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Background The purpose of this study was to compare initial fixation strength between various stemless and stemmed humeral components and to correlate implant fixation strength with bone mineral density (BMD). Methods Five humeral stem designs were investigated: Stemless-A (four hollow fins), Stemless-B (central body, three solid fins), Stemless-C (central screw, peripheral rim-fit), Short stem (50 mm), and Standard stem (130 mm). Fifty cadaveric human humerii were obtained and divided into five groups. BMD within the humeral head was determined for all samples. The mean BMD was similar between groups. The 25 samples with the lowest and highest BMDs were categorized as “Low” and “High,” respectively, with a BMD threshold of 0.35 g/cm2, creating BMD subgroups. After implantation, each sample underwent a standardized biomechanical testing protocol, with axial loading followed by torsional loading. Sensors attached to the specimen recorded micromotion throughout testing. Axial loading consisted of cyclic loading for 100 cycles at 3 peak forces (220, 520, and 820 N). Torsional loading consisted of 100 cycles of internal/external rotation at 0.1 Hz at 6 peak torques, or until failure (±2.5, 5, 7.5, 10, 12.5, and 15 Nm). Failure was defined as the torque at which any bone fracture, implant detachment from anchor/stem, or an excess of 50° internal/external rotation occurred. Groups and BMD subgroups were compared. Results At maximal axial loading, Stemless-B demonstrated greater micromotion (540 μm) than Stemless-C (192 μm) (P = .003). Stemless-B and Stemless-A (387 μm) also had greater micromotion than Short stem (118 μm, P Conclusion Stemless humeral implants should be used with caution in low-BMD settings ( Level of evidence Basic Science Study; Cadaveric Study

When you walk into a large room, you perceive visual information that is both close to you in depth and farther in the background. Here, we investigated how initial scene representations are affected by information across depth. We examined the role of background and foreground information on scene gist by using chimera scenes (images with a foreground and background from different scene categories). Across three experiments, we found a foreground bias: Information in the foreground initially had a strong influence on the interpretation of the scene. This bias persisted when the initial fixation position was on the scene background and when the task was changed to emphasize scene information. We concluded that the foreground bias arises from initial processing of scenes for understanding and suggests that scene information closer to the observer is initially prioritized. We discuss the implications for theories of scene and depth perception.

Avoidance of the eye region, especially of faces showing anger, may maintain social anxiety symptoms by negatively reinforcing expectations and fears associated with social situations. Eye-tracking research, however, has yet to explicitly examine differences in attention allocation to the eye region of emotional faces among adolescents with social anxiety disorder (SAD). Gaze patterns were explored in a sample of youth with and without SAD matched on age and sex. Adolescents with SAD were quicker to fixate, and maintained their initial gaze longer, to the eye region, regardless of emotion, relative to teens without SAD. Group-level differences also emerged for initial fixation duration directed to the eye region of angry faces (when compared with happy faces). These findings suggest that vigilance to the eye region of faces, especially angry faces, (when compared with happy faces) is characteristic of adolescents with SAD. Adolescents with SAD seem drawn to the eye region, more so than teens without SAD.

Background The objectives of this study are to (1) evaluate if there is a potential difference in cemented implant fixation strength between tibial components made out of cobalt-chromium (CrCoMo) and of a ceramic zirconium nitride (ZrN) multilayer coating and to (2) test their behavior with 5 different bone cements in a standardized in vitro model for testing of the implant-cement-bone interface conditions. We also analyzed (3) whether initial fixation strength is a function of timing of the cement apposition and component implantation by an early, mid-term, and late usage within the cement-specific processing window. Methods An in vitro study using a synthetic polyurethane foam model was performed to investigate the implant fixation strength after cementation of tibial components by a push-out test. A total of 20 groups (n = 5 each) was used: Vega PS CrCoMo tibia and Vega PS ZrN tibia with the bone cements BonOs R, SmartSet HV, Cobalt HV, Palacos R, and Surgical Simplex P, respectively, using mid-term cement apposition. Three different cement apposition times—early, mid-term, and late usage—were tested with a total of 12 groups (n = 5 each) with the bone cements BonOs R and SmartSet HV. Results There was no significant difference in implant-cement-bone fixation strength between CrCoMo and ZrN multilayer-coated Vega tibial trays tested with 5 different commonly used bone cements. Conclusion Apposition of bone cements and tibial tray implantation in the early to mid of the cement-specific processing window is beneficial in regard to interface fixation in TKA.

Large glenoid bone loss defects are associated with higher failure rates after arthroscopic Bankart repair in cases of glenohumeral anterior instability, further necessitating bone graft reconstruction. Because most techniques use strong initial fixation using metal devices, bone graft resorption considered to be closely related to the presence of metal components is a potential shortcoming of these techniques. We describe an arthroscopic technique for anatomical reconstruction of the glenoid that uses a tricortical iliac crest with a metal-free fixation method using 2 ultra-high-strength sutures (FiberTape Cerclage System; Arthrex, Naples, FL), which provide substantial stability to the graft, and finishing with a capsulolabral reconstruction.

The congruent-arc Latarjet (CAL) allows reconstruction of a greater percentage of glenoid bone deficit because the inferior surface of the coracoid is wider than the lateral edge of the coracoid used with the traditional Latarjet (TL). Biomechanical studies have shown higher initial fixation strength between the graft and the glenoid with the TL. In the TL, the undersurface of the coracoid, which is wider than the medial edge used with the CAL, remains in contact with the anterior edge of the glenoid, increasing the contact surface between both bones and thus facilitating bone consolidation. The shorter bone distance around the screw with the CAL is potentially less tolerant of screw-positioning error compared to the TL. Moreover, the wall of the screw tunnel is potentially more likely to fracture with the CAL due to the minimal space between the screw and the graft wall. CAL may be very difficult to perform in patients with very small coracoids such as small women or skeletally immature patients. Radius of curvature of the inferior face of the coracoid graft (used with the CAL) is similar to that of the native glenoid. This may potentially decrease contact pressure across the glenohumeral joint, avoiding degenerative changes in the long term. Cite this article: EFORT Open Rev 2021;6:280-287. DOI: 10.1302/2058-5241.6.200074

Objectives To compare the rate of initial fixation failure and clinical outcomes in anterior cruciate ligament reconstruction (ACL-R) surgery with a rectangular tunnel bone-patellar tendon-bone (RT-BTB) graft (RT-BTB ACL-R) using metallic interference screws (M-IFSs) and bioabsorbable interference screws (B-IFSs) for femoral fixation. Methods Data were prospectively collected from patients undergoing RT-BTB ACL-R and CT within 2 weeks after surgery. Femoral fixation was performed using M-IFSs (M-IFS group) or B-IFSs (B-IFS group). Screw selections were historically controlled. The following parameters were intraoperatively assessed: IFS breakage and initial fixation failure examined by movement of the graft pulled with maximum manual force. Posterior wall breakage was assessed using CT. Lysholm Score, the 2000 International Knee Documentation Committee Knee Examination Form and the KT-2000 arthrometer was evaluated as the clinical outcome measures. Results The study included 116 patients. Of these, 26 were included in the M-IFS group and 92 in the B-IFS group. The rate of IFS breakage was not significantly different between the M-IFS and B-IFS groups (0.0% vs 2.2%). The rate of initial fixation failure was not significantly different between the M-IFS and B-IFS groups (3.8% vs 5.6%). Logistic regression analysis revealed that only posterior wall breakage predicted initial fixation failure (p=0.02). No significant difference of the clinical outcomes was observed between the M-IFS and B-IFS groups. Conclusion Initial fixation failure or clinical outcomes is not different between M-IFS and B-IFS use for femoral fixation in RT-BTB ACL-R. Level of evidence Prospective study using historical controls, level IV.

Introduction: The uncemented total hip arthroplasty relies on a secure initial fixation of the femoral stem to achieve osseointegration. Undersizing of the femoral implant compromises this. Surgeons routinely review postoperative radiographs to assess appropriate sizing, but existing methods of assessment lack standardisation. We present a system of accurately and reliably classifying radiological undersizing, which will help us better understand the factors that might have led to undersizing. Aim: To describe and evaluate a classification system for assessing radiological undersizing of the uncemented stem in hip arthroplasty. Method: We conducted a retrospective review of 1,337 consecutive hip arthroplasties using the Corail stem. Two independent investigators reviewed post-operative radiographs and classified them as either appropriately sized or undersized. Undersized stems were sub-categorised into four subtypes: uniformly undersized, varus undersized, valgus undersized or ‘cocktail-glass’ undersized. Inter- and intra-observer agreement was determined. The accuracy of our classification system was validated by comparison with digital re-templating. We further assessed patient demographics and stem size in relation to sizing. Results: 1 in 5 cases (19.75%) were deemed radiologically undersized. The commonest subtypes of undersizing were uniformly (47%) and varus (39%) undersized. When assessing sizing and subtype categorisation, inter-observer agreement was 89–92% and intra-observer agreement 86%. Classification decisions showed 92% and 97% accuracy for uniformly undersizing and varus undersizing respectively when validated against digital re-templating. Age, gender and smaller stem size were significantly associated with radiological undersizing. The Corail KLA model (125° neck) was found to have a higher incidence of stems undersized in varus. Conclusions: This study describes and validates a classification system for the analysis of radiological undersizing.

Dual-curing adhesives offer a high precision, and, due to their manifold curing mechanisms a unique process speed and flexibility in production processes. To reach short cycle times, fast UV fixation is utilized allowing for an immediate continuation of the production process. This initial fixation step is followed by a second final curing step. The example of the production process of a camera for e.g. autonomous driving shows how to finally obtain the adhesive’s properties in the second process step. We present a new hybrid system, a lightfixable 2-component adhesives that allow final curing at room temperature. It therefore saves time, energy and space in the production plant.

As the biologically friendly and biomechanically sound technique of intramedullary fixation has been increasingly applied to distal tibia diaphyseal fractures, challenges with the technique have emerged. Malalignment, most often valgus and recurvatum, is more common than with mid-diaphyseal patterns, given the lack of endosteal fit, and this can be challenging to prevent. Key technical steps can ensure success. These include recognition and initial fixation of intra-articular fracture planes, the use of percutaneous clamps, a slightly lateral terminal nail position, and the use of blocking wires or screws to prevent malalignment after nail passage. With thorough preoperative planning and early recognition of troublesome patterns, a variety of techniques can be applied to obtain and maintain a stable reduction throughout the procedure.

Initial stability of cementless stems used in total hip arthroplasty (THA) is critical for subsequent osseointegration at the bone/implant interface. In the setting of revision THA, there is frequently less intact femoral bone available for fixation of the new stem. This study aims to compare the initial fixation stability between a cylindrical and tapered stem, designed for diaphyseal fixation in a revision THA setting, with increasing bone defect severity. Using finite element analysis, severe Paprosky Type III femoral bone defects were simulated. The cylindrical stem had a 13.3% higher construct stiffness as compared to the tapered stem for the least severe bone defect modeled. In contrast, for the most severe bone defect, the tapered stem showed a 12.3% higher construct stiffness than the cylindrical stem. At the bone/implant interface, the tapered design resulted in less than 20 μm of maximum tangential micromotion for all the bone defect models, whereas the cylindrical stem exceeded 20 μm for all and was as high as 70 μm in the most severe case. Given the limitations of the models presented, the results suggest the tapered stem obtained superior initial fixation as compared to cylindrical stem with increasing bone defect severity.

Children localize sounds using binaural cues when navigating everyday auditory environments. While sensitivity to binaural cues reaches maturity by 8–10 years of age, large individual variability has been observed in the just-noticeable-difference (JND) thresholds for interaural time difference (ITD) among children in this age range. To understand the development of binaural sensitivity beyond JND thresholds, the “looking-while-listening” paradigm was adapted in this study to reveal the real-time decision-making behavior during ITD processing. Children ages 8–14 years with normal hearing (NH) and a group of young NH adults were tested. This novel paradigm combined eye gaze tracking with behavioral psychoacoustics to estimate ITD JNDs in a two-alternative forced-choice discrimination task. Results from simultaneous eye gaze recordings during ITD processing suggested that children had adult-like ITD JNDs, but they demonstrated immature decision-making strategies. While the time course of arriving at the initial fixation and final decision in providing a judgment of the ITD direction was similar, children exhibited more uncertainty than adults during decision-making. Specifically, children made more fixation changes, particularly when tested using small ITD magnitudes, between the target and non-target response options prior to finalizing a judgment. These findings suggest that, while children may exhibit adult-like sensitivity to ITDs, their eye gaze behavior reveals that the processing of this binaural cue is still developing through late childhood.

Studies assessing the relationship between high-level meaning and low-level image salience on real-world attention have shown that meaning better predicts eye movements than image salience. However, it is not yet clear whether the advantage of meaning over salience is a general phenomenon or whether it is related to center bias: the tendency for viewers to fixate scene centers. Previous meaning mapping studies have shown meaning predicts eye movements beyond center bias whereas saliency does not. However, these past findings were correlational or post hoc in nature. Therefore, to causally test whether meaning predicts eye movements beyond center bias, we used an established paradigm to reduce center bias in free viewing: moving the initial fixation position away from the center and delaying the first saccade. We compared the ability of meaning maps and image salience maps to account for the spatial distribution of fixations with reduced center bias. We found that meaning continued to explain both overall and early attention significantly better than image salience even when center bias was reduced by manipulation. In addition, although both meaning and image salience capture scene-specific information, image salience is driven by significantly greater scene-independent center bias in viewing than meaning. In total, the present findings indicate that the strong association of attention with meaning is not due to center bias.

Background Various features are provided in dental implants to improve initial fixation. Purpose To compare the implant stability of the nonself-tapping tapered implant and self-tapping hybrid implant over a 3-month healing period. Materials and methods A randomized controlled trial was conducted. Patients were randomly divided into tapered and self-tapping groups. Patients in the tapered group received NobelReplace Tapered (Nobel Biocare, Sweden) implants, while those in the self-tapping group received NobelSpeedy (Nobel Biocare, Sweden) implants. Implant stability was measured by resonance frequency analysis at surgery and 3 months following implant insertion. Data were analyzed using an independent t-test. Results Forty-three patients (tapered group: 21, self-tapping group: 22) received a total of 88 implants. Initial stability in the tapered group was significantly higher (mean: 60.14, SD: 12.40) than that in the self-tapping group (mean: 54.72, SD: 7.92). Implant stability significantly increased 3 months after implantation in the tapered group (mean: 66.61, SD: 9.00) and self-tapping group (mean: 64.01, SD: 5.78). No significant intergroup difference in implant stability was noted 3 months after surgery. Conclusions The tapered shape affected initial fixation more than the self-tapping function. However, during the second fixation, both implants showed good stability, and the difference disappeared.

The Rorschach inkblot test (RIBT) is a standardized projective technique. It uses a subjective way of collecting and mapping responses of different regions like large (D) and small details (d). In this paper, eye tracking parameters like Initial Fixation Location, SF Ratio, Mean Fixation Duration and Mean Return are used to develop some objective measures which would be helpful in the assessment of the Rorschach responses. The study was conducted on 25 normal subjects who were administered RIBT cards I, II and X. The result shows an initial tendency to fixate in the central regions of the Rorschach cards. Computation of SF ratio helps in understanding most frequently fixated regions leading to popular response. Certain locations of each card have high attentional value where most shifts and fixations occur. The study supplements to the information obtained by the subjective scoring of RIBT and also indicates that specific eye tracking parameters could be an objective marker for personality assessment with RIBT.

Contains fulltext : 212259.pdf (Publisher’s version ) (Open Access) People with an increased motivation for rewarding substances show increased automatic selective attention towards cues that are related to that specific substance. The aim of this study was to explore if overweight and hungry children have an attentional bias for food cues in food advertising. A randomized between-subject design was used with 95 children who played an advergame that promoted either energy-dense snacks or non-food products. Overweight children had a higher gaze duration for the food cues compared to normal weight children. No effects were found of overweight on the attentional bias measurements for the non-food cues. Furthermore, hungrier children had a higher gaze duration, a higher number of fixations, and a faster latency of initial fixation on the food cues than less hungry children, while we found the opposite results for the non-food cues. The findings largely confirm our expectations, adding important knowledge about individual susceptibility to food advertisements. Overweight and hungrier children seem to be stronger affected by food advertising than normal weight and less hungry children. This study is the first that examined attentional bias in a food advertisement that is highly comparable to advertisements that are used by food companies, thereby increasing the external validity of the findings. The second strength is that the development of an attentional bias for food cues is developing at a young age and it was examined in a real-life situation. 8 p.

Attention bias, conceptualized to be involved in the development and maintenance of SAD, may differentiate teens with SAD from those without. Although SAD typically emerges during adolescence, eye-tracking research has not explicitly focused on biased attention in adolescents with SAD relative to healthy controls, using stimuli specifically developed for adolescents, thus prompting the rationale for the present study. Youth with SAD were quicker to fixate their gaze on angry faces and maintained their gaze longer toward both angry and neutral faces. Findings suggest that socially anxious teenagers demonstrate bias, relative to teens without SAD. The bias is marked by shortened latency to fixate on angry faces. Additionally, given that the adolescents with SAD also exhibited longer initial fixation duration to both angry and neutral faces, relative to controls, these results suggest the possibility of heightened reactivity to social stimuli regardless of emotional valence. Alternatively, it may be the case, that youth with SAD perceive neutral faces as threatening. Given the role attention bias plays in the etiology and maintenance of SAD, better understanding of the cognitive processes which underlie the disorder is warranted. The current study offers initial findings for informing treatment for adolescents with the condition.

Modal parameters are often investigated in order to assess the initial fixation of an implant. Most of studies are focused on the natural frequencies and frequency response function. Usually the femoral stem is tested although the acetabular cup fixation is important as well. The results of implant stability assessment are inconsistent and seem to suggest that frequency as a stability indicator is not sufficiently sensitive. In this study the sensitivity of the modal properties to changes in the bone-implant interface was investigated with the help of the finite element method (FEM). A novel fixation index based on modal shape curvature was investigated as a potential measure of the implant fixation. Modal frequencies are sensitive to interface changes in some manner, but suffer from insensitivity to local changes at bone-implant interface. The sensitivity up to 44% of natural frequencies to stiffness change due insertion steps was observed. The tested damage indicators are able to detect localized small changes in peripheral stiffness (5% stiffness reduction) with 95% confidence under the noise up to 1%. The modal shapes and their curvatures have a great potential to be a robust fixation indicator. ispartof: MEDICAL ENGINEERING & PHYSICS vol:60 pages:30-38 ispartof: location:England status: published

Durable humeral component fixation in shoulder arthroplasty is important to prevent loosening. Humeral component designs include metaphyseal fitting, diaphyseal fitting with traditional stem length, short stem, and stemless designs. Stem geometry helps resist rotational and axial stress. Stem collars may prevent subsidence, and may be smooth for full cementation or textured proximally for bone ingrowth. Ideally, the humeral component has solid initial fixation, durable long-term fixation, minimizes humeral stress shielding, has low intra-operative complication rates, and can easily be revised. Excellent outcomes can be achieved, but there remain relative indications and contraindications for cementing or press-fitting the humeral component.

Short stem total hip arthroplasty (SHA) has gained increasing popularity as it conserves bone stock and is supposed to allow revision with a conventional stem. However, no study has evaluated whether the revision of a SHA with a standard total hip arthroplasty (THA) stem provides sufficient primary stability to allow osseous integration. A neck preserving SHA (Metha) and a standard THA (CLS) stem were implanted into six composite femurs respectively and dynamically loaded (300–1700 N, 1 Hz). Primary stability was evaluated by three dimensional-micromotions (3D micro motion) at five points of the interface. Then, a revision scenario was created by removing the SHA and using the same CLS stem as a revision implant (CLS-revision group), with subsequent evaluation of the 3D micro motion according to the primary CLS stem. The 3D micro motion pattern significantly differed in the primary situation between the short and the standard stem. The highest 3D micro motion were registered proximally for the Metha and distally for the CLS stem. Revising the Metha with a CLS stem revealed a bony defect at the calcar. However, the 3D micro motion of the CLS-revision group were not significant higher compared to those of the primary CLS stem. Our results show, that SHA (Metha) and standard THA (CLS) provide a good primary stability, however with different pattern of anchorage. The CLS stem reached a similar stability in this revision scenario as the CLS in the primary situation, wherefore it can be assumed that in uncomplicated revisions the Metha short stem can safely be revised with a CLS standard stem.

Background The RM Pressfit vitamys is a titanium particle-coated monoblock cup with vitamin E stabilised highly cross-linked polyethylene. Initial fixation is achieved via press-fit with subsequent stability by bone on-growth. This is the first study to report the 5-year results of this design. Methods We performed a prospective cohort study according to STROBE guidelines of 100 consecutive total hip replacements (THRs) in 92 patients all with ceramic heads. Demographic data, pre/postoperative visual analogue scale (VAS) for pain and satisfaction, Harris Hip Scores (HHS) and complications were recorded. Radiographic analysis of osteolysis and loosening was complemented by EBRA (Einzel-Bild-Röntgen-Analyse) evaluation of cup movement. Results Our cohort comprised 48 women (mean age 67; SD 10.4) and 44 men (mean age 69; SD 7.8). The mean body mass index was 27 kg/m2 (SD 4.6). Surgical indications were osteoarthritis 96%, avascular necrosis 3% and fracture 1%. 82% had a direct anterior approach, 15% anterolateral and 3% trans-gluteal. 4 surgeons were involved. 1 cup was repositioned and fixed with screws within a week of index surgery. There were 2 intraoperative femoral fractures, 3 haematomata with 1 requiring drainage and 1 deep infection settling with an open washout and modular exchange. Mean VAS satisfaction increased from 3.8 (SD 2.0) to 8.8 at 6 weeks (SD 1.4) and 9.5 (SD 1.3) at 5 years. The HHS functional scores were 58.9 (SD 13.2) preoperatively and 94.6 (SD 6.6) at 5 years. Radiographic analysis showed neither progressive radiolucency nor osteolysis. Mean migration was 1.5 mm after 5 years. Conclusions Mid-term results of the RM Pressfit vitamys cup are encouraging.

espanolSe evalua la inhibicion de la fijacion microalgal en sustratos artificiales, previamente colonizado con bacterias marinas. Debido a la escasez de agua, la region de Antofagasta en Chile desarrolla la desalinizacion del agua de mar para sus procesos mineros. La carga biologica del agua de mar genera bioincrustaciones que obstruyen los sistemas de flujo. Las bioincrustaciones se inician con la fijacion inicial de moleculas y microorganismos como bacterias y microalgas, los cuales sirven de sustrato y alimento para otros colonizadores. Dos cepas de Bacillus pumilus inhibieron la adherencia de mezclas microalgales, demostrando que estarian secretando metabolitos inhibidores de la fijacion. Por lo tanto se concluye que es viable utilizar bacterias marinas como B. pumilus para inhibir la fijacion inicial a sustratos artificiales como PVC, de microalgas nativas de las costas del norte de Chile. EnglishThe inhibition of microalgal fixation in artificial substrates, previously colonized with marine bacteria is evaluated. Due to the shortage of water, the region of Antofagasta in Chile develops desalination of seawater for its mining processes. The Bioburden of the seawater generates biofouling and obstructing of the flow systems. Biofouling start with the initial attachment of molecules and microorganisms like bacteria and microalgae, which serve as substrate and food for other colonists. Two strains of Bacillus pumilus inhibited adhesion of microalgal mix, showing that they produce metabolites that inhibits fixation. It is therefore concluded that it is feasible to use of the marine bacteria B. pumilus to inhibit the initial fixation to artificial substrates such as PVC, of native microalgae the coasts of northern Chile.

During scene perception our eyes generate complex sequences of fixations. Predictors of fixation locations are bottom-up factors like luminance contrast, top-down factors like viewing instruction, and systematic biases like the tendency to place fixations near the center of an image. However, comparatively little is known about the dynamics of scanpaths after experimental manipulation of specific fixation locations. Here we investigate the influence of initial fixation position on subsequent eye-movement behavior on an image. We presented 64 colored photographs to participants who started their scanpaths from one of two experimentally controlled positions in the right or left part of an image. Additionally, we computed the images' saliency maps and classified them as balanced images or images with high saliency values on either the left or right side of a picture. As a result of the starting point manipulation, we found long transients of mean fixation position and a tendency to overshoot to the image side opposite to the starting position. Possible mechanisms for the generation of this overshoot were investigated using numerical simulations of statistical and dynamical models. We conclude that inhibitory tagging is a viable mechanism for dynamical planning of scanpaths., 34 pages with 10 figures submitted to Vision Research. Reviews Received on June 8th, 2016 (Minor Revision). Updated Version will be uploaded within the year 2016

Background The purpose of this study was to objectively investigate the initial fixation of highly porous cups in THA for femoral neck fractures. Methods THA for displaced femoral neck fractures was performed in 52 consecutive patients. We objectively measured the rotational torque for cup stability, and the primary endpoint was the success rate of press-fit fixation without screws. Results The success rate of press-fit fixation without screws was 96.1%. No specific complications were occurred. Conclusion The initial stability of highly porous cups was excellent for femoral neck fractures with a high success rate of press-fit fixation without screws.

Several studies demonstrated similarities of eye fixations during mental imagery and visual perception but-to our knowledge-the temporal characteristics of eye movements during imagery have not yet been considered in detail. To fill this gap, the same data is analyzed with conventional spatial techniques such as analysis of areas of interest (AOI), ScanMatch, and MultiMatch and with recurrence quantification analysis (RQA), a new way of analyzing gaze data by tracking re-fixations and their temporal dynamics. Participants viewed and afterwards imagined three different kinds of pictures (art, faces, and landscapes) while their eye movements were recorded. While fixation locations during imagery were related to those during perception, participants returned more often to areas they had previously looked at during imagery and their scan paths were more clustered and more repetitive when compared to visual perception. Furthermore, refixations of the same area occurred sooner after initial fixation during mental imagery. The results highlight not only content-driven spatial similarities between imagery and perception but also shed light on the processes of mental imagery maintenance and interindividual differences in these processes.

It is a universal feature of seed plants that their phloem consists of a continuous sieve-tube system throughout the plant that is highly pressurized by its sugar contents. Cellular continuity and the pressure flow, osmotically generated in the source leaves, allow the assimilates to reach all sinks organs. However, both phloem features, the cellular continuity and the high pressure, are challenges when fixing the phloem for transmission electron microscopy. With very few exceptions, the tissue preparation necessary for the fixation evokes rapid wound responses that eventually result in artifacts.This chapter describes the steps necessary to minimize development of artifacts in the phloem and includes preparation of fixatives, a dissection procedure that optimizes penetration of the fixatives and application to axial and lateral plant organs. Moreover, as alternative to the established fixation of fresh hand sections, we suggest a xylem-assisted perfusion fixation method for herbaceous plants. After the initial fixation, the subsequent dehydration, embedding, and ultrathin sectioning of the material follow routine procedures, which are briefly discussed, as is the orientation of samples for obtaining transverse and longitudinal phloem sections.

Cancer appears as a result of mutation of normal tissue cells. In this paper, we consider the initial stage of the cancer appearance and development. In particular, we study the conditions that are necessary for an initial fixation of the mutant cells in a patient tissue and their further successful development. In order to do this, we are using a reasonably simple mutation-selection model composed of two interacting populations, namely, the normal cells and the mutant cells. Conditions for persistence of the mutant cells are found.

It takes years to build up a thick layer of nacre in a cultured pearl. The initial fixation and formation of the pearl nucleus, and the growth rate of nacre are important indicators to pearl cultivators. These indicators are traditionally assessed by opening the shellfish for pearl acquisition mechanically causing inevitable waste in aquaculture. Here we report a noninvasive and rapid method based on micro-computed tomography (micro-CT) to evaluate the amount, size, and growth rate of pearls in living freshwater mussel, Hyriopsis schlegelii. Our results show successful detection of overall shapes and amount of pearls through both transmission imaging and 8-s rapid scanning. Accurate dimension-measurements of the cultured pearls were achieved through micro-CT quantitative analysis. This in vivo pearl evaluation did not affect subsequent growth of scanned shellfishes. Our work provides a novel method for quality control in pearl aquaculture.

The fixation of larval and juvenile fishes in 95% ethanol can be substituted for formalin and bears several advantages for morphological and molecular studies: 1) specimens clear and double stain rapidly and brilliantly; 2) otoliths are preserved; and 3) high-quality DNA is available from the tissues. We present merits and limitations of 70% ethanol and 95% ethanol as alternative fixatives to 4% buffered formalin. In particular, we compare our results of clearing and double staining teleost larvae and juveniles from these three fixatives and those that have been frozen at −20°C prior to the initial fixation. With our results, we can refute the long-standing notion that ethanol-fixed specimens disintegrate during clearing and staining.

Clinical and theoretical models suggest deficient volitional initiation of action in schizophrenia patients. Recent research provided an experimental model of testing this assumption using saccade tasks. However, inconsistent findings necessitate a specification of conditions on which the deficit may occur. The present study sought to detect mechanisms that may contribute to poor performance. Sixteen schizophrenia patients and 16 healthy control participants performed visually guided and two types of volitional saccade tasks. All tasks varied as to whether the initial fixation stimulus disappeared (fixation stimulus offset) or continued during saccade initiation, and whether a direction cue allowed motor preparation of the specific saccade. Saccade latencies of the two groups were differentially affected by task type, fixation stimulus offset, and cueing, suggesting abnormal volitional saccade generation, fixation release, and motor preparation in schizophrenia. However, substantial performance deficits may only occur if all affected processes are required in a task.

Aim To assess technical features of multiple biopsy devices for post-mortem CT-guided biopsy (PMCTB). Methods Five different BARD® clinical biopsy devices, including spring-loaded and vacuum-assisted, were used to perform percutaneous biopsy of the liver in a deceased person using the largest gauge needle size available in each. A standard co-axial biopsy technique was used for all devices except SenoRX®. Specimens were placed on sponge in cassettes for initial fixation and then processed using routine histological techniques. The devices were assessed by a team consisting of a forensic technician, forensic radiologist and two forensic pathologists (one blinded to the type of device used). Assessment parameters included technical performance, cost of device, and specimen review under light microscopy. Results/discussion The Max-core® and Magnum® devices were mechanically easy to load, fire and retrieve specimens. The Finesse® and Vacora® provided advanced technical features. On histological review the tissue sample from the Vacora® was judged to be of higher quality. Due to the permanent needle attachment to the vacuum machine, the SenoRX® was deemed impractical. Histological artefacts identified included stretch-crush cellular damage likely from the use of vacuum-assisted devices, and tissue breakage from the use of cassette sponges. Conclusion The 2 spring-loaded biopsy devices are considered the most appropriate for PMCTB tissue sampling based on ease-of-use, lowest cost and provision of diagnosable biopsy specimens.

Intertrochanteric femoral fractures are common in old patients, but the ideal implant for these unstable fractures remains controversial. In this study, finite element modeling was used to quantitatively analyze the fixating force of cementless stems (tapered rectangular and cone) at the femur diaphysis of a patient with type A2 intertrochanteric fractures who underwent hemiarthroplasty. Interfacial stress distribution and micromotion at the interface between cancellous bone and stem were assessed to determine initial stability. Results showed that the rectangular stem provided similar or higher initial fixation force than the cone stem in A2 intertrochanteric fractures.

Reverse total shoulder arthroplasty (rTSA) is commonly used in the shoulder replacement surgeries for the relief of pain and to restore function, in patients with grossly deficient rotator cuff. Primary instability due to glenoid loosening is one of the critical complications of rTSA; the implants are designed and implanted such that the motion between the glenoid baseplate and underlying bone is minimized to facilitate adequate primary fixation. Finite element analysis (FEA) is commonly used to simulate the test setup per ASTM F2028-14 for comparing micromotion between designs or configurations to study the pre-clinical indications for stability. The FEA results can be influenced by the underlying modeling assumptions. It is a common practice to simplify the screw shafts by modeling them as cylinders and modeling the screw-bone interface using bonded contact, to evaluate micromotion in rTSA components. The goal of this study was to evaluate the effect of three different assumptions for modeling the screw-bone interface on micromotion predictions. The credibility of these modeling assumptions was examined by comparing the micromotion rank order predicted among three different modular configurations with similar information from the literature. Eight configurations were modeled using different number of screws, glenosphere offset, and baseplate sizes. An axial compression and shear load was applied through the glenosphere and micromotion at the baseplate-bone interface was measured. Three modeling assumptions pertaining to modeling of the screw-bone interface were used and micromotion results were compared to study the effect of number of peripheral screws, eccentricities, and baseplate diameter. The relative comparison of micromotion between configurations using two versus four peripheral screws remained unchanged irrespective of the three modeling assumptions. However, the relative comparison between two inferior offsets and baseplate sizes changed depending on the modeling assumptions used for the screw-bone interface. The finding from this study challenges the generally believed hypothesis that FEA models can be used to make relative comparison of micromotion in rTSA designs as long as the same modeling assumptions are used across all models. The comparisons with previously published work matched the finding from this study in some cases, whereas the comparison was contradicting in other cases. It is essential to validate the computer modeling approach with an experiment using similar designs and methods to increase the confidence in the predictions to make design decisions.

Introduction For supracondylar humeral (SCH) fractures, biomechanical studies suggest the most stable wire configuration achieves bi-columnar fixation. Achieving medial column fixation using lateral-entry-only wires may require an intracapsular entry point. The aim of this study was to identify the rate of bi-columnar fixation achieved in our department when treating SCH fractures with percutaneous wire fixation. A secondary aim was to identify the rate of placement of an intra-articular wire. Further aims were to examine if failure to achieve bi-columnar fixation was associated with an increased loss of fixation and whether the placement of an intra-articular wire resulted in any cases of deep infection or septic arthritis. Material and methods All Gartland type 3 supracondylar humeral fractures, June 2014 to December 2016, were retrospectively identified. Intra-operative films were reviewed to determine bi-columnar fixation and the presence/absence of an intra-articular wire. Loss of reduction requiring revision and post-operative infections were determined from the electronic patient record. Results Of 49 supracondylar fractures identified, 42 were fixed with lateral-entry only wires (24 with two wires and 18 with three wires), and seven were fixed with medial/lateral cross wires (four with one lateral wire, two with two wires, and one with three wires). Bi-columnar fixation was achieved in 41/49 cases (84%). All cases where bi-columnar fixation was not achieved were fixed with lateral-entry-only wires. One out of 49 fractures (2%) required the revision of fixation at 10 days due to loss of reduction. In this case, the initial fixation was with two lateral-entry-only wires, without bi-columnar fixation. An intra-articular wire was present in 44 out of 49 cases (90%). One out of 49 cases (2%) had a superficial wound infection. There were no cases of deep infection or septic arthritis. Conclusion In our department, the rate of bi-columnar fixation was high and, in this group, no cases required revision fixation. One of eight cases judged to not have bi-columnar fixation initially, required revision due to loss of fixation. We contend that bi-columnar fixation generally achieves a stable wire configuration even using lateral-entry-only wires for SCH fractures. The rate of intra-articular wire placement was high; however, infection rates were low with no cases of septic arthritis.

Item does not contain fulltext To achieve long-lasting fixation of cementless implants, an adequate primary stability is required. We aimed to compare primary stability of a new cementless femoral knee component (Attune(R)) against a conventional implant (LCS(R)) under different loading conditions. Six pairs of femora were prepared following the normal surgical procedure. Calibrated CT-scans and 3D-optical scans of the bones were obtained to measure bone mineral density (BMD) and cut accuracy, respectively. Micromotions were measured in nine regions of interest at the bone-implant interface using digital image correlation. The reconstructions were subjected to the implant-specific's peak tibiofemoral load of gait and a deep knee bend loading profiles. Afterwards, the implants were pushed-off at a flexion angle of 150 degrees . Micromotions of Attune were significantly lower than LCS under both loading conditions (P