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https://www.readbyqxmd.com/read/29779258/hyperpolarized-porous-silicon-nanoparticles-potential-theragnostic-material-for-%C3%A2-%C3%A2-si-magnetic-resonance-imaging
#1
Hyeonglim Seo, Ikjang Choi, Nicholas Whiting, Jingzhe Hu, Quy Son Luu, Shivanand Pudakalakatti, Caitlin McCowan, Yaewon Kim, Niki Zacharias, Seunghyun Lee, Pratip Bhattacharya, Youngbok Lee
Porous silicon nanoparticles have recently garnered attention as potentially-promising biomedical platforms for drug delivery and medical diagnostics. Here, we demonstrate porous silicon nanoparticles as contrast agents for ²⁹Si magnetic resonance imaging. Size-controlled porous silicon nanoparticles were synthesized by magnesiothermic reduction of silica nanoparticles and were surface activated for further functionalization. Particles were hyperpolarized via dynamic nuclear polarization to enhance their ²⁹Si MR signals; the particles demonstrated long ²⁹Si spin-lattice relaxation (T₁) times (~ 25 mins), which suggests potential applicability for medical imaging...
May 20, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/29779079/preparation-and-adsorption-characteristics-for-heavy-metals-of-active-silicon-adsorbent-from-leaching-residue-of-lead-zinc-tailings
#2
Chang Lei, Bo Yan, Tao Chen, Xian-Ming Xiao
To comprehensively reuse the leaching residue obtained from lead-zinc tailings, an active silicon adsorbent (ASA) was prepared from leaching residue and studied as an adsorbent for copper(II), lead(II), zinc(II), and cadmium(II) in this paper. The ASA was prepared by roasting the leaching residue with either a Na2 CO3 /residue ratio of 0.6:1 at 700 °C for 1 h or a CaCO3 /residue ratio of 0.8:1 at 800 °C for 1 h. Under these conditions, the available SiO2 content of the ASA was more than 20%. The adsorption behaviors of the metal ions onto the ASA were investigated and the Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were used to analyze the adsorption isotherm...
May 19, 2018: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29777312/evaluating-organochlorine-pesticide-residues-in-the-aquatic-environment-of-the-lake-naivasha-river-basin-using-passive-sampling-techniques
#3
Yasser Abbasi, Chris M Mannaerts
Passive sampling techniques can improve the discovery of low concentrations by continuous collecting the contaminants, which usually go undetected with classic and once-off time-point grab sampling. The aim of this study was to evaluate organochlorine pesticide (OCP) residues in the aquatic environment of the Lake Naivasha river basin (Kenya) using passive sampling techniques. Silicone rubber sheet and Speedisk samplers were used to detect residues of α-HCH, β-HCH, γ-HCH, δ-HCH, heptachlor, aldrin, heptachlor epoxide, pp-DDE, endrin, dieldrin, α-endosulfan, β-endosulfan, pp-DDD, endrin aldehyde, pp-DDT, endosulfan sulfate, and methoxychlor in the Malewa River and Lake Naivasha...
May 18, 2018: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/29777186/anti-reflectance-investigation-of-a-micro-nano-hybrid-structure-fabricated-by-dry-wet-etching-methods
#4
Xiao Tan, Zhi Tao, Mingxing Yu, Hanxiao Wu, Haiwang Li
Black silicon fabrication and manipulation have been well reported by institutes around the world and are quite useful for solar absorption and photovoltaic conversion. In this study, silicon micro-nano hybrid structures were fabricated, and the morphologies of the hybrid structures were analyzed. This paper studied nanostructures formed on tips, pits and a flat surface using a dry etching method and a wet etching method. In terms of nanostructure morphology, nanostructures etched by the wet etching method (13 μm) were taller than those etched by the dry etching method (1 μm), but the wet etched morphology was less organized...
May 18, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29775760/synthesis-of-axially-disubstituted-silicon-phthalocyanines-and-investigation-of-photodynamic-effects-on-hct-116-colorectal-cancer-cell-line
#5
Ceren Sarı, Figen Celep Eyüpoğlu, İsmail Değirmencioğlu, Rıza Bayrak
Photodynamic therapy is one of the hot topics in cancer studies recently. Basically, photosensitizing chemical substrates which are stimulated by light having a specific wavelength cause fatal effect on different kind of cells in photodynamic therapy. In this study, axially 4-{[(1E)-2-furylmethylene]amino}phenol, 4-{[(1E)-2-thienylmethylene]amino}phenol and 4-{[(1E)-(4-nitro-2-thienyl)methylene]amino}phenol disubstituted silicon phthalocyanines were synthesized as Photosensitizers for photodynamic therapy in cancer treatment for the first time...
May 15, 2018: Photodiagnosis and Photodynamic Therapy
https://www.readbyqxmd.com/read/29775306/mechanistic-study-on-water-splitting-reactions-by-small-silicon-clusters-si-3-x-x-si-be-mg-ca
#6
Tran Dieu Hang, Minh Tho Nguyen
(Abstract) Interaction, dissociation and dehydrogenation reactions of water monomer and dimer with pure and mixed tetrameric silicon clusters Si3X with X = Si, Be, Mg, Ca were investigated using high accuracy quantum chemical calculations. While geometries were optimized using the DFT/B3LYP functional with the aug-cc-pVTZ basis set, reaction energy profiles were constructed making use of the coupled-cluster theory with extrapolation to complete basis set, CCSD(T)/CBS. Cleavage of the O-H bond in water dimer is found to be more favored than that of water monomer in the reaction with Si4...
May 18, 2018: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29775096/silicon-alleviates-arsenic-induced-toxicity-in-wheat-through-vacuolar-sequestration-and-ros-scavenging
#7
Md Monayem Hossain, Most Amena Khatun, Md Najmul Haque, Md Azizul Bari, Md Firoz Alam, Abul Mandal, Ahmad Humayan Kabir
Arsenic (As) is a phytotoxic element causing health hazards. This work investigates whether and how silicon (Si) alleviates As toxicity in wheat. The addition of Si under As-stress significantly improved morphophysiological characteristics, total protein, and membrane stability compared to As-stressed plants, suggesting that Si does have critical roles in As detoxification in wheat. Analysis of arsenate reductase activity and phytosiderophore (PS) release reveals their no involvement in the Si-mediated alleviation of As in wheat...
July 3, 2018: International Journal of Phytoremediation
https://www.readbyqxmd.com/read/29774924/fluorescence-resonance-energy-transfer-fret-based-nanoparticles-composed-of-aie-luminogens-and-nir-dyes-with-enhanced-three-photon-near-infrared-emission-for-in-vivo-brain-angiography
#8
Wen Liu, Yalun Wang, Xiao Han, Ping Lu, Liang Zhu, Chaowei Sun, Jun Qian, Sailing He
Near-infrared (NIR) fluorescence is very important for high-contrast biological imaging of high-scattering tissues such as brain tissue. Unfortunately, commercial NIR dyes are excited usually by visible light, and their multi-photon absorption (MPA) cross-sections are small. Here, we design new co-encapsulated NIR nanoparticles (NPs) with a large three-photon (3PA) absorption cross-section. A form of aggregation-induced emission (AIE) luminogen (AIEgen), 2,3-bis(4'-(diphenylamino)-[1,1'-biphenyl]-4-yl) fumaronitrile (TPATCN), is introduced as the donor, and a form of NIR dye, silicon 2,3-naphthalocyanine bis-(trihexylsilyloxide) (NIR775), is adopted as the acceptor...
May 18, 2018: Nanoscale
https://www.readbyqxmd.com/read/29774896/low-temperature-solution-synthesis-of-silicon-germanium-and-si-ge-axial-heterostructures-in-nanorod-and-nanowire-form
#9
G Flynn, K Stokes, K M Ryan
Herein, we report the formation of silicon, germanium and more complex Si-SixGe1-x and Si-Ge axial 1D heterostructures, at low temperatures in solution. These nanorods/nanowires are grown using phenylated compounds of silicon and germanium as reagents, with precursor decomposition achieved at substantially reduced temperatures (200 °C for single crystal nanostructures and 300 °C for heterostructures), through the addition of a reducing agent. This low energy route for the production of these functional nanostructures as a wet chemical in high yield is attractive to meet the processing needs for next generation photovoltaics, batteries and electronics...
May 18, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29774672/glucose-sensitive-silicone-hydrogel-contact-lens-toward-tear-glucose-monitoring
#10
Ramachandram Badugu, Edward Albert Reece, Joseph R Lakowicz
Accurate and reliable monitoring of blood glucose is needed for the treatment of diabetes, which has many challenges, including lack of patient compliance. Measuring tear glucose is an alternative to traditional finger-stick tests used to track blood sugar levels, but glucose sensing using tears has yet to be achieved. We report a methodology for possible tear glucose monitoring using glucose-sensitive silicone hydrogel (SiHG) contact lenses, the primary type of lenses available in today's market. Initially, we assessed the interpenetrating polymer network, with nearly pure silicone and water regions, existing in the SiHGs using a polarity-sensitive probe Prodan...
May 2018: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/29774333/optical-tweezing-using-tunable-optical-lattices-along-a-few-mode-silicon-waveguide
#11
C Pin, J-B Jager, M Tardif, E Picard, E Hadji, F de Fornel, B Cluzel
Fourteen years ago, optical lattices and holographic tweezers were considered as a revolution, allowing for trapping and manipulating multiple particles at the same time using laser light. Since then, near-field optical forces have aroused tremendous interest as they enable efficient trapping of a wide range of objects, from living cells to atoms, in integrated devices. Yet, handling at will multiple objects using a guided light beam remains a challenging task for current on-chip optical trapping techniques...
May 18, 2018: Lab on a Chip
https://www.readbyqxmd.com/read/29773945/predictive-factors-in-the-treatment-of-streptococcal-endophthalmitis
#12
Yosanan Yospaiboon, Kidakarn Meethongkam, Suthasinee Sinawat, Wipada Laovirojjanakul, Tanapat Ratanapakorn, Thuss Sanguansak, Chavakij Bhoomibunchoo
Objective: To evaluate visual outcomes and possible predictive factors in the treatment of infectious endophthalmitis caused by Streptococcus species during 2012-2016 at a large referral eye center in northeastern Thailand. Methods: A retrospective medical record chart review of patients with culture-positive endophthalmitis caused by Streptococcus species was conducted. Demographic data including age, gender, occupation, duration of symptoms, time to surgery, surgical procedures, initial visual acuity at presentation, and final visual acuity after treatment were collected and analyzed...
2018: Clinical Ophthalmology
https://www.readbyqxmd.com/read/29773788/immunogene-therapy-with-fusogenic-nanoparticles-modulates-macrophage-response-to-staphylococcus-aureus
#13
Byungji Kim, Hong-Bo Pang, Jinyoung Kang, Ji-Ho Park, Erkki Ruoslahti, Michael J Sailor
The incidence of adverse effects and pathogen resistance encountered with small molecule antibiotics is increasing. As such, there is mounting focus on immunogene therapy to augment the immune system's response to infection and accelerate healing. A major obstacle to in vivo gene delivery is that the primary uptake pathway, cellular endocytosis, results in extracellular excretion and lysosomal degradation of genetic material. Here we show a nanosystem that bypasses endocytosis and achieves potent gene knockdown efficacy...
May 17, 2018: Nature Communications
https://www.readbyqxmd.com/read/29772828/wetting-behaviors-of-a-nano-droplet-on-a-rough-solid-substrate-under-perpendicular-electric-field
#14
Fenhong Song, Long Ma, Jing Fan, Qicheng Chen, Lihui Zhang, Ben Q Li
Molecular dynamic simulations were adopted to study the wetting properties of nanoscale droplets on rough silicon solid substrate subject to perpendicular electric fields. The effect of roughness factor and electric field strength on the static and dynamic wetting behaviors of a nano-droplet on a solid surface was investigated at the molecular level. Results show that the static contact angle tends to decrease slightly and show small difference with the increase of roughness factor, while it shows an obvious increase for the ramp-shaped surface because the appearing bottom space reduces the wettability of solid surface...
May 17, 2018: Nanomaterials
https://www.readbyqxmd.com/read/29772740/tactile-estimation-of-molded-plastic-plates-based-on-the-estimated-impulse-responses-of-mechanoreceptive-units
#15
Lisako Nobuyama, Yuta Kurashina, Kei Kawauchi, Koji Matsui, Kenjiro Takemura
This study proposes a tactile estimation method of molded plastic plates based on human tactile perception characteristics. Plastic plates are often used in consumer products. The tactile evaluation plays an important role in product development. However, physical quantities not taking into account human tactile perception have been employed in previous tactile estimation procedures. Hence, in this study, we adopted the vibrational thresholds of the mechanoreceptive units-FA I, FA II, SA I and SA II-for stimuli detection and developed a tactile estimation method for plastic plates that clarified the mechanoreceptive units related to tactile sensation...
May 16, 2018: Sensors
https://www.readbyqxmd.com/read/29772248/scaffolds-for-peripheral-nerve-repair-and-reconstruction
#16
REVIEW
Sheng Yi, Lai Xu, Xiaosong Gu
Trauma-associated peripheral nerve defect is a widespread clinical problem. Autologous nerve grafting, the current gold standard technique for the treatment of peripheral nerve injury, has many internal disadvantages. Emerging studies showed that tissue engineered nerve graft is an effective substitute to autologous nerves. Tissue engineered nerve graft is generally composed of neural scaffolds and incorporating cells and molecules. A variety of biomaterials have been used to construct neural scaffolds, the main component of tissue engineered nerve graft...
May 14, 2018: Experimental Neurology
https://www.readbyqxmd.com/read/29770578/effect-of-silicon-doped-calcium-phosphate-bone-grafting-materials-on-bone-regeneration-and-osteogenic-marker-expression-after-implantation-in-the-ovine-scapula
#17
Christine Knabe, Doaa Adel-Khattab, Wolf-Dietrich Hübner, Fabian Peters, Tom Knauf, Barbara Peleska, Dirk Barnewitz, Antje Genzel, Roderik Kusserow, Florian Sterzik, Michael Stiller, Christian Müller-Mai
Compared to the currently clinically available bone grafting materials for alveolar ridge augmentation, there is a great demand for bioactive bone substitutes with higher resorbability, which enhance osteogenesis at the same time. This has prompted the development of a silicon-doped rapidly resorbable calcium alkali orthophosphate (Si-CAOP) and silicon-doped β-tricalcium phosphate (Si-TCP). This study evaluated the effect of these two particulate graft materials as compared to the currently clinically used β-TCP on bone formation and osteogenic marker expression after 2 weeks, 1, 3, 6, 12, and 18 months of implantation in critical size defects in the sheep scapula...
May 16, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
https://www.readbyqxmd.com/read/29770576/the-extracellular-zn-2-concentration-surrounding-excited-neurons-is-high-enough-to-bind-amyloid-%C3%AE-revealed-by-a-nanowire-transistor
#18
Ankur Anand, Chih-Hung Chi, Subhasree Banerjee, Ming-Yi Chou, Fan-Gang Tseng, Chien-Yuan Pan, Yit-Tsong Chen
The Zn2+ stored in the secretory vesicles of glutamatergic neurons is coreleased with glutamate upon stimulation, resulting in the elevation of extracellular Zn2+ concentration (CZn2+ex). This elevation of CZn2+ex regulates the neurotransmission and facilitates the fibrilization of amyloid-β (Aβ). However, the exact CZn2+ex surrounding neurons under (patho)physiological conditions is not clear and the connection between CZn2+ex and the Aβ fibrilization remains obscure. Here, a silicon nanowire field-effect transistor (SiNW-FET) with the Zn2+ -sensitive fluorophore, FluoZin-3 (FZ-3), to quantify the CZn2+ex in real time is modified...
May 16, 2018: Small
https://www.readbyqxmd.com/read/29770160/active-tube-shaped-actuator-with-embedded-square-rod-shaped-ionic-polymer-metal-composites-for-robotic-assisted-manipulation
#19
Yanjie Wang, Jiayu Liu, Denglin Zhu, Hualing Chen
This paper reports a new technique involving the design, fabrication, and characterization of an ionic polymer-metal composite- (IPMC-) embedded active tube, which can achieve multidegree-of-freedom (MODF) bending motions desirable in many applications, such as a manipulator and an active catheter. However, traditional strip-type IPMC actuators are limited in only being able to generate 1-dimensional bending motion. So, in this paper, we try to develop an approach which involves molding or integrating rod-shaped IPMC actuators into a soft silicone rubber structure to create an active tube...
2018: Applied Bionics and Biomechanics
https://www.readbyqxmd.com/read/29769623/microwave-effects-in-the-dilute-acid-hydrolysis-of-cellulose-to-5-hydroxymethylfurfural
#20
Nick Sweygers, Niels Alewaters, Raf Dewil, Lise Appels
In this study, the effect of microwaves on the production of 5-hydroxymethylfurfural (HMF) in a biphasic system was evaluated via a kinetic analysis. The reaction system consisted of an acidified aqueous phase and methyl isobutyl ketone (MIBK) as an organic phase, in which HMF is extracted directly upon formation during the reaction. Two identically shaped reactors were used to assess the influence of microwaves on the production of HMF. A borosilicate glass reactor was used to heat the reaction mixture via microwaves directly, whereas the silicon carbide (SiC) wall of the second reactor absorbed all microwaves and hence the reactor content was heated via convective heat transfer...
May 16, 2018: Scientific Reports
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