Nanogold-based materials in medicine: from their origins to their future.

The properties of gold-based materials have been explored for centuries in several research fields, including medicine. Multiple published production methods for gold nanoparticles (AuNPs) have shown that the physicochemical and optical properties of AuNPs depend on the production method used. These different AuNP properties have allowed exploration of their usefulness in countless distinct biomedical applications over the last few years. Here we present an extensive overview of the most commonly used AuNP production methods, the resulting distinct properties of the AuNPs and the potential application of these AuNPs in diagnostic and therapeutic approaches in biomedicine

Connection between the Affine and Conformal Affine Toda Models and their Hirota's Solution

It is shown that the Affine Toda models (AT) constitute a ``gauge fixed'' version of the Conformal Affine Toda model (CAT). This result enables one to map every solution of the AT models into an infinite number of solutions of the corresponding CAT models, each one associated to a point of the orbit of the conformal group. The Hirota's $\tau$-function are introduced and soliton solutions for the AT and CAT models associated to $\hat {SL}(r+1)$ and $\hat {SP}(r)$ are constructed.Comment: 11 pages, LaTe

A Step Forward in Breast Cancer Research: Gold Nanoparticles as Photothermal Therapy Enhancers

Gold nanoparticles (AuNPs) have been widely used and characterized for multiple biomedical applications, including the enhancement of photothermal therapy (PTT). AuNPs present a particular plasmon resonance band and are able to convert the absorbed optical radiation into heat, which validates their use in PTT. Several production methods have already been proposed for the synthesis of AuNPs, allowing to optimize the particles' morphology, size and optical properties. However, the production methods commonly used are frequently associated with the use of toxic reagents such as Cetyltrimethylammonium bromide, which presents some concerns for clinical applications. Herein, it is proposed a novel AuNPs' core synthesis method using tetrachloroauric acid and a mixture of reducing agents, later on coated with a combination of hyaluronic and oleic acids. The coating here represents a potential improvement of AuNPs biocompatibility, biodegradability and lifetime, while simultaneously potentiating the attachment towards specific ligands, such as the CD44 receptor, to develop more localized and highly selective tools. The produced functionalized nanoparticles were characterized by Dynamic Light Scattering, Microscopy Techniques and Spectroscopy, showing diameter sizes under 350 nm, polydispersity index smaller than 0.4 and enhanced absorbance in the Near Infrared (NIR, 650 to 900 nm) range. Moreover, the AuNPs safety and efficacy were preliminarily assessed in vitro using breast cancer cell lines. No toxicity was observed by MTT assay, both in breast cancer cell lines, and red blood cells. The irradiation process was proved to be safe; however, when combined with the AuNPs administration, it resulted in a significant reduction of cell viability for some of the breast cell lines tested. Thus, the results highlight the potential of the proposed system for some type of tumors, even though further tests are required to better understand the mechanisms behind the obtained results

Hirota's Solitons in the Affine and the Conformal Affine Toda Models

We use Hirota's method formulated as a recursive scheme to construct complete set of soliton solutions for the affine Toda field theory based on an arbitrary Lie algebra. Our solutions include a new class of solitons connected with two different type of degeneracies encountered in the Hirota's perturbation approach. We also derive an universal mass formula for all Hirota's solutions to the Affine Toda model valid for all underlying Lie groups. Embedding of the Affine Toda model in the Conformal Affine Toda model plays a crucial role in this analysis.Comment: 36 pages, LaTe

The Role of Rosmarinic Acid on the Bioproduction of Gold Nanoparticles as Part of a Photothermal Approach for Breast Cancer Treatment.

Breast cancer is a high-burden malignancy for society, whose impact boosts a continuous search for novel diagnostic and therapeutic tools. Among the recent therapeutic approaches, photothermal therapy (PTT), which causes tumor cell death by hyperthermia after being irradiated with a light source, represents a high-potential strategy. Furthermore, the effectiveness of PTT can be improved by combining near infrared (NIR) irradiation with gold nanoparticles (AuNPs) as photothermal enhancers. Herein, an alternative synthetic method using rosmarinic acid (RA) for synthesizing AuNPs is reported. The RA concentration was varied and its impact on the AuNPs physicochemical and optical features was assessed. Results showed that RA concentration plays an active role on AuNPs features, allowing the optimization of mean size and maximum absorbance peak. Moreover, the synthetic method explored here allowed us to obtain negatively charged AuNPs with sizes favoring the local particle accumulation at tumor site and maximum absorbance peaks within the NIR region. In addition, AuNPs were safe both in vitro and in vivo. In conclusion, the synthesized AuNPs present favorable properties to be applied as part of a PTT system combining AuNPs with a NIR laser for the treatment of breast cancer

A quantum mechanical investigation of positively charged defects in SiO{sub 2} thin film devices

Ab initio Hartree-Fock and second-order Moeller-Plesset theory calculations have been performed to investigate the stability of triply-coordinated O{sup +} centers in the Si-O-Si network of amorphous SiO{sub 2}. The calculations reveal that the H{sup +} ion binds with a bridging O center to form a very stable (D{sub e} > 6 eV) trivalent O complex. Capture of an electron by the positively charged protonated complex, however, is predicted to immediately lead to the dissociation of the O-H bond. A relatively weaker, but stable bond is also formed between the bridging O atom and a {sup +}SiH{sub 3} ion

Isolation and characterization of new genetic types of Toxoplasma gondii and prevalence of Trichinella murrelli from black bear (Ursus americanus)

Black bears (Ursus americanus) are hosts for two important zoonotic parasites, Toxoplasma gondii and Trichinella spp. and bears are hunted for human consumption in the USA. Little is known of the genetic diversity of T. gondii circulating in wildlife. In the present study, antibodies to T. gondii were found in juice from tongues of 17 (25.7%) of 66 wild black bear from Maryland during the hunting season of 2010 and 2011. Antibodies to T. gondii were assessed by the modified agglutination test. Tongues of 17 seropositive bears were bioassayed in mice and viable T. gondii was isolated from three samples. These three T. gondii isolates (TgBbMd1-3) were further propagated in cell culture and DNA isolated from culture-derived tachyzoites was characterized using 11 PCR-RFLP markers (SAG1, 5′ - and 3′ -SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico). Results revealed three genotypes. TgBbMd1 is a Type 12 strain (ToxoDB PCR-RFLP genotype #4) and TgBbMd2 is ToxoDB PCR- RFLP genotype #216, and TgBbMd3 is a Type II clonal strain (ToxoDB PCR-RFLP genotype #1). The isolate TgBbMd2 was highly virulent for outbred Swiss Webster mice; all infected mice died of acute toxoplasmosis. Results indicate that mouse virulent strains of T. gondii are circulating in wildlife in the USA. These 66 tongues in addition to tongues collected during hunts in previous years were further investigated for the presence of muscle larvae of Trichinella spp. Tongues from 40 bears in 2005, 41 in 2006, 51 in 2007, 56 in 2008, 68 in 2009, 67 in 2010, and 66 in 2011 were subjected to digestion with pepsin/HCl and microscopic examination. Two bears were infected with Trichinella spp.; one in 2008 and one in 2009. Genotyping of collected muscle larvae revealed that the infecting species in both cases was Trichinella murrelli

Gold nanoparticles as a part of a photothermal therapy system.

Introduction Photothermal therapy (PTT) is attracting increased attention for the treatment of superficial localized tumors, relying on the induction of local hyperthermia of tumor cells upon their irradiation with light beams1. PTT efficacy depends, however, on the heat generated and, on the depth reached by the light. Some strategies to improve PTT efficacy includes the use of the near infrared (NIR, 650 to 900 nm) radiation to enhance the penetration depth of the light, combined with gold nanoparticles (AuNPs) to enhance the photothermal effect2. Experimental Methods Core AuNPs were synthesized by a novel method using tetrachloroauric acid and a mixture of reducing agents, and subsequently coated with a combination of hyaluronic and oleic acids, for improving the NPs biocompatibility, biodegradability, and lifetime. This coating also promotes the binding of specific cell receptors of the tumor cells. The particles were physico-chemically characterized, and in vitro and in vivo tests were carried out in breast cancer models to assess their safety and efficacy, when applied alone or combined with NIR irradiation3. Results and Discussion AuNPs presented a predominant spherical morphology with sizes under 350 nm, polydispersity index lower than 0.4 and enhanced absorbance in the NIR. The particles showed no toxicity in vitro and promising efficacy in vivo when administering the NPs in situ and later irradiating them externally. Histopathological analysis of tumors treated with both AuNPs and laser irradiation showed the presence of necrosis in most of the tumors and no effect or practically absence in healthy surrounding cells, which are very encouraging outcomes. Conclusion The results are promising, however, there is still room for improving the system, namely by reducing even more the invasiveness of the treatment through the combined use of aerogels structures. Aerogel’s unique properties4 make them ideal candidates to minimize the exposure of healthy tissues to laser radiation, acting as light and thermal insulators, as well as to incorporate the nanoparticles into their skeletal structure and thus potentiating a topical application of the particles. For these reasons, some exploratory methods were carried to produce and design aerogels structures for PTT applications

Survival-extinction phase transition in a bit-string population with mutation

A bit-string model for the evolution of a population of haploid organisms, subject to competition, reproduction with mutation and selection is studied, using mean field theory and Monte Carlo simulations. We show that, depending on environmental flexibility and genetic variability, the model exhibits a phase transtion between extinction and survival. The mean-field theory describes the infinite-size limit, while simulations are used to study quasi-stationary properties.Comment: 11 pages, 5 figure

Growth, feed intake, carcass characteristics, and meat fatty acid profile of lambs fed soybean oil partially replaced by fish oil blend

AbstractThe objective of this study was to evaluate the effects of partial replacement of soybean oil by fish oil on dry matter intake (DMI), growth, carcass characteristics, and meat fatty acid profile of feedlot lambs. Fifty Santa Ines male lambs with 17.1±2.8 of initial body weight (BW) were individually penned and used in a randomized complete block design with 10 blocks and 5 treatments. Dietary treatments, dry matter (DM) basis, consisted of: (1) control diet (CONT) with a 10:90 of forage to concentrate ratio, (2) control diet supplemented with 40g/kg of soybean oil (0FO), (3) control diet supplemented with 2.5g/kg of fish oil blend+37.5g/kg of soybean oil (25FO), (4) control diet supplemented with 5g/kg of fish oil blend+35g/kg of soybean oil (50FO), and (5) control diet supplemented with 7.5g/kg of fish oil blend+32.5g/kg of soybean oil (75FO). Diets were mixed once daily and fed ad libitum. At the end of the 84-day feeding trial, all animals were slaughtered for carcass characteristics evaluations and meat fat acid profile determination. Animals fed soybean oil had reduced DMI compared to control; however, the average daily gain (ADG), feed efficiency (FE) and final BW were not affected. The animals fed fish oil had similar DMI, ADG, FE and final BW to those receiving the control treatment. The DMI, ADG, FE and final BW were not affected by the increasing substitution of soybean oil for fish oil. Most carcass characteristics were not affected by treatments. The shrink after chilling was lower for the 50FO diet. Short, medium, and long-chain fatty acids were similar for all diets. Stearic acid concentration was higher for lambs fed the fat diets vs. control. However, stearic acid concentration decreased linearly when fish oil replaced soybean oil. Vaccenic acid concentration was higher for lambs fed fat diets vs. control. In addition, vaccenic acid increased linearly with fish oil inclusion. The conjugated linoleic acid (CLA) C18:2 cis-9, trans-11 showed higher concentration in meat of animals fed diets containing fish oil compared to control, but it was not affected by soybean oil inclusion. Feeding small amounts of fish oil blend plus soybean oil does not exert an additional effect on the concentration of CLA C18:2 cis-9, trans-11 in relation to the exclusive use of soybean oil. However, the mixture of 7.5g/kg DM of fish oil blend with 32.5g/kg DM of soybean oil is recommended, because it improves the lipid profile of the meat by increasing the concentration of vaccenic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Additionally, supplementing 7.5g/kg DM of fish oil blend mixed with 32.5g/kg DM of soybean had no negative effect on the feed intake, ADG, FE and carcass characteristics of the lambs fed high concentrate diet