THA performed using conventional and navigated tissue-preserving techniques

Less invasive methods of performing total hip arthroplasty have been considered controversial after increased complication rates and component malpositioning were reported. A new method of performing total hip arthroplasty through an incision in the superior capsule, posterior to the abductors and anterior to the posterior capsule, was developed with the aim of producing a technique that maintained the joint stability of the transgluteal exposure and the rapid abductor recovery of the posterior exposure. We assessed the recovery and complications of this technique performed with surgical navigation. The study group was compared with similar subjects who had conventional total hip arthroplasty, without surgical navigation, using the transgluteal exposure. There were 185 consecutive total hip arthroplasties in the study group and 189 nonconsecutive historical total hip arthroplasties in the control group. The two groups were controlled for complexity and had no differences in body mass index, gender, diagnosis, operative side, bilateral operations, and previous surgeries. Patients were evaluated for clinical recovery and perioperative complications at 9 and 24 weeks. The study group recovered faster at both followup examinations. The study group had fewer perioperative and postoperative complications compared with the control group. Accuracy of component positioning was not compromised compared to the control group. Less invasive surgery with the philosophy of maximally preserving the abductors, posterior capsule, and short rotators may result in a safer operation with faster recovery than traditional techniques.

Substrate binding tunes conformational flexibility and kinetic stability of an amino acid antiporter

We used single molecule dynamic force spectroscopy to unfold individual serine/threonine antiporters SteT from Bacillus subtilis. The unfolding force patterns revealed interactions and energy barriers that stabilized structural segments of SteT. Substrate binding did not establish strong localized interactions but appeared to be facilitated by the formation of weak interactions with several structural segments. Upon substrate binding, all energy barriers of the antiporter changed thereby describing the transition from brittle mechanical properties of SteT in the unbound state to structurally flexible conformations in the substrate-bound state. The lifetime of the unbound state was much shorter than that of the substrate-bound state. This leads to the conclusion that the unbound state of SteT shows a reduced conformational flexibility to facilitate specific substrate binding and a reduced kinetic stability to enable rapid switching to the bound state. In contrast, the bound state of SteT showed an increased conformational flexibility and kinetic stability such as required to enable transport of substrate across the cell membrane. This result supports the working model of antiporters in which alternate substrate access from one to the other membrane surface occurs in the substrate-bound state.

Do Ads Add Up? The Impact of Parties' Advertisements on the Stability of Vote Choice at the Swiss National Elections 2011

Our contribution analyses the influence of campaign advertisements on vote choice in the 2011 elections to the Swiss National Council. Concretely, we ask whether and to what extent the relative exposure to party ads of a preferred party exerts a reinforcing effect on an individual's party choice. We make use of the two-wave panel structure contained in the RCS survey data of the Selects 2011 and combine it with data on advertisements in 20 important national and regional newspapers. We find that increasing exposure to the campaign of one's preferred party may reinforce individuals with strong party attachment in their initial vote choice. Yet this effect only materializes with substantial campaign duration and exposure. Additional and exploratory analyses revealed that particularly the two recently emerged parties, the GLP and BDP, might have made a slight difference by potentially persuading defecting voters with the help of their campaign.

Species richness, but not phylogenetic diversity, influences community biomass production and temporal stability in a re-examination of 16 grassland biodiversity studies

* Hundreds of experiments have now manipulated species richness (SR) of various groups of organisms and examined how this aspect of biological diversity influences ecosystem functioning. Ecologists have recently expanded this field to look at whether phylogenetic diversity (PD) among species, often quantified as the sum of branch lengths on a molecular phylogeny leading to all species in a community, also predicts ecological function. Some have hypothesized that phylogenetic divergence should be a superior predictor of ecological function than SR because evolutionary relatedness represents the degree of ecological and functional differentiation among species. But studies to date have provided mixed support for this hypothesis. * Here, we reanalyse data from 16 experiments that have manipulated plant SR in grassland ecosystems and examined the impact on above-ground biomass production over multiple time points. Using a new molecular phylogeny of the plant species used in these experiments, we quantified how the PD of plants impacts average community biomass production as well as the stability of community biomass production through time. * Using four complementary analyses, we show that, after statistically controlling for variation in SR, PD (the sum of branches in a molecular phylogenetic tree connecting all species in a community) is neither related to mean community biomass nor to the temporal stability of biomass. These results run counter to past claims. However, after controlling for SR, PD was positively related to variation in community biomass over time due to an increase in the variances of individual species, but this relationship was not strong enough to influence community stability. * In contrast to the non-significant relationships between PD, biomass and stability, our analyses show that SR per se tends to increase the mean biomass production of plant communities, after controlling for PD. The relationship between SR and temporal variation in community biomass was either positive, non-significant or negative depending on which analysis was used. However, the increases in community biomass with SR, independently of PD, always led to increased stability. These results suggest that PD is no better as a predictor of ecosystem functioning than SR. * Synthesis. Our study on grasslands offers a cautionary tale when trying to relate PD to ecosystem functioning suggesting that there may be ecologically important trait and functional variation among species that is not explained by phylogenetic relatedness. Our results fail to support the hypothesis that the conservation of evolutionarily distinct species would be more effective than the conservation of SR as a way to maintain productive and stable communities under changing environmental conditions.

Effects of pH, light and temperature on (1→3,1→4)-β-glucanase stability in wheat leaves

Changes in (1→3,1→4)-β-D-glucan endohydrolase (EC 3.2.1.73) protein levels were investigated in segments from second leaves of wheat (Triticum aestivum L.). The abundance of the enzyme protein markedly increased when leaf segments were incubated in the dark whereas the enzyme rapidly disappeared when dark-incubated segments were illuminated or fed with sucrose. Addition of cycloheximide (CHI) to the incubation medium led to the disappearance of previously synthesized (1→3,1→4)-β-glucanase and suppressed the dark-induced accumulation indicating that the enzyme was rather unstable. The degradation of (1→3,1→4)-β-glucanase was analyzed without the interference of de-novo synthesis in intercellular washing fluid (IWF). The loss of the enzyme protein during incubation of IWF (containing naturally present peptide hydrolases) indicated that the stability increased from pH 4 to pH 7 and that an increase in the temperature from 25 to 35 °C considerably decreased the stability. Chelating divalent cations in the IWF with o-phenanthroline also resulted in a lowered stability of the enzyme. A strong temperature effect in the range from 25 to 35 °C was also observed in wheat leaf segments. Diurnal changes in (1→3,1→4)-β-glucanase activity were followed in intact second leaves from young wheat plants. At the end of the dark period, the activity was high but constantly decreased during the light phase and remained low if the light period was extended. Activity returned to the initial level during a 10-h dark phase. During a diurnal cycle, changes in (1→3,1→4)-β-glucanase activity were associated with reciprocal changes in soluble carbohydrates. The results suggest that the synthesis and the proteolytic degradation of an apoplastic enzyme may rapidly respond to changing environmental conditions.

Dynamic intraligamentary stabilization: novel technique for preserving the ruptured ACL

PURPOSE Replacement of the torn anterior cruciate ligament (ACL) with a transplant is today`s gold standard. A new technique for preserving and healing the torn ACL is presented. HYPOTHESIS a dynamic intraligamentary stabilization (DIS) that provides continuous postinjury stability of the knee and ACL in combination with biological improvement of the healing environment [leucocyte- and platelet-rich fibrin (L-PRF) and microfracturing] should enable biomechanically stable ACL self-healing. METHODS Ten sportive patients were treated by DIS employing an internal stabilizer to keep the unstable knee in a posterior translation, combined with microfracturing and platelet-rich fibrin induction at the rupture site to promote self-healing. Postoperative clinical [Tegner, Lysholm, International Knee Documentation Committee (IKDC), visual analogue scale patient satisfaction score] and radiological evaluation, as well as assessment of knee laxity was performed at 6 weeks, 3, 6, 12, and 24 months. RESULTS One patient had a re-rupture 5 months postoperative and was hence excluded from further follow-ups. The other nine patients presented the following outcomes at 24 months: median Lysholm score of 100; IKDC score of 98 (97-100); median Tegner score of 6 (range 9-5); anterior translation difference of 1.4 mm (-1 to 3 mm); median satisfaction score of 9.8 (9-10). MRI showed scarring and continuity of the ligament in all patients. CONCLUSIONS DIS combined with microfracturing and L-PRF resulted in stable clinical and radiological healing of the torn ACL in all but one patient of this first series. They attained normal knee scores, reported excellent satisfaction and could return to their previous levels of sporting activity. LEVEL OF EVIDENCE Case series with no comparison group, Level IV.