Plasmonic heating of gold nanoparticles and its exploitation

Nanoscale particles of metals such as gold can interact with light by means of a plasmon resonance, even though they are much smaller than the wavelengths of visible light. The proportions of light that are absorbed and scattered vary with wavelength. Any light that is absorbed will cause heating of the particles, and this effect may potentially be exploited for solar glazing coatings, nanoscale lithography or medical treatments. The position of maximum absorption of an isolated spherical nanoparticle is 518 nm, but this may be significantly red-shifted by means of decreasing the symmetry to an prolate spheroid or 'nanorod', or by producing a metal 'nanoshell' on a dielectric core, or by aggregating insulated spherical particles. Absorption peaks in the vicinity of 655 nm for aggregated particles and 780 nm for prolate spheroids are demonstrated here. Absorbed energy is released as heat into the environment of the particles, and will cause a temperature rise within the particle the magnitude of which depends upon the value of the effective heat transfer coefficient between particle and environment. The latter is not known, but we show how highly localized temperature rises of some tens of Celsius might be conceivable in systems illuminated by sunlight

Improved efficacy of a dendritic cell-based vaccine against a murine model of colon cancer: The helper protein effect

Purpose Targeted immunotherapy using dendritic cells (DCs) has been employed in numerous investigations aiming at combating neoplasms. We previously showed that copulsing of an antigen with a helper protein could considerably enhance antigen presenting capacity of ex vivo-generated DCs. In this study, we attempted to administer an effective treatment in a murine model of colon cancer with DCs pulsed with the mixture of a tumor-specific gp70-derived peptide (AH1) and a helper protein, ovalbumin (OVA). Materials and Methods First, the presence of gp70 in CT26 tumor cells and tumor tissues was verified using immunofluorescence and Western blot analyses. Next, DCs were purified from normal mice, loaded ex vivowith AH1 and OVA (DC-Pep-OVA), and injected into tumor-bearing mice. Tumor volume, in vitro antigen (Ag)-specific proliferation of splenic cells, and survival rate were measured to determine the efficacy of DC-Pep-OVA. As the control groups, tumor-bearing mice were vaccinated with DC-Pep, unpulsed DC, and DCs loaded with a mixture of OVA and an irrelevant peptide (P15), or were not vaccinated at all. Results DC-Pep-OVA showed superior efficacy over other groups, as indicated by smaller tumor volume, higher Ag-specific proliferation rate of splenic cells, and prolonged survival. Conclusion Overall, in the present study we showed for the first time that DCs copulsed with AH1 (tumor Ag) and OVA (helper molecule) could be considered as potentially robust weapons for use in future antitumor immunotherapies. © 2015 by the Korean Cancer Association

How reliable are scanning tunneling microscopy measurements of electron transport in molecules ?

Scanning tunneling microscopy measurements of tunneling through molecules adsorbed on a surface have been simulated using a standard empirical model based upon the Wentzel-Kramer-Brillouin method applied to tunneling through a barrier. The Gaussian noise inherent in these experiments has been added to the model data using a Monte Carlo technique. By generating multiple sets of current-voltage curves and fitting these to the model we have evaluated how reliably barrier height can be determined as a function of noise level. The results suggest that for constant percentage standard deviation in the noise greater than 5% the barrier height cannot be determined reliably. At this level, the standard deviation in the estimate of the barrier height is about 10%. Weighted fits give more reliable estimates of the barrier height. If the height of the tip above the molecule is known, so that the fit is only a single parameter the barrier height can be determined reliably even at percentage noise levels as high as 20%. However, in this case unweighted fits must be used otherwise the estimated value deviates by up to 15% from the true value. Data with constant absolute noise give similar results. The effects of experimental resolution have been evaluated in a similar manner and are shown to have a significant influence on the reliability. At a resolution of about 0.1% of full scale the standard deviation in the estimate of barrier height is only about 2% but increases rapidly to 10% for a resolution of about 1%

Label-Free Nanometer-Resolution Imaging of Biological Architectures through Surface Enhanced Raman Scattering

Label free imaging of the chemical environment of biological specimens would readily bridge the supramolecular and the cellular scales, if a chemical fingerprint technique such as Raman scattering can be coupled with super resolution imaging. We demonst

The characteristics of patients with possible Transient Ischemic Attack and Minor Stroke in the Hunter and Manning Valley regions, Australia (the INSIST Study)

This is the final version. Available on open access from the American Academy of Neurology via the DOI in this record. Background: Transient ischemic attack (TIA) and minor stroke (TIAMS) are risk factors for stroke recurrence. Some TIAMS may be preventable by appropriate primary prevention. We aimed to recruit “possible-TIAMS” patients in the INternational comparison of Systems of care and patient outcomes In minor Stroke and TIA (INSIST) study. Methods: A prospective inception cohort study performed across 16 Hunter–Manning region, Australia, general practices in the catchment of one secondary-care acute neurovascular clinic. Possible-TIAMS patients were recruited from August 2012 to August 2016. We describe the baseline demographics, risk factors and pre-event medications of participating patients. Results: There were 613 participants (mean age; 69 ± 12 years, 335 women), and 604 (99%) were Caucasian. Hypertension was the most common risk factor (69%) followed by hyperlipidemia (52%), diabetes mellitus (17%), atrial fibrillation (AF) (17%), prior TIA (13%) or stroke (10%). Eighty-nine (36%) of the 249 participants taking antiplatelet therapy had no known history of cardiovascular morbidity. Of 102 participants with known AF, 91 (89%) had a CHA2DS2-VASc score ≥ 2 but only 47 (46%) were taking anticoagulation therapy. Among 304 participants taking an antiplatelet or anticoagulant agent, 30 (10%) had stopped taking these in the month prior to the index event. Conclusion: This study provides the first contemporary data on TIAMS or TIAMS-mimics in Australia. Community and health provider education is required to address the under-use of anticoagulation therapy in patients with known AF, possibly inappropriate use of antiplatelet therapy and possibly inappropriate discontinuation of antiplatelet or anticoagulation therapy.National Health and Medical Research Counci

One-year risk of stroke after transient ischemic attack or minor stroke in Hunter New England, Australia (INSIST Study)

Background: One-year risk of stroke in transient ischemic attack and minor stroke (TIAMS) managed in secondary care settings has been reported as 5–8%. However, evidence for the outcomes of TIAMS in community care settings is limited. Methods: The INternational comparison of Systems of care and patient outcomes In minor Stroke and TIA (INSIST) study was a prospective inception cohort community-based study of patients of 16 general practices in the Hunter–Manning region (New South Wales, Australia). Possible-TIAMS patients were recruited from 2012 to 2016 and followed-up for 12 months post-index event. Adjudication as TIAMS or TIAMS-mimics was by an expert panel. We established 7-days, 90-days, and 1-year risk of stroke, TIA, myocardial infarction (MI), coronary or carotid revascularization procedure and death; and medications use at 24 h post-index event. Results: Of 613 participants (mean age; 70 ± 12 years), 298 (49%) were adjudicated as TIAMS. TIAMS-group participants had ischemic strokes at 7-days, 90-days, and 1-year, at Kaplan-Meier (KM) rates of 1% (95% confidence interval; 0.3, 3.1), 2.1% (0.9, 4.6), and 3.2% (1.7, 6.1), respectively, compared to 0.3, 0.3, and 0.6% of TIAMS-mimic-group participants. At one year, TIAMS-group-participants had twenty-five TIA events (KM rate: 8.8%), two MI events (0.6%), four coronary revascularizations (1.5%), eleven carotid revascularizations (3.9%), and three deaths (1.1%), compared to 1.6, 0.6, 1.0, 0.3, and 0.6% of TIAMS-mimic-group participants. Of 167 TIAMS-group participants who commenced or received enhanced therapies, 95 (57%) were treated within 24 h post-index event. For TIAMS-group participants who commenced or received enhanced therapies, time from symptom onset to treatment was median 9.5 h [IQR 1.8–89.9]. Conclusion: One-year risk of stroke in TIAMS participants was lower than reported in previous studies. Early implementation of antiplatelet/anticoagulant therapies may have contributed to the low stroke recurrence

Quantitative Histomorphometry of the Healthy Peritoneum

The peritoneum plays an essential role in preventing abdominal frictions and adhesions and can be utilized as a dialysis membrane. Its physiological ultrastructure, however, has not yet been studied systematically. 106 standardized peritoneal and 69 omental specimens were obtained from 107 patients (0.1-60 years) undergoing surgery for disease not affecting the peritoneum for automated quantitative histomorphometry and immunohistochemistry. The mesothelial cell layer morphology and protein expression pattern is similar across all age groups. Infants below one year have a thinner submesothelium; inflammation, profibrotic activity and mesothelial cell translocation is largely absent in all age groups. Peritoneal blood capillaries, lymphatics and nerve fibers locate in three distinct submesothelial layers. Blood vessel density and endothelial surface area follow a U-shaped curve with highest values in infants below one year and lowest values in children aged 7-12 years. Lymphatic vessel density is much lower, and again highest in infants. Omental blood capillary density correlates with parietal peritoneal findings, whereas only few lymphatic vessels are present. The healthy peritoneum exhibits major thus far unknown particularities, pertaining to functionally relevant structures, and subject to substantial changes with age. The reference ranges established here provide a framework for future histomorphometric analyses and peritoneal transport modeling approaches. © 2016, EDP Science. All rights reserved

Gut-central nervous system axis is a target for nutritional therapies

Historically, in the 1950s, the chemist Linus Pauling established a relationship between decreased longevity and obesity. At this time, with the advent of studies involving the mechanisms that modulate appetite control, some researchers observed that the hypothalamus is the "appetite centre" and that peripheral tissues have important roles in the modulation of gut inflammatory processes and levels of hormones that control food intake. Likewise, the advances of physiological and molecular mechanisms for patients with obesity, type 2 diabetes mellitus, inflammatory bowel diseases, bariatric surgery and anorexia-associated diseases has been greatly appreciated by nutritionists. Therefore, this review highlights the relationship between the gut-central nervous system axis and targets for nutritional therapies