988 research outputs found
Physical Manifestations Associated with Neurofibromatosis (NF-1)
Neurofibromatosis (NF-1), know as Von Recklinghausen's disease, is one of the most common genetic disorders, affecting about 1 in 3,500 people. Inherited in an autosomal dominant fashion, this disorder results in lesions of the nervous, visual and integumentary system that are highly variable in their level of severity. NF-1 is caused by a mutation of a gene located on chromosome 17 which encodes the protein neurofibromin, a negative regulator of cell signaling pathways for the control of cellular division. Thusly, the NF gene is referred to as a tumor suppressing gene and mutations result in mostly benign tumorous growths and more rarely malignancies. NF-1 phenotypically presents itself with a variety of characteristic manifestations. While these manifestations are highly disfiguring they are generally painless and very rarely become life threatening. In addition to the neurofibromas of the central and peripheral nervous system, NF-1 may affect any part of the body resulting in a variety of complications. In this case study, we present the results of a cadaveric dissection of a donor with NF-1 to catalog the most common manifestations of this disease
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Marketing the Research Missions of Academic Medical Centers: Why Messages Blurring Lines Between Clinical Care and Research Are Bad for both Business and Ethics.
Academic Medical Centers (AMCs) offer patient care and perform research. Increasingly, AMCs advertise to the public in order to garner income that can support these dual missions. In what follows, we raise concerns about the ways that advertising blurs important distinctions between them. Such blurring is detrimental to AMC efforts to fulfill critically important ethical responsibilities pertaining both to science communication and clinical research, because marketing campaigns can employ hype that weakens research integrity and contributes to therapeutic misconception and misestimation, undermining the informed consent process that is essential to the ethical conduct of research. We offer ethical analysis of common advertising practices that justify these concerns. We also suggest the need for a deliberative body convened by the Association of American Medical Colleges and others to develop a set of voluntary guidelines that AMCs can use to avoid in the future, the problems found in many current AMC advertising practices
Postnatal Experiences Influence How the Brain Integrates Information from Different Senses
Sensory processing disorder (SPD) is characterized by anomalous reactions to, and integration of, sensory cues. Although the underlying etiology of SPD is unknown, one brain region likely to reflect these sensory and behavioral anomalies is the superior colliculus (SC), a structure involved in the synthesis of information from multiple sensory modalities and the control of overt orientation responses. In the present review we describe normal functional properties of this structure, the manner in which its individual neurons integrate cues from different senses, and the overt SC-mediated behaviors that are believed to manifest this “multisensory integration.” Of particular interest here is how SC neurons develop their capacity to engage in multisensory integration during early postnatal life as a consequence of early sensory experience, and the intimate communication between cortex and the midbrain that makes this developmental process possible
Design and evaluation of an osteogenesis-on-a-chip microfluidic device incorporating 3D cell culture
Microfluidic-based tissue-on-a-chip devices have generated significant research interest for biomedical applications, such as pharmaceutical development, as they can be used for small volume, high throughput studies on the effects of therapeutics on tissue-mimics. Tissue-on-a-chip devices are evolving from basic 2D cell cultures incorporated into microfluidic devices to complex 3D approaches, with modern designs aimed at recapitulating the dynamic and mechanical environment of the native tissue. Thus far, most tissue-on-a-chip research has concentrated on organs involved with drug uptake, metabolism and removal (e.g., lung, skin, liver, and kidney); however, models of the drug metabolite target organs will be essential to provide information on therapeutic efficacy. Here, we develop an osteogenesis-on-a-chip device that comprises a 3D environment and fluid shear stresses, both important features of bone. This inexpensive, easy-to-fabricate system based on a polymerized High Internal Phase Emulsion (polyHIPE) supports proliferation, differentiation and extracellular matrix production of human embryonic stem cell-derived mesenchymal progenitor cells (hES-MPs) over extended time periods (up to 21 days). Cells respond positively to both chemical and mechanical stimulation of osteogenesis, with an intermittent flow profile containing rest periods strongly promoting differentiation and matrix formation in comparison to static and continuous flow. Flow and shear stresses were modeled using computational fluid dynamics. Primary cilia were detectable on cells within the device channels demonstrating that this mechanosensory organelle is present in the complex 3D culture environment. In summary, this device aids the development of ‘next-generation’ tools for investigating novel therapeutics for bone in comparison with standard laboratory and animal testing
From Macroscopic to Microscopic: Experimental and Computational Methods to Investigate Bio-tribology
Tribology is an important factor (among other factors) during biological interactions of devices and tissues. The paper discusses how new computational and experimental methods can be used to understand and improve the design and development of medical devices at macro and micro scales to sustain life beyond 50 years. We have used pre-clinical experiments and computational methods to understand interactions between orthopaedic implants at the macro scale. The computational model has been validated with experiments. Now this computational model can predict damage in implants for different patients. One such application was successfully tried and tested in collaboration with University National Autonomous Mexico. This methodology can be used in future to design patient specific, affordable (using 3D printing) and robust implants which will be useful for developing countries like Vietnam, India and Mexico. Improvement of catheter designs is important to reduce damage to the internal tissues while being used for cardiovascular problems. We are developing new experimental techniques (in micro scale) that can be used to understand the interaction of cells with the catheter material. These will help reduce the hospital costs incurred during longer stay of the patients admitted for cardiovascular related problems
Pre-analytical factors affecting whole blood and plasma glucose concentrations in loggerhead sea turtles (Caretta caretta)
Blood glucose is vital for many physiological pathways and can be quantified by clinical chemistry analyzers and in-house point-of-care (POC) devices. Pre-analytical and analytical factors can influence blood glucose measurements. This project aimed to investigate pre-analytical factors on whole blood and plasma glucose measurements in loggerhead sea turtles (Caretta caretta) by evaluating the effects of storage (refrigeration) up to 48h after sampling and of packed cell volume (PCV) on whole blood glucose analysis by POC glucometer (time series n = 13); and by evaluating the effects of storage (room temperature and refrigeration) on plasma glucose concentrations using a dry slide chemistry analyzer (DCA) at various conditions: immediate processing and delayed plasma separation from erythrocytes at 24h and 48h (time series n = 14). The POC glucometer had overall strong agreement with the DCA (CCC = 0.76, r = 0.84, Cb = 0.90), but consistently overestimated glucose concentrations (mean difference: +0.4 mmol/L). The POC glucometer results decreased significantly over time, resulting in a substantial decline within the first 2h (0.41±0.47 mmol/L; 8±9%) that could potentially alter clinical decisions, thereby highlighting the need for immediate analysis using this method. The effects of PCV on glucose could not be assessed, as the statistical significance was associated with one outlier. Storage method significantly affected plasma glucose measurements using DCA, with room temperature samples resulting in rapid decreases of 3.57±0.89 mmol/L (77±9%) over the first 48h, while refrigerated samples provided consistent plasma glucose results over the same time period (decrease of 0.26±0.23 mmol/L; 6±5%). The results from this study provide new insights into optimal blood sample handling and processing for glucose analysis in sea turtles, show the suitability of the POC glucometer as a rapid diagnostic test, and confirm the reliability of plasma glucose measurements using refrigeration. These findings emphasize the need to consider pre-/analytical factors when interpreting blood glucose results from loggerhead sea turtles
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Plasma proteomics of green turtles (\u3cem\u3eChelonia mydas\u3c/em\u3e) reveals pathway shifts and potential biomarker candidates associated with health and disease
Evaluating sea turtle health can be challenging due to an incomplete understanding of pathophysiologic responses in these species. Proteome characterization of clinical plasma samples can provide insights into disease progression and prospective biomarker targets. A TMT-10-plex-LC–MS/MS platform was used to characterize the plasma proteome of five, juvenile, green turtles (Chelonia mydas) and compare qualitative and quantitative protein changes during moribund and recovered states. The 10 plasma samples yielded a total of 670 unique proteins. Using ≥1.2-fold change in protein abundance as a benchmark for physiologic upregulation or downregulation, 233 (34.8%) were differentially regulated in at least one turtle between moribund and recovered states. Forty-six proteins (6.9%) were differentially regulated in all five turtles with two proteins (0.3%) demonstrating a statistically significant change. A principle component analysis showed protein abundance loosely clustered between moribund samples or recovered samples and for turtles that presented with trauma (n = 3) or as intestinal floaters (n = 2). Gene Ontology terms demonstrated that moribund samples were represented by a higher number of proteins associated with blood coagulation, adaptive immune responses and acute phase response, while recovered turtle samples included a relatively higher number of proteins associated with metabolic processes and response to nutrients. Abundance levels of 48 proteins (7.2%) in moribund samples significantly correlated with total protein, albumin and/or globulin levels quantified by biochemical analysis. Differentially regulated proteins identified with immunologic and physiologic functions are discussed for their possible role in the green turtle pathophysiologic response and for their potential use as diagnostic biomarkers. These findings enhance our ability to interpret sea turtle health and further progress conservation, research and rehabilitation programs for these ecologically important species
Metaphoric coherence: Distinguishing verbal metaphor from `anomaly\u27
Theories and computational models of metaphor comprehension generally circumvent the question of metaphor versus “anomaly” in favor of a treatment of metaphor versus literal language. Making the distinction between metaphoric and “anomalous” expressions is subject to wide variation in judgment, yet humans agree that some potentially metaphoric expressions are much more comprehensible than others. In the context of a program which interprets simple isolated sentences that are potential instances of cross‐modal and other verbal metaphor, I consider some possible coherence criteria which must be satisfied for an expression to be “conceivable” metaphorically. Metaphoric constraints on object nominals are represented as abstracted or extended along with the invariant structural components of the verb meaning in a metaphor. This approach distinguishes what is preserved in metaphoric extension from that which is “violated”, thus referring to both “similarity” and “dissimilarity” views of metaphor. The role and potential limits of represented abstracted properties and constraints is discussed as they relate to the recognition of incoherent semantic combinations and the rejection or adjustment of metaphoric interpretations
The ultraviolet and vacuum ultraviolet absorption spectrum of gamma-pyrone; the singlet states studied by configuration interaction and density functional calculations
A synchrotron based vacuum ultraviolet absorption spectrum for γ-pyrone has been interpreted in terms of singlet excited electronic states, using a variety of coupled cluster, configuration interaction, and density functional calculations. The extremely weak spectral onset at 3.557 eV shows 8 vibrational peaks and following previous analyses is attributed to a forbidden 1A2 state. A contrasting broad peak with maximum at 5.381 eV has a relatively high cross-section of 30 Mb; this arises from three overlapping states, where a 1A1 state dominates over progressively weaker 1B2 and 1B1 states. After fitting the second band to a polynomial Gaussian function, and plotting the regular residuals (RR), over 20 vibrational peaks were revealed. We have had limited success in analyzing this fine structure. However, the small separation between these three states clearly shows that their vibrational satellites must overlap. Singlet valence and Rydberg state vibrational profiles were determined by configuration interaction using the CAM-B3LYP density functional. Vibrational analysis, using both Franck-Condon and Herzberg-Teller procedures showed that both procedures contributed to the profiles. Theoretical Rydberg states were evaluated by a highly focused CI procedure. Super-position of the lowest photoelectron spectral band on the VUV spectrum near 6.4 eV, shows that the 3s and 3p Rydberg states based on the 2B2 ionic state are present; those based on the other low-lying ionic state (X2B1) are destroyed by broadening; this is a dramatic extension of the broadening previously witnessed in our studies of halogenobenzenes.Peer reviewe
Non-thermal transport of energy driven by photoexcited carriers in switchable solid states of GeTe
Phase change alloys have seen widespread use from rewritable optical discs to
the present day interest in their use in emerging neuromorphic computing
architectures. In spite of this enormous commercial interest, the physics of
carriers in these materials is still not fully understood. Here, we describe
the time and space dependence of the coupling between photoexcited carriers and
the lattice in both the amorphous and crystalline states of one phase change
material, GeTe. We study this using a time-resolved optical technique called
picosecond acoustic method to investigate the \textit{in situ} thermally
assisted amorphous to crystalline phase transformation in GeTe. Our work
reveals a clear evolution of the electron-phonon coupling during the phase
transformation as the spectra of photoexcited acoustic phonons in the amorphous
(-GeTe) and crystalline (-GeTe) phases are different. In particular
and surprisingly, our analysis of the photoinduced acoustic pulse duration in
crystalline GeTe suggests that a part of the energy deposited during the
photoexcitation process takes place over a distance that clearly exceeds that
defined by the pump light skin depth. In the opposite, the lattice
photoexcitation process remains localized within that skin depth in the
amorphous state. We then demonstrate that this is due to supersonic diffusion
of photoexcited electron-hole plasma in the crystalline state. Consequently
these findings prove the existence of a non-thermal transport of energy which
is much faster than lattice heat diffusion
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