Experimental and computational analyses reveal that environmental restrictions shape HIV-1 spread in 3D cultures

Here, using an integrative experimental and computational approach, Imle et al. show how cell motility and density affect HIV cell-associated transmission in a three-dimensional tissue-like culture system of CD4+ T cells and collagen, and how different collagen matrices restrict infection by cell-free virions

Self Assembly of Copper(I) and Silver(I) Butterfly Clusters with 2-Mercaptothiazoline

X-ray data obtained from poor crystals which formed from the reaction of copper(II) acetate with 2-mercaptothiazoline reveal the formation of a product that is a polymer formed of tetranuclear, butterfly shaped Cu4(MT)4, 1, clusters. Preparation, isolation and structural characterization of a series of isostructural butterfly complexes was accomplished by addition of a Lewis base (pyridine, PPh3, or ASPI13) to the precipitate obtained from the reaction of copper(II) and/or silver(I) acetate with the appropriate stoichiometric amount of 2-mercaptothiazoline. The general formula of these clusters is L2M4(MT)4; 2, L = PPI13 and M = Cu; 3, L = AsPh3 and M = Cu; 6, L = PPI13 and M = Ag; MT = C3H4NS2_, known as 2-mer- captothiazolinate. The polymer [pyCu4(MT)4]„, 4, formed by the addition of pyridine to 1, was also characterized crystallographically. A mixed metal butterfly complex, (PPh3)2Ag2Cu2(MT)4, 8, is formed by addition of PPI13 to a suspension of the precipitate formed upon reaction of the free HMT ligand with a 1:1 mixture of copper(II) and silver(I) acetates in CH2CI2. FD-MS results of each of the precipitates obtained from the metal acetates and the free ligand indicate that the monomeric unit is M4(MT)4. 1H-NMR and 31P{1H}-NMR, both in solution and in the solid state are presented and interpreted

Microstructured blood vessel surrogates reveal structural tropism of motile malaria parasites

Plasmodium sporozoites, the highly motile forms of the malaria parasite, are transmitted naturally by mosquitoes and traverse the skin to find, associate with, and enter blood capillaries. Research aimed at understanding how sporozoites select blood vessels is hampered by the lack of a suitable experimental system. Arrays of uniform cylindrical pillars can be used to study small cells moving in controlled environments. Here, an array system displaying a variety of pillars with different diameters and shapes is developed in order to investigate how Plasmodium sporozoites associate to the pillars as blood vessel surrogates. Investigating the association of sporozoites to pillars in arrays displaying pillars of different diameters reveals that the crescent-shaped parasites prefer to associate with and migrate around pillars with a similar curvature. This suggests that after transmission by a mosquito, malaria parasites may use a structural tropism to recognize blood capillaries in the dermis in order to gain access to the blood stream

Solar models and solar neutrino oscillations

We provide a summary of the current knowledge, theoretical and experimental, of solar neutrino fluxes and of the masses and mixing angles that characterize solar neutrino oscillations. We also summarize the principal reasons for doing new solar neutrino experiments and what we think may be learned from the future measurements.Comment: Submitted to the Neutrino Focus Issue of New Journal of Physics at http://www.njp.or

Maximal regularity for non-autonomous equations with measurable dependence on time

In this paper we study maximal $L^p$-regularity for evolution equations with time-dependent operators $A$. We merely assume a measurable dependence on time. In the first part of the paper we present a new sufficient condition for the $L^p$-boundedness of a class of vector-valued singular integrals which does not rely on H\"ormander conditions in the time variable. This is then used to develop an abstract operator-theoretic approach to maximal regularity. The results are applied to the case of $m$-th order elliptic operators $A$ with time and space-dependent coefficients. Here the highest order coefficients are assumed to be measurable in time and continuous in the space variables. This results in an $L^p(L^q)$-theory for such equations for $p,q\in (1, \infty)$. In the final section we extend a well-posedness result for quasilinear equations to the time-dependent setting. Here we give an example of a nonlinear parabolic PDE to which the result can be applied.Comment: Application to a quasilinear equation added. Accepted for publication in Potential Analysi

Testing the inverse-square law of gravity on a 465-m tower

We have performed a test of Newton’s universal theory of gravitation by comparing gravity measured on a tower to an upward continuation of the surface gravity field. We measured gravity at 12 heights on a 465-m tower at the Nevada Test Site and, in addition, made measurements at 281 locations on the ground. The surface points fell within 91 optimally chosen sectors that extended out to 2.6 km from the tower. These data were combined with 60000 additional surface gravity measurements within 300 km of the tower. We used a surface integral derived from Laplace’s equation to upward continue the surface gravity field and our observations are consistent with the Newtonian predictions to within (-60±95)×10^-8 m sec^-2 at the top of the tower

Successful oxytocin-assisted nipple aspiration in women at increased risk for breast cancer

The high rate of interval malignancies urges for new screening methods for women at high risk for breast cancer. Nipple aspiration provides direct access to the breast tissue and its DNA, and therefore is a likely candidate, but clinical applications have been limited by the failure to obtain nipple aspiration fluid from most women. We performed oxytocin-assisted nipple aspiration in 90 women at increased risk for breast cancer based on family history or genetic test results (n = 63) and/or previous breast cancer (n = 34). Nipple fluid was obtained from 81/90 women (90%) and bilaterally in 77%. Mean discomfort rating was 0.6 (on a 0–10 scale), which was significantly lower than for mammography or MRI. These findings suggest that a new tool for biomarker detection in oxytocin-assisted nipple fluid of women at high risk for breast cancer is at hand

A search for direct muon production in the forward direction

We propose to search for direct muon production in the forward direction from 300 GeV protons incident on a heavy nuclear target. By using the first stage of the Ml beam as a source of a diffracted proton beam and the second and third stages of Ml as a spectrometer, one can make a measurement of the direct muon to pion ratio at values of x between 0.3 and 0.75. If this ratio is on the order of 10{sup -4}, the event rates are on the order of 800 direct muons/hr. at an x of .5. The modifications to the Ml beam are minor

Damping of supernova neutrino transitions in stochastic shock-wave density profiles

Supernova neutrino flavor transitions during the shock wave propagation are known to encode relevant information not only about the matter density profile but also about unknown neutrino properties, such as the mass hierarchy (normal or inverted) and the mixing angle theta_13. While previous studies have focussed on "deterministic" density profiles, we investigate the effect of possible stochastic matter density fluctuations in the wake of supernova shock waves. In particular, we study the impact of small-scale fluctuations on the electron (anti)neutrino survival probability, and on the observable spectra of inverse-beta-decay events in future water-Cherenkov detectors. We find that such fluctuations, even with relatively small amplitudes, can have significant damping effects on the flavor transition pattern, and can partly erase the shock-wave imprint on the observable time spectra, especially for sin^2(theta_13) > O(10^-3).Comment: v2 (23 pages, including 6 eps figures). Typos removed, references updated, matches the published versio