The Shape of Protein Crowders is a Major Determinant of Protein Diffusion

AbstractAs a model for understanding how molecular crowding influences diffusion and transport of proteins in cellular environments, we combined experimental and theoretical approaches to study the diffusion of proteins in highly concentrated protein solutions. Bovine serum albumin and γ-Globulin were chosen as molecular crowders and as tracers. These two proteins are representatives of the main types of plasma protein and have different shapes and sizes. Solutions consisting of one or both proteins were studied. The self-diffusion coefficients of the fluorescently labeled tracer proteins were measured by means of fluorescence correlation spectroscopy at a total protein concentration of up to 400 g/L. γ-Globulin is found to have a stronger influence as a crowder on the tracer self-diffusion coefficient than Bovine serum albumin. Brownian dynamics simulations show that the excluded volume and the shape of the crowding protein have a significantly stronger influence on translational and rotational diffusion coefficients, as well as transient oligomerization, than hydrodynamic or direct interactions. Anomalous subdiffusion, which is not observed at the experimental fluorescence correlation spectroscopy timescales (>100 μs), appears only at very short timescales (<1 μs) in the simulations due to steric effects of the proteins. We envision that the combined experimental and computational approach employed here can be developed to unravel the different biophysical contributions to protein motion and interaction in cellular environments by systematically varying protein properties such as molecular weight, size, shape, and electrostatic interactions

Comparison of volume-controlled and pressure-controlled ventilation during laparoscopic gastric banding in morbidly obese patients

Background There are no guidelines on ventilation modes in morbidly obese patients. We investigated the effects of volume-controlled (VCV) and pressure-controlled ventilation (PCV) on gas exchange, respiratory mechanics, and cardiovascular responses in laparoscopic gastric banding procedures. Methods After Institutional Review Board approval, 24 adult consenting patients scheduled for laparoscopic gastric banding were studied. Anesthesia was standardized using remifentanil, propofol, rocuronium, and sevoflurane. All patients started with VCV with a tidal volume of 10 ml kg(-1) ideal body weight, respiratory rate adjusted to obtain an end-tidal carbon dioxide of 35-40 mmHg, positive end-expiratory pressure of 5 cmH(2)O, an inspiratory pause of 10% and an inspiratory/expiratory ratio of 1:2. Fifteen minutes after pneumoperitoneum, the patients were randomly allocated to two groups. In Group VCV (n=12), ventilation was with the same parameters. In Group PCV (n=12), the airway pressure was set to provide a tidal volume of 10 ml kg(-1) ideal body weight without exceeding 35 cm H2O. Respiratory rate was adjusted to keep an end-tidal carbon dioxide of 35-40 mmHg. Arterial blood samples were drawn after surgical positioning and 15 min after allocation. Analysis of variance (ANOVA) was used for statistical analysis. Results With constant minute ventilation, VCV generates equal airway pressures and cardiovascular effects with a lower Pa-CO2 as compared to PCV (42.5 (5.2) mmHg versus 48.9 (4.3) mmHg, p < 0.01 ANOVA). Arterial oxygenation remained unchanged. Conclusion VCV and PCV appear to be an equally suited ventilatory technique for laparoscopic procedures in morbidly obese patients. Carbon dioxide elimination is more efficient when using VCV

Measurement of the charm structure function F_{2,c)^{γ} of the photon at LEP

The production of charm quarks is studied in deep-inelastic electron–photon scattering using data recorded by the OPAL detector at LEP at nominal e⁺e⁻ centre-of-mass energies from 183 to 209 GeV. The charm quarks have been identified by full reconstruction of charged D* mesons using their decays into D⁰π with the D⁰ observed in two decay modes with charged particle final states, Kπ and Kπππ. The cross-section σ^{D*} for production of charged D* in the reaction e⁺e⁻→e⁺e⁻D*Χ is measured in a restricted kinematical region using two bins in Bjorken x, 0.00140.1 the perturbative QCD calculation at next-to-leading order agrees perfectly with the measured cross-section. For x<0.1 the measured cross-section is 43.8±14.3±6.3±2.8 pb with a next-to-leading order prediction of 17.0⁺²·⁹_₂.₃ pb

Companion Animals in Zoonoses Research – Ethical Considerations

Non-human animals are commonly classified according to their "role", such as "livestock", "wild" or "companion" animals. But what if those classifications overlap? This article presents a report of the retreat week "ZooCan – Zoonoses of companion animals as case study for animal ethics" at the University of Veterinary Medicine Hannover, Germany, in November 2022. The workshop included participants from different European countries with interdisciplinary backgrounds (animal law, bioethics, epidemiology, philosophy, biology and veterinary medicine). We address ethically relevant issues that emerge when companion animals are used as research animals, particularly in zoonoses research. The outcomes of the multi-disciplinary approach are used to i) define criteria to classify "companion" and "research" animals, ii) provide guidance to overcome the challenges with classificational overlaps, iii) give insights into cutting-edge zoonoses research with an example of SARS-CoV-2 in cats, and iv) discuss animal ethics approaches with regard to classifications

Determination of alpha_s using Jet Rates at LEP with the OPAL detector

Hadronic events produced in e+e- collisions by the LEP collider and recorded by the OPAL detector were used to form distributions based on the number of reconstructed jets. The data were collected between 1995 and 2000 and correspond to energies of 91 GeV, 130-136 GeV and 161-209 GeV. The jet rates were determined using four different jet-finding algorithms (Cone, JADE, Durham and Cambridge). The differential two-jet rate and the average jet rate with the Durham and Cambridge algorithms were used to measure alpha(s) in the LEP energy range by fitting an expression in which order alpah_2s calculations were matched to a NLLA prediction and fitted to the data. Combining the measurements at different centre-of-mass energies, the value of alpha_s (Mz) was determined to be alpha(s)(Mz)=0.1177+-0.0006(stat.)+-0.0012$(expt.)+-0.0010(had.)+-0.0032(theo.) \.Comment: 40 pages, 17 figures, Submitted to Euro. Phys. J.

Factsheets. Netwerken Multifunctioneel Ondernemerschap

Zo’n 400 ondernemers werkten in 2012 en 2013 aan een krachtige koers voor hun eigen bedrijf en de sector binnen het project 'Netwerken Multifunctioneel Ondernemerschap'. Verdeeld over 20 netwerken zorgden deze ondernemers voor ontwikkeling en professionalisering op individueel en sectoraal niveau. Elk netwerk stelde hierbij eigen doelen waardoor een brede variatie aan onderwerpen aan de orde is gekomen binnen de sectoren zorglandbouw, plattelandstoerisme, agrarisch natuurbeheer, boerderijeducatie, agrarische kinderopvang of boerderijwinkels/afzet streekproducten. De netwerkbegeleiders hebben de ontwikkeling met de deelnemers doorlopen vanuit eigen expertise en door externen in te zetten. De gedrevenheid van de deelnemers, begeleiders en het projectteam resulteren in aansprekende resultaten. Dit boekje presenteert per netwerk een factsheet met de leerpunten en resultaten. Iets waar we met elkaar als sector trots op mogen zijn

Colour reconnection in e+e- -> W+W- at sqrt(s) = 189 - 209 GeV

The effects of the final state interaction phenomenon known as colour reconnection are investigated at centre-of-mass energies in the range sqrt(s) ~ 189-209 GeV using the OPAL detector at LEP. Colour reconnection is expected to affect observables based on charged particles in hadronic decays of W+W-. Measurements of inclusive charged particle multiplicities, and of their angular distribution with respect to the four jet axes of the events, are used to test models of colour reconnection. The data are found to exclude extreme scenarios of the Sjostrand-Khoze Type I (SK-I) model and are compatible with other models, both with and without colour reconnection effects. In the context of the SK-I model, the best agreement with data is obtained for a reconnection probability of 37%. Assuming no colour reconnection, the charged particle multiplicity in hadronically decaying W bosons is measured to be (nqqch) = 19.38+-0.05(stat.)+-0.08 (syst.).Comment: 30 pages, 9 figures, Submitted to Euro. Phys. J.

Measurements of Flavour Dependent Fragmentation Functions in Z^0 -> qq(bar) Events

Fragmentation functions for charged particles in Z -> qq(bar) events have been measured for bottom (b), charm (c) and light (uds) quarks as well as for all flavours together. The results are based on data recorded between 1990 and 1995 using the OPAL detector at LEP. Event samples with different flavour compositions were formed using reconstructed D* mesons and secondary vertices. The \xi_p = ln(1/x_E) distributions and the position of their maxima \xi_max are also presented separately for uds, c and b quark events. The fragmentation function for b quarks is significantly softer than for uds quarks.Comment: 29 pages, LaTeX, 5 eps figures (and colour figs) included, submitted to Eur. Phys. J.

Bose-Einstein Correlations of Three Charged Pions in Hadronic Z^0 Decays

Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4 x 10^6 hadronic Z^0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected for the Coulomb effect, were separated from the known two-pion correlations by a new subtraction procedure. A significant genuine three-pion BEC enhancement near threshold was observed having an emitter source radius of r_3 = 0.580 +/- 0.004 (stat.) +/- 0.029 (syst.) fm and a strength of \lambda_3 = 0.504 +/- 0.010 (stat.) +/- 0.041 (syst.). The Coulomb correction was found to increase the \lambda_3 value by \~9% and to reduce r_3 by ~6%. The measured \lambda_3 corresponds to a value of 0.707 +/- 0.014 (stat.) +/- 0.078 (syst.) when one takes into account the three-pion sample purity. A relation between the two-pion and the three-pion source parameters is discussed.Comment: 19 pages, LaTeX, 5 eps figures included, accepted by Eur. Phys. J.