Analysis of free analyte fractions by rapid affinity chromatography

The invention is generally directed toward an analytical method to determine the concentration of the free analyte fraction in a sample. More particularly, the method encompasses applying a sample comprising a free and bound analyte fraction to an affinity column capable of selectively extracting the free fraction in the millisecond time domain. The signal generated by the free fraction is then quantified by standard analytical detection techniques. The concentration of the free fraction may then be determined by comparison of its signal with that of a calibration curve depicting the signal of known concentration of the same analyte

Experimental demonstration of continuous variable purification of squeezed states

We report on the first experimental demonstration of purification of nonclassical continuous variable states. The protocol uses two copies of phase-diffused states overlapped on a beam splitter and provides Gaussified, less mixed states with the degree of squeezing improved. The protocol uses only linear optical devices such as beam splitters and homodyne detection, thereby proving these optical elements can be used for successful purification of this type of state decoherence which occurs in optical transmission channels

Alleys: Negotiating Identity in Traditional, Urban, And New Urban Communities

Alleys evoke powerful images in our collective fear and, yet, play an important role in our American culture. Currently, communities are recognizing the value of the alley to their social landscape and designers and planners are reviving the alley in designs for new communities. What is it about the alley that has communities so excited? Why are alleys being reincorporated into today’s design language? What do alleys contribute to a community’s landscape and how do they contribute to its identity? What do we have to learn about community and urban design from the alley? To answer these questions, this study compares a spectrum of five communities with various types of alleys – Holyoke, Amherst, and Northampton, Massachusetts; New York City; and Kentlands, Maryland. The conclusions drawn from this study indicate that the alley is an expressive landscape in which communities communicate their collective values and ideals and residents negotiate their community’s identity through control, order, and organization, including the naming, maintenance and use of the alley. It is also where boundaries of class, economic status, and affluence are navigated and expressed. Furthermore, the implications of these findings are that urban designers, landscape architects, planners, and engineers must resist the temptation to over-design and micro-manage a place if a truly organic and expressive community is desired. Within this framework, these professionals must also anticipate that a community will change and to allow for its alleys and other spaces to respond to, and reflect, these changes

Preparing the bound instance of quantum entanglement

Among the possibly most intriguing aspects of quantum entanglement is that it comes in "free" and "bound" instances. Bound entangled states require entangled states in preparation but, once realized, no free entanglement and therefore no pure maximally entangled pairs can be regained. Their existence hence certifies an intrinsic irreversibility of entanglement in nature and suggests a connection with thermodynamics. In this work, we present a first experimental unconditional preparation and detection of a bound entangled state of light. We consider continuous-variable entanglement, use convex optimization to identify regimes rendering its bound character well certifiable, and realize an experiment that continuously produced a distributed bound entangled state with an extraordinary and unprecedented significance of more than ten standard deviations away from both separability and distillability. Our results show that the approach chosen allows for the efficient and precise preparation of multimode entangled states of light with various applications in quantum information, quantum state engineering and high precision metrology.Comment: The final version accounts for a recent comment in Nature Physics [24] clarifying that a previous claim of having generated bound entanglement [23] was not supported by the authors' data. We also extended our introduction and discussion and also added reference

Sodium-activated potassium channels are functionally coupled to persistent sodium currents

We report a novel coupled system of sodium-activated potassium currents (I(KNa)) and persistent sodium currents (I(NaP)), the components of which are widely distributed throughout the brain. Its existence and importance has not been previously recognized. Although I(KNa) was known to exist in many cell types, the source of Na(+) which activates I(KNa) remained a mystery. We now show in single membrane patches generated from the somas of rat neurons that sodium influx through I(NaP) is sufficient for activation of K(Na) channels, without substantial contribution from the transient sodium current or bulk [Na(+)](i). I(NaP) was found to be active at cell membrane resting potentials, a finding that may explain why I(KNa) can be evoked from negative holding potentials. These results show an unanticipated role for I(NaP) in activating a negative feedback system countering the excitable effects I(NaP); the interrelatedness of I(NaP) and I(KNa) suggests new ways neurons can tune their excitability

High Rayleigh number convection with double diffusive fingers

An electrodeposition cell is used to sustain a destabilizing concentration difference of copper ions in aqueous solution between the top and bottom boundaries of the cell. The resulting convecting motion is analogous to Rayleigh-B\'enard convection at high Prandtl numbers. In addition, a stabilizing temperature gradient is imposed across the cell. Even for thermal buoyancy two orders of magnitude smaller than chemical buoyancy, the presence of the weak stabilizing gradient has a profound effect on the convection pattern. Double diffusive fingers appear in all cases. The size of these fingers and the flow velocities are independent of the height of the cell, but they depend on the ion concentration difference between top and bottom boundaries as well as on the imposed temperature gradient. The scaling of the mass transport is compatible with previous results on double diffusive convection

Towards Einstein-Podolsky-Rosen quantum channel multiplexing

A single broadband squeezed field constitutes a quantum communication resource that is sufficient for the realization of a large number N of quantum channels based on distributed Einstein-Podolsky-Rosen (EPR) entangled states. Each channel can serve as a resource for, e.g. independent quantum key distribution or teleportation protocols. N-fold channel multiplexing can be realized by accessing 2N squeezed modes at different Fourier frequencies. We report on the experimental implementation of the N=1 case through the interference of two squeezed states, extracted from a single broadband squeezed field, and demonstrate all techniques required for multiplexing (N>1). Quantum channel frequency multiplexing can be used to optimize the exploitation of a broadband squeezed field in a quantum information task. For instance, it is useful if the bandwidth of the squeezed field is larger than the bandwidth of the homodyne detectors. This is currently a typical situation in many experiments with squeezed and two-mode squeezed entangled light.Comment: 4 pages, 4 figures. In the new version we cite recent experimental work bei Mehmet et al., arxiv0909.5386, in order to clarify the motivation of our work and its possible applicatio

Analysis of free analyte fractions by rapid affinity chromatography

The invention is generally directed toward an analytical method to determine the concentration of the free analyte fraction in a sample. More particularly, the method encompasses applying a sample comprising a free and bound analyte fraction to an affinity column capable of selectively extracting the free fraction in the millisecond time domain. The signal generated by the free fraction is then quantified by standard analytical detection techniques. The concentration of the free fraction may then be determined by comparison of its signal with that of a calibration curve depicting the signal of known concentration of the same analyte