The study of adaptation helps explain biodiversity and predict future evolution. Yet the process of adaptation can be difficult to observe due to limited phenotypic variation in contemporary populations. Furthermore, the scarcity of male fitness estimates has made it difficult to both understand adaptation and evaluate sexual conflict hypotheses.
View Article and Find Full Text PDFThe growth of Sn-rich group-IV semiconductors at the nanoscale can enrich the understanding of the fundamental properties of metastable GeSn alloys. Here, we demonstrate the effect of the growth conditions on the morphology and composition of Ge/GeSn core/shell nanowires by correlating the experimental observations with a theoretical interpretation based on a multiscale approach. We show that the cross-sectional morphology of Ge/GeSn core/shell nanowires changes from hexagonal to dodecagonal upon increasing the supply of the Sn precursor.
View Article and Find Full Text PDFEmbryonic development is driven by tightly regulated patterns of gene expression, despite extensive genetic variation among individuals. Studies of expression quantitative trait loci (eQTL) indicate that genetic variation frequently alters gene expression in cell-culture models and differentiated tissues. However, the extent and types of genetic variation impacting embryonic gene expression, and their interactions with developmental programs, remain largely unknown.
View Article and Find Full Text PDFThe functionality of semiconductor devices is determined by the incorporation of dopants at concentrations down to the parts per million (ppm) level and below. Optimization of intentional and unintentional impurity doping relies on methods to detect and map the level of impurities. Detecting such low concentrations of impurities in nanostructures is however challenging to date as on the one hand methods used for macroscopic samples cannot be applied due to the inherent small volumes or faceted surfaces and on the other hand conventional microscopic analysis techniques are not sufficiently sensitive.
View Article and Find Full Text PDFGroup IV materials with the hexagonal diamond crystal structure have been predicted to exhibit promising optical and electronic properties. In particular, hexagonal silicon-germanium (SiGe) should be characterized by a tunable direct band gap with implications ranging from Si-based light-emitting diodes to lasers and quantum dots for single photon emitters. Here we demonstrate the feasibility of high-quality defect-free and wafer-scale hexagonal SiGe growth with precise control of the alloy composition and layer thickness.
View Article and Find Full Text PDFAnnu Int Conf IEEE Eng Med Biol Soc
September 2015
A regularly spiking neuron can be studied using a phase model. The effect of an input stimulus current on the phase time derivative is captured by a phase response curve. This paper adapts a technique that was previously applied to conductance-based models to discover optimal input stimulus currents for phase models.
View Article and Find Full Text PDFBeilstein J Nanotechnol
December 2014
Background: The omnipresence of nanoparticles (NPs) in numerous goods has led to a constant risk of exposure and inadvertent uptake for humans. This situation calls for thorough investigation of the consequences of NP intake. As the vast mucosa of the human gastrointestinal tract represents an attractive site of entry, we wanted to take a look on the fate that ingested NPs suffer in the gut.
View Article and Find Full Text PDFTo study the genetic architecture of anther exsertion, a trait under stabilizing selection in wild radish, artificial selection on anther exsertion was applied for 11 generations. Two replicate lines each of increased and decreased exsertion plus two randomly-mated controls were included. Full pedigree information is available from generation five.
View Article and Find Full Text PDFObjectives: To determine whether risk for implantable cardioverter-defibrillator (ICD) therapy varies by body mass index (BMI) in systolic heart failure (HF).
Background: It is unknown whether obesity increases sudden death risk in patients with systolic HF.
Methods: Secondary analysis of patients with HF, left ventricular ejection fraction ≤0.
Ultra-high molecular weight polyethylene (UHMWPE) is the most common counterface material against metals or ceramics in artificial hip or knee joints. Wear and the resulting particulate debris, however, limit the life span of the implant. In this study, the general feasibility of using Europium (Eu) as tracer material to quantify UHMWPE wear in joint fluid is investigated.
View Article and Find Full Text PDFThe laser-assisted Atom Probe has been proposed as a metrology tool for next generation semiconductor technologies requiring sub-nm spatial resolution. In order to assess its potential for the analysis of three-dimensional semiconductor structures like FinFETs, we have studied the Atom Probes lateral resolution on a silicon, silicon-germanium multilayer structure. We find that the interactions of the laser with the semiconductor materials in the sample distort the sample surface.
View Article and Find Full Text PDFWith the continuous shrinking of transistors and advent of new transistor architectures to keep in pace with Moore's law and ITRS goals, there is a rising interest in multigate 3D-devices like FinFETs where the channel is surrounded by gates on multiple surfaces. The performance of these devices depends on the dimensions and the spatial distribution of dopants in source/drain regions of the device. As a result there is a need for new metrology approach/technique to characterize quantitatively the dopant distribution in these devices with nanometer precision in 3D.
View Article and Find Full Text PDFInt J Radiat Oncol Biol Phys
January 2011
Purpose: Cardiac toxicity is an important sequela of breast radiotherapy. However, the relationship between dose to cardiac structures and subsequent toxicity has not been well defined, partially due to variations in substructure delineation, which can lead to inconsistent dose reporting and the failure to detect potential correlations. Here we have developed a heart atlas and evaluated its effect on contour accuracy and concordance.
View Article and Find Full Text PDFBackground: The Model for End-Stage Liver Disease (MELD) predicts events in cirrhotic subjects undergoing major surgery and may offer similar prognostication in left ventricular assist device candidates with comparable degrees of multisystem dysfunction.
Methods And Results: Preoperative MELD scores were calculated for subjects enrolled in the University of Michigan Health System (UMHS) mechanical circulatory support database. Univariate and multiple regression analyses were performed to investigate the ability of patient characteristics, laboratory data (including MELD scores), and hemodynamic measurements to predict total perioperative blood product exposure and operative mortality.
We present an approach to obtain nonlinear information about neuronal response by computing multiple linear approximations. By calculating local linear approximations centered around particular stimuli, one can obtain insight into stimulus features that drive the response of highly nonlinear neurons, such as neurons highly selective to a small set of stimuli. We implement this approach based on stimulus-spike correlation (i.
View Article and Find Full Text PDFThe benefits of heart failure (HF) care management have been demonstrated, yet health systems are often unable to meet patients' needs for support between outpatient visits. Informal care provided by family or friends is a low-cost, and potentially effective, adjunct to care management services. The authors evaluated the feasibility of augmenting HF care management with weekly, automated assessment and behavior change calls to patients, feedback via the Internet to an out-of-home informal caregiver or CarePartner (CP), and faxes to the patient's health care team.
View Article and Find Full Text PDFAs a member of the thrombospondin gene family, cartilage oligomeric protein (COMP) is found mainly in the extracellular matrix often associated with cartilage tissue. COMP exhibits a wide binding repertoire and has been shown to be involved in the regulation of chondrogenesis in vitro. Not much is known about the role of COMP in human cartilage tissue in vivo.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2002
We develop a novel technique which deduces the surface tension in air of a fluid as a function of surface age, beginning at age zero. The technique utilizes pointwise measurements of perpendicular free surface profiles of a steady oscillating jet corresponding to a discretization interval on the order of 0.1 ms.
View Article and Find Full Text PDFWe describe a 1-year multidisciplinary initiative to improve the quality of care for patients with acute myocardial infarction and heart failure. In January 2002, this rapid-cycle improvement project began with a partnership of inpatient cardiology nursing and physician leadership. This inpatient leadership team analyzed clinical and operational processes, and revised and developed tools such as standard order sets, discharge instructions, clinical pocket guides, and daily monitoring logs.
View Article and Find Full Text PDFBackground: Performance of ambulatory electrocardiography (AECG) may provide data useful for counseling patients regarding prognosis and for selecting potential patients for defibrillator implantation, but this practice remains controversial.
Methods: We reviewed clinical and AECG data on 355 patients diagnosed with dilated cardiomyopathy (DCM). Predictors of survival were identified in a multivariable analysis using a Cox proportional hazard model.