A Virus Harvest Unit for the continuous harvesting of lentivirus from suspension cell cultures

For virus particles produced by cell culture systems, free intact virus particles as well as virus particles associated with host cell membranes or other viral particles and damaged virus fragments will be present. To reduce the amount of host cell fragments and/or virus aggregates it is critically important to reduce the shear stress applied to the cell culture during the harvesting step as much as possible. This is mainly accomplished by utilizing a low-shear Virus Harvest Unit (VHUÔ) with large pore size membranes (5-15mM) and by utilizing a low-shear pump. As shown in Table I, the VHUÔ, is able to clarify the broth containing the viral vectors from less than 500 Nephelometric Turbidity Units (NTU) down to less than 16 NTU. In contrast the turbidity of a broth harvested by centrifugation from a batch is around 50-90 NTU and the turbidity of the harvest stream from an acoustic filter (Biosep) is 33 NTU. These results suggest it may be possible to eliminate the secondary clarification steps when using the VHU unit as the virus harvesting process mode. Please click Additional Files below to see the full abstract

1D-Disordered Conductor with Loops Immersed in a Magnetic Field

We investigate the conductance of a 1-D disordered conducting loop with two contacts, immersed in a magnetic flux. We show the appearance in this model of the Al'tshuler-Aronov-Spivak behaviour. We also investigate the case of a chain of loops distributed with finite density: in this case we show that the interference effects due to the presence of the loops can lead to the delocalization of the wave function.Comment: 8 pages; LaTeX; IFUM 463/FT; to appear in Phys. Lett.

Topological Yang-Mills cohomology in pure Yang-Mills Theory

Using the first order formalism (BFYM) of the Yang-Mills theory we show that it displays an embedded topological sector corresponding to the field content of the Topological Yang-Mills theory (TYM). This picture arises after a proper redefinition of the fields of BFYM and gives a clear representation of the non perturbative part of the theory in terms of the topological sector. In this setting the calculation of the $vev$ of a YM observable is translated into the calculation of a corresponding (non topological) quantity in TYM. We then compare the topological observables of TYM with a similar set of observables for BFYM and discuss the possibility of describing topological observables in YM theory.Comment: 12 pages, Latex, one reference added, to appear in Phys. Lett.

On static vs dynamic (switching of) operational policies in aircraft turnaround team allocation and management

Aircraft turnaround operations represent the fulcrum of airport operations. They include all services to be provided to an aircraft between two consecutive flights. These services are executed by human operators, often organised in teams, who employ some related equipment and vehicles (e.g. conveyor belts, trolleys and tugs for baggage loading/unloading and transportation). In this paper, we focus on the real-time management of turnaround operations, and assess the relative merits and limitations of so-called dispatching rules that originate from the manufacturing literature. More precisely, we focus on the real-time allocation, on the day of operation, of teams of ground handling operators to aircraft turnarounds. This is pursued from the viewpoint of third-party service providers. We employ simulation, in conjunction with deep reinforcement learning, and work on the case of a real airport and the entirety of its turnaround operations involving multiple service providers

Topological BF Theories in 3 and 4 Dimensions

In this paper we discuss topological BF theories in 3 and 4 dimensions. Observables are associated to ordinary knots and links (in 3 dimensions) and to 2-knots (in 4 dimensions). The vacuum expectation values of such observables give a wide range of invariants. Here we consider mainly the 3-dimensional case, where these invariants include Alexander polynomials, HOMFLY polynomials and Kontsevich integrals.Comment: 25 pages, latex, no figures. Transmission problems have been solve

Neuropotent self-renewing neural stem (NS) cells derived from mouse induced pluripotent stem (iPS) cells

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The BF Formalism for QCD and Quark Confinement

Using the BF version of pure Yang-Mills, it is possible to find a covariant representation of the 't Hooft magnetic flux operator. In this framework, 't Hooft's pioneering work on confinement finds an explicit realization in the continuum. Employing the Abelian projection gauge we compute the expectation value of the magnetic variable and find the expected perimeter law. We also check the area law behaviour for the Wilson loop average and compute the string tension which turns out to be of the right order of magnitude.Comment: Various changes, version to appear in Nucl.Phys.

Early raise of BDNF in hippocampus suggests induction of posttranscriptional mechanisms by antidepressants

<p>Abstract</p> <p>Background</p> <p>The neurotrophin BDNF has been implicated in the regulation of neuroplasticity, gene expression, and synaptic function in the adult brain, as well as in the pathophysiology of neuropsychiatric disorders and the mechanism of action of antidepressants. Antidepressant treatments have been shown to increase the expression of BDNF mRNA, although the changes measured were found to be different depending on various factors. A few studies only have measured levels of BDNF protein after antidepressant treatments, and poor correlation was found between mRNA and protein changes. We studied the time course of expression of BDNF mRNA and protein during drug treatments, in order to elucidate the temporal profile of regulation of this effector and whether mRNA and protein levels correlate. Rat groups were treated for 1, 2 or 3 weeks with fluoxetine or reboxetine; in additional groups drug treatment was followed by a washout week (3+1). Total BDNF mRNA was measured by Real Time PCR, pro- and mature BDNF proteins were measured by Western blot.</p> <p>Results</p> <p>We found that mature BDNF protein is induced more rapidly than mRNA, by both drugs in hippocampus (weeks 1–2) and by reboxetine in prefrontal/frontal cortex (week 1). The temporal profile of BDNF protein expression was largely inconsistent with that of mRNA, which followed the protein induction and reached a peak at week 3.</p> <p>Conclusion</p> <p>These results suggest that BDNF protein is rapidly elevated by antidepressant treatments by posttranscriptional mechanisms, and that induction of BDNF mRNA is a slower process.</p

Three-dimensional BF Theories and the Alexander-Conway Invariant of Knots

We study 3-dimensional BF theories and define observables related to knots and links. The quantum expectation values of these observables give the coefficients of the Alexander-Conway polynomial.Comment: 32 pages (figures available upon request); LaTe

The Donaldson-Witten Invariants in Pure QCD with Order and Disorder 't Hooft-like Operators

We study the first-order formalism of pure four-dimensional ${\rm SU}(2)$ Yang--Mills theory with theta-term. We describe the Green functions associated to electric and magnetic flux operators \`a la 't~Hooft by means of gauge-invariant non-local operators. These Green functions are related to Witten's invariants of four-manifolds.Comment: 12 pages, LaTeX file, no macros used. Revised Versio