDM groups, respectively. Of note are high rates of hyperbilirubinemia in infants born to mothers treated with insulin (13.5% for PGDM and 14.4% for GDMG2) vs infants born to mothers with diet (GDMG1) (3.4%).

CONCLUSIONS

In Poland, the prevalence of HIP has nearly doubled in the past twenty years. Even with appropriate management, HIP is a significant risk factor for a cesarean section delivery, bearing an LGA infant and adverse neonatal outcomes.

Thermal Mass Effect on the Solution Cooling Rate and on HIPped Astroloy Component Properties

Astroloy is a Ni-based superalloy with high-volume fraction of γ′, which gives high temperature properties but reduces its forgeability. Therefore, powder metallurgy manufacturing processes such as Near Net Shape HIPping are the most suitable manufacturing technology for Astroloy. However, NNSHIP has its own drawbacks, such as the formation of prior particle boundaries (PPBs), which usually tend to decrease material mechanical properties. The detrimental effect of PPBs can be reduced by optimizing the entire HIP processing route. Conventional HIP cycles have very low cooling rates, especially in big components from industry, and thus a series of post-heat treatments must be applied in order to achieve desirable microstructures and improve the mechanical properties. Standard heat treatments for Astroloy are long and tedious with several steps of solutioning, stabilization and precipitation. In this work, two main studies have been performed. First, the effect of the cooling rate after the solutioning treatment, which is driven by the materials’ thermal mass, on the Astroloy microstructure and mechanical properties was studied. Experimental analyses and simulation techniques have been used in the present work and it has been found that higher cooling rates after solutioning increase the density of tertiary γ′ precipitates by 85%, and their size decreases by 22%, which leads to an increase in hardness from 356 to 372 HB30. This hardness difference tends to reduce after subsequent standard heat treatment (HT) that homogenizes the microstructure. The second study shows the effect of different heat treatments on the microstructure and hardness of samples with two different thermal masses (can and cube). More than double the density of γ′ precipitates was found in small cubes in comparison with cans with a higher thermal mass. Therefore, the hardness in cubes is between 4 and 20 HB 30 higher than in large cans, depending on the applied HT.

A feasibility study to assess the design of a multicentre randomized controlled trial of the clinical and cost-effectiveness of a caregiving intervention for people following hip fracture surgery

Aims

This study aims to assess the feasibility of conducting a pragmatic, multicentre randomized controlled trial (RCT) to test the clinical and cost-effectiveness of an informal caregiver training programme to support the recovery of people following hip fracture surgery.

Methods

This will be a mixed-methods feasibility RCT, recruiting 60 patients following hip fracture surgery and their informal caregivers. Patients will be randomized to usual NHS care, versus usual NHS care plus a caregiver-patient dyad training programme (HIP HELPER). This programme will comprise of three, one-hour, one-to-one training sessions for the patient and caregiver, delivered by a nurse, physiotherapist, or occupational therapist. Training will be delivered in the hospital setting pre-patient discharge. It will include practical skills for rehabilitation such as: transfers and walking; recovery goal setting and expectations; pacing and stress management techniques; and introduction to the HIP HELPER Caregiver Workbook, which provides information on recovery, exercises, worksheets, and goal-setting plans to facilitate a ‘good’ recovery. After discharge, patients and caregivers will be supported in delivering rehabilitation through three telephone coaching sessions. Data, collected at baseline and four months post-randomization, will include: screening logs, intervention logs, fidelity checklists, quality assurance monitoring visit data, and clinical outcomes assessing quality of life, physical, emotional, adverse events, and resource use outcomes. The acceptability of the study intervention and RCT design will be explored through qualitative methods with 20 participants (patients and informal caregivers) and 12 health professionals.

Discussion

A multicentre recruitment approach will provide greater external validity across population characteristics in England. The mixed-methods approach will permit in-depth examination of the intervention and trial design parameters. The findings will inform whether and how a definitive trial may be undertaken to test the effectiveness of this caregiver intervention for patients after hip fracture surgery.

Cite this article: Bone Jt Open 2021;2(11):909–920.

Texturing and Phase Evolution in Ti-6Al-4V: Effect of Electron Beam Melting Process, Powder Re-Using, and HIP Treatment

The research demonstrates microstructural changes and development of specific texture in Ti-6Al-4V specimens produced by electron beam melting (EBM) under different conditions. The effect of two factors, namely, raw material (powder) recycling and hot isostatic pressing (HIP), on the EBM produced samples structure and properties, has been explored. The as-printed and treated samples were investigated using electron backscattered diffraction (EBSD) analysis. Modification of mechanical properties after the EBM and HIP are explained by the EBSD data on microstructural phenomena and phase transformations. The work is devoted to assessing the possibility of reusing the residual titanium alloy powder for the manufacture of titanium components by the combination of EBM and HIP methods.

Neonatal diabetes mutations disrupt a chromatin pioneering function that activates the human insulin gene

Despite the central role of chromosomal context in gene transcription, human noncoding DNA variants are generally studied outside of their genomic location. This limits our understanding of disease-causing regulatory variants. INS promoter mutations cause recessive neonatal diabetes. We show that all INS promoter point mutations in 60 patients disrupt a CC dinucleotide, whereas none affect other elements important for episomal promoter function. To model CC mutations, we humanized an ∼3.1-kb region of the mouse Ins2 gene. This recapitulated developmental chromatin states and cell-specific transcription. A CC mutant allele, however, abrogated active chromatin formation during pancreas development. A search for transcription factors acting through this element revealed that another neonatal diabetes gene product, GLIS3, has a pioneer-like ability to derepress INS chromatin, which is hampered by the CC mutation. Our in vivo analysis, therefore, connects two human genetic defects in an essential mechanism for developmental activation of the INS gene.

The STI1-domain is a flexible alpha-helical fold with a hydrophobic groove

STI1-domains are present in a variety of co-chaperone proteins and are required for the transfer of hydrophobic clients in various cellular processes. The domains were first identified in the yeast Sti1 protein where they were referred to as DP1 and DP2. Based on hidden Markov model searches, this domain had previously been found in other proteins including the mammalian co-chaperone SGTA, the DNA damage response protein Rad23, and the chloroplast import protein Tic40. Here, we refine the domain definition and carry out structure-based sequence alignment of STI1-domains showing conservation of five amphipathic helices. Upon examinations of these identified domains, we identify a preceding helix 0 and unifying sequence properties, determine new molecular models, and recognize that STI1-domains nearly always occur in pairs. The similarity at the sequence, structure, and molecular levels likely supports a unified functional role.

Tailoring Microstructure and Mechanical Properties of Additively-Manufactured Ti6Al4V Using Post Processing

Additively-manufactured Ti-6Al-4V (Ti64) exhibits high strength but in some cases inferior elongation to those of conventionally manufactured materials. Post-processing of additively manufactured Ti64 components is investigated to modify the mechanical properties for specific applications while still utilizing the benefits of the additive manufacturing process. The mechanical properties and fatigue resistance of Ti64 samples made by electron beam melting were tested in the as-built state. Several heat treatments (up to 1000 °C) were performed to study their effect on the microstructure and mechanical properties. Phase content during heating was tested with high reliability by neutron diffraction at Los Alamos National Laboratory. Two different hot isostatic pressings (HIP) cycles were tested, one at low temperature (780 °C), the other is at the standard temperature (920 °C). The results show that lowering the HIP holding temperature retains the fine microstructure (~1% β phase) and the 0.2% proof stress of the as-built samples (1038 MPa), but gives rise to higher elongation (~14%) and better fatigue life. The material subjected to a higher HIP temperature had a coarser microstructure, more residual β phase (~2% difference), displayed slightly lower Vickers hardness (~15 HV_10N), 0.2% proof stress (~60 MPa) and ultimate stresses (~40 MPa) than the material HIP'ed at 780 °C, but had superior elongation (~6%) and fatigue resistance. Heat treatment at 1000 °C entirely altered the microstructure (~7% β phase), yield elongation of 13.7% but decrease the 0.2% proof-stress to 927 MPa. The results of the HIP at 780 °C imply it would be beneficial to lower the standard ASTM HIP temperature for Ti6Al4V additively manufactured by electron beam melting.

The Arthroplasty Candidacy Help Engine tool to select candidates for hip and knee replacement surgery: development and economic modelling

BACKGROUND

There is no good evidence to support the use of patient-reported outcome measures (PROMs) in setting preoperative thresholds for referral for hip and knee replacement surgery. Despite this, the practice is widespread in the NHS.

OBJECTIVES/RESEARCH QUESTIONS

Can clinical outcome tools be used to set thresholds for hip or knee replacement? What is the relationship between the choice of threshold and the cost-effectiveness of surgery?

METHODS

A systematic review identified PROMs used to assess patients undergoing hip/knee replacement. Their measurement properties were compared and supplemented by analysis of existing data sets. For each candidate score, we calculated the absolute threshold (a preoperative level above which there is no potential for improvement) and relative thresholds (preoperative levels above which individuals are less likely to improve than others). Owing to their measurement properties and the availability of data from their current widespread use in the NHS, the Oxford Knee Score (OKS) and Oxford Hip Score (OHS) were selected as the most appropriate scores to use in developing the Arthroplasty Candidacy Help Engine (ACHE) tool. The change in score and the probability of an improvement were then calculated and modelled using preoperative and postoperative OKS/OHSs and PROM scores, thereby creating the ACHE tool. Markov models were used to assess the cost-effectiveness of total hip/knee arthroplasty in the NHS for different preoperative values of OKS/OHSs over a 10-year period. The threshold values were used to model how the ACHE tool may change the number of referrals in a single UK musculoskeletal hub. A user group was established that included patients, members of the public and health-care representatives, to provide stakeholder feedback throughout the research process.

RESULTS

From a shortlist of four scores, the OHS and OKS were selected for the ACHE tool based on their measurement properties, calculated preoperative thresholds and cost-effectiveness data. The absolute threshold was 40 for the OHS and 41 for the OKS using the preferred improvement criterion. A range of relative thresholds were calculated based on the relationship between a patient's preoperative score and their probability of improving after surgery. For example, a preoperative OHS of 35 or an OKS of 30 translates to a 75% probability of achieving a good outcome from surgical intervention. The economic evaluation demonstrated that hip and knee arthroplasty cost of < £20,000 per quality-adjusted life-year for patients with any preoperative score below the absolute thresholds (40 for the OHS and 41 for the OKS). Arthroplasty was most cost-effective for patients with lower preoperative scores.

LIMITATIONS

The ACHE tool supports but does not replace the shared decision-making process required before an individual decides whether or not to undergo surgery.

CONCLUSION

The OHS and OKS can be used in the ACHE tool to assess an individual patient's suitability for hip/knee replacement surgery. The system enables evidence-based and informed threshold setting in accordance with local resources and policies. At a population level, both hip and knee arthroplasty are highly cost-effective right up to the absolute threshold for intervention. Our stakeholder user group felt that the ACHE tool was a useful evidence-based clinical tool to aid referrals and that it should be trialled in NHS clinical practice to establish its feasibility.

FUTURE WORK

Future work could include (1) a real-world study of the ACHE tool to determine its acceptability to patients and general practitioners and (2) a study of the role of the ACHE tool in supporting referral decisions.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

How Systemic Sclerosis Affects Healthcare Use and Complication Rates after Total Hip Arthroplasty

OBJECTIVE

To assess whether outcomes after primary total hip arthroplasty (THA) differ in systemic sclerosis (SSc).

METHODS

We used the 1998-2014 US National Inpatient Sample. THA and SSc were identified using procedure and diagnostic codes, respectively. Multivariable-adjusted logistic regression analyses assessed the association of SSc with in-hospital complications (implant infection, revision, transfusion, mortality) post-THA and associated healthcare use (hospital charges, hospital stay, discharge to non-home setting), adjusting for age, sex, race, Deyo-Charlson comorbidity index, primary diagnosis for THA, household income, and insurance payer.

RESULTS

Of the 4,116,485 primary THA performed in the United States in 1998-2014, SSc patients made up 0.06% (n = 2672). In multivariable-adjusted analyses, compared to people without SSc, people with SSc had higher adjusted OR (95% CI) of the following post-primary THA: (1) non-home discharge, 1.25 (95% CI 1.03-1.50); (2) hospital stay > 3 days, 1.61 (95% CI 1.35-1.92); (3) transfusion, 1.54 (95% CI 1.28-1.84); and (4) in-hospital revision, 9.53 (95% CI 6.75-13.46). Differences in in-hospital mortality had a nonsignificant trend [2.19 (95% CI 0.99-4.86)]. There were no differences in total hospital charges or implant infection rates.

CONCLUSION

SSc was associated with a higher rate of in-hospital complications and healthcare use after primary THA. Future studies should examine whether pre- or postoperative interventions can reduce the risk of post-THA complications in people with SSc.

Hydrophobic ion pairing of a GLP-1 analogue for incorporating into lipid nanocarriers designed for oral delivery

The lipophilic character of peptides can be tremendously improved by hydrophobic ion pairing (HIP) with counterions to be efficiently incorporated into lipid-based nanocarriers (NCs). Herein, HIPs of exenatide with the cationic surfactant tetraheptylammonium bromide (THA) and the anionic surfactant sodium docusate (DOC) were formed to increase its lipophilicity. These HIPs were incorporated into lipid based NCs comprising 41% Capmul MCM, 15% Captex 355, 40% Cremophor RH and 4% propylene glycol. Exenatide-THA NCs showed a log Dlipophilic phase (LPh)/release medium (RM) of 2.29 and 1.92, whereas the log DLPh/RM of exenatide-DOC was 1.2 and -0.9 in simulated intestinal fluid and Hanks' balanced salts buffer (HBSS), respectively. No significant hemolytic activity was induced at a concentration of 0.25% (m/v) of both blank and loaded NCs. Exenatide-THA NCs and exenatide-DOC NCs showed a 10-fold and 3-fold enhancement in intestinal apparent membrane permeability compared to free exenatide, respectively. Furthermore, orally administered exenatide-THA and exenatide-DOC NCs in healthy rats resulted in a relative bioavailability of 27.96 ± 5.24% and 16.29 ± 6.63%, respectively, confirming the comparatively higher potential of the cationic surfactant over the anionic surfactant. Findings of this work highlight the potential of the type of counterion used for HIP as key to successful design of lipid-based NCs for oral exenatide delivery.

Validation of Spanish version of the human papilloma virus impact profile (HIP)

Objective: To examine the construct validity and reliability of the Spanish version of the HPV Impact Profile scale (HIP) among women in Medellin, Colombia.Methods: We conducted a nested analysis of data from the pragmatic randomized controlled trial "Evaluation of Strategies for Optimal Clinical Management of Women with Atypical Squamous Cells of Undetermined Significance" (ASCUS-COL; NCT02067468). Women with Atypical Squamous Cells of Undetermined Significance (ASCUS) were randomly assigned to one of three triage strategies (Pap smear, colposcopy, HPV). Participants completed a questionnaire with sociodemographic information and the HIP scale translated into Spanish at baseline, two weeks after receiving triage test results, and one year after the second questionnaire. We conducted exploratory and confirmatory factorial analysis, and then assessed test reliability using Cronbach's alpha. Subsequently, we conducted multigroup confirmatory factor analysis to assess differences according to women´s age, and configurational invariance of the factor structure over the three time measures.Results: The sample consisted of 675 women, with a mean age of 40 years. The exploratory and confirmatory factor analysis for the HIP showed a seven-factor structure with appropriate adjustment indicators ([Formula: see text]= 1466.783, p < .0001). Only two items (1 and 10) had low factor loads and were removed from the confirmatory analysis. Multigroup analysis according to women's age showed acceptable goodness of fit (RMSEA = 0.037, CFI/TLI:0.998/0.998). The factor structure was similar among the tree measures and the model preserved acceptable goodness of fit (RMSEA = 0.079, CFI:0.86). The Cronbach's alpha for the total score was 0.91, with the lowest score for sexual impact (0.49) and the highest score for worries and concerns (0.90).Conclusions: The Spanish version of the HIP had adequate reliability and construct validity, and its use could be considered in clinic and research settings.

Microstructure Evolution and Mechanical Properties of PM-Ti43Al9V0.3Y Alloy

A novel strategy of microstructure design is introduced to improve the mechanical properties of TiAl alloys, fabricated by powder metallurgy. The gas atomization powder and as-HIPed (Hot isostatic pressing) TiAl are investigated by scanning electron microscopy, energy dispersive spectrometry, transmission electron microscopy, and electron backscattered diffraction. The dispersed submicron precipitate in the microstructure is determined to be Y₂O₃. A microstructure with uniform fine grain is obtained. The room temperature strength and strain reach 793 MPa and 1.5%, respectively. The strength and strain at 700 °C are still as high as 664 MPa and 9.2%, respectively. The fine grain and precipitate lead to a high room-temperature plasticity.

Ten-year outcomes of cementless anatomical femoral implants after 3D computed tomography planning. Follow-up note

BACKGROUND

Pre-operative 3D planning based on computed tomography (CT) imaging is used to optimise the restitution of normal hip anatomy during primary total hip arthroplasty (THA). Although CT planning has been proven effective and reproducible, its influence on long-term THA outcomes is unknown. In this 10-year follow-up study of patients managed with the same technique of CT-planned primary anatomical THA, the objectives were to assess femoral implant survival, long-term functional outcomes, 10-year outcomes of titanium modular femoral necks, and associations with the dislocation rate. Hypothesis Pre-operative CT planning of primary THA ensures achievement of the NICE criterion of a lower than 5% femoral revision rate within 10 years.

MATERIAL AND METHODS

The study included 61 patients (61 hips) managed between 2004 and 2007 by CT-planned primary THA via the posterior approach, with an uncemented anatomical femoral component (SPS^®, Symbios); when deemed necessary by the surgeon to restore normal anatomy, a titanium modular femoral neck was used (35/61 patients). After 10 years, 17 patients had died and 3 were lost to follow-up, leaving 41 patients with a mean age of 76 years (range, 60-91 years) for re-evaluation. Clinical outcomes were assessed by determining the Harris Hip Score (HHS) and the Postel-Merle d'Aubigné (PMA) score, which were compared to baseline values. Radiographs were evaluated using the AGORA Roentgenographic Assessment system (ARA).

RESULTS

The 10-year femoral component survival rate was 96% (95%CI, 88;99%). Revision was required in 4 patients, to treat delayed peri-prosthetic fractures (n=2) or to correct initial cup malposition (n=2). No changes occurred from 2010 to last follow-up in the mean HHS (90 [95%CI, 84;95] and 91 [95%CI, 77;96], respectively) or mean PMA score (16 [95%CI, 14;17] and 15.5 [95%CI, 14;16.5], respectively). The mean ARA score was 5.2 (range, 3-6) at last follow-up. No complications related to the use of modular femoral necks were recorded. Dislocation occurred in 2 patients, but in neither was the pre-operative plan followed during surgery.

DISCUSSION

The SPS^® stem produced good 10-year clinical and radiographic outcomes. No patients experienced complications related to use of a titanium modular femoral neck. The restoration of anatomical hip geometry made possible by pre-operative CT planning provided sustained clinical improvements with a low complication rate.

LEVEL OF EVIDENCE

IV, retrospective observational cohort study.

Appropriateness and Total Hip Arthroplasty: Determining the Structure of the American Academy of Orthopaedic Surgeons System of Classification

OBJECTIVE

In late 2017, the American Academy of Orthopaedic Surgeons (AAOS) published an appropriateness classification system using the RAND/University of California, Los Angeles (UCLA) approach for patients with hip osteoarthritis (OA). We determined the contribution of predictor variables in the system to final classification, rated as "appropriate," "may be appropriate," or "rarely appropriate" for hip arthroplasty.

METHODS

An AAOS-appointed expert panel developed 270 clinical vignettes incorporating all permutations of 5 evidence-driven indication variables associated with hip arthroplasty outcome or need. Indication variables were age, function-limiting pain severity, radiographic hip OA severity, hip motion, and presence of modifiable prognostic risk factors. Multinomial regression determined the relative contribution of each variable and a classification tree method determined variable combinations contributing to final classification.

RESULTS

Patient age and hip OA severity were the dominant predictors of appropriateness classification in both statistical models. Function-limiting pain made a slight contribution relative to age and hip OA severity while hip motion and the presence of modifiable prognostic factors did not meaningfully contribute to final classification. The regression model explained about 99% of the variance and the classification tree had an accuracy of 87.8%.

CONCLUSION

Classification for hip arthroplasty appropriateness in the AAOS system is driven almost exclusively by age and OA severity. Function-limiting pain, a major reason patients seek surgery, contributes only slightly to the AAOS appropriateness criteria. The system relies heavily on traditional variables of patient age and radiographic hip OA severity. Future study of actual patient outcomes is needed to further test the validity of the AAOS system.

Mechanical Loading of the Femoral Neck in Human Locomotion

Advancing age and reduced loading are associated with a reduction in bone formation. Conversely, loading increases periosteal apposition and may reduce remodeling imbalance and slow age-related bone loss, an important outcome for the proximal femur, which is a common site of fracture. The ability to take advantage of bone's adaptive response to increase bone strength has been hampered by a lack of knowledge of which exercises and specific leg muscles load the superior femoral neck: a common region of microcrack initiation and progression following a sideways fall. We used an in vivo method of quantifying focal strains within the femoral neck in postmenopausal women during walking, stair ambulation, and jumping. Relative to walking, stair ambulation and jumping induced significantly higher strains in the anterior and superior aspects of the femoral neck, common regions of microcrack initiation and progression following a fall. The gluteus maximus, a hip extensor muscle, induced strains in the femoral neck during stair ambulation and jumping, in contrast to walking which induced strains via the iliopsoas, a hip flexor. The ground reaction force was closely associated with the level of strain during each task, providing a surrogate indicator of the potential for a given exercise to load the femoral neck. The gluteal muscles combined with an increased ground reaction force relative to walking induce high focal strains within the anterosuperior region of the femoral neck and therefore provide a target for exercise regimens designed to slow bone loss and maintain or improve microstructural strength. Model files used for calculating femoral neck strains are available at uitbl.mechse.illinois.edu/downloads © 2018 American Society for Bone and Mineral Research.

Association of Physical Activity with Late-life Mobility Limitation among Women with Total Joint Replacement for Knee or Hip Osteoarthritis

OBJECTIVE

To examine the association between leisure-time physical activity (PA) and survival to age 85 with mobility limitation or death before age 85 after total knee (TKR) or total hip replacement (THR) for osteoarthritis (OA).

METHODS

This was a prospective study among participants from the Women's Health Initiative (WHI), recruited 1993-1998 (baseline age 65-79 yrs) and followed through 2012. Medicare claims data were linked to WHI data to determine TKR (n = 1986) and THR (n = 1034). Self-reported PA was collected before total joint replacement (TJR).

RESULTS

Women who were physically inactive before THR had the highest risk of mobility limitation at age 85 (OR 2.36, 95% CI 1.30-4.26) compared with women who had the highest amount of PA [> 17.42 metabolic equivalent of task (MET)-hrs/week]. Women who reported no moderate to vigorous PA (MVPA) before THR had the strongest risk of mobility limitation (OR 2.00, 95% CI 1.24-3.22) compared with women with the highest level of MPVA (≥ 15 MET-hrs/week). Women who were physically inactive before TKR had the highest risk of mobility limitation (OR 1.68, 95% CI 1.15-2.45) compared with women who had the highest PA level. Women who reported no MVPA before TKR had the strongest risk of mobility limitation (OR 1.60, 95% CI 1.16-2.19) compared with women with the highest level of MPVA. There were significant dose-response associations of lower PA levels with increased risk of late-life mobility limitation and death.

CONCLUSION

Women with lower PA levels before TJR were more likely to experience mobility limitation in late life following TJR for hip or knee OA.

Shuffling peptides to create T-cell epitopes: does the immune system play cards?

For a long time, immunologists have believed that classical CD4⁺ and CD8⁺ T cells recognize peptides (referred to as epitopes), derived from protein antigens presented by MHC/HLA class I or II. Over the past 10-15 years, it has become clear that epitopes recognized by CD8⁺, and more recently CD4⁺ T cells, can be formed by protein splicing. Here, we review the discovery of spliced epitopes recognized by tumor-specific human CD8⁺ T cells. We discuss how these epitopes are formed and some of the unusual variants that have been reported. Now, over a decade since the first report, evidence is emerging that spliced CD8⁺ T-cell epitopes are much more common, and potentially much more important, than previously imagined. Recent work has shown that epitopes recognized by CD4⁺ T cells can also be formed by protein splicing. We discuss the recent discovery of spliced CD4⁺ T-cell epitopes and their potential role as targets of autoimmune T-cell responses. Finally, we highlight some of the new questions raised from our growing appreciation of T-cell epitopes formed by peptide splicing.

Traumatic brain injury in pedestrian-vehicle collisions: Convexity and suitability of some functionals used as injury metrics

BACKGROUND AND OBJECTIVE

Abrupt accelerations or decelerations can cause large strain in brain tissues and, consequently, different forms of Traumatic Brain Injury (TBI). In order to predict the effect of the accelerations on the soft tissues of the brain, many different injury metrics have been proposed (typically, an injury metric is a real valued functional of the accelerations). The objective of this article is to make a formal and empirical comparison, in order to identify general criteria for reasonable injury metrics, and propose a general guideline to avoid ill-proposed injury metrics.

METHODS

A medium-sized sample of vehicle-pedestrian collisions, from Post Mortem Human Subject (PMHS) tests, is analyzed. A statistical study has been conducted in order to determine the discriminant power of the usual metrics. We use Principal Component Analysis to reduce dimensionality and to check consistency among the different metrics. In addition, this article compares the mathematical properties of some of these functionals, trying to identify the desirable properties that any of those functionals needs to fulfill in order to be useful for optimization.

RESULTS

We have found a pair-wise consistency of all the currently used metrics (any two injury metrics are always positively related). In addition, we observed that two independent principal factors explain about 72.5% of the observed variance among all collision tests. This is remarkable because it indicates that despite high number of different injury metrics, a reduced number of variables can explain the results of all these metrics. With regard to the formal properties, we found that essentially all injury mechanisms can be accounted by means of scalable, differentiable and convex functionals (we propose to call minimization suitable injury metric any metric having these three formal properties). In addition three useful functionals, usable as injury metrics, are identified on the basis of the empirical comparisons.

CONCLUSIONS

The commonly used metrics are highly consistent, but also highly redundant. Formal minimal conditions of a reasonable injury metric has been identified. Future proposals of injury metrics can benefit from the results of this study.

Association Between Dietary Intake of Antioxidants and Prevalence of Femoral Head Cartilage Defects and Bone Marrow Lesions in Community-based Adults

OBJECTIVE

Although there is evidence for a beneficial effect of dietary antioxidants on knee joint health, the data are sparse for the hip. Our aim was to examine the relationship between dietary antioxidants and early hip structural abnormalities in community-based adults.

METHODS

The study included 214 participants without diagnosed hip osteoarthritis (OA) who underwent hip magnetic resonance imaging in 2009-2010. The prevalence of femoral head cartilage defects and bone marrow lesions (BML) was assessed. Intakes of antioxidant vitamins and their food sources were estimated from a food frequency questionnaire during 1990-1994.

RESULTS

Higher intakes of Vitamin E (OR 0.63, 95% CI 0.41-0.96), lutein/zeaxanthin (OR 0.58, 95% CI 0.34-0.99), and lycopene (OR 0.64, 95% CI 0.44-0.95) were associated with a reduced prevalence of femoral head cartilage defects. Higher intakes of α-carotene (OR 0.42, 95% CI 0.19-0.94), β-carotene (OR 0.31, 95% CI 0.13-0.78), and lutein/zeaxanthin (OR 0.42, 95% CI 0.18-0.98) were associated with a reduced prevalence of femoral head BML. Higher vegetable consumption was associated with a reduced prevalence of femoral head cartilage defects (OR 0.65, 95% CI 0.46-0.91) and BML (OR 0.60, 95% CI 0.37-0.97).

CONCLUSION

Higher carotenoids intake and vegetable consumption were associated with reduced risk of hip cartilage defects and BML, and higher Vitamin E intake was associated with reduced risk of hip cartilage defects. These findings suggest a beneficial effect of dietary antioxidants on hip joint health. Although our findings need to be confirmed in other longitudinal studies, they suggest that the modification of dietary antioxidant intake may be a strategy for the prevention of hip OA.

Growth and aging of proximal femoral bone: a study with women spanning three generations

Osteoporotic hip fracture is a serious clinical event associated with high morbidity and mortality. Understanding femoral growth patterns is important for promoting bone health in the young and preventing fractures in later life. In this study, growth patterns of areal bone mineral density (aBMD) and geometric properties of the proximal femur were measured by dual-energy X-ray absorptiometry. They were studied in 251 girls from premenarche (11.2 ± 0.7 years) to late adolescence (18.3 ± 1.1 years) and compared with their premenopausal mothers (n = 128, aged 44.9 ± 4.1 years) and postmenopausal grandmothers (n = 128, aged 70.0 ± 6.3 years). Hip axis length (HAL) was the first to reach peak growth velocity (-10.5 months before menarche), followed by neck diameter (ND) and neck cross-sectional area (CSA), (-7.1 and -4.1 months before menarche, respectively). Both neck-shaft angle (NSA) and aBMD of neck and total hip peaked at menarche. At 18 years (7-year follow-up), girls already had higher femoral neck aBMD but similar HAL and NSA compared with their mothers. Grandmothers had the longest HAL, narrowest NSA, widest ND but lowest aBMD and CSA. Hip strength index (HSI), an index of femoral neck strength during a fall, dropped rapidly after menarche in girls but thereafter remained relatively constant. Grandmothers had lower HSI than either mothers or girls. In conclusion, differences in proximal femoral bone mass and structure in adulthood are largely established before menarche, indicating that heritable factors are responsible for most of the individual variance. The development of geometric properties precedes aBMD in puberty, resulting in relatively constant hip strength after menarche. This asynchronous growth leads to adaptation of bone strength to the imposed loads, avoiding fractures in a biologically efficient manner. Both deterioration of aBMD and inadequate compensatory change in bone geometry after menopause contribute to the increased fracture risk later in life.

Reliability and clinically important improvement thresholds for osteoarthritis pain and function scales: a multicenter study

OBJECTIVE

To assess the reliability and clinically meaningful thresholds of intermittent and constant osteoarthritis pain (ICOAP) score, the Knee injury and Osteoarthritis Outcome Score Physical function Short-form (KOOS-PS), the Hip disability and Osteoarthritis Outcome Score Physical function Short-form (HOOS-PS), and the Quality of life subscales of HOOS/KOOS (HOOS-QOL/KOOS-QOL) in patients with knee or hip arthritis.

METHODS

One hundred and ninety-five patients (141 knee, 54 hip) seen at 2 orthopedic outpatient clinics with a diagnosis of knee or hip OA completed patient-reported questionnaires (ICOAP pain scale, KOOS-PS, HOOS-PS, KOOS-QOL, HOOS-QOL) at baseline and 2-week followup. Reliability was assessed using intraclass correlation coefficients (ICC). We calculated minimum clinically important difference (MCID) and moderate improvement in the subgroup that reported change in the status of their affected joint.

RESULTS

The reliability as assessed by ICC was as follows: ICOAP pain scale, 0.63 (0.48, 0.74) in patients with knee arthritis, and 0.86 (0.73, 0.93) for hip arthritis; KOOS-PS, 0.66 (0.52, 0.77); HOOS-PS, 0.82 (0.66, 0.91); KOOS-QOL, 0.79 (0.69, 0.86); and HOOS-QOL, 0.67 (0.42, 0.83). MCID and moderate improvement estimates in patients with knee arthritis were ICOAP pain scale, 18.5 and 26.7; KOOS-PS, 2.2 and 15.0; and KOOS-QOL, 8.0 and 15.6. A smaller sample in patients with hip arthritis precluded MCID and moderate improvement estimates.

CONCLUSION

We found that ICOAP pain and KOOS-PS/HOOS-PS scales were reasonably reliable in patients with hip OA. Reliability of these scales was much lower in patients with knee arthritis. Thresholds for clinically meaningful change in pain or function on these scales were estimated for patients with knee arthritis.

Lack of BDNF expression through promoter IV disturbs expression of monoamine genes in the frontal cortex and hippocampus

Brain-derived neurotrophic factor (BDNF) is implicated in the pathophysiology of psychiatric conditions including major depression and schizophrenia. Mice lacking activity-driven BDNF expression through promoter IV (knock-in promoter IV: KIV) exhibit depression-like behavior, inflexible learning, and impaired response inhibition. Monoamine systems (serotonin, dopamine, and noradrenaline) are suggested to be involved in depression and schizophrenia since many of the current antidepressants and antipsychotics increase the brain levels of monoamines and/or act on monoamine receptors. To elucidate the impact of activity-driven BDNF on the monoamine systems, we examined mRNA levels for 30 monoamine-related genes, including receptors, transporters, and synthesizing enzymes, in KIV and control wild-type mice by using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). mRNA levels were measured in the frontal cortex and hippocampus, which are regions related to depression and schizophrenia and where promoter IV is active. The frontal cortex of KIV mice showed reduced levels of mRNA expression for serotonin receptors 1b, 2a, and 5b (5HTR1b, 5HTR2a, 5HTR5b), dopamine D2 receptors (DRD2), and adrenergic receptors alpha 1a and 1d (AdRα1a and AdRα1b), but increased levels for serotonin synthesizing enzyme, tryptophan hydroxylase (TPH), and dopamine D4 receptor (DRD4) when compared to control wild-type mice. The hippocampus of KIV mice showed decreased levels of 5HTR5b. Our results provide causal evidence that lack of promoter IV-driven BDNF disturbs expression of monoaminergic genes in the frontal cortex and hippocampus. These disturbed expression changes in the monoamine systems may mediate the depression- and schizophrenia-like behavior of KIV mice. Our results also suggest that antidepressant and antipsychotic treatments may actually interfere with and normalize the disturbed monoamine systems caused by reduced activity-dependent BDNF, while the treatment responses to these drugs may differ in the subject with reduced BDNF levels caused by stress and lack of neuronal activity.

Methodologies for semiquantitative evaluation of hip osteoarthritis by magnetic resonance imaging: approaches based on the whole organ and focused on active lesions

OBJECTIVE

As a wider variety of therapeutic options for osteoarthritis (OA) becomes available, there is an increasing need to objectively evaluate disease severity on magnetic resonance imaging (MRI). This is more technically challenging at the hip than at the knee, and as a result, few systematic scoring systems exist. The OMERACT (Outcome Measures in Rheumatology) filter of truth, discrimination, and feasibility can be used to validate image-based scoring systems. Our objective was (1) to review the imaging features relevant to the assessment of severity and progression of hip OA; and (2) to review currently used methods to grade these features in existing hip OA scoring systems.

METHODS

A systematic literature review was conducted. MEDLINE keyword search was performed for features of arthropathy (such as hip + bone marrow edema or lesion, synovitis, cyst, effusion, cartilage, etc.) and scoring system (hip + OA + MRI + score or grade), with a secondary manual search for additional references in the retrieved publications.

RESULTS

Findings relevant to the severity of hip OA include imaging markers associated with inflammation (bone marrow lesion, synovitis, effusion), structural damage (cartilage loss, osteophytes, subchondral cysts, labral tears), and predisposing geometric factors (hip dysplasia, femoral-acetabular impingement). Two approaches to the semiquantitative assessment of hip OA are represented by Hip OA MRI Scoring System (HOAMS), a comprehensive whole organ assessment of nearly all findings, and the Hip Inflammation MRI Scoring System (HIMRISS), which selectively scores only active lesions (bone marrow lesion, synovitis/effusion). Validation is presently confined to limited assessment of reliability.

CONCLUSION

Two methods for semiquantitative assessment of hip OA on MRI have been described and validation according to the OMERACT Filter is limited to evaluation of reliability.

Impact of partial volume effect correction on cerebral β-amyloid imaging in APP-Swe mice using [(18)F]-florbetaben PET

We previously investigated the progression of β-amyloid deposition in brain of mice over-expressing amyloid-precursor protein (APP-Swe), a model of Alzheimer's disease (AD), in a longitudinal PET study with the novel β-amyloid tracer [(18)F]-florbetaben. There were certain discrepancies between PET and autoradiographic findings, which seemed to arise from partial volume effects (PVE). Since this phenomenon can lead to bias, most especially in the quantitation of brain microPET studies of mice, we aimed in the present study to investigate the magnitude of PVE on [(18)F]-florbetaben quantitation in murine brain, and to establish and validate a useful correction method (PVEC). Phantom studies with solutions of known radioactivity concentration were performed to measure the full-width-at-half-maximum (FWHM) resolution of the Siemens Inveon DPET and to validate a volume-of-interest (VOI)-based PVEC algorithm. Several VOI-brain-masks were applied to perform in vivo PVEC on [(18)F]-florbetaben data from C57BL/6(N=6) mice, while uncorrected and PVE-corrected data were cross-validated with gamma counting and autoradiography. Next, PVEC was performed on longitudinal PET data set consisting of 43 PET scans in APP-Swe (13-20months) and age-matched wild-type (WT) mice using the previously defined masks. VOI-based cortex-to-cerebellum ratios (SUVR) were compared for uncorrected and PVE-corrected results. Brains from a subset of transgenic mice were ultimately examined by autoradiography ex vivo and histochemistry in vitro as gold standard assessments, and compared to VOI-based PET results. The phantom study indicated a FWHM of 1.72mm. Applying a VOI-brain-mask including extracerebral regions gave robust PVEC, with increased precision of the SUVR results. Cortical SUVR increased with age in APP-Swe mice compared to baseline measurements (16months: +5.5%, p<0.005; 20months: +15.5%, p<0.05) with uncorrected data, and to a substantially greater extent with PVEC (16months: +12.2% p<0.005; 20months: +36.4% p<0.05). WT animals showed no binding changes, irrespective of PVEC. Relative to autoradiographic results, the error [%] for uncorrected cortical SUVR was 18.9% for native PET data, and declined to 4.8% upon PVEC, in high correlation with histochemistry results. We calculate that PVEC increases by 10% statistical power for detecting altered [(18)F]-florbetaben uptake in aging APP-Swe mice in planned studies of disease modifying treatments on amyloidogenesis.

Annotation of Selaginella moellendorffii Major Intrinsic Proteins and the Evolution of the Protein Family in Terrestrial Plants

Major intrinsic proteins (MIPs) also called aquaporins form pores in membranes to facilitate the permeation of water and certain small polar solutes across membranes. MIPs are present in virtually every organism but are uniquely abundant in land plants. To elucidate the evolution and function of MIPs in terrestrial plants, the MIPs encoded in the genome of the spikemoss Selaginella moellendorffii were identified and analyzed. In total 19 MIPs were found in S. moellendorffii belonging to 6 of the 7 MIP subfamilies previously identified in the moss Physcomitrella patens. Only three of the MIPs were classified as members of the conserved water specific plasma membrane intrinsic protein (PIP) subfamily whereas almost half were found to belong to the diverse NOD26-like intrinsic protein (NIP) subfamily permeating various solutes. The small number of PIPs in S. moellendorffii is striking compared to all other land plants and no other species has more NIPs than PIPs. Similar to moss, S. moellendorffii only has one type of tonoplast intrinsic protein (TIP). Based on ESTs from non-angiosperms we conclude that the specialized groups of TIPs present in higher plants are not found in primitive vascular plants but evolved later in a common ancestor of seed plants. We also note that the silicic acid permeable NIP2 group that has been reported from angiosperms appears at the same time. We suggest that the expansion of the number MIP isoforms in higher plants is primarily associated with an increase in the different types of specialized tissues rather than the emergence of vascular tissue per se and that the loss of subfamilies has been possible due to a functional overlap between some subfamilies.

The use of an artificial femoral head for arthroplasty of the hip joint

We have endeavoured to make known the results of a simple type of arthroplasty of the hip which is well tolerated even by elderly patients. It has not been the purpose of this article to compare former operations with our own, a newcomer in the field of surgery of the hip. In particular we do not wish to compare our comparatively recent results with Smith-Petersen's well-established method of cup arthroplasty—a magnificent contribution to the surgery of the region. The results we have already obtained, however, appear sufficiently favourable to merit further study and development of the method. If the future confirms the value of our early results, we shall perhaps be able to suggest operation to patients who suffer more from loss of function than from pain.

Pseudarthrosis of the hip joint

1. The operation of pseudarthrosis of the hip joint is described and the results are assessed in ninety-three patients.

2. The result was good in eighty-three cases and poor in seven cases. Three patients died as a result of the operation.

3. Pseudarthrosis is the most satisfactory and the most reliable operation: 1) in ankvlosing spondylitis, and 2) in patients over sixty years of age with disabling osteoarthritis.

4. The more formidable operation of cup arthoplasty may prove to be superior in younger patients with osteoarthritis.