Electron Microprobe Analysis of Electrolytes in Whole Cultured Epithelial Cells

Microprobe analysis was used to determine electrolyte contents in whole epithelial sheets of A6 cells and to investigate the most critical points of this method. Analysis of dextran standard sections of different thickness revealed that low accelerating voltages of about 10 kV are best suited for whole freeze-dried cells on thick supports, since 5 μm thick sections are not penetrated by 10 kV electrons. Washing of A6 cells for 10 sec with distilled water led to cell swelling of about 40%, but the molar concentration ratios and the concentrations per dry weight (dw) were not altered. Washing for 60 sec with distilled water caused a further increase in cell volume (120%) and loss of cellular K and Cl (90 mmol/kg dw). Washing with isotonic NH4-acetate led to a loss of cell Cl already after 10 sec. To characterize the Na transport compartment, A6 cells cultured on permeable supports were washed for 5 sec with distilled water, freeze-dried, and analyzed. Inhibition of transepithelial Na transport by ouabain increased Na/P from 0.15±0.07 to 0.75±0.03 and Cl/P from 0.21±0.001 to 0.38±0.003 while KIP decreased from 0.83±0.08 to 0.32±0.03. The changes in cell Na and K contents can be explained by K/Na exchange; the increase in Cl content indicates some cell swelling. Since the ouabain-induced changes could be prevented by apical amiloride, the apical membrane provides the most important pathway for Na entry in A6 cells

Q-Value and Half-Lives for the Double-Beta-Decay Nuclide 110Pd

The 110Pd double-beta decay Q-value was measured with the Penning-trap mass spectrometer ISOLTRAP to be Q = 2017.85(64) keV. This value shifted by 14 keV compared to the literature value and is 17 times more precise, resulting in new phase-space factors for the two-neutrino and neutrinoless decay modes. In addition a new set of the relevant matrix elements has been calculated. The expected half-life of the two-neutrino mode was reevaluated as 1.5(6) E20 yr. With its high natural abundance, the new results reveal 110Pd to be an excellent candidate for double-beta decay studies

Using self-drilling screws in volar plate osteosynthesis for distal radius fractures: a feasibility study

Background: Symptomatic extensor tendon irritation is a frequent complication in volar plate osteosynthesis of distal radius fractures. It is typically caused by dorsal screw protrusion and overdrilling of the dorsal cortex. The use of self-drilling locking screws (SDLS) could overcome both causes. The practical applicability of SDLS depends on two prerequisites: (1) the feasibility of preoperative distal screw length determination, and (2) sufficient primary biomechanical stability of SDLS compared to standard locking screws (SLS). Methods: We first assessed the feasibility of preoperative screw length determination (1): Distal radius width, depth and distal screw lengths were measured in 38 human radii. Correlations between distal radius width and depth were assessed, a cluster analysis (Ward's method and squared Euclidean distance) for distal radius width conducted, and intra-cluster screw lengths analyzed (ANOVA). The biomechanical performance of SDLS (2) was assessed by comparison to SLS in a distal radius fracture model (AO-23 A3). 75 % distal screw length was chosen for both groups to simulate a worst-case scenario. Uniaxial compression tests were conducted to measure stiffness, elastic limit, maximum force and residual tilt. Statistics comprised of independent sample t-tests and a Bonferroni correction (p 36.9 mm. ANOVA and Tukey post-hoc analysis revealed significantly different volar-dorsal depths (p < 0.05) for nearly all screws. (2) To assess biomechanical stability nine specimens were tested each;no significant differences were found between the SDLS and SLS groups. Conclusions: This feasibility study demonstrates that (1) distal radius width can be used as a predictor for distal screw length and (2) that SDLS provides mechanical stability equivalent to SLS. These results highlight the feasibility of applying SDLS screws in volar plate osteosynthesis at least in extraarticular fractures

Probing the N = 32 shell closure below the magic proton number Z = 20: Mass measurements of the exotic isotopes 52,53K

The recently confirmed neutron-shell closure at N = 32 has been investigated for the first time below the magic proton number Z = 20 with mass measurements of the exotic isotopes 52,53K, the latter being the shortest-lived nuclide investigated at the online mass spectrometer ISOLTRAP. The resulting two-neutron separation energies reveal a 3 MeV shell gap at N = 32, slightly lower than for 52Ca, highlighting the doubly-magic nature of this nuclide. Skyrme-Hartree-Fock-Boguliubov and ab initio Gorkov-Green function calculations are challenged by the new measurements but reproduce qualitatively the observed shell effect.Comment: 5 pages, 5 figure

Junior doctors' experiences with interprofessional collaboration:Wandering the landscape

Context The transition from medical student to junior doctor is challenging. Junior doctors need to become part of the physician community of practice (CoP), while dealing with new responsibilities, tasks and expectations. At the same time, they need to learn how to navigate the frontiers and intersections with the other communities of practice that form the Landscape of Practice (LoP). This study aims to understand how junior doctors experience interprofessional collaboration (IPC) and what elements shape these experiences considering their transition to clinical practice. Methods In this multicentre qualitative study, 13 junior doctors individually drew two rich pictures of IPC experiences, one positive and one negative. A rich picture is a visual representation, a drawing of a particular situation intended to capture the complex and non-verbal elements of an experience. We used semi-structured interviews to deepen the understanding of junior doctors' depicted IPC experiences. We analysed both visual materials and interview transcripts iteratively, for which we adopted an inductive constructivist thematic analysis. Results While transitioning into a doctor, junior doctors become foremost members of the physician CoP and shape their professional identity based on perceived values in their physician community. Interprofessional learning occurs implicitly, without input from the interprofessional team. As a result, junior doctors struggle to bridge the gap between themselves and the interprofessional team, preventing IPC learning from developing into an integrative process. This professional isolation leaves junior doctors wandering the landscape of practice without understanding roles, attitudes and expectations of others. Conclusions Learning IPC needs to become a collective endeavour and an explicit learning goal, based on multisource feedback to take advantage of the expertise already present in the LoP. Furthermore, junior doctors need a safe environment to embrace and reflect on the emotions aroused by interprofessional interactions, under the guidance of experienced facilitators

Resposta genética à aclimatação como fator de redução de danos causados por geadas em trigo.

Editores técnicos: Joseani Mesquita Antunes, Ana Lídia Variani Bonato, Márcia Barrocas Moreira Pimentel

Cognition-Enhancing Drugs: Can We Say No?

Normative analysis of cognition-enhancing drugs frequently weighs the liberty interests of drug users against egalitarian commitments to a level playing field. Yet those who would refuse to engage in neuroenhancement may well find their liberty to do so limited in a society where such drugs are widespread. To the extent that unvarnished emotional responses are world-disclosive, neurocosmetic practices also threaten to provide a form of faulty data to their users. This essay examines underappreciated liberty-based and epistemic rationales for regulating cognition-enhancing drugs