Local fluctuations of vibrational polaritons monitored by two-dimensional infrared spectroscopy

We study the collective behavior of molecules placed in an infrared (IR) microcavity, incorporating the local fluctuations, i.e., dynamical disorder. The cooperative feature in vibrational polaritons is shown to be dynamically eroded, due to intermolecule coherence. To further resolve such process, we develop a two-dimensional infrared spectroscopy (2D-IR) for molecules interacting with cavity modes. The cooperative feature in correspondence to the spectroscopic signal is specified. The results reveal the dark states by the cross peaks apart from the ones for polaritons, as a result of the breakdown of cooperativity between molecules. We further show that the breakdown of cooperativity profoundly connects to the localization of the vibrational excitations whereas the polariton modes are extended wave over several molecules. Besides, our work offers new physical insight for understanding the recent 2D-IR experiments where the interaction between dark modes and bright polaritons was evident.Comment: 11 pages, 6 figure

Time-Dependent Quasiparticle Current Density Functional Theory of X-Ray Nonlinear Response Functions

A real-space representation of the current response of many-electron systems with possible applications to x-ray nonlinear spectroscopy and magnetic susceptibilities is developed. Closed expressions for the linear, quadratic and third-order response functions are derived by solving the adiabatic Time Dependent Current Density Functional (TDCDFT) equations for the single-electron density matrix in Liouville space.Comment: 11 page

Multiple Core-Hole Coherence in X-Ray Four-Wave-Mixing Spectroscopies

Correlation-function expressions are derived for the coherent nonlinear response of molecules to three resonant ultrafast pulses in the x-ray regime. The ability to create two-core-hole states with controlled attosecond timing in four-wave-mixing and pump probe techniques should open up new windows into the response of valence electrons, which are not available from incoherent x-ray Raman and fluorescence techniques. Closed expressions for the necessary four-point correlation functions are derived for the electron-boson model by using the second order cumulant expansion to describe the fluctuating potentials. The information obtained from multidimensional nonlinear techniques could be used to test and refine this model, and establish an anharmonic oscillator picture for electronic excitations

Inhibition of immunoglobulin production by parathyroid hormone. Implications in chronic renal failure

Inhibition of immunoglobulin production by parathyroid hormone. Implications in chronic renal failure. Available data indicate that B cell proliferation is inhibited in chronic renal failure and this is due to excess blood levels of PTH. This defect may also affect immunoglobulin production. We examined production of IgG, IgM and IgA by B cells stimulated with Staphylococcus aureus Cowan I (SAC) or with pokeweed mitogen (PWM) after eight days of culture and evaluated the effect of PTH on this process in 34 hemodialysis patients and 44 normal subjects. IgG, IgM and IgA production by B cells from patients was lower (P < 0.01) than by B cells from normal subjects. Both 1-34 and 1-84 PTH inhibited (P < 0.01) immunoglobulin production by B cells from normal subjects and dialysis patients. However, this inhibitory effect was evident in dialysis patients only with the higher dose of PTH. The inhibition of immunoglobulin production by PTH occurred only when the hormone was added at the initiation of the B cell culture. Inactivation of PTH abolished its inhibitory effect on immunoglobulin production. Agents that stimulate cAMP production (forskolin, cholera toxin) and the cAMP analogue, 8-bromoadenosine 3′,5′ cyclic monophosphate inhibited immunoglobulin production by B cells from both normal and dialysis patients, and the degree of inhibition was not different between the two groups. The calcium inophore A23187 also inhibited IgG, IgA and IgM production by B cells from normal subjects and dialysis patients; there was no significant difference in the degree of inhibition between the two groups. The resting levels of cytosolic calcium in B cells of dialysis patients was significantly (P < 0.01) higher than that of B cells from normal subjects. The data show that: (1) immunoglobulin production is impaired in dialysis patients; (2) B cells of dialysis patients have elevated resting levels of cytosolic calcium; (3) PTH inhibits IgG, IgA and IgM production and this effect is at least partly mediated by PTH-induced cAMP production and alterations in cytosolic calcium into B cells; (4) this inhibitory effect is mediated by events that affect initial stages of B cell proliferation and maturation; (5) the requirement for high dose of PTH for its inhibitory effect on B cells from dialysis patients is probably due to desensitization and/or down-regulation of PTH receptors on B cells. The results are consistent with the proposition that impaired immunoglobulin production by B cells from dialysis patients is at least partly due to the state of secondary hyperparathyroidism in these patients

Current Profiles of Molecular Nanowires; DFT Green Function Representation

The Liouville-space Green function formalism is used to compute the current density profile across a single molecule attached to electrodes. Time ordering is maintained in real, physical, time, avoiding the use of artificial time loops and backward propagations. Closed expressions for molecular currents, which only require DFT calculations for the isolated molecule, are derived to fourth order in the molecule/electrode coupling.Comment: 21 page

SV40 Assembly In Vivo

The Simian virus 40 (SV40) capsid is a T = 7d icosahedral lattice ∼45 nm in diameter surrounding the ∼5 kb circular minichromosome. The outer shell is composed of 360 monomers of the major capsid protein VP1, tightly bound in 72 pentamers. VP1 is a jellyroll β-barrel, with extending N- and C-terminal arms. The N-terminal arms bind DNA and face the interior of the capsid. The flexible C-arms tie together the 72 pentamers in three distinct kinds of interactions, thus facilitating the formation of a T = 7 icosahedron from identical pentameric building blocks. Assembly in vivo was shown to occur by addition of capsomers around the DNA. We apply a combination of biochemical and genetic approaches to study SV40 assembly. Our in vivo and in vitro studies suggest the following model: one or two capsomers bind at a high affinity to ses, the viral DNA encapsidation signal, forming the nucleation centre for assembly. Next, multiple capsomers attach concomitantly, at lower affinity, around the minichromosome. This increases their local concentration facilitating rapid, cooperative assembly reaction. Formation of the icosahedron proceeds either by gradual addition of single pentamers to the growing shell or by concerted assembly of pentamer clusters

Making Maps Of The Cosmic Microwave Background: The MAXIMA Example

This work describes Cosmic Microwave Background (CMB) data analysis algorithms and their implementations, developed to produce a pixelized map of the sky and a corresponding pixel-pixel noise correlation matrix from time ordered data for a CMB mapping experiment. We discuss in turn algorithms for estimating noise properties from the time ordered data, techniques for manipulating the time ordered data, and a number of variants of the maximum likelihood map-making procedure. We pay particular attention to issues pertinent to real CMB data, and present ways of incorporating them within the framework of maximum likelihood map-making. Making a map of the sky is shown to be not only an intermediate step rendering an image of the sky, but also an important diagnostic stage, when tests for and/or removal of systematic effects can efficiently be performed. The case under study is the MAXIMA data set. However, the methods discussed are expected to be applicable to the analysis of other current and forthcoming CMB experiments.Comment: Replaced to match the published version, only minor change

DNA-binding transcription factor NF-1A negatively regulates JC virus multiplication

JC virus (JCV) DNA replication occurs in the nuclei of infected cells. The level of JCV genome expression depends on nucleotide sequences in the viral regulatory region and their interaction with host-cell nuclear transcription factors. Our previous studies showed a higher level of NF-1X in JCV-permissive cells compared with the other members of the NF-1 family, NF-1A, B and C, which suggests that NF-1X plays a positive role in JCV multiplication. It remained unclear whether a reduction in the level of NF-1A, which is expressed abundantly in JCV-non-permissive cell types, leads to an increase in JCV multiplication. In this study, we show that downregulation of NF-1A expression in JCV-non-susceptible progenitor and HeLa cells results in a reversion to susceptibility for JCV multiplication. These data demonstrate that a higher level of NF-1A protein in JCV-non-permissive cell types, compared with the level of NF-1X, may be acting as a negative regulator at the JCV promoter to control JCV multiplication

Nitric oxide synthase isoforms play distinct roles during acute peritonitis

Background. Acute peritonitis is the most frequent complication of peritoneal dialysis (PD). Increased nitric oxide (NO) release by NO synthase (NOS) isoforms has been implicated in acute peritonitis, but the role played by the NOS isoforms expressed in the peritoneum is unknown

State space modelling and data analysis exercises in LISA Pathfinder

LISA Pathfinder is a mission planned by the European Space Agency to test the key technologies that will allow the detection of gravitational waves in space. The instrument on-board, the LISA Technology package, will undergo an exhaustive campaign of calibrations and noise characterisation campaigns in order to fully describe the noise model. Data analysis plays an important role in the mission and for that reason the data analysis team has been developing a toolbox which contains all the functionalities required during operations. In this contribution we give an overview of recent activities, focusing on the improvements in the modelling of the instrument and in the data analysis campaigns performed both with real and simulated data.Comment: Plenary talk presented at the 9th International LISA Symposium, 21-25 May 2012, Pari