Non-Plasmonic SERS with Silicon: Is It Really Safe? New Insights into Opto-Thermics of Core/Shell Microbeads

<p>Here we investigate for the first time the opto-thermal behavior of SiO<sub>2</sub>/Si core/shell microbeads (Si-rex) irradiated with three common Raman laser sources (lambda=532, 633, 785 nm) under real working conditions. We obtained an experimental proof of the critical role played by bead size and aggregation in heat and light management, demonstrating that in the case of strong opto-thermal coupling the temperature can exceed that of the melting points of both core and shell components. In addition, we also show that weakly coupled beads can be utilized as stable substrates for plasmon-free SERS experiments.</p>

Download Full-text

6d (2, 0) and M-theory at 1-loop

Journal of High Energy Physics ◽

10.1007/jhep01(2021)133 ◽

2021 ◽

Vol 2021 (1) ◽

Author(s):

Luis F. Alday ◽

Shai M. Chester ◽

Himanshu Raj

Keyword(s):

Flat Space ◽

Lagrangian Description ◽

Loop Correction ◽

Higher Derivative ◽

Weakly Coupled ◽

S Matrix ◽

Space Limit ◽

Tensor Multiplet ◽

First Time ◽

M Theory

Abstract We study the stress tensor multiplet four-point function in the 6d maximally supersymmetric (2, 0) AN−1 and DN theories, which have no Lagrangian description, but in the large N limit are holographically dual to weakly coupled M-theory on AdS7× S4 and AdS7× S4/ℤ2, respectively. We use the analytic bootstrap to compute the 1-loop correction to this holographic correlator coming from Witten diagrams with supergravity R and the first higher derivative correction R4 vertices, which is the first 1-loop correction computed for a non-Lagrangian theory. We then take the flat space limit and find precise agreement with the corresponding terms in the 11d M-theory S-matrix, some of which we compute for the first time using two-particle unitarity cuts.

Download Full-text

Synthesis of an azadioxa-planar triphenylborane and investigation of its structural and photophysical properties

Chemical Communications ◽

10.1039/d0cc08331c ◽

2021 ◽

Author(s):

Y. Kitamoto ◽

K. Oda ◽

K. Ogino ◽

K. Hiyama ◽

H. Kita ◽

...

Keyword(s):

Photophysical Properties ◽

Critical Role ◽

Molecular Properties ◽

Bridging Groups ◽

First Time

An azadioxa-planar triphenylborane was synthesized for the first time and it was found that bridging groups have a critical role in changing its molecular properties.

Download Full-text

Prediction of IL4 Inducing Peptides

Clinical and Developmental Immunology ◽

10.1155/2013/263952 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 57

Author(s):

Sandeep Kumar Dhanda ◽

Sudheer Gupta ◽

Pooja Vir ◽

G. P. S. Raghava

Keyword(s):

Mhc Class Ii ◽

Critical Role ◽

Interleukin 4 ◽

Th2 Response ◽

Data Set ◽

T Helper 2 ◽

Cell Responses ◽

Antibody Class ◽

First Time ◽

Motif Information

The secretion of Interleukin-4 (IL4) is the characteristic of T-helper 2 responses. IL4 is a cytokine produced by CD4+ T cells in response to helminthes and other extracellular parasites. It has a critical role in guiding antibody class switching, hematopoiesis and inflammation, and the development of appropriate effector T-cell responses. In this study, it is the first time an attempt has been made to understand whether it is possible to predict IL4 inducing peptides. The data set used in this study comprises 904 experimentally validated IL4 inducing and 742 noninducing MHC class II binders. Our analysis revealed that certain types of residues are preferred at certain positions in IL4 inducing peptides. It was also observed that IL4 inducing and noninducing epitopes differ in compositional and motif pattern. Based on our analysis we developed classification models where the hybrid method of amino acid pairs and motif information performed the best with maximum accuracy of 75.76% and MCC of 0.51. These results indicate that it is possible to predict IL4 inducing peptides with reasonable precession. These models would be useful in designing the peptides that may induce desired Th2 response.

Download Full-text

Updating the knowledge of the flower flies (Diptera: Syrphidae) from Chile: Illustrated catalog, extinction risk and biological notes

Zootaxa ◽

10.11646/zootaxa.4959.1.1 ◽

2021 ◽

Vol 4959 (1) ◽

pp. 1-178

Author(s):

RODRIGO M. BARAHONA-SEGOVIA ◽

PAMELA RIERA ◽

LAURA PAÑINAO-MONSÁLVEZ ◽

VICENTE VALDÉS GUZMÁN ◽

PATRICIA HENRÍQUEZ-PISKULICH

Keyword(s):

Extinction Risk ◽

Critical Role ◽

Floral Biology ◽

Iucn Red List ◽

Decomposition Of Organic Matter ◽

Management Plans ◽

Flower Flies ◽

Iucn Red List Criteria ◽

Definition Of ◽

First Time

Syrphidae, more commonly known as flower flies, are considered one of the most important Diptera families worldwide because of their critical role in pollination, biological control and decomposition of organic matter. The study of these flies in Chile has stagnated due to a lack of local experts as well as the absence of an updated catalog of species. This study is an attempt to remedy the latter of these issues by providing an illustrated and updated catalog to the Syrphidae of Chile. Species are presented under currently accepted names, with synonyms and previous combinations listed and original references. Type localities, world and Chilean distribution by geopolitical Chilean regions, taxonomic and biological notes, a complete record of bibliographic references and extinction risk under IUCN Red List criteria are provided. This catalog recognizes 132 species of Syrphidae, belonging to four subfamilies (Eristalinae, Microdontinae, Pipizinae and Syrphinae), 13 tribes and 47 genera. A total of 46 species (34.84 %) is restricted to the geopolitical territory of Chile. Eight species are considered exotic, one is considered incertae sedis and three are based on doubtful records. Seventeen species of 10 different genera (Copestylum Macquart, 1846; Dolichogyna Macquart, 1842; Eosalpingogaster Hull, 1949b; Eupeodes Osten Sacken, 1877; Meromacrus Rondani, 1848; Palpada Macquart, 1834; Paragus Latreille, 1804; Sphiximorpha Rondani, 1850; Sterphus Philippi, 1865 and Toxomerus Macquart, 1855) are reported from Chile for the first time. A total of 44 species (33.33 %) reported from Chile are directly threatened by human activities such as agriculture, forestry, mining and/or urbanization and indirectly by climate change. The gaps found in the geographic distribution of Chilean flower fly species and what it means for its use by disciplines such as ecology, floral biology and agronomy, are discussed. In addition, the use of this illustrated catalog for biological conservation, the potential definition of priority areas and ecosystem management plans based on this group of Diptera are also discussed.

Download Full-text

Protection of Petroleum Pipeline Carbon Steel Alloys with New Modified Core-Shell Magnetite Nanogel against Corrosion in Acidic Medium

Journal of Chemistry ◽

10.1155/2013/125731 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 9

Author(s):

Gamal A. El Mahdy ◽

Ayman M. Atta ◽

Amro K. F. Dyab ◽

Hamad A. Al-Lohedan

Keyword(s):

Carbon Steel ◽

Sulfonic Acid ◽

Electrochemical Impedance ◽

Electrochemical Techniques ◽

Core Shell ◽

Magnetite Nanoparticle ◽

Potassium Peroxydisulfate ◽

Redox Initiator ◽

Initiator System ◽

First Time

New method was used to prepare magnetite nanoparticle based on reduction of Fe(III) ions with potassium iodide to produce Fe3O4nanoparticle. The prepared magnetite was stabilized with cross-linked polymer based on 2-acrylamido-2-methylpropane sulfonic acid (AMPS to prepare novel core-shell nanogel. In this respect, Fe3O4/poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) magnetic nanogels with controllable particle size produced via free aqueous polymerization at 65°C have been developed for the first time. The polymer was crosslinked in the presence of N,N-methylenebisacrylamide (MBA) as a crosslinker and potassium peroxydisulfate (KPS) as redox initiator system. The structure and morphology of the magnetic nanogel were characterized by Fourier transform infrared spectroscopy (FTIR) and transmission and scanning electron microscopy (TEM and SEM). The effectiveness of the synthesized compounds as corrosion inhibitors for carbon steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed enhancement in inhibition efficiencies with increasing the inhibitor concentrations. The results showed that the nanogel particles act as mixed inhibitors. EIS data revealed thatRctincreases with increasing inhibitor concentration.

Download Full-text

Obesity Accelerates Age-Associated Defects in Human B Cells Through a Metabolic Reprogramming Induced by the Fatty Acid Palmitate

Frontiers in Aging ◽

10.3389/fragi.2021.828697 ◽

2022 ◽

Vol 2 ◽

Author(s):

Daniela Frasca ◽

Maria Romero ◽

Denisse Garcia ◽

Alain Diaz ◽

Bonnie B. Blomberg

Keyword(s):

Fatty Acid ◽

B Cells ◽

Critical Role ◽

Metabolic Reprogramming ◽

Autoimmune Antibodies ◽

Human B Cells ◽

Initial Hypothesis ◽

First Time ◽

Culture Supernatants

We have measured the secretion of autoimmune antibodies in plasma samples and in culture supernatants of blood-derived B cells from four groups of individuals: young lean (YL), elderly lean (EL), young obese (YO) and elderly obese (EO). We found secretion comparable in YO and EL individuals, suggesting that obesity accelerates age-associated defects in circulating B cells. To define at least one possible molecular pathway involved, we used an in vitro model in which B cells from YL and EL individuals have been stimulated with the Fatty Acid (FA) palmitate, the most common saturated FA in the human body. The rationale to use palmitate is that there is a chronic increase in circulating levels of palmitate, due to increased spontaneous lipolysis occurring during aging and obesity, and this may induce autoimmune B cells. Results herein show that in vitro incubation of B cells from YL and EL individuals with the FA palmitate induces mRNA expression of T-bet, the transcription factor for autoimmune antibodies, as well as secretion of autoimmune IgG antibodies, with B cells from YL individuals looking similar to B cells from EL individuals, confirming our initial hypothesis. The generation of autoimmune B cells in the presence of the FA palmitate was found to be associated with a metabolic reprogramming of B cells from both YL and EL individuals. These results altogether show the critical role of the FA palmitate in inducing human B cell immunosenescence and show for the first time the importance of metabolic pathways in this process.

Download Full-text

Co-Extrusion Technology for Functioned Nature Fiber Reinforced Polymer Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.773.497 ◽

2013 ◽

Vol 773 ◽

pp. 497-501

Author(s):

Run Zhou Huang ◽

Cheng Jun Zhou ◽

Yang Zhang ◽

Qing Lin Wu

Keyword(s):

Polymer Composites ◽

Shell Structure ◽

Critical Role ◽

Core Shell ◽

Green Composite ◽

Reinforced Polymer ◽

Fiber Reinforced Polymer Composites ◽

Core Shell Structure ◽

Extrusion Technology ◽

New Generation

As a new-generation green composite, core-shell structure nature fibers/ polymer composites (NFPC) has been recently developed and used to enhance performance characteristics of composites. The shell layer, made of thermopolymers unfilled or filled with minerals or nature fibers and other additives, plays a critical role in enhancing overall composite properties. The co-extrusion technology for different structural and material combinations are, however, needed to achieve desired processing. In this paper, co-extrusion technology and core-shell structure NFPC have been discussed by systematically studying the effect of structure on properties of NFPC. The result of this paper can help provide a fundamental base for developing new functional applications of core-shell structure NFPCs.

Download Full-text

Review of the Synthetic Chemistry Involved in the Production of Core/Shell Semiconductor Nanocrystals

Australian Journal of Chemistry ◽

10.1071/ch07046 ◽

2007 ◽

Vol 60 (7) ◽

pp. 457 ◽

Cited By ~ 90

Author(s):

Joel van Embden ◽

Jacek Jasieniak ◽

Daniel E. Gómez ◽

Paul Mulvaney ◽

Michael Giersig

Keyword(s):

Semiconductor Nanocrystals ◽

Critical Role ◽

Charge Carriers ◽

Core Shell ◽

Synthetic Chemistry ◽

Shell Material ◽

Growth Processes ◽

Passivating Layer ◽

Spectral Shifts

Passivation of CdSe semiconductor nanocrystals can be achieved by overcoating the particles with a homogeneous shell of a second semiconductor. Shell layers are grown in monolayer steps to ensure homogeneous growth of the shell. The relative band edges of the two materials determine the photoreactiveity of the resultant core-shell nanocrystals. The critical role of ligands in minimizing nucleation of the shell material during the growth of the passivating layer is emphasized. The delocalization of charge carriers into the shell layers can be followed spectroscopically during the growth processes. The relative spectral shifts are directly correlated to the relative energies of the band edges.

Download Full-text

Controllable Preparation of Silver Orthophosphate@Carbon Layer Core/Shell Heterostructure with Enhanced Visible Photocatalytic Properties and Stability

NANO ◽

10.1142/s1793292015500228 ◽

2015 ◽

Vol 10 (02) ◽

pp. 1550022 ◽

Cited By ~ 3

Author(s):

Yangcun Xie ◽

Xiuwen Wang ◽

Xu Wen

Keyword(s):

High Stability ◽

Separation Efficiency ◽

Visible Region ◽

Carbon Layer ◽

Core Shell ◽

Photogenerated Electrons ◽

First Time ◽

Fabrication Parameters ◽

Controllable Preparation ◽

High Separation

In this study, silver orthophosphate@carbon layer ( Ag 3 PO 4@ C ) core/shell heterostructure photocatalyst was prepared for the first time. The results showed that a uniform carbon layer was formed around the Ag 3 PO 4. By adjusting the hydrothermal fabrication parameters, the thickness of carbon layer could be easily controlled. Furthermore, the Ag 3 PO 4@ C had remarkable light absorption in the visible region. Photocatalytic tests displayed that the Ag 3 PO 4@ C heterostructures possessed a much higher degradation rate of phenol than pure Ag 3 PO 4 under visible light. The enhanced photocatalytic activity could be attributed to high separation efficiency of photogenerated electrons and holes based on the synergistic effect between carbon as a sensitizer and Ag 3 PO 4. Recycle tests showed that the Ag 3 PO 4@ C core/shell heterostructures maintained high stability over several cycles. The good stability could be attributed to the protection of insoluble carbon layer on the surfaces of Ag 3 PO 4 crystals in aqueous solution.

Download Full-text