Quality Assurance in Biobanking for Pre-Clinical Research

It is estimated that not less than USD 28 billion are spent each year in the USA alone on irreproducible pre-clinical research, which is not only a fundamental loss of investment and resources but also a strong inhibitor of efficiency for upstream processes regarding the translation towards clinical applications and therapies. The issues and cost of irreproducibility has mainly been published on pre-clinical research. In contrast to pre-clinical research, test material is often being transferred into humans in clinical research. To protect treated human subjects and guarantee a defined quality standard in the field of clinical research, the manufacturing and processing infrastructures have to strictly follow and adhere to certain (inter-)national quality standards. It is assumed and suggested by the authors that by an implementation of certain quality standards within the area of pre-clinical research, billions of USD might be saved and the translation phase of promising pre-clinical results towards clinical applications may substantially be improved. In this review, we discuss how an implementation of a quality assurance (QA) management system might positively improve sample quality and sustainability within pre-clinically focused biobank infrastructures. Biobanks are frequently positioned at the very beginning of the biomedical research value chain, and, since almost every research material has been stored in a biobank during the investigated life cycle, biobanking seems to be of substantial importance from this perspective. The role model of a QA-regulated biobank structure can be found in biobanks within the context of clinical research organizations such as in regenerative medicine clusters

Spontane durale arteriovenöse Fistel am Sinus cavernosus: Demaskierung nach endoskopischer Nasennebenhöhlen-Operation

Zusammenfassung: Spontane arteriovenöse Fisteln können sich über längere Zeit symptomlos entwickeln, bevor sie mit Strömungsgeräuschen, Visusminderung, Exophthalmos und konjunktivaler Injektion symptomatisch werden. Wir stellen den seltenen Fall einer okkulten parainfektiösen duralen arteriovenösen Fistel vor. Diese demaskierte sich postoperativ durch akute Verschlechterung der venösen Drainage, möglicherweise aufgrund der intraoperativen Lagerung, positiver Beatmungsdrucke und Stauung durch die Nasentamponad

Portable compiler optimisation across embedded programs and microarchitectures using machine learning

Building an optimising compiler is a difficult and time consuming task which must be repeated for each generation of a microprocessor. As the underlying microarchitecture changes from one generation to the next, the compiler must be retuned to optimise specifically for that new system. It may take several releases of the compiler to effectively exploit a processor’s performance potential, by which time a new generation has appeared and the process starts again. We address this challenge by developing a portable optimising compiler. Our approach employs machine learning to automatically learn the best optimisations to apply for any new program on a new microarchitectural configuration. It achieves this by learning a model off-line which maps a microarchitecture description plus the hardware counters from a single run of the program to the best compiler optimisation passes. Our compiler gains 67 % of the maximum speedup obtainable by an iterative compiler search using 1000 evaluations. We obtain, on average, a 1.16x speedup over the highest default optimisation level across an entire microarchitecture configuration space, achieving a 4.3x speedup in the best case. We demonstrate the robustness of this technique by applying it to an extended microarchitectural space where we achieve comparable performance

Heart valve replacement with the Björk-Shiley and St Jude Medical prostheses: A randomized comparison in 178 patients

In 178 patients, a randomized prospective comparison between the 60° spherical disc Björk-Shiley (BS) and the St Jude Medical (SJM) heart valve prostheses was performed. Four-week perioperative mortality was zero in the BS (n = 84) and 4.3% in the SJM group (n = 94). During a mean ( ± SD) follow-up of 52 ± 20 months or 778 patient-years, late cardiac mortality per year was 2.4% in the BS and 2.2% in the SJM group. The yearly thromboembolic rates were 1.4% in the BS and 2.0% in the SJM group. There was no mechanical valve failure or haemolytic anaemia. Paravalvular leaks and major bleeding complications occurred at low rates in both groups (1.1% and2.2% per year in BS; 0.7% and 1.7% per year in SJM). Functional results were similarly good with 96% of patients with BS valves and 95% of patients with SJM prostheses being in NYHA classes I and II, respectively. We conclude that heart valve replacement with mechanical prostheses can be performed with equally good results using either the Björk-Shiley spherical disc valve or the St Jude Medical bileaflet prosthesi

The nonmesonic weak decay of the hypertriton

The nonmesonic decay of the hypertriton is calculated based on a hypertriton wavefunction and 3N scattering states, which are rigorous solutions of 3-body Faddeev equations using realistic NN and hyperon-nucleon interactions. The pion-exchange together with heavier meson exchanges for the $\Lambda N \to N N$ transition is considered. The total nonmesonic decay rate is found to be 0.5% of the free $\Lambda$ decay rate. Integrated as well as differential decay rates are given. The p- and n- induced decays are discussed thoroughly and it is shown that the corresponding total rates cannot be measured individually.Comment: 27 pages, 20 figures, revtex, submitted to Phys. Rev.

Optical Drug Monitoring: Photoacoustic Imaging of Nanosensors to Monitor Therapeutic Lithium in Vivo

Personalized medicine could revolutionize how primary care physicians treat chronic disease and how researchers study fundamental biological questions. To realize this goal, we need to develop more robust, modular tools and imaging approaches for in vivo monitoring of analytes. In this report, we demonstrate that synthetic nanosensors can measure physiologic parameters with photoacoustic contrast, and we apply that platform to continuously track lithium levels in vivo. Photoacoustic imaging achieves imaging depths that are unattainable with fluorescence or multiphoton microscopy. We validated the photoacoustic results that illustrate the superior imaging depth and quality of photoacoustic imaging with optical measurements. This powerful combination of techniques will unlock the ability to measure analyte changes in deep tissue and will open up photoacoustic imaging as a diagnostic tool for continuous physiological tracking of a wide range of analytes

The nucleon-nucleon interaction

We review the major progress of the past decade concerning our understanding of the nucleon-nucleon interaction. The focus is on the low-energy region (below pion production threshold), but a brief outlook towards higher energies is also given. The items discussed include charge-dependence, the precise value of the $\pi NN$ coupling constant, phase shift analysis and high-precision NN data and potentials. We also address the issue of a proper theory of nuclear forces. Finally, we summarize the essential open questions that future research should be devoted to.Comment: 42 pages, 12 figures, iopart.cls style; Topical Review prepared for J. Phys. G: Nucl. Part. Phy

Strangeness production in proton-proton and proton-nucleus collisions

In these lectures we discuss the investigation of the strange meson production in proton-proton ($pp$) and in proton-nucleus ($pA$) reactions within an effective Lagrangian model. The kaon production proceeds mainly via the excitations of $N^*$(1650), $N^*$(1710), and $N^*$(1720) resonant intermediate nucleonic states, in the collision of two initial state nucleons. Therefore, the strangeness production is expected to provide information about the resonances lying at higher excitation energies. For beam energies very close to the kaon production threshold the hyperon-proton final state interaction effects are quite important. Thus, these studies provide a check on the models of hyperon-nucleon interactions. The in-medium production of kaons show strong sensitivity to the self energies of the intermediate mesons.Comment: 16 pages, 9 figures, Talk presented in the workshop on Hadron Physics, Puri, India, March 7-17,200

Many-Body Currents and the Strange-Quark Content of 4he

Meson-exchange current (MEC) contributions to the parity-violating (PV) asymmetry for elastic scattering of polarized electrons from $^4$He are calculated over a range of momentum transfer using Monte Carlo methods and a variational $^4$He ground state wavefunction. The results indicate that MEC's generate a negligible contribution to the asymmetry at low-|\qv|, where a determination of the nucleon's mean square strangeness radius could be carried out at CEBAF. At larger values of momentum transfer -- beyond the first diffraction minimum -- two-body corrections from the $\rho$-$\pi$ \lq\lq strangeness charge" operator enter the asymmetry at a potentially observable level, even in the limit of vanishing strange-quark matrix elements of the nucleon. For purposes of constraining the nucleon's strangeness electric form factor, theoretical uncertainties associated with these MEC contributions do not appear to impose serious limitations.Comment: 32 TEX pages and 7 figures (not included, available from authors upon request), CEBAF Preprint #TH-94-1