2,687 research outputs found
Pilomatrix carcinoma of the lacrimal caruncle: a case report.
A 45-year-old man presented with a 3-month history of a mass located in the caruncle of his right eye. An incisional biopsy had been performed one month prior by another specialist, and the histopathology report showed basal cell carcinoma. The mass was completely excised with a 2 mm safety margin, and the large conjunctival defect was reconstructed with one sheet of amniotic membrane allograft. A histological diagnosis of pilomatrix carcinoma was established. To prevent recurrence after surgery, we added bevacizumab (25 mg/mL, 1.25 mg/mL per drop) eye drops four times per day for three months. At the one-year follow-up, the patient showed no evidence of local recurrence or distant metastasis after initial excision and remains under close follow-up. Pilomatrix carcinoma should be considered in the differential diagnosis of a caruncular mass
Hydrogeomorphic and Landscape Influences on Dissolved Organic Matter in Streams and Rivers on the South Carolina Coastal Plain
The polymerisation of oligo(ethylene glycol methyl ether) methacrylate from a multifunctional poly(ethylene imine) derived amide: a stabiliser for the synthesis and dispersion of magnetite nanoparticles
A facile synthetic route to poly(ethylene imine)-graft-poly(oligo(ethylene glycol methyl ether)) (PEI-graft-POEGMA) functionalised superparamagnetic magnetite nanoparticles is described. The polymerisation of OEGMA from a model molecular amide demonstrated the feasibility of POEGMA synthesis under mild ATRP conditions (20 °C in ethanol) albeit with low initiator efficiencies. DFT studies suggest that the amide functionality is intrinsically of lower activity than ester functional monomers and initiators for atom transfer polymerisation (ATRP) as a consequence of higher bond dissociation energies and bond dissociation free energies (BDFE). However these studies further highlighted that use of an appropriate solvent could reduce the free energy of dissociation thereby reducing the relative difference in BDFE between the ester and amide groups. A commercial branched PEI sample was functionalised by reaction with 2-bromo-2-methylpropanoyl bromide giving an amide macroinitiator suitable for the atom transfer radical polymerisation (ATRP) of oligo(ethylene glycol methyl ether) methacrylate. The resulting PEI-graft-POEGMA copolymers were characterised by SEC, FT-IR and 1H and 13C NMR spectroscopy. PEI-graft-POEGMA coated magnetite nanoparticles were synthesised by a basic aqueous co-precipitation method and were characterised by transmission electron microscopy, thermogravimetric analysis and vibrating sample magnetometry and dynamic light scattering. These copolymer coated magnetite nanoparticles were demonstrated to be effectively stabilised in an aqueous medium. Overall the particle sizes and magnetic and physical properties of the coated samples were similar to those of uncoated samples
Geometrical Effects in Determination of Fickian Mass Diffusivity of Polymers
Hydrophilicity of polymers makes them prone to moisture absorption that leads to degradation of mechanical properties. Kinetics of moisture ingress needs to be fully characterized to perform reliable designs with polymeric materials.
The rate of diffusion is the essential parameter in determining the time scale of the moisture uptake in polymeric materials. The model from which the diffusion coefficient is to be determined can be mathematically complex when the viscoelastic relaxation and diffusion time scales are comparable (i.e. Deborah Number ~ l). However, Fickian type of diffusion is shown to be adequate in modeling the moisture absorption into a broad range of polymers. Most methods for determining the diffusion coefficient are based on the solution of Fick's second law in semi-infinite and slab domains from which, a closed form solution has been adapted by the American Society of Testing and Materials (ASTM). However, those techniques either do not consider the errors due to finite sample dimension or the correction factors provided are not precise enough. In addition, fabrication of samples conforming ASTM standard (i.e. length or width to thickness ratio of 100 or greater) may not be practical due to difficulties in producing and testing very thin coupons.
In this study, the solution of the Fickian diffusion equation for a three-dimensional rectangular domain is utilized to generate mass gain data for geometries with length to thickness ratios ranging from l to I 00. These data are then used to demonstrate the errors introduced by the two conventional methods used to determine the diffusion coefficient for sample dimensions deviating from an infinitely wide slab. After applying the correction factor suggested by ASTM, up to 13% error is observed in the diffusion coefficient. In order to improve the prediction of diffusion coefficient, a least square curve fit method, which yields accurate predictions regardless of the sample geometry, is proposed.YesPeer reviewed and presented at the 23rd Oklahoma AIAA/ASME Symposium
Engaging and disengaging recurrent inhibition coincides with sensing and unsensing of a sensory stimulus
AbstractEven simple sensory stimuli evoke neural responses that are dynamic and complex. Are the temporally patterned neural activities important for controlling the behavioral output? Here, we investigated this issue. Our results reveal that in the insect antennal lobe, due to circuit interactions, distinct neural ensembles are activated during and immediately following the termination of every odorant. Such non-overlapping response patterns are not observed even when the stimulus intensity or identities were changed. In addition, we find that ON and OFF ensemble neural activities differ in their ability to recruit recurrent inhibition, entrain field-potential oscillations and more importantly in their relevance to behaviour (initiate versus reset conditioned responses). Notably, we find that a strikingly similar strategy is also used for encoding sound onsets and offsets in the marmoset auditory cortex. In sum, our results suggest a general approach where recurrent inhibition is associated with stimulus ‘recognition’ and ‘derecognition’.</jats:p
Tumor detection and elimination by a targeted gallium corrole
Sulfonated gallium(III) corroles are intensely fluorescent macrocyclic compounds that spontaneously assemble with carrier proteins to undergo cell entry. We report in vivo imaging and therapeutic efficacy of a tumor-targeted corrole noncovalently assembled with a heregulin-modified protein directed at the human epidermal growth factor receptor (HER). Systemic delivery of this protein-corrole complex results in tumor accumulation, which can be visualized in vivo owing to intensely red corrole fluorescence. Targeted delivery in vivo leads to tumor cell death while normal tissue is spared. These findings contrast with the effects of doxorubicin, which can elicit cardiac damage during therapy and required direct intratumoral injection to yield similar levels of tumor shrinkage compared with the systemically delivered corrole. The targeted complex ablated tumors at >5 times a lower dose than untargeted systemic doxorubicin, and the corrole did not damage heart tissue. Complexes remained intact in serum and the carrier protein elicited no detectable immunogenicity. The sulfonated gallium(III) corrole functions both for tumor detection and intervention with safety and targeting advantages over standard chemotherapeutic agents
Discerning Aggregation in Homogeneous Ensembles: A General Description of Photon Counting Spectroscopy in Diffusing Systems
In order to discern aggregation in solutions, we present a quantum mechanical
analog of the photon statistics from fluorescent molecules diffusing through a
focused beam. A generating functional is developed to fully describe the
experimental physical system as well as the statistics. Histograms of the
measured time delay between photon counts are fit by an analytical solution
describing the static as well as diffusing regimes. To determine empirical
fitting parameters, fluorescence correlation spectroscopy is used in parallel
to the photon counting. For expedient analysis, we find that the distribution's
deviation from a single Poisson shows a difference between two single fluor
moments or a double fluor aggregate of the same total intensities. Initial
studies were performed on fixed-state aggregates limited to dimerization.
However preliminary results on reactive species suggest that the method can be
used to characterize any aggregating system.Comment: 30 pages, 5 figure
Nano-scale Flexible Interphase in a Glass Fiber/Epoxy Resin System Obtained by Admicellar Polymerization
Organosilane coupling agents are widely used in the composites industry to improve the wetting of inorganic reinforcements by low surface energy resins. An increased wettability is often a harbinger of better mechanical properties in a structural composite. Silane coatings effectively increase the spreading of liquid matrixes over glass reinforcement by altering the surface energetics of glass, not by extensive coverage, but by eradication of the high-energy sites present in the oxide surface. Commercial sizings often applied to glass fibers contain up to 10% of the active silane agent, while the remaining 90% is a mixture of lubricants, surfactants, anti-stats, and film formers. Recent investigations have demonstrated that non-reactive components tend to remain in high concentrations within the interphase, thus weakening the resin network crosslink density and increasing the potential for water ingress. Further, sizing formulations are proprietary and designed for specific resin system, which make them expensive, consequently limiting their widespread use.
In this paper, admicellar polymerization, a versatile technique to prepare elastomeric thin films of styrene-isoprene copolymer and polystyrene on the surface of random glass-fiber mats is presented. This hydrophobic coating of monolayer thickness applied to the glass fibers is not expected to disrupt the matrix cross-linking reaction; and due to its higher elastic modulus, is believed to cause a change in the stress distribution along the fiber length. Admicellar-modified reinforcements were impregnated with an epoxy resin system: EPON 815C/EPICURE 3232, and molded by Resin Transfer Molding (RTM) into disk shaped parts. Tensile strength, stiffness and interlaminar shear strength (ILSS) were measured for the flexible interphase composites, and compared to parts containing commercially sized and bare fibers. Void fraction, void size and shape distributions, as well as water diffusivity were investigated for each system.YesPeer reviewed and presented at the 18th International Conference of the Polymer processing Society
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Activated Bone Marrow-Derived Macrophages Eradicate Alzheimer's-Related Aβ42 Oligomers and Protect Synapses.
Impaired synaptic integrity and function due to accumulation of amyloid β-protein (Aβ42) oligomers is thought to be a major contributor to cognitive decline in Alzheimer's disease (AD). However, the exact role of Aβ42 oligomers in synaptotoxicity and the ability of peripheral innate immune cells to rescue synapses remain poorly understood due to the metastable nature of oligomers. Here, we utilized photo-induced cross-linking to stabilize pure oligomers and study their effects vs. fibrils on synapses and protection by Aβ-phagocytic macrophages. We found that cortical neurons were more susceptible to Aβ42 oligomers than fibrils, triggering additional neuritic arborization retraction, functional alterations (hyperactivity and spike waveform), and loss of VGluT1- and PSD95-excitatory synapses. Co-culturing neurons with bone marrow-derived macrophages protected synapses against Aβ42 fibrils; moreover, immune activation with glatiramer acetate (GA) conferred further protection against oligomers. Mechanisms involved increased Aβ42 removal by macrophages, amplified by GA stimulation: fibrils were largely cleared through intracellular CD36/EEA1+-early endosomal proteolysis, while oligomers were primarily removed via extracellular/MMP-9 enzymatic degradation. In vivo studies in GA-immunized or CD115+-monocyte-grafted APPSWE/PS1ΔE9-transgenic mice followed by pre- and postsynaptic analyses of entorhinal cortex and hippocampal substructures corroborated our in vitro findings of macrophage-mediated synaptic preservation. Together, our data demonstrate that activated macrophages effectively clear Aβ42 oligomers and rescue VGluT1/PSD95 synapses, providing rationale for harnessing macrophages to treat AD
The impact of integrating food supplementation, nutritional education and HAART (Highly Active Antiretroviral Therapy) on the nutritional status of patients living with HIV/AIDS in Mozambique: result from the DREAM programme
DREAM (Drug Resources Enhancement against AIDS and Malnutrition) is
a multiregional health program active in Mozambique since 2002 and provides free of charge an integrating package of care consisting of peer to peer nutritional and health education,
food supplementation, voluntary counseling and testing, immunological, virological, clinical
assessment and HAART (Highly Active AntiRetroviral Treatment). The main goals of this
paper are to describe the state of health and nutrition and the adequacy of the diet of a
sample of HIV/AIDS patients in Mozambique on HAART and not.
A single-arm retrospective cohort study was conducted. 106 HIV/AIDS adult patients (84 in
HAART), all receiving food supplementation and peer-to-peer nutritional education, were
randomly recruited in Mozambique in two public health centres where DREAM is running.
The programme is characterized by: provision of HAART, clinical and laboratory monitoring,
peer to peer health and nutritional education and food supplementation. We measured
BMI, haemoglobin, viral load, CD4 count at baseline (T0) and after at least 1 year (T1).
Dietary intake was estimated using 24h food recall and dietary diversity was assessed by
using the Dietary Diversity Score (DDS) at T1.
Overall, the patients'diet appeared to be quite balanced in nutrients. In the cohort not in
HAART the mean BMI values showed an increases but not significant (initial value: 21.9±2.9;
final value: 22.5±3.3 ) and the mean haemoglobin values (g/dl) showed a significant increases
(initial value: 10.5+ 2.1; final value: 11.5±1.7 p< 0.024) . In the cohort in HAART, both the
mean of BMI value (initial value: 20.7±3.9; final value: 21.9±3.3 p< 0.001) and of haemoglobin
(initial value: 9.9±2.2; final value: 10.8±1.7 p< 0.001) showed a higher significant increase.
The increase in BMI was statistically associated with the DDS in HAART patients.
In conclusion nutritional status improvement was observed in both cohorts. The improvement
in BMI was significant and substantially higher in HAART patients because of the impact
of HAART on nutritional status of AIDS patients. Subjects on HAART and with a DDS >
5, showed a substantial BMI gain. This association showed an additional expression of the
synergic effect of integrating food supplementation, nutritional education and HAART on
the nutritional status of African AIDS patients and also highlights the complementary role
of an adequate and diversified diet in persons living with HIV/AIDS in resources limited
settings
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