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Bin Hua, John Yang, Fengjing Liu, Guocheng Zhu, Baolin Deng, Jingdong Mao
Characterization of dissolved organic matter/nitrogen (DOM/DON) is critical in water quality assessment and nutrient management in watershed or ecosystem. This study was to investigate the link between DOM/DON and its source using fluorescence excitation-emission matrix (EEM) spectroscopy coupled with parallel factor analysis (PARAFAC). Water samples were collected from various aquatic systems in a watershed located in central Missouri, including rural watershed with various land use and land cover (LULC), landfill, and constructed wetland...
March 6, 2018: Chemosphere
Shelley HuaLei Zhang, Stephan E Maier, Lawrence P Panych
PURPOSE: Magnetic resonance spectroscopic imaging (MRSI), under low-spatial resolution settings, often suffers signal contamination from neighboring voxels due to ringing artifacts. Spatial localization can be improved by constraining the point-spread-function (PSF). Here the effectiveness of the two-dimensional PSF-Choice technique in providing improved spatial localization for MRSI is demonstrated. THEORY AND METHODS: The PSF-Choice technique constrains the PSF to a desired shape by manipulating the weighting of RF excitation pulse throughout phase-encode steps...
March 3, 2018: Journal of Magnetic Resonance
Isabel Aparici-Espert, Miguel A Miranda, Virginie Lhiaubet-Vallet
Photosensitization by drugs is a problem of increasing importance in modern life. This phenomenon occurs when a chemical substance in the skin is exposed to sunlight. Photosensitizing drugs are reported to cause severe skin dermatitis, and indeed, it is generally advised to avoid sunbathing and to apply sunscreen. In this context, the nonsteroidal anti-inflammatory drug (NSAID) diclofenac is a photosensitive drug, especially when administered in topical form. In this work, efforts have been made to design and study an innovative pro-drug/pro-filter system containing diclofenac and the UVA filter avobenzone in order to develop a safer use of this topical drug...
March 16, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Peter Stacey, Anne Mai Wassermann, Laura Kammonen, Emma Impey, Anna Wilbrey, Darren Cawkill
Screening against a disease-relevant phenotype to identify compounds that change the outcome of biological pathways, rather than just the activity of specific targets, offers an alternative approach to find modulators of disease characteristics. However, in pain research, use of in vitro phenotypic screens has been impeded by the challenge of sourcing relevant neuronal cell types in sufficient quantity and developing functional end-point measurements with a direct disease link. To overcome these hurdles, we have generated human induced pluripotent stem cell (hiPSC)-derived sensory neurons at a robust production scale using the concept of cryopreserved "near-assay-ready" cells to decouple complex cell production from assay development and screening...
March 1, 2018: SLAS Discovery
Hirofumi Akamatsu, Yakun Yuan, Vladimir A Stoica, Greg Stone, Tiannan Yang, Zijian Hong, Shiming Lei, Yi Zhu, Ryan C Haislmaier, John W Freeland, Long-Qing Chen, Haidan Wen, Venkatraman Gopalan
Using time- and spatially resolved hard x-ray diffraction microscopy, the striking structural and electrical dynamics upon optical excitation of a single crystal of BaTiO_{3} are simultaneously captured on subnanoseconds and nanoscale within individual ferroelectric domains and across walls. A large emergent photoinduced electric field of up to 20×10^{6}  V/m is discovered in a surface layer of the crystal, which then drives polarization and lattice dynamics that are dramatically distinct in a surface layer versus bulk regions...
March 2, 2018: Physical Review Letters
T R Hartke, Y-Y Liu, M J Gullans, J R Petta
Quantum confinement leads to the formation of discrete electronic states in quantum dots. Here we probe electron-phonon interactions in a suspended InAs nanowire double quantum dot (DQD) that is electric-dipole coupled to a microwave cavity. We apply a finite bias across the wire to drive a steady state population in the DQD excited state, enabling a direct measurement of the electron-phonon coupling strength at the DQD transition energy. The amplitude and phase response of the cavity field exhibit oscillations that are periodic in the DQD energy level detuning due to the phonon modes of the nanowire...
March 2, 2018: Physical Review Letters
C E Whittaker, E Cancellieri, P M Walker, D R Gulevich, H Schomerus, D Vaitiekus, B Royall, D M Whittaker, E Clarke, I V Iorsh, I A Shelykh, M S Skolnick, D N Krizhanovskii
We study exciton polaritons in a two-dimensional Lieb lattice of micropillars. The energy spectrum of the system features two flat bands formed from S and P_{x,y} photonic orbitals, into which we trigger bosonic condensation under high power excitation. The symmetry of the orbital wave functions combined with photonic spin-orbit coupling gives rise to emission patterns with pseudospin texture in the flat band condensates. Our Letter shows the potential of polariton lattices for emulating flat band Hamiltonians with spin-orbit coupling, orbital degrees of freedom, and interactions...
March 2, 2018: Physical Review Letters
Harry J Shirley, Megan L Jamieson, Margaret A Brimble, Christopher D Bray
Covering: 2009 up to the end of 2017There has been a recent eruption in the number of known marine sesterterpenoids which have been isolated from Pacific Rim marine organisms. These compounds have novel and unusual structures that exhibit incredibly potent and varied bioactivities. This review details the isolation, biological testing and prospects for this exciting new family with discussion of their potential biogenetic origins.
March 16, 2018: Natural Product Reports
A-Ra Hong, Youngsun Kim, Tae Sup Lee, Sehoon Kim, Kwangyeol Lee, Gayoung Kim, Ho Seong Jang
In this study, intense single-band red-emitting upconversion nanophosphors (UCNPs) excited with 800 nm near infrared (NIR) light are reported. When a NaYF4 :Nd,Yb active-shell is formed on the 12.7 nm-sized NaGdF4 :Yb,Ho,Ce UCNP core, the core/shell (C/S) UCNPs show tunable emission from green to red depending on the Ce3+ concentration under excitation with 800 nm NIR light. Thirty mol% Ce3+ -doped C/S UCNPs exhibit single-band red emission peaking at 644 nm via a5 F5 →5 I8 transition of Ho3+ . A high Nd3+ concentration in the shell results in strong absorption at around 800 nm NIR light even though the shell thickness is not large, and small-sized C/S UCNPs (16...
March 16, 2018: ACS Applied Materials & Interfaces
Alexander Sumich, Anthony Harris, Thomas Whitford, Daniel Hermens, Nadja Heym, John Anderson, Claire Bloxsom, Fraenze Kibowski, Veena Kumari
OBJECTIVE: Right frontal function, as indicated by the N200 component of the event-related potential during target detection, has previously been associated with excitement (excitement, impulsivity, hostility, uncooperativeness) in men with a long-term diagnosis of schizophrenia. The current study investigated excitement in relation to N200 in men who had recently experienced their first episode of psychosis. SUBJECTS AND METHODS: Twenty men who had recently suffered their first psychotic episode underwent a clinical interview and auditory oddball task...
March 2018: Psychiatria Danubina
Sophie Meuret, Toon Coenen, Steffi Woo, Yong-Ho Ra, Zetian Mi, Albert Polman
Cathodoluminescence (CL) imaging spectroscopy provides two-dimensional optical excitation images of photonic nanostructures with deep-subwavelength spatial resolution. So far, CL imaging was unable to provide a direct measurement of the excitation and emission probabilities of photonic nanostructures in a spatially resolved manner. Here, we demonstrate that by mapping the cathodoluminescence autocorrelation function g(2) together with the CL spectral distribution the excitation and emission rates can be disentangled at every excitation position...
March 16, 2018: Nano Letters
Toru Imai, Junhui Shi, Terence T W Wong, Lei Li, Liren Zhu, Lihong V Wang
Ultraviolet photoacoustic microscopy (UV-PAM) is a promising intraoperative tool for surgical margin assessment (SMA), one that can provide label-free histology-like images with high resolution. In this study, using a microlens array and a one-dimensional (1-D) array ultrasonic transducer, we developed a high-throughput multifocal UV-PAM (MF-UV-PAM). Our new system achieved a 1.6  ±  0.2  μm lateral resolution and produced images 40 times faster than the previously developed point-by-point scanning UV-PAM...
March 2018: Journal of Biomedical Optics
Ari Rosenberg, Mark Agulnik
Epithelioid hemangioendothelioma (EHE) is an extremely rare sarcoma, as such it can pose a clinical dilemma based solely on its rarity. Also, the spectrum of disease varies greatly between an indolent disease and aggressive disease with widespread metastases. In our clinical practice, the primary focus has been to get a handle on the aggressive nature of the disease, which will then dictate how urgently one needs to treat the patient. Pathological review with immunohistochemistry and molecular characterization is paramount...
March 15, 2018: Current Treatment Options in Oncology
Wail Alkashkari, Amani Alsubei, Ziyad M Hijazi
PURPOSE OF REVIEW: The past couple of decades have brought tremendous advances to the field of pediatric and adult congenital heart disease (CHD). Percutaneous valve interventions are now a cornerstone of not just the congenital cardiologist treating patients with congenital heart disease, but also-and numerically more importantly-for adult interventional cardiologists treating patients with acquired heart valve disease. Transcatheter pulmonary valve replacement (tPVR) is one of the most exciting recent developments in the treatment of CHD and has evolved to become an attractive alternative to surgery in patients with right ventricular outflow tract (RVOT) dysfunction...
March 15, 2018: Current Cardiology Reports
Angelica Nakagawa Lima, Ronaldo Junio de Oliveira, Antônio Sérgio Kimus Braz, Maurício Garcia de Souza Costa, David Perahia, Luis Paulo Barbour Scott
There are two different prion conformations: (1) the cellular natural (PrPC ) and (2) the scrapie (PrPSc ), an infectious form that tends to aggregate under specific conditions. PrPC and PrPSc are widely different regarding secondary and tertiary structures. PrPSc contains more and longer β-strands compared to PrPC . The lack of solved PrPSc structures precludes a proper understanding of the mechanisms related to the transition between cellular and scrapie forms, as well as the aggregation process. In order to investigate the conformational transition between PrPC and PrPSc , we applied MDeNM (molecular dynamics with excited normal modes), an enhanced sampling simulation technique that has been recently developed to probe large structural changes...
March 15, 2018: European Biophysics Journal: EBJ
Dorothy W Gietzen, Sarah H Lindström, James W Sharp, Pok Swee Teh, Michael J Donovan
Background: Low protein amounts are used in ketogenic diets (KDs), where an essential (indispensable) amino acid (IAA) can become limiting. Because the chemically sensitive, seizurogenic, anterior piriform cortex (APC) is excited by IAA limitation, an imbalanced KD could exacerbate seizure activity. Objective: We questioned whether dietary IAA depletion worsens seizure activity in rodents fed KDs. Methods: In a series of 6 trials, male rats or gerbils of both sexes (6-8/group) were given either control diets (CDs) appropriate for each trial, a KD, or a threonine-devoid (ThrDev) diet for ≥7 d, and tested for seizures using various stimuli...
March 1, 2018: Journal of Nutrition
Davide Bartesaghi, Adam H Slavney, María C Gélvez-Rueda, Bridget A Connor, Ferdinand C Grozema, Hemamala I Karunadasa, Tom J Savenije
Double perovskites, comprising two different cations, are potential nontoxic alternatives to lead halide perovskites. Here, we characterized thin films and crystals of Cs2 AgBiBr6 by time-resolved microwave conductance (TRMC), which probes formation and decay of mobile charges upon pulsed irradiation. Optical excitation of films results in the formation of charges with a yield times mobility product, φΣμ > 1 cm2 /Vs. On excitation of millimeter-sized crystals, the TRMC signals show, apart from a fast decay, a long-lived tail...
March 8, 2018: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Misato Yoshikawa, Yoshiyuki Soeda, Makoto Michikawa, Osborne F X Almeida, Akihiko Takashima
Hippocampal hyperactivity, ascribed to amyloid β (Aβ)-induced imbalances in neural excitation and inhibition, is found in patients with mild cognitive impairment, a prodromal stage of Alzheimer's disease (AD). To better understand the relationship between hippocampal hyperactivity and the molecular triggers of behavioral impairments in AD, we used Mn-enhanced MRI (MEMRI) to assess neuronal activity after subjecting mice to a task requiring spatial learning and memory. Depletion of endogenous tau in an amyloid precursor protein (APP) transgenic (J20) mouse line was shown to ameliorate hippocampal hyperactivity in J20 animals, tau depletion failed to reverse memory deficits associated with APP/Aβ overproduction...
2018: Frontiers in Neuroscience
Amy M Bittel, Ashley M Davis, Lei Wang, Michel A Nederlof, Jorge O Escobedo, Robert M Strongin, Summer L Gibbs
Multicolor microscopy tools necessary to localize and visualize the complexity of subcellular systems are limited by current fluorophore technology. While commercial fluorophores cover spectral space from the ultraviolet to the near infrared region and are optimized for conventional bandpass based fluorescence microscopy, they are not ideal for highly multiplexed fluorescence microscopy as they tend to have short Stokes shifts, restricting the number of fluorophores that can be detected in a single sample to four to five...
March 15, 2018: Scientific Reports
Ramūnas Aleksiejūnas, Žydrūnas Podlipskas, Saulius Nargelas, Arūnas Kadys, Marek Kolenda, Kazimieras Nomeika, Jūras Mickevičius, Gintautas Tamulaitis
Indium nitride has a good potential for infrared optoelectronics, yet it suffers from fast nonradiative recombination, the true origin of which has not been established with certainty. The diffusion length of free carriers at high densities is not well investigated either. Here, we study carrier recombination and diffusion using the light-induced transient grating technique in InN epilayers grown by pulsed MOCVD on c-plane sapphire. We show that direct Auger recombination governs the lifetime of carriers at densities above ~1018  cm-3 ...
March 15, 2018: Scientific Reports
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