Acceleration of imaging in atomic force microscopy working in sub-resonance tapping mode.

Sub-resonance tapping (SRT) mode of atomic force microscopy (AFM) enables researchers to image surfaces with well-controlled load forces and to collect maps of multiple physical properties of samples. The major bottleneck of this mode is a relatively low scan speed compared to other scanning modes. This paper presents a novel control algorithm that substantially improves the scanning speed over the standard SRT.

Recurrence rate of venous thromboembolic events in granulomatosis with polyangiitis.

Objective: The incidence of first-time venous thromboembolic events (VTEs) is high in granulomatosis with polyangiitis (GPA). The incidence of recurrent VTEs is unknown. We aimed to describe the recurrence rate of second VTEs in patients with GPA.

Differentiation between neurosarcoidosis and primary central nervous system vasculitis based on demographic, cerebrospinal and imaging features.

Objectives: Neurosarcoidosis (NS) and primary angiitis of central nervous system (PACNS) are inflammatory diseases affecting central nervous system, with overlapping clinical and pathological characteristics. Distinguishing these diseases is important given distinct therapeutic implications. In this study, we aimed to compare demographic, CSF and MRI characteristics between these two conditions.

Cognitive Aging and Tests of Rationality.

We investigated whether older adults are more likely than younger adults to violate a foundational property of rational decision making, the axiom of transitive preference. Our experiment consisted of two groups, older (ages 60-75; 21 participants) and younger (ages 18-30; 20 participants) adults. We used Bayesian model selection to investigate whether individuals were better described via (transitive) weak order-based decision strategies or (possibly intransitive) lexicographic semiorder decision strategies.

Long-term outcomes of patients with primary angiitis of the central nervous system.

Objectives: Primary angiitis of the central nervous system (PACNS) is a vasculitis confined to the brain and spinal cord, which often presents with severe cognitive and functional deficits. Despite progress in diagnosis, little is still known about long-term outcomes. Our aim was to evaluate long-term functional capabilities, quality of life, and depression, and to determine the effect of treatment duration on patient outcomes.

Birmingham hip resurfacing versus cementless total hip arthroplasty in patients 55 years or younger: A minimum five-year follow-up.

Objective: The optimal reconstructive method for advanced degenerative hip disease in young adults is a topic of ongoing discussion. The purpose of this study is to report the largest single institution experience from the United States on the outcomes of Birmingham hip resurfacing (BHR) vs. cementless total hip arthroplasty (THA) in patients 55 years or younger at a minimum follow-up of five years.

Overlapping Lower Extremity Total Joint Arthroplasty Does Not Increase the Risk of 90-Day Complications.

Although total hip arthroplasty and total knee arthroplasty commonly overlap, there are concerns about the safety and quality of this scenario. The objectives of this study were to (1) compare the operative time and the incidence of 90-day complications between overlapping and nonoverlapping total joint arthroplasties; and (2) evaluate the effect of the duration of overlap on operative time and the incidence of 90-day complications. A total of 9192 patients who underwent primary total hip arthroplasty or total knee arthroplasty at a large academic hospital from 2005 to 2014 were identified.

Total hip arthroplasty in patients 55 years or younger: Risk factors for poor midterm outcomes.

Background: Total hip arthroplasty (THA) is increasingly performed in younger patients. The purpose of this study is to report on the midterm outcomes of primary cementless THA in patients 55 years and younger; and specifically to examine the risk factors for aseptic failure, all-cause revision, and mortality in this patient population.

Methods: Four hundred and twenty-six consecutive patients with minimum 5-year follow-up were retrospectively reviewed.

Implementation of a Total Hip Arthroplasty Care Pathway at a High-Volume Health System: Effect on Length of Stay, Discharge Disposition, and 90-Day Complications.

Background: Standardized care pathways are evidence-based algorithms for optimizing an episode of care. Despite the theoretical promise of care pathways, there is an inconsistent literature demonstrating improvements in patient care. The authors hypothesized that implementing a care pathway, across 11 hospitals, would decrease hospital length of stay (LOS), decrease postoperative complications at 90 days, and increase discharges to home.

Predictors of Hip Pain and Function in Femoroacetabular Impingement: A Prospective Cohort Analysis.

Background: Validated patient-reported outcome measures (PROMs) of hip pain and function at the time of arthroscopy could be predictors of the final outcome. Little is known about how patient factors or pathologic intra-articular findings relate to hip pain or function at the time of surgery for those presenting with femoroacetabular impingement (FAI).

Purpose: To evaluate all patient and operative factors that contribute to hip pain and dysfunction in patients with FAI.

Birmingham Hip Resurfacing in Patients 55 Years or Younger: Risk Factors for Poor Midterm Outcomes.

Background: Birmingham hip resurfacing (BHR) is the only Food and Drug Administration-approved hip resurfacing system available in the United States and is used as an alternative to conventional total hip arthroplasty in younger patients. The purpose of this study is to report on the midterm outcomes of BHR in patients 55 years and younger, and specifically to examine the risk factors for aseptic failure, all-cause revision, and complications in this patient population.

Methods: Four hundred forty-two consecutive patients with 5-year follow-up were retrospectively reviewed.

The impact of identifying carotid plaque on addressing cardiovascular risk in psoriatic arthritis.

Background: Patients with psoriatic arthritis (PsA) are at an increased risk for cardiovascular (CV) disease.  The aim of this study was to identify the frequency of carotid plaque in asymptomatic patients with psoriatic arthritis at baseline and follow-up screening, and to assess for the impact of demonstrating plaque on management of traditional cardiovascular risk factors.

Methods: Eighty-seven PsA patients underwent carotid duplex ultrasound screening.

Sudden motility reversal indicates sensing of magnetic field gradients in Magnetospirillum magneticum AMB-1 strain.

Many motile unicellular organisms have evolved specialized behaviors for detecting and responding to environmental cues such as chemical gradients (chemotaxis) and oxygen gradients (aerotaxis). Magnetotaxis is found in magnetotactic bacteria and it is defined as the passive alignment of these cells to the geomagnetic field along with active swimming. Herein we show that Magnetospirillum magneticum (AMB-1) show a unique set of responses that indicates they sense and respond not only to the direction of magnetic fields by aligning and swimming, but also to changes in the magnetic field or magnetic field gradients.

Mechanochemical actuators of embryonic epithelial contractility.

Spatiotemporal regulation of cell contractility coordinates cell shape change to construct tissue architecture and ultimately directs the morphology and function of the organism. Here we show that contractility responses to spatially and temporally controlled chemical stimuli depend much more strongly on intercellular mechanical connections than on biochemical cues in both stimulated tissues and adjacent cells. We investigate how the cell contractility is triggered within an embryonic epithelial sheet by local ligand stimulation and coordinates a long-range contraction response.

QTest: Quantitative Testing of Theories of Binary Choice.

The goal of this paper is to make modeling and quantitative testing accessible to behavioral decision researchers interested in substantive questions. We provide a novel, rigorous, yet very general, quantitative diagnostic framework for testing theories of binary choice. This permits the nontechnical scholar to proceed far beyond traditionally rather superficial methods of analysis, and it permits the quantitatively savvy scholar to triage theoretical proposals before investing effort into complex and specialized quantitative analyses.

Controlling magnetotactic bacteria through an integrated nanofabricated metallic island and optical microscope approach.

Herein, we demonstrate the control of magnetotactic bacteria through the application of magnetic field gradients with real-time visualization. We accomplish this control by integrating a pair of macroscale Helmholtz coils and lithographically fabricated nanoscale islands composed of permalloy (Ni₈₀Fe₂₀). This system enabled us to guide and steer amphitrichous Magnetospirillum magneticum strain AMB-1 to specific location via magnetic islands.

How do control-based approaches enter into biology?

Control is intrinsic to biological organisms, whose cells are in a constant state of sensing and response to numerous external and self-generated stimuli. Diverse means are used to study the complexity through control-based approaches in these cellular systems, including through chemical and genetic manipulations, input-output methodologies, feedback approaches, and feed-forward approaches. We first discuss what happens in control-based approaches when we are not actively examining or manipulating cells.

Dynamic control of 3D chemical profiles with a single 2D microfluidic platform.

Dynamic control of three-dimensional (3D) chemical patterns with both high precision and high speed is important in a range of applications from chemical synthesis, flow cytometry, and multi-scale biological manipulation approaches. A central challenge in controlling 3D chemical patterns is the inability to create rapidly tunable 3D profiles with simple and direct approaches that avoid complicated microfabrication. Here, we present the ability to rapidly and precisely create 3D chemical patterns using a single two-dimensional (2D) microfluidic platform.

Detection of dynamic spatiotemporal response to periodic chemical stimulation in a Xenopus embryonic tissue.

Embryonic development is guided by a complex and integrated set of stimuli that results in collective system-wide organization that is both time and space regulated. These regulatory interactions result in the emergence of highly functional units, which are correlated to frequency-modulated stimulation profiles. We have determined the dynamic response of vertebrate embryonic tissues to highly controlled, time-varying localized chemical stimulation using a microfluidic system with feedback control.

Three-dimensional chemical profile manipulation using two-dimensional autonomous microfluidic control.

The ability to specify or control spatiotemporal chemical environments is critical for controlling diverse processes from chemical synthesis to cellular responses. When established by microfluidics methods, this chemical control has largely been limited to two dimensions and by the need for using complex approaches. The ability to create three-dimensional (3D) chemical patterns is becoming more critical as microfluidics is beginning to have novel applications at larger millifluidic scales, including model organism behavior, embryonic development, and optofluidics.

Modulation of fluidic resistance and capacitance for long-term, high-speed feedback control of a microfluidic interface.

Existing microfluidic systems can control local chemical environments by directing the interface between laminar flowing streams for applications ranging from subcellular stimulation to fuel cells. However, conventional flow modulation methods have not yet provided a robust and reliable way to dynamically control laminar flow interfaces for very long time periods. Such control is important in biological investigations, since response times for living cells and tissues can be as long as several days.

Probing cellular dynamics with a chemical signal generator.

Observations of material and cellular systems in response to time-varying chemical stimuli can aid the analysis of dynamic processes. We describe a microfluidic "chemical signal generator," a technique to apply continuously varying chemical concentration waveforms to arbitrary locations in a microfluidic channel through feedback control of the interface between parallel laminar (co-flowing) streams. As the flow rates of the streams are adjusted, the channel walls are exposed to a chemical environment that shifts between the individual streams.

Behavioural social choice: a status report.

Behavioural social choice has been proposed as a social choice parallel to seminal developments in other decision sciences, such as behavioural decision theory, behavioural economics, behavioural finance and behavioural game theory. Behavioural paradigms compare how rational actors should make certain types of decisions with how real decision makers behave empirically. We highlight that important theoretical predictions in social choice theory change dramatically under even minute violations of standard assumptions.

Pressure-driven spatiotemporal control of the laminar flow interface in a microfluidic network.

We describe a system for dynamically adjusting the position of the laminar interface between two fluids flowing inside a microfluidic channel, with a time response of less than 0.1 s, through feedback control of the channel inlet pressure.