Interaction of surface-modified silica nanoparticles with clay minerals

Abstract In this study, the adsorption of 5-nm silica nanoparticles onto montmorillonite and illite is investigated. The effect of surface functionalization was evaluated for four different surfaces: unmodified, surface-modified with anionic (sulfonate), cationic (quaternary ammonium (quat)), and nonionic (polyethylene glycol (PEG)) surfactant. We employed ultraviolet–visible spectroscopy to determine the concentration of adsorbed nanoparticles in conditions that are likely to be found in subsurface reservoir environments. PEG-coated and quat/PEG-coated silica nanoparticles were found to significantly adsorb onto the clay surfaces, and the effects of electrolyte type (NaCl, KCl) and concentration, nanoparticle concentration, pH, temperature, and clay type on PEG-coated nanoparticle adsorption were studied. The type and concentration of electrolytes were found to influence the degree of adsorption, suggesting a relationship between the interlayer spacing of the clay and the adsorption ability of the nanoparticles. Under the experimental conditions reported in this paper, the isotherms for nanoparticle adsorption onto montmorillonite at 25 °C indicate that adsorption occurs less readily as the nanoparticle concentration increases

Internal avalanches in a pile of superconducting vortices

Using an array of miniature Hall probes, we monitored the spatiotemporal variation of the internal magnetic induction in a superconducting niobium sample during a slow sweep of external magnetic field. We found that a sizable fraction of the increase in the local vortex population occurs in abrupt jumps. The size distribution of these avalanches presents a power-law collapse on a limited range. In contrast, at low temperatures and low fields, huge avalanches with a typical size occur and the system does not display a well-defined macroscopic critical current.Comment: 5 pages including 5 figure

Behavioral, physiological, and molecular differences in response to dietary restriction in three inbred mouse strains

, physiological, and molecular differences in response to dietary restriction in three inbred mouse strains. Am J Physiol Endocrinol Metab 291: E574 -E581, 2006. First published May 2, 2006; doi:10.1152/ajpendo.00068.2006.-Food restriction paradigms are widely used in animal studies to investigate systems involved in energy regulation. We have observed behavioral, physiological, and molecular differences in response to food restriction in three inbred mouse strains, C57BL/6J, A/J, and DBA/2J. These are the progenitors of chromosome substitution and recombinant inbred mouse strains used for mapping complex traits. DBA/2J and A/J mice increased their locomotor activity during food restriction, and both displayed a decrease in body temperature, but the decrease was significantly larger in DBA/2J compared with A/J mice. C57BL/6J mice did not increase their locomotor activity and displayed a large decrease in their body temperature. The large decline in body temperature during food restriction in DBA/2J and C57BL/6J strains was associated with a robust reduction in plasma leptin levels. DBA/2J mice showed a marked decrease in white and brown adipose tissue masses and an upregulation of the antithermogenic hypothalamic neuropeptide Y Y1 receptor. In contrast, A/J mice showed a reduction in body temperature to a lesser extent that may be explained by downregulation of the thermogenic melanocortin 3 receptor and by behavioral thermoregulation as a consequence of their increased locomotor activity. These data indicate that genetic background is an important parameter in controlling an animal's adaptation strategy in response to food restriction. Therefore, mouse genetic mapping populations based on these progenitor lines are highly valuable for investigating mechanisms underlying strain-dependent differences in behavioral physiology that are seen during reduced food availability. locomotor activity; body temperature; food intake; neuropeptide Y; melanocortin ENERGY BALANCE is regulated by processes that influence food intake and energy expenditure. The main components of energy expenditure are metabolism and thermogenesis induced by exercise, cold, and diet, and these are regulated by the interaction of behavioral, physiological, and molecular mechanisms. Imbalances in energy state can result in health problems, such as malnutrition, eating disorders, or obesity Food restriction paradigms are widely used in animal studies to investigate mechanisms involved in the regulation of energy balance Behavioral thermoregulation is one of the mechanisms by which endothermic animals achieve and maintain a stable body temperature during times of food shortage In addition to behavioral thermogenesis, endothermic animals use autonomic mechanisms to regulate their core temperature (47). For example, brown adipose tissue (BAT)-mediated nonshivering thermogenesis is involved in heat production when animals are exposed to cold. Mitochondrial uncoupling proteins (UCPs) in the BAT generate heat by uncoupling oxidative phosphorylation, and, in mice, targeted inactivation of the gene coding for UCP1 leads to cold sensitivity (13). Leptin increases the thermogenesis in BAT by increasing UCP1 expression (48); therefore, decreased heat production resulting from hypoleptinemia could be associated with the increased locomotor activity seen in some inbred mice strains and rats in response to restricted feeding. Leptin's effects on the hypothalamic neuropeptide Y (NPY) and melanocortin systems have been implicated in the regulation of energy balance (56, 59). For example, selective NPY Y 1 and Y 5 receptor agonists increase food consumption and decrease circulating levels of thyroid hormones, showing that both receptors mediate the stimulatory effects of NPY on foo

Mechanistic analysis of the wave-current interaction in the plume region of a partially mixed tidal inlet

In this research, a three-dimensional coupled wave-circulation model, including meteorological forcing, freshwater inflow and time varying open boundary conditions, for New River Inlet is validated. A mechanistic approach is taken to investigate how various wave-current interaction mechanisms affect the nearshore circulation, plume expansion and surface wave field in the plume region of a relatively small partially mixed tidal estuarine system. More specifically, focus is comparing four different modeling cases including: (1) a three-dimensional ocean circulation model (no wave effects), (2) a coupled wave-circulation model, (3) a coupled wave and circulation model including vertical mixing enhancement due to wave breaking, and (4) a wave model without surface current effects. Findings reveal forces are applied by incoming waves due to various wave-current interaction mechanisms. Wave momentum released by incoming waves pushes the outgoing freshwater ebb plume back to the shoreline and prevents the plume from expanding freely towards the open ocean. Findings also reveals that releasing wave-dissipated energy in the expanding plume region enhances vertical mixing, mixes down freshwater, and therefore thickens the plume. These results are congruent with observations at the mouth of the Columbia River

Case Report Papillary Thyroid Microcarcinoma with a Large Cystic Dilated Lymph Node Metastasis to the Neck Mimicking a Branchial Cleft Cyst: A Potential Pitfall

Lateral cervical cystic mass in a young adult very rarely could be a first sign of an occult thyroid papillary microcarcinoma metastasis. In this paper, we presented a 37-year-old male patient whose preoperative 6 cm left lateral cervical cystic mass was initially diagnosed as branchial cleft cyst, but then the postoperative histopathological examination of the mass was revealed as papillary thyroid carcinoma metastasis. Preoperative fine needle aspiration biopsy was relevant with a branchial cleft cyst. In the left thyroid lobe there were 3 solid nodules with 4, 6, and 12 mm dimensions, respectively. One of the nodules had malignant well-differentiated cells diagnosed after fine needle aspiration biopsy. After total thyroidectomy, histopathologic evaluation of biopsy material's showed papillary thyroid microcarcinomas. This case indicates that especially in a young adult lateral cervical cystic mass should be carefully considered preoperatively for the possibility of metastatic occult thyroid carcinoma, especially for papillary carcinoma in differential diagnosis, and evaluation of the thyroid gland should be taken into account

Assessment of Volumetric versus Manual Measurement in Disseminated Testicular Cancer; No Difference in Assessment between Non-Radiologists and Genitourinary Radiologist

The aim of this study was to assess the feasibility and reproducibility of semi-automatic volumetric measurement of retroperitoneal lymph node metastases in testicular cancer (TC) patients treated with chemotherapy versus the standardized manual measurements based on RECIST criteria.21 TC patients with retroperitoneal lymph node metastases of testicular cancer were studied with a CT scan of chest and abdomen before and after cisplatin based chemotherapy. Three readers, a surgical resident, a radiological technician and a radiologist, assessed tumor response independently using computerized volumetric analysis with Vitrea software® and manual measurement according to RECIST criteria (version 1.1). Intra- and inter-rater variability were evaluated with intra class correlations and Bland-Altman analysis.Assessment of intra observer and inter observer variance proved non-significant in both measurement modalities. In particularly all intraclass correlation (ICC) values for the volumetric analysis were > .99 per observer and between observers. There was minimal bias in agreement for manual as well as volumetric analysis.In this study volumetric measurement using Vitrea software® appears to be a reliable, reproducible method to measure initial tumor volume of retroperitoneal lymph node metastases of testicular cancer after chemotherapy. Both measurement methods can be performed by experienced non-radiologists as well

Primary osteosarcoma of the urinary bladder following cyclophosphamide therapy for systemic lupus erythematosus: a case report

<p>Abstract</p> <p>Introduction</p> <p>The association of systemic lupus erythematosus with malignancies is an uncommon occurrence. We present the case of an osteosarcoma of the urinary bladder developing in a patient with a prolonged history of active systemic lupus erythematosus. This is a previously unreported association. Primary osteosarcoma is an extremely rare disease in the urinary bladder.</p> <p>Case presentation</p> <p>A 24-year-old Caucasian woman with a 13-year history of systemic lupus erythematosus, who had been treated with high dose immunosuppressive agents, presented with pain and hematuria. A deeply invasive high-grade tumor was detected in the urinary bladder and the patient underwent radical surgery. A diagnosis of osteosarcoma was made based on the characteristic histology.</p> <p>Conclusion</p> <p>Predisposing factors for primary sarcomas in the urinary bladder are mostly unknown; however, in our case, long-term administration of immunosuppressive agents, as well as long standing systemic lupus erythematosus, may both be of significance.</p

Being tolerated and being discriminated against:Links to psychological well-being through threatened social identity needs

We investigated whether and how the experience of being tolerated and of being discriminated against are associated with psychological well‐being in three correlational studies among three stigmatized groups in Turkey (LGBTI group members, people with disabilities, and ethnic Kurds, total N = 862). Perceived threat to social identity needs (esteem, meaning, belonging, efficacy, and continuity) was examined as a mediator in these associations. Structural equation models showed evidence for the detrimental role of both toleration and discrimination experiences on positive and negative psychological well‐being through higher levels of threatened social identity needs. A mini‐meta analysis showed small to moderate effect sizes and toleration was associated with lower positive well‐being through threatened needs among all three stigmatized groups

Molecular changes during extended neoadjuvant letrozole treatment of breast cancer: distinguishing acquired resistance from dormant tumours

Abstract Background The risk of recurrence for endocrine-treated breast cancer patients persists for many years or even decades following surgery and apparently successful adjuvant therapy. This period of dormancy and acquired resistance is inherently difficult to investigate; previous efforts have been limited to in-vitro or in-vivo approaches. In this study, sequential tumour samples from patients receiving extended neoadjuvant aromatase inhibitor therapy were characterised as a novel clinical model. Methods Consecutive tumour samples from 62 patients undergoing extended (4–45 months) neoadjuvant aromatase inhibitor therapy with letrozole were subjected to transcriptomic and proteomic analysis, representing before (≤ 0), early (13–120 days), and long-term (> 120 days) neoadjuvant aromatase inhibitor therapy with letrozole. Patients with at least a 40% initial reduction in tumour size by 4 months of treatment were included. Of these, 42 patients with no subsequent progression were classified as “dormant”, and the remaining 20 patients as “acquired resistant”. Results Changes in gene expression in dormant tumours begin early and become more pronounced at later time points. Therapy-induced changes in resistant tumours were common features of treatment, rather than being specific to the resistant phenotype. Comparative analysis of long-term treated dormant and resistant tumours highlighted changes in epigenetics pathways including DNA methylation and histone acetylation. The DNA methylation marks 5-methylcytosine and 5-hydroxymethylcytosine were significantly reduced in resistant tumours compared with dormant tissues after extended letrozole treatment. Conclusions This is the first patient-matched gene expression study investigating long-term aromatase inhibitor-induced dormancy and acquired resistance in breast cancer. Dormant tumours continue to change during treatment whereas acquired resistant tumours more closely resemble their diagnostic samples. Global loss of DNA methylation was observed in resistant tumours under extended treatment. Epigenetic alterations may lead to escape from dormancy and drive acquired resistance in a subset of patients, supporting a potential role for therapy targeted at these epigenetic alterations in the management of resistance to oestrogen deprivation therapy