Estimating the wage premium to supervision for middle managers in different contexts: evidence from Germany and the UK

The analysis of wage distribution has attracted scholars from different disciplines seeking to develop theoretical arguments to explain the upward or downward trend. In particular, how the middle management wage premium changes in different contexts is a relatively neglected area of research. This study argues that wage distribution changes in different contexts, representing different forms of capitalism. To shed light on this, we considered the size and the shape of the wage premium to supervision paid to middle managers in Germany and the UK. We find evidence of two forms of context: middle managers are paid differently for the same task according to the economy where they work; of this amount, about half of the difference is related to the context. We frame the analysis within the literature on varieties of capitalism

Effect of incorporation of 2-tert-butylaminoethyl methacrylate on flexural strength of a denture base acrylic resin

Polymethyl methacrylate (PMMA) resins have commonly been used as a denture base material. However, denture bases may act as a reservoir for microorganisms and contribute to oral diseases in denture wearers. It is hypothesized that the 2-tert-butylaminoethyl methacrylate (TBAEMA) incorporated to acrylic resins should have antimicrobial activity related to the presence of amino groups on acrylic resin surface. OBJECTIVES: The objectives of this study were to evaluate the presence of amino groups on acrylic resin surface and the influence on flexural strength after incorporation of TBAEMA. MATERIAL AND METHODS: Six groups were divided according to the concentration of TBAEMA incorporated to acrylic resin (Lucitone 550): 0, 0.5, 1.0, 1.5, 1.75 and 2%. Specimens surface were evaluated by Electron Spectroscopy for Chemical Analysis (ESCA) to detect the presence of amino groups, represented by nitrogen ratios. Flexural strength of the specimens was tested and results were analyzed by ANOVA and Tukey's test (α=0.05). RESULTS: Different nitrogen ratios were observed on specimen surfaces: 0, 0.13, 0.74, 0.66, 0.92 and 0.33% for groups 0, 0.5, 1.0, 1.5, 1.75, and 2%, respectively. Significant differences were found for flexural strength (

Effect of an acrylic resin combined with an antimicrobial polymer on biofilm formation

OBJECTIVES: The purpose of this study was to evaluate the antimicrobial activity of an acrylic resin combined with an antimicrobial polymer poly (2-tert-butylaminoethyl) methacrylate (PTBAEMA) to inhibit Staphylococcus aureus, Streptococcus mutans and Candida albicans biofilm formation. MATERIAL AND METHODS: Discs of a heat-polymerized acrylic resin were produced and divided according to PTBAEMA concentration: 0 (control), 10 and 25%. The specimens were inoculated (10(7) CFU/mL) and incubated at 37ºC for 48 h. After incubation, the wells were washed and each specimen was sonicated for 20 min. Replicate aliquots of resultant suspensions were plated at dilutions at 37ºC for 48 h. The number of colony-forming units (CFU) was counted and expressed as log (CFU+1)/mL and analyzed statistically with α=.05. RESULTS: The results showed that 25% PTBAEMA completely inhibited S. aureus and S. mutans biofilm formation. A significant reduction of log (CFU+1)/mL in count of S. aureus (control: 7.9±0.8A; 10%: 3.8±3.3B) and S. mutans (control: 7.5±0.7A; 10%: 5.1±2.7B) was observed for the group containing 10% PTBAEMA (Mann-Whitney,

The effect of tibial slope on the biomechanics of cruciate-retaining total knee arthroplasty:A musculoskeletal simulation study

Introduction/Aim: More posterior tibial slope (PTS) can prevent flexion gap tightness in cruciate-retaining Total Knee Arthroplasty (TKA) and help achieving better knee function. However, the influence of PTS on knee function during activities of daily living (ADLs) is scarcely documented. The aim of this study was to investigate the effect of PTS and surgical referencing technique on tibiofemoral joint (TFJ) kinematics, quadriceps force, and patellofemoral joint (PFJ) force during ADLs. Materials and Methods: We used a previously validated musculoskeletal model of cruciate-retaining TKA [1] to simulate a squat activity. A baseline case with the original post-operative PTS (0°) was simulated, plus four PTS cases (-3°, +3°, +6°, +9°) obtained using anterior tibial cortex-referencing (ACR, Fig. 1a) technique and four using centre of tibial plateau-referencing (CPR, Fig. 1b) technique. Results: More PTS with ACR technique caused a larger and more anterior excursion of the TFJ contact point on the lateral side, and more posterior, on the medial side, in extension (Fig. 2). More PTS with the CPR technique caused the contact point in extension to shift gradually more posterior on both medial and lateral sides, and in flexion to shift gradually more posterior mainly on the lateral side. The peak quadriceps force decreased on average by 1.7 and 1.2 % BW for every degree of more PTS, with the ACR and CPR techniques, respectively. The peak PFJ contact force decreased more importantly with more PTS with the CPR technique rather than with the ACR technique (-3.9 vs. -1.5 % BW/degree more PTS, Fig. 3). Discussion: The ACR technique loosens the TFJ, thus leading to more unstable TFJ kinematics and anterior shift on the lateral side. More PTS also reduces the quadriceps force to squat. More PTS with the CPR technique resulted in stable and more posterior TFJ kinematics, and a greater reduction of the PFJ contact force, due to preservation of patellar height. Conclusions: TFJ stability should be maximally preserved to improve knee function. More PTS with the ACR technique has severe consequences on knee kinematics and function, whilst CPR technique results in more effective reduction of quadriceps and PFJ forces, while preserving TFJ stability. References: [1] Marra MA, Vanheule V, Fluit R, et al. A Subject-Specific Musculoskeletal Modeling Framework to Predict In Vivo Mechanics of Total Knee Arthroplasty. ASME. J Biomech Eng. 2015;137(2):020904-020904-1

The effect of flexion of the femoral component in TKA:A musculoskeletal simulation study

Introduction/Aim: More flexion of the femoral component (FFC) is a surgical option to better restore the femur anatomy in the sagittal plane in Total Knee Arthroplasty (TKA), and to prevent notching of the anterior femoral cortex. However, its true effects on the patellofemoral joint (PFJ) during activities of daily living (ADLs) remain unknown. We studied the effect of FFC on quadriceps and PFJ forces during ADLs. We hypothesised that more FFC has advantages for the knee extensor mechanism. Materials and Methods: A previous validated musculoskeletal model of cruciate-retaining TKA was used (Fig. 1) to simulate a rising-from-a-chair activity [1]. We simulated a baseline case with the original post-operative FFC (0°). We then increased the FFC by 3°, 6°, 9°, by referencing the posterior femoral condyles (Fig. 2) and repeated the simulation. Quadriceps forces, PFJ ligament forces and PFJ contact forces were calculated. Results: Peak quadriceps force decreased by 48 N (6.5 %BW), on average, for every 3° of FFC at 90° flexion (Fig. 3a). The peak PFJ contact force decreased by 64 N (8.7 %BW), on average, for every 3° of FFC at 90° flexion. Conversely, peak medial and lateral PFJ ligament forces increased by 23 N and 25 N, respectively, on average, for every 3° more FFC (Fig. 3c-d). Discussion: FFC moderately affects the PFJ mechanics. Reduced PFJ contact force with more FFC is explained by reduced quadriceps force. More FFC, thus, benefits the knee extensor mechanism, due to increased quadriceps moment arm. More FFC over-tightens both medial and lateral PFJ ligaments, due to a wider PFJ gap, although the effect on ligament forces is not dramatic. Conclusions: More FFC reduces the quadriceps and PFJ force to rise from and sit on a chair. This surgical option can potentially help preventing anterior femoral notching, while at the same time provide a better knee function. References: [1] Marra MA, Vanheule V, Fluit R, et al. A Subject-Specific Musculoskeletal Modeling Framework to Predict In Vivo Mechanics of Total Knee Arthroplasty. ASME. J Biomech Eng. 2015;137(2):020904-020904-1

The effect of posterior tibial slope on simulated laxity tests in cruciate-retaining total knee arthroplasty

Introduction/Aim: More posterior tibial slope (PTS) can potentially prevent flexion gap tightness in Total Knee Arthroplasty (TKA). However, the effects of more PTS on knee laxity remain unclear. The aim of this study was to investigate the effect of PTS on the anterior-posterior (AP) and varus-valgus (VV) laxity in TKA. We hypothesised that the effects also depend on whether an anterior tibial cortex-referencing (ACR) technique or a centre of tibial plateau-referencing (CPR) technique is used. Materials and Methods: A previous validated musculoskeletal model of cruciate-retaining TKA was configured to simulate AP and VV laxity tests [1]. First the model was simulated without any external loads applied, with the knee spanning a 0-90° flexion range of motion (ROM). Subsequently, anterior and posterior loads of 70 N were applied alternately to the proximal tibia, and the resulting AP tibial displacement recorded throughout the knee ROM. Similarly, varus and valgus loads of 15 Nm were applied alternately to the tibia, and the resulting knee VV rotation recorded. The simulations were repeated with -3°, +3°, +6°, +9° of PTS both with the ACR and CPR techniques (Fig. 1). Laxity were calculated as the unloaded case curves minus the loaded case curves. Results: More PTS with the ACR technique increased dramatically the anterior, varus and valgus laxities, throughout the knee flexion ROM. The anterior laxity was maximal (23 mm) at 60° of knee flexion in the +9° ACR case. Conversely, variations of PTS with the CPR technique hardly affected the AP and VV laxities. Discussion: More PTS with the ACR technique compromises the overall knee stability, throughout the knee flexion-extension ROM and, most interestingly, also in extension. This is due to an increase of the flexion gap. In contrast, the CPR technique preserves the translational and rotational laxities of the knee, throughout the ROM. CPR could be achieved by pre-planning the PTS and by accurately executing the tibial cut or by using inserts with built-in PTS. Conclusions: More PTS with the ACR technique has large effects on knee stability and laxity, therefore surgeons should avoid increasing PTS using the ACR technique and, instead, reference the tibial cut height and slope from the posterior one third of the tibia. References: [1] Marra MA, Vanheule V, Fluit R, et al. A Subject-Specific Musculoskeletal Modeling Framework to Predict In Vivo Mechanics of Total Knee Arthroplasty. ASME. J Biomech Eng. 2015;137(2):020904-020904-1

Tagging genes with cassette-exchange sites

In an effort to make transgenesis more flexible and reproducible, we developed a system based on novel 5′ and 3′ ‘gene trap’ vectors containing heterospecific Flp recognition target sites and the corresponding ‘exchange’ vectors allowing the insertion of any DNA sequence of interest into the trapped locus. Flp-recombinase-mediated cassette exchange was demonstrated to be highly efficient in our system, even in the absence of locus-specific selection. The feasibility of constructing a library of ES cell clones using our gene trap vectors was tested and a thousand insertion sites were characterized, following electroporation in ES cells, by RACE–PCR and sequencing. We validated the system in vivo for two trapped loci in transgenic mice and demonstrated that the reporter transgenes inserted into the trapped loci have an expression pattern identical to the endogenous genes. We believe that this system will facilitate in vivo studies of gene function and large-scale generation of mouse models of human diseases, caused by not only loss but also gain of function alleles

Prevalence of right ventricular dysfunction and impact on all-cause death in hospitalized patients with COVID-19: a systematic review and meta-analysis

The Coronavirus Disease (COVID-19) pandemic imposed a high burden of morbidity and mortality. In COVID-19, direct lung parenchymal involvement and pulmonary microcirculation dysfunction may entail pulmonary hypertension (PH). PH and direct cardiac injury beget right ventricular dysfunction (RVD) occurrence, which has been frequently reported in COVID-19 patients; however, the prevalence of RVD and its impact on outcomes during COVID-19 are still unclear. This study aims to evaluate the prevalence of RVD and associated outcomes in patients with COVID-19, through a Systematic Review and Meta-Analysis. MEDLINE and EMBASE were systematically searched from inception to 15th July 2021. All studies reporting either the prevalence of RVD in COVID-19 patients or all-cause death according to RVD status were included. The pooled prevalence of RVD and Odds Ratio (OR) for all-cause death according to RVD status were computed and reported. Subgroup analysis and meta-regression were also performed. Among 29 studies (3813 patients) included, pooled prevalence of RVD was 20.4% (95% CI 17.1-24.3%; 95% PI 7.8-43.9%), with a high grade of heterogeneity. No significant differences were found across geographical locations, or according to the risk of bias. Severity of COVID-19 was associated with increased prevalence of RVD at meta-regression. The presence of RVD was found associated with an increased likelihood of all-cause death (OR 3.32, 95% CI 1.94-5.70). RVD was found in 1 out of 5 COVID-19 patients, and was associated with all-cause mortality. RVD may represent one crucial marker for prognostic stratification in COVID-19; further prospective and larger are needed to investigate specific management and therapeutic approach for these patients