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https://www.readbyqxmd.com/read/29786740/shear-density-coupling-for-a-compressible-single-component-yield-stress-fluid
#1
Markus Gross, Fathollah Varnik
Flow behavior of a single-component yield stress fluid is addressed on the hydrodynamic level. A basic ingredient of the model is a coupling between fluctuations of density and velocity gradient via a Herschel-Bulkley-type constitutive model. Focusing on the limit of low shear rates and high densities, the model approximates well-but is not limited to-gently sheared hard sphere colloidal glasses, where solvent effects are negligible. A detailed analysis of the linearized hydrodynamic equations for fluctuations and the resulting cubic dispersion relation reveals the existence of a range of densities and shear rates with growing flow heterogeneity...
May 22, 2018: Soft Matter
https://www.readbyqxmd.com/read/29786615/morphological-control-of-gold-nanorods-via-thermally-driven-bi-surfactant-growth-and-application-for-detection-of-heavy-metal-ions
#2
Hao Huang, Huiyi Li, Huaiyu Wang, Jia Li, Penghui Li, Qidan Chen, Yue Chen, Paul K Chu, Bo Li, Xuefeng Yu
We report a modified synthesis route of colloidal gold nanorods (AuNRs) by combining the thermal re-shaping treatment and bi-surfactant modification using hexadecyltrimethylammonium bromide (CTAB) and sodium oleate (NaOL). Aspect ratios down to 1.3 ± 0.1 can be achieved in addition to good monodispersity, uniformity, and chemical stability of the materials. Furthermore, without needing post-treatment, metal ions directly interact with the AuNRs efficiently, allowing rapid and sensitive colorimetric detection of heavy metal ions such as Pb<sup>2+</sup> and Cu<sup>2+</sup> with a low concentration down to 2...
May 22, 2018: Nanotechnology
https://www.readbyqxmd.com/read/29785202/opto-thermoelectric-nanotweezers
#3
Linhan Lin, Mingsong Wang, Xiaolei Peng, Emanuel N Lissek, Zhangming Mao, Leonardo Scarabelli, Emily Adkins, Sahin Coskun, Husnu Emrah Unalan, Brian A Korgel, Luis M Liz-Marzán, Ernst-Ludwig Florin, Yuebing Zheng
Optical manipulation of plasmonic nanoparticles provides opportunities for fundamental and technical innovation in nanophotonics. Optical heating arising from the photon-to-phonon conversion is considered as an intrinsic loss in metal nanoparticles, which limits their applications. We show here that this drawback can be turned into an advantage, by developing an extremely low-power optical tweezing technique, termed opto-thermoelectric nanotweezers (OTENT). Through optically heating a thermoplasmonic substrate, alight-directed thermoelectric field can be generated due to spatial separation of dissolved ions within the heating laser spot, which allows us to manipulate metal nanoparticles of a wide range of materials, sizes and shapes with single-particle resolution...
April 2018: Nature Photonics
https://www.readbyqxmd.com/read/29784806/restoration-of-paper-artworks-with-microemulsions-confined-in-hydrogels-for-safe-and-efficient-removal-of-adhesive-tapes
#4
Nicole Bonelli, Costanza Montis, Antonio Mirabile, Debora Berti, Piero Baglioni
The presence of pressure-sensitive tapes (PSTs) on paper artworks, either fortuitous or specifically applied for conservation purposes, is one of the most frequent and difficult issues encountered during restoration. Aged PSTs can damage or disfigure artworks, compromising structural integrity, readability, and enjoyment. Current procedures are often inherently hazardous for artistic media and paper support. Challenged by the necessity to remove PSTs from a contemporary and an ancient drawing (20th century, by artists da Silva and Hayter, and a 16th century drawing of one figure from the Sistine Chapel by Michelangelo), we addressed this issue from a physicochemical perspective, leveraging colloid and interface science...
May 21, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29784422/development-of-a-sers-strategy-to-overcome-the-nanoparticle-stabilisation-effect-in-serum-containing-samples-application-to-the-quantification-of-dopamine-in-the-culture-medium-of-pc-12-cells
#5
E Dumont, C De Bleye, J Cailletaud, P-Y Sacré, P-B Van Lerberghe, B Rogister, G A Rance, J W Aylott, Ph Hubert, E Ziemons
The analysis of serum samples by surface-enhanced Raman spectroscopy (SERS) has gained ground over the last few years. However, the stabilisation of colloids by the proteins contained in these samples has restricted their use in common practice, unless antibodies or aptamers are used. Therefore, this work was dedicated to the development of a SERS methodology allowing the analysis of serum samples in a simple and easy-to-implement way. This approach was based on the pre-aggregation of the colloid with a salt solution...
August 15, 2018: Talanta
https://www.readbyqxmd.com/read/29784383/sensitive-and-simple-determination-of-zwitterionic-morphine-in-human-urine-based-on-liquid-liquid-micro-extraction-coupled-with-surface-enhanced-raman-spectroscopy
#6
Borong Yu, Chentai Cao, Pan Li, Mei Mao, Qiwen Xie, Liangbao Yang
Morphine, a kind of illicit drugs, is also one of the main heroin metabolites. In consideration of a noninvasive way to monitor and identify drug abuse during forensic cases, the urine samples are usually detected. Here, colloidal gold nanorods (Au NRs) were introduced to act as active substrate, because of the strong optical extinction and spectral tunability of the longitudinal surface plasmon resonance (SPR). Thus, well surface-enhanced Raman spectra of morphine even at low concentrations could be obtained by portable Raman spectrometer...
August 15, 2018: Talanta
https://www.readbyqxmd.com/read/29783802/-clinicopathologic-and-molecular-features-of-cribriform-morular-variant-of-papillary-thyroid-carcinoma
#7
X J Cui, H O Zhao, P Su, J Chen, R Y Zhang, Y Pan, X M Ouyang, J Liu, J Q Zhang, Y Yang, R Yang, L Ding, Z Y Liu
Objective: To investigate the clinicopathologic and molecular features of the rare cribriform morular variant of papillary thyroid carcinoma (CMV-PTC). Methods: The clinicopathologic data of 10 patients with CMV-PTC were retrospectively reviewed. Immunohistochemical (IHC) staining was done using LSAB method. DNA sequencing for APC were applied using Sanger method. BRAF V600E mutation was examined using ARMS method. The cytological, morphological, IHC and molecular features were analyzed. Results: All patients were female at an average age of 27 years old...
May 8, 2018: Zhonghua Bing Li Xue za Zhi Chinese Journal of Pathology
https://www.readbyqxmd.com/read/29783745/loading-of-indocyanine-green-within-polydopamine-coated-laponite-nanodisks-for-targeted-cancer-photothermal-and-photodynamic-therapy
#8
Fanli Xu, Mengxue Liu, Xin Li, Zhijuan Xiong, Xueyan Cao, Xiangyang Shi, Rui Guo
The combination of photothermal therapy (PTT) and photodynamic therapy (PDT) in cancer treatment has attracted much attention in recent years. However, developing highly efficient and targeted therapeutic nanoagents for amplifying PTT and PDT treatments remains challenging. In this work, we developed a novel photothermal and photodynamic therapeutic nanoplatform for treatment of cancer cells overexpressing integrin αv β₃ through the coating of polydopamine (PDA) on indocyanine green (ICG)-loaded laponite (LAP) and then further conjugating polyethylene glycol-arginine-glycine-aspartic acid (PEG-RGD) as targeted agents on the surface...
May 19, 2018: Nanomaterials
https://www.readbyqxmd.com/read/29783645/carbon-dots-doped-with-dysprosium-a-bimodal-nanoprobe-for-mri-and-fluorescence-imaging
#9
Timur Sh Atabaev, Zhonglie Piao, Anara Molkenova
In recent years, functional nanoprobes with multiple imaging modalities have become an emerging field of biomedical research. In this preliminary study, we utilized a facile hydrothermal method for the preparation of magneto-fluorescent bimodal carbon dots doped with dysprosium (Dy-CDs). The prepared Dy-CDs have shown a good colloidal stability in a water solution and strong blue⁻green fluorescence, with a maximum at 452 nm. In addition, the excellent transverse relaxivity of the prepared Dy-CDs (r₂ = 7...
May 18, 2018: Journal of Functional Biomaterials
https://www.readbyqxmd.com/read/29783089/self-stabilized-silk-sericin-based-nanoparticles-in-vivo-biocompatibility-and-reduced-doxorubicin-induced-toxicity
#10
Doudou Hu, Ting Li, Zongpu Xu, Di Liu, Mingying Yang, Liangjun Zhu
A variety of colloid stabilizers and cryoprotectants confer improved nanoparticle (NP) colloidal stability and redisperability. However, the discounted tumor targetability, delivery efficacy and possible side effects limit the application in the vascular delivery of NPs. Here we present the water-soluble silk sericin (SS) not only as a material for the preparation of NPs, but also both a dispersion stabilizer and a cryoprotectant. In the absence of any stabilizers, SS-based NPs (SSC@NPs) could resist to the serum protein adsorption, preventing the formation of particle agglomerates...
May 18, 2018: Acta Biomaterialia
https://www.readbyqxmd.com/read/29782982/process-optimization-purification-and-characterization-of-a-novel-acidic-thermostable-chitinase-from-humicola-grisea
#11
Manish Kumar, Amandeep Brar, V Vivekanand, Nidhi Pareek
An extracellular acidic and thermostable chitinase (HgChi) from thermophilic Humicola grisea was purified and characterized. Enhancement in chitinase production (Qp  = 2.9662 Ul-1  h-1 ) was achieved through derivation of optimum fermentation conditions via central composite design. H. grisea observed to produce various isoforms of chitinase, among which the major expressed form has molecular mass of about 50 kDa. Purified chitinases exhibited optimal activity at pH 3.0 and 70 °C. Chitinase showed notable stability at increasing temperatures...
May 18, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29781617/unexpected-optical-blue-shift-in-large-colloidal-quantum-dots-by-anionic-migration-and-exchange
#12
Maria Acebron, Juan F Galisteo-López, Cefe Lopez, Facundo C Herrera, Martin D Mizrahi, Felix G Requejo, Francisco Javier Palomares, Beatriz H Juarez
Compositional changes taking place during the synthesis of alloyed CdSeZnS nanocrystals (NCs) allow shifting the optical features to higher energy as the NCs grow. Under certain synthetic conditions, the effect of those changes on the surface/interface chemistry competes with and dominates over the conventional quantum confinement effect in growing NCs. These changes, identified by means of complementary advanced spectroscopic techniques such as XPS (X-ray Photoelectron Spectroscopy) and XAS (X-ray absorption Spectroscopy), are understood in the frame of an ion migration and exchange mechanism taking place during the synthesis...
May 21, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29781488/electrohydrodynamic-fibrillation-governed-enhanced-thermal-transport-in-dielectric-colloids-under-a-field-stimulus
#13
Purbarun Dhar, Lakshmi Sirisha Maganti, A R Harikrishnan
Electrorheological (ER) fluids are known to exhibit enhanced viscous effects under an electric field stimulus. The present article reports the hitherto unreported phenomenon of greatly enhanced thermal conductivity in such electro-active colloidal dispersions in the presence of an externally applied electric field. Typical ER fluids are synthesized employing dielectric fluids and nanoparticles and experiments are performed employing an in-house designed setup. Greatly augmented thermal conductivity under a field's influence was observed...
May 21, 2018: Soft Matter
https://www.readbyqxmd.com/read/29781281/comparison-of-phonon-damping-behavior-in-quantum-dots-capped-with-organic-and-inorganic-ligands
#14
Kyle J Schnitzenbaumer, Gordana Dukovic
Surface ligand modification of colloidal semiconductor nanocrystals has been widely used as a means of controlling photoexcited state generation, relaxation, and coupling to the environment. While progress has been made in understanding how surface ligand modification affects the behavior of excitonic states, less is known about the influence of surface ligand modification on phonon behavior, which impacts relaxation dynamics and transport phenomena. In this work we compare the dynamics of optical and acoustic phonons in CdTe quantum dots (QDs), CdTe/CdSe core/shell QDs capped with octadecylphosphonic acid ligands, and CdTe QDs capped with Se2- to ascertain how ligand exchange from native aliphatic ligands to single-atom Se2- ligands affects phonon behavior...
May 21, 2018: Nano Letters
https://www.readbyqxmd.com/read/29781269/crystallization-of-nanocrystals-in-spherical-confinement-probed-by-in-situ-x-ray-scattering
#15
Federico Montanarella, Jaco J Geuchies, Tonnishtha Dasgupta, P Tim Prins, Carlo van Overbeek, Rajeev Dattani, Patrick Baesjou, Marjolein Dijkstra, Andrei V Petukhov, Alfons van Blaaderen, Daniël Vanmaekelbergh
We studied the formation of supraparticles from nanocrystals confined in slowly evaporating oil droplets in an oil-in-water emulsion. The nanocrystals consist of an FeO core, a CoFe2 O4 shell, and oleate capping, with an overall diameter of 12.5 nm. We performed in-situ Small- and Wide-Angle X-ray Scattering experiments during the entire period of solvent evaporation and colloidal crystallization. We observed a slow increase in the volume fraction of nanocrystals inside the oil droplets up to 20%, at which a sudden crystallization occurs...
May 21, 2018: Nano Letters
https://www.readbyqxmd.com/read/29780568/anisotropic-functionalization-of-upconversion-nanoparticles
#16
Wei Ren, Shihui Wen, Sherif Abdulkader Tawfik, Qian P Su, Gungun Lin, Lining A Ju, Michael J Ford, Harshad Ghodke, Antoine M van Oijen, Dayong Jin
Despite significant advances toward accurate tuning of the size and shape of colloidal nanoparticles, the precise control of the surface chemistry thereof remains a grand challenge. It is desirable to conjugate functional bio-molecules onto the selected facets of nanoparticles owing to the versatile capabilities rendered by the molecules. We report here facet-selective conjugation of DNA molecules onto upconversion nanoparticles via ligand competition reaction. Different binding strengths of phosphodiester bonds and phosphate groups on DNA and the surfactant molecules allow one to create heterogeneous bio-chemistry surface for upconversion nanoparticles...
May 14, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780536/thermoreversible-crystallization-driven-aggregation-of-diblock-copolymer-nanoparticles-in-mineral-oil
#17
Matthew J Derry, Oleksandr O Mykhaylyk, Anthony J Ryan, Steven P Armes
A poly(behenyl methacrylate)37 (PBeMA37 ) macromolecular chain transfer agent is utilized for the reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of benzyl methacrylate (BzMA) directly in mineral oil at 90 °C. Polymerization-induced self-assembly (PISA) occurs under these conditions, yielding a series of sterically-stabilized PBeMA37 -PBzMA x diblock copolymer spheres of tunable diameter as confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM) studies...
May 7, 2018: Chemical Science
https://www.readbyqxmd.com/read/29778982/efficient-co-delivery-of-neo-epitopes-using-dispersion-stable-layered-double-hydroxide-nanoparticles-for-enhanced-melanoma-immunotherapy
#18
Ling-Xiao Zhang, Xi-Xiu Xie, Dong-Qun Liu, Zhi Ping Xu, Rui-Tian Liu
Cancer immunotherapy has shown tremendous progresses in recent years for various cancers and layered double hydroxide (LDH) nanoparticles are demonstrated as effective adjuvants for protein-based vaccines. This research further shows that the colloidal stability of LDH-based vaccines significantly influences the therapeutic efficacy and LDH nanoparticles are able to adjuvant multiple tumor-associated antigen peptides to provoke strong cell-mediated immune responses for effective inhibition of cancer growth...
May 10, 2018: Biomaterials
https://www.readbyqxmd.com/read/29778782/acyclovir-lipid-nanocapsules-gel-for-oromucosal-delivery-a-preclinical-evidence-of-efficacy-in-the-chicken-pouch-membrane-model
#19
Darine Abozaid, Alyaa Ramadan, Heba Barakat, Nawal Khalafallah
The study aimed to develop a patient-friendly acyclovir gel with improved efficacy in viral mouth infections, in response to patients' need for an intraoral acyclovir product. Acyclovir was loaded in lipid nanocapsules in gel form, and formulae were evaluated for oromucosal delivery. Lipid nanocapsules were prepared by the phase inversion method. Formulae were optimized to achieve maximum acyclovir entrapment and minimum acyclovir precipitation. Colloidal properties, and pharmaceutical performance indicators were assessed...
May 17, 2018: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/29777270/-rathke-cysts-craniopharyngioma-and-colloid-cysts-what-are-the-differences-between-these-pathologies
#20
REVIEW
R Eymann, M Kiefer
CLINICAL ISSUE: Headache is the most common symptom of colloid cysts, Rathke cysts, and craniopharyngioma due to their location in the midline, being extra-axial and typically presenting in the parasellar region. THERAPEUTIC PROBLEMS: Although these tumors are generally considered benign, each has its typical characteristics defined by its location and histology. These individual characteristics define whether surgery is necessary at all and if so, the preferred surgical approach and resection's totality...
May 17, 2018: Der Radiologe
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