A lab-based test of the gravitational redshift with a miniature clock network.

Einstein's theory of general relativity predicts that a clock at a higher gravitational potential will tick faster than an otherwise identical clock at a lower potential, an effect known as the gravitational redshift. Here we perform a laboratory-based, blinded test of the gravitational redshift using differential clock comparisons within an evenly spaced array of 5 atomic ensembles spanning a height difference of 1 cm. We measure a fractional frequency gradient of [ - 12.

Antiplatelet Effects of Clopidogrel Vs Aspirin in Virologically Controlled HIV: A Randomized Controlled Trial.

Patients with HIV exhibit platelet activation and increased risk of cardiovascular disease, the prevention of which is not fully known. Fifty-five HIV-positive patients were randomized to clopidogrel, aspirin, or no-treatment for 14 days, and the platelet phenotype and ability to induce endothelial inflammation assessed. Clopidogrel as opposed to aspirin and no-treatment reduced platelet activation (P-selectin and PAC-1 expression).

Nanoscale covariance magnetometry with diamond quantum sensors.

Nitrogen vacancy (NV) centers in diamond are atom-scale defects that can be used to sense magnetic fields with high sensitivity and spatial resolution. Typically, the magnetic field is measured by averaging sequential measurements of single NV centers, or by spatial averaging over ensembles of many NV centers, which provides mean values that contain no nonlocal information about the relationship between two points separated in space or time. Here, we propose and implement a sensing modality whereby two or more NV centers are measured simultaneously, and we extract temporal and spatial correlations in their signals that would otherwise be inaccessible.

Probing Charge Dynamics in Diamond with an Individual Color Center.

Control over the charge states of color centers in solids is necessary to fully utilize them in quantum technologies. However, the microscopic charge dynamics of deep defects in wide-band-gap semiconductors are complex, and much remains unknown. We utilize a single-shot charge-state readout of an individual nitrogen-vacancy (NV) center to probe the charge dynamics of the surrounding defects in diamond.

Increased ischemic complications in fenestrated and branched endovascular abdominal aortic repair compared with standard endovascular aortic repair.

Objective: Ischemic complications (including in the lower extremity, visceral, spinal, and pelvic territories) following standard endovascular aortic repair (EVAR) are well recognized but fortunately uncommon. The incidence of such complications following fenestrated and branched aortic repair (F/BEVAR) has not been well defined in the literature. The objective of this study was to compare the incidence of ischemic complications between EVAR and F/BEVAR and to elucidate potential risk factors for these complications.

Dynamics of Reaction-Diffusion Oscillators in Star and other Networks with Cyclic Symmetries Exhibiting Multiple Clusters.

We experimentally and theoretically investigate the dynamics of inhibitory coupled self-driven oscillators on a star network in which a single central hub node is connected to k peripheral arm nodes. The system consists of water-in-oil Belousov-Zhabotinsky ∼100  μm emulsion drops contained in storage wells etched in silicon wafers. We observed three dynamical attractors by varying the number of arms in the star graph and the coupling strength: (i) unlocked, uncorrelated phase shifts between all oscillators; (ii) locked, arm hubs synchronized in phase with a k-dependent phase shift between the arm and central hub; and (iii) center silent, a central hub stopped oscillating and the arm hubs oscillated without synchrony.

Platelet Transcriptome Profiling in HIV and ATP-Binding Cassette Subfamily C Member 4 (ABCC4) as a Mediator of Platelet Activity.

An unbiased platelet transcriptome profile identified ATP binding cassette subfamily C member 4 (ABCC4) as a novel mediator of platelet activity in virologically suppressed human immunodeficiency virus (HIV)-infected subjects on antiretroviral therapy. Using ex vivo and in vitro cellular and molecular assays we demonstrated that ABCC4 regulated platelet activation by altering granule release and cyclic nucleotide homeostasis through a cAMP-protein kinase A (PKA)-mediated mechanism. Platelet ABCC4 inhibition attenuated platelet activation and effector cell function by reducing the release of inflammatory mediators, such as sphingosine-1-phosphate.

Creation and perturbation of planar networks of chemical oscillators.

Methods for creating custom planar networks of diffusively coupled chemical oscillators and perturbing individual oscillators within the network are presented. The oscillators consist of the Belousov-Zhabotinsky (BZ) reaction contained in an emulsion. Networks of drops of the BZ reaction are created with either Dirichlet (constant-concentration) or Neumann (no-flux) boundary conditions in a custom planar configuration using programmable illumination for the perturbations.

Clinical and anatomic outcomes after carotid endarterectomy.

Objective: The purpose of this study was to examine 30-day and long-term outcomes after carotid endarterectomy (CEA) in a contemporary series and to identify variables associated with stroke and death after CEA.

Methods: This was a retrospective review of patients undergoing an isolated CEA at a single institution between January 1989 and December 2005. Primary study end points were 30-day and long-term overall stroke, ipsilateral stroke, and death.

Further experience with distal aortic perfusion and motor-evoked potential monitoring in the management of extent I-III thoracoabdominal aortic anuerysms.

Background: Prior studies indicated improved early mortality and paraplegia rates in a small cohort of patients with type I-III thoracoabdominal aortic aneurysms (TAAs) treated with atriofemoral bypass (AFB) and motor-evoked potentials (MEVPs) when compared with a propensity-matched cohort of patients treated with the clamp and sew (CS) method, wherein epidural cooling was the principal spinal cord protective adjunct. The use of AFB/MEVP increases the complexity of TAA repair and in this study, we address whether the early benefits will be sustained when this is applied to a general population with type I-III TAAs.

Methods: Consecutive patients undergoing repair of nonruptured Crawford extent I-III TAAs from 1/1987 to 12/2011 were identified.

Continued favorable results with open surgical repair of type IV thoracoabdominal aortic aneurysms.

Objectives: Type IV thoracoabdominal aortic aneurysm (TAAA) repair, despite low risk of spinal cord ischemia (SCI), is reported to have significant morbidity and mortality. This has led some to apply adjuncts (eg, extracorporeal circulation) used in more extensive TAAA repair or to consider alternative approaches, such as hybrid operations. We have used a consistent, simplified surgical approach to type IV TAAA, and the goal of the present study is to review experience over 2 decades with such treatment and to identify correlates of surgical morbidity.

Evolution of operative strategies in open thoracoabdominal aneurysm repair.

Objective: During a 24-year interval, we managed >90% of thoracoabdominal aortic aneurysm (TAA) repairs with a clamp-and-sew (clamp/sew) approach supplemented with protective adjuncts, including renal hypothermia and epidural cooling with aggressive intercostal reconstruction for spinal cord protection. A finite paraplegia rate led to operative modifications using distal aortic perfusion (DAP) through atriofemoral bypass to support cord collateral circulation and selective intercostal reconstruction based on motor evoked potential (MEP) monitoring. This study evaluated the effect of DAP/MEP on perioperative outcomes.

Effect of chronic dissection on early and late outcomes after descending thoracic and thoracoabdominal aneurysm repair.

Objective: Although chronic aortic dissection (CD) has traditionally been considered a predictor of perioperative morbidity and mortality after descending thoracic/thoracoabdominal aneurysm repair (thoracoabdominal aortic aneurysm [TAA]), recent reports have rejected this assertion. Still, few contemporary studies document late outcomes after TAA for CD, which is the goal of this study.

Methods: From August 1987 to December 2005, 480 patients underwent TAA; 73 (15%) CD and 407 (85%) degenerative aneurysms (DA).