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https://www.readbyqxmd.com/read/28345859/aqueous-nanoparticle-polymer-solar-cells-the-effects-of-surfactant-concentration-and-processing-on-device-performance
#1
Fallon J M Colberts, Martijn M Wienk, René A J Janssen
Polymer solar cells based on PDPP5T and PCBM as donor and acceptor materials have been processed from aqueous nanoparticle miniemulsions. Careful monitoring and optimizing the concentration of free and surface-bound surfactants in the dispersion, by measuring the conductivity and zeta potential, is essential to avoid aggregation of nanoparticles at low concentration and de-wetting of the film at high concentration. The surfactant concentration is crucial for creating reproducible processing conditions that aid in further developing aqueous nanoparticle processed solar cells...
March 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28344982/transbronchial-cryobiopsy-in-interstitial-lung-disease-experience-in-106-cases-how-to-do-it
#2
Antonio Bango-Álvarez, Miguel Ariza-Prota, Hector Torres-Rivas, Luis Fernández-Fernández, Amador Prieto, Inmaculada Sánchez, Maria Gil, Ana Pando-Sandoval
Transbronchial biopsy using forceps (TBB) is the first diagnostic technique performed on patients with interstitial lung disease (ILD). However, the small size of the samples and the presence of artefacts in the tissue obtained make the yield variable. Our objectives were 1) to attempt to reproduce transbronchial cryobiopsy under the same conditions with which we performed conventional TBB, that is, in the bronchoscopy unit without intubating the patient and without fluoroscopy or general anaesthesia; 2) to describe the method used for its execution; and 3) to analyse the diagnostic yield and its complications...
January 2017: ERJ Open Research
https://www.readbyqxmd.com/read/28344776/the-mechanism-of-translation
#3
REVIEW
Joachim Frank
Translation of the genetic code on the ribosome into protein is a process of extraordinary complexity, and understanding its mechanism has remained one of the major challenges even though x-ray structures have been available since 2000. In the past two decades, single-particle cryo-electron microscopy has contributed a major share of information on structure, binding modes, and conformational changes of the ribosome during its work cycle, but the contributions of this technique in the translation field have recently skyrocketed after the introduction of a new recording medium capable of detecting individual electrons...
2017: F1000Research
https://www.readbyqxmd.com/read/28344036/focus-the-interface-between-data-collection-and-data-processing-in-cryo-em
#4
Nikhil Biyani, Ricardo D Righetto, Robert McLeod, Daniel Caujolle-Bert, Daniel Castano-Diez, Kenneth N Goldie, Henning Stahlberg
We present a new software package called Focus that interfaces cryo-transmission electron microscopy (cryo-EM) data collection with computer image processing. Focus creates a user-friendly environment to import and manage data recorded by direct electron detectors and perform elemental image processing tasks in a high-throughput manner while new data is being acquired at the microscope. It provides the functionality required to remotely monitor the progress of data collection and data processing, which is essential now that automation in cryo-EM allows a steady flow of images of single particles, two-dimensional crystals, or electron tomography data to be recorded in overnight sessions...
March 23, 2017: Journal of Structural Biology
https://www.readbyqxmd.com/read/28342772/elucidating-the-structural-organization-of-a-novel-low-density-lipoprotein-nanoparticle-reconstituted-with-docosahexaenoic-acid
#5
Rohit S Mulik, Hui Zheng, Kumar Pichumani, James Ratnakar, Qiu-Xing Jiang, Ian R Corbin
Low-density lipoprotein nanoparticles reconstituted with unesterified docosahexaenoic acid (LDL-DHA) is promising nanomedicine with enhanced physicochemical stability and selective anticancer cytotoxic activity. The unique functionality of LDL-DHA ultimately relates to the structure of this nanoparticle. To date, however, little is known about the structural organization of this nanoparticle. In this study chemical, spectroscopic and electron microscopy analyses were undertaken to elucidate the structural and molecular organization of LDL-DHA nanoparticles...
March 22, 2017: Chemistry and Physics of Lipids
https://www.readbyqxmd.com/read/28342396/high-resolution-cryo-em-the-nuts-and-bolts
#6
REVIEW
Dominika Elmlund, Sarah N Le, Hans Elmlund
Cryogenic electron microscopy (cryo-EM) and single-particle analysis now enables the determination of high-resolution structures of macromolecular assemblies that have resisted X-ray crystallography and other approaches. Successful high-resolution structure determination by cryo-EM always depends on the quality of the protein sample. While structural heterogeneity remains a key challenge for cryo-EM, it also represents a rare opportunity to study the intrinsic conformational flexibility of macromolecular assemblies...
March 22, 2017: Current Opinion in Structural Biology
https://www.readbyqxmd.com/read/28340353/molecular-structure-of-the-human-cftr-ion-channel
#7
Fangyu Liu, Zhe Zhang, László Csanády, David C Gadsby, Jue Chen
The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that uniquely functions as an ion channel. Here, we present a 3.9 Å structure of dephosphorylated human CFTR without nucleotides, determined by electron cryomicroscopy (cryo-EM). Close resemblance of this human CFTR structure to zebrafish CFTR under identical conditions reinforces its relevance for understanding CFTR function. The human CFTR structure reveals a previously unresolved helix belonging to the R domain docked inside the intracellular vestibule, precluding channel opening...
March 23, 2017: Cell
https://www.readbyqxmd.com/read/28340349/structure-reveals-mechanisms-of-viral-suppressors-that-intercept-a-crispr-rna-guided-surveillance-complex
#8
Saikat Chowdhury, Joshua Carter, MaryClare F Rollins, Sarah M Golden, Ryan N Jackson, Connor Hoffmann, Lyn'Al Nosaka, Joseph Bondy-Denomy, Karen L Maxwell, Alan R Davidson, Elizabeth R Fischer, Gabriel C Lander, Blake Wiedenheft
Genetic conflict between viruses and their hosts drives evolution and genetic innovation. Prokaryotes evolved CRISPR-mediated adaptive immune systems for protection from viral infection, and viruses have evolved diverse anti-CRISPR (Acr) proteins that subvert these immune systems. The adaptive immune system in Pseudomonas aeruginosa (type I-F) relies on a 350 kDa CRISPR RNA (crRNA)-guided surveillance complex (Csy complex) to bind foreign DNA and recruit a trans-acting nuclease for target degradation. Here, we report the cryo-electron microscopy (cryo-EM) structure of the Csy complex bound to two different Acr proteins, AcrF1 and AcrF2, at an average resolution of 3...
March 23, 2017: Cell
https://www.readbyqxmd.com/read/28340337/structural-basis-of-rna-polymerase-i-transcription-initiation
#9
Christoph Engel, Tobias Gubbey, Simon Neyer, Sarah Sainsbury, Christiane Oberthuer, Carlo Baejen, Carrie Bernecky, Patrick Cramer
Transcription initiation at the ribosomal RNA promoter requires RNA polymerase (Pol) I and the initiation factors Rrn3 and core factor (CF). Here, we combine X-ray crystallography and cryo-electron microscopy (cryo-EM) to obtain a molecular model for basal Pol I initiation. The three-subunit CF binds upstream promoter DNA, docks to the Pol I-Rrn3 complex, and loads DNA into the expanded active center cleft of the polymerase. DNA unwinding between the Pol I protrusion and clamp domains enables cleft contraction, resulting in an active Pol I conformation and RNA synthesis...
March 23, 2017: Cell
https://www.readbyqxmd.com/read/28340334/advances-in-phase-plate-cryo-em-imaging-of-dna-and-nucleosomes
#10
Eugene Y D Chua, Sara Sandin
Contrast in electron cryo-microscopy (cryo-EM) is limited by the weak phase and radiation sensitive nature of biologic samples embedded in vitrified ice. We have recently shown that a new contrast enhancement technique utilizing the Volta phase plate can be combined with single particle analysis to determine the structure of a small chromatin complex, the nucleosome core particle, at near-atomic resolution. Here, we discuss advantages and limitations of the technique in terms of data collection, particle detection, and visualization of individual DNA molecules and higher-order chromatin structure...
February 7, 2017: Nucleus
https://www.readbyqxmd.com/read/28339813/microstructural-observation-of-fuel-cell-catalyst-inks-by-cryo-sem-and-cryo-tem
#11
Junichi Shimanuki, Shinichi Takahashi, Hajime Tohma, Atsushi Ohma, Ayumi Ishihara, Yoshiko Ito, Yuri Nishino, Atsuo Miyazawa
In order to improve the electricity generation performance of fuel cell electric vehicles, it is necessary to optimize the microstructure of the catalyst layer of a polymer electrolyte fuel cell. The catalyst layer is formed by a wet coating process using catalyst inks. Therefore, it is very important to observe the microstructure of the catalyst ink. In this study, the morphology of carbon-supported platinum (Pt/C) particles in catalyst inks with a different solvent composition was investigated by cryogenic scanning electron microscopy (cryo-SEM)...
February 9, 2017: Microscopy
https://www.readbyqxmd.com/read/28339603/optimization-of-stem-imaging-conditions-for-cryo-tomography
#12
Kazuhiro Aoyama, Kotaro Nagano, Kaoru Mitsuoka
For three-dimensional analysis of cryo-specimens using tomography at low and medium magnifications, the use of STEM images has some important advantages over TEM. A clear understanding of the electron dose in STEM is essential for optimized cryo-microscopy so a dose estimation technique for STEM imaging has been developed. The STEM convergence angle was shown to have a large impact on the image quality, in particular on the signal-to-noise ratio in the acquired images. Importantly, there is a clear trade-off between good STEM spatial resolution in the images with a large convergence angle and the signal-to-noise ratio, which is improved by reducing the convergence angle as much as possible...
February 9, 2017: Microscopy
https://www.readbyqxmd.com/read/28336870/evidence-of-protein-adsorption-in-pegylated-liposomes-influence-of-liposomal-decoration
#13
Marc Sangrà, Joan Estelrich, Raimon Sabaté, Alba Espargaró, Maria Antònia Busquets
In order to contribute to a better knowledge of the events involved in the formation of the protein corona when nanoparticles (NPs) come in contact with proteins, we report a study about the changes on the physicochemical properties of pristine, PEGylated and Cyclic Arginine-Glycine-Aspartate peptide (RGD)-functionalized large unilamelar liposomes (LUVs) or magnetoliposomes (MLs) upon incubation with Bovine Serum Albumin (BSA). The main phospholipid component of both LUVs and MLs was l-α-phosphatydylcholine (PC) or 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) with 20% of cholesterol...
February 10, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28335215/rapamycin-loaded-solid-lipid-nanoparticles-as-a-new-tool-to-deliver-mtor-inhibitors-formulation-and-in-vitro-characterization
#14
Alice Polchi, Alessandro Magini, Jarosław Mazuryk, Brunella Tancini, Jacek Gapiński, Adam Patkowski, Stefano Giovagnoli, Carla Emiliani
Recently, the use of mammalian target of rapamycin (mTOR) inhibitors, in particular rapamycin (Rp), has been suggested to improve the treatment of neurodegenerative diseases. However, as Rp is a strong immunosuppressant, specific delivery to the brain has been postulated to avoid systemic exposure. In this work, we fabricated new Rp loaded solid lipid nanoparticles (Rp-SLN) stabilized with polysorbate 80 (PS80), comparing two different methods and lipids. The formulations were characterized by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), wide angle X-ray scattering (WAXS), cryo-transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS) and particle tracking...
May 9, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28333145/the-cryo-thermal-therapy-eradicated-melanoma-in-mice-by-eliciting-cd4-t-cell-mediated-antitumor-memory-immune-response
#15
Kun He, Ping Liu, Lisa X Xu
Tumor metastasis is a major concern in tumor therapy. In our previous studies, a novel tumor therapeutic modality of the cryo-thermal therapy has been presented, highlighting its effect on the suppression of distal metastasis and leading to long-term survival in 4T1 murine mammary carcinoma model. To demonstrate the therapeutic efficacy in other aggressive tumor models and further investigate the mechanism of long-term survival induced, in this study, spontaneous metastatic murine B16F10 melanoma model was used...
March 23, 2017: Cell Death & Disease
https://www.readbyqxmd.com/read/28333030/semen-quality-before-cryopreservation-and-after-thawing-in-543-patients-with-testicular-cancer
#16
Antonio MacKenna, Javier Crosby, Cristián Huidobro, Eduardo Correa, Gonzalo Duque
OBJECTIVE: The main objective of this study was to assess semen characteristics of patients with testicular cancer before cryopreservation and after thawing, to evaluate the consequences of this technique on sperm quality in patients with testicular cancer. METHODS: Five hundred eighty-nine samples from 543 patients with testicular cancer were cryopreserved between 1995 and 2015, one aliquot per patient was used for a thawing test to assess the impact of cryopreservation on sperm motility; semen analysis was performed before cryo preservation and after thawing, the result interpretation was carried out using the 2010 World Health Organization (WHO) Laboratory Manual, and consent forms were signed by the patients for freezing and when sperm was used for reproductive purposes...
February 1, 2017: JBRA Assisted Reproduction
https://www.readbyqxmd.com/read/28332496/cell-free-reconstitution-reveals-centriole-cartwheel-assembly-mechanisms
#17
P Guichard, V Hamel, M Le Guennec, N Banterle, I Iacovache, V Nemčíková, I Flückiger, K N Goldie, H Stahlberg, D Lévy, B Zuber, P Gönczy
How cellular organelles assemble is a fundamental question in biology. The centriole organelle organizes around a nine-fold symmetrical cartwheel structure typically ∼100 nm high comprising a stack of rings that each accommodates nine homodimers of SAS-6 proteins. Whether nine-fold symmetrical ring-like assemblies of SAS-6 proteins harbour more peripheral cartwheel elements is unclear. Furthermore, the mechanisms governing ring stacking are not known. Here we develop a cell-free reconstitution system for core cartwheel assembly...
March 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28331315/improved-chemotherapeutic-efficacy-of-injectable-chrysin-encapsulated-by-copolymer-nanoparticles
#18
Kyoung Mee Kim, Hyun Kyung Lim, Sang Hee Shim, Joohee Jung
Chrysin is a flavone that is found in several plants and in honeycomb and possesses various biological activities. However, its low solubility means it has poor bioavailability, which must be resolved to enable its pharmaceutical applications. In the present study, chrysin was incorporated into methoxy poly(ethylene glycol)-β-polycaprolactone nanoparticles (chrysin-NPs) using the oil-in-water technique in order to overcome problems associated with chrysin. The properties of chrysin-NPs were analyzed, and their anticancer effects were investigated in vitro and in vivo...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28331084/structural-insights-into-emerging-pediatric-pathogens-human-bocaparvoviruses
#19
Mario Mietzsch, Shweta Kailasan, Jamie Garrison, Maria Ilyas, Paul Chipman, Kalle Kantola, Mandy E Janssen, John Spear, Duncan Sousa, Robert McKenna, Kevin Brown, Maria Söderlund-Venermo, Timothy Baker, Mavis Agbandje-McKenna
Bocaparvoviruses are emerging pathogens of the Parvoviridae family. Human bocaviruses 1 (HBoV1) causes severe respiratory infections and HBoV2-4 gastrointestinal infections in young children. Recent reports of life threatening cases, lack of direct treatment or vaccination, and a limited understanding of their disease mechanisms demand the need to study these pathogens on a molecular and structural level for the development of therapeutics. Towards this end, the capsid structures of HBoV1, HBoV3, and HBoV4 were determined to 2...
March 22, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28330771/deciphering-the-molecular-architecture-of-membrane-contact-sites-by-cryo-electron-tomography
#20
REVIEW
Javier Collado, Rubén Fernández-Busnadiego
At membrane contact sites (MCS) two cellular membranes form tight appositions that play critical roles in fundamental phenomena such as lipid metabolism or Ca(2+) homeostasis. The interest for these structures has surged in recent years, bringing about the characterization of a plethora of MCS-resident molecules. How those molecules are structurally organized at MCS remains enigmatic, limiting our understanding of MCS function. Whereas such molecular detail is obscured by conventional electron microscopy sample preparation, cryo-electron tomography (cryo-ET) is uniquely positioned to address this challenge by allowing high resolution imaging of cellular landscapes in close-to-native conditions...
March 19, 2017: Biochimica et Biophysica Acta
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