bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micronutrient intake and the probability of nutrient adequacy among children 9–24 months of age: results from the MAL-ED birth cohort study
Authors: Antiporta DA , Ambikapathi R , Bose A , Maciel B , Mahopo TC , Patil C , Turab A , Olortegui MP , Islam M , Bauck A , McCormick BJJ , Caulfield LE ,   MAL-ED Network Investigators
Published: July 2020

AbstractObjective:To estimate the total energy and micronutrient intakes of children 9–24 months of age and evaluate the probability of adequacy (PA) of the diet in seven MAL-ED sites.Design:Cohort study. Food intake was registered monthly using 24-h recalls beginning at 9 months. We estimated PA for thirteen nutrients and overall mean PA (MPA) by site and 3-month periods considering estimated breast milk intake.Setting:Seven sites in Asia, Africa and Latin America.Participants:1669 children followed from birth to 24 months of age.Results:Median estimated %energy from breast milk ranged from 4 to 70 % at 9–12 months, and declined to 0–39 % at 21–24 months. Iron bioavailability was low for all sites, but many diets were of moderate bioavailability for zinc. PA was optimal for most nutrients in Brazil and South Africa, except for iron and vitamin E (both), calcium and zinc (South Africa). PA for zinc increased only for children consuming a diet with moderate bioavailability. MPA increased 12–24 months as the quantity of complementary foods increased; however, PA for vitamin A remained low in Bangladesh and Tanzania. PA for vitamins D and E and iron was low for most sites and age groups.Conclusions:MPA increased from 12 to 24 months as children consumed higher quantities of food, while nutrient density remained constant for most nutrients. Ways to increase the consumption of foods containing vitamins D, E and A, and calcium are needed, as are ways to increase the bioavailability of iron and zinc.
Structure of Carbon Dioxide Crystals (Martian Snow) as Observed in TEM Replicas and Low Temperature SEM Images
Authors: Wergin W P , Foster J L , Chang A T C , Hall D K , Rango A , Erbe E F 
Published: July 2020

Abstract
Earth and Mars are the only planets in our solar system having polar ice caps that expand and contract in response to changes in the seasons. On Earth, the polar caps are composed of water-ice (snow crystals). Whereas, on Mars the extreme low temperatures at the polar cap regions result in the precipitation of CO2 ice (Martian snow) in addition to water-ice. Viking spacecraft have recorded various spectral data on this CO2 mantle and the transmission spectra for solid CO2 have been measured in the laboratory; however, little is known about the structural features of the crystals. Because previous studies have shown that low temperature SEM could be used to image structural variation of snow crystals34 and because data on the structure of CO2 crystals are needed to develop scattering and emission models of CO2 ice, we have attempted to image CO2 crystals.
Freeze-etch replicas were made from frozen-fractured plasma membranes of yeast cells that were used as a substrate for CO2 crystal growth.
Automated Montaging HVEM Tomography of Large Cellular Volumes
Authors: Mastronarde D N , Marsh B J , Otegui M 
Published: July 2020

Abstract
We have developed methods for generating tomographic reconstructions of large cellular volumes efficiently and at relatively high resolution. One key component of these methods is the ability to capture images from our high voltage electron microscope (HVEM) with a sensitive lenscoupled CCD camera. to overcome the limited resolution and field of view of this 1k × 1K camera, we have used the image shift capability of the HVEM to develop automatic montaging of images from an array of positions, with about 10% overlap between adjacent positions. We have also developed automatic repositioning and autofocusing after each tilt of the specimen, so that it is now possible to acquire single-frame or montaged images at a series of tilt angles, with no operator intervention. with these capabilities, up to 2 GB of image data can be acquired in a single session.
Tilt series are processed with the IMOD software package developed in our laboratory, which now runs on a PC under Linux, as well as on SGI computers. Several features are notable for working with large data sets.
Electron Crystallography of a Small Membrane-Bound Enzyme, Microsomal Glutathione Transferase
Authors: Hebert Hans , Schmidt-Krey Ingeborg , Mitsuoka Kaoru , Hirai Teruhisa , Murata Kazuyoshi , Cheng Yifan , Fujiyoshi Yoshinori , Morgenstern Ralf 
Published: July 2020

Abstract
Microsomal glutathione transferase 1, MGST1, belongs to a recently characterised superfamily named MAPEG (membrane associated proteins in eicosanoid and glutathione metabolism) which has evolved divergent functions to protect against reactive lipid intermediates (lipid hydroperoxides and hydroxyalkenals) or indeed harness these molecules for key physiological functions (leukotrienes and prostaglandins). The most thoroughly studied member of this superfamily is MGST1 which is an abundant detoxication enzyme displaying both glutathione transferase and peroxidase activities.
The MGST1 monomer has a molecular mass of 17.5 kD and three to four transmembrane regions can be localized from hydropathy plots (Fig. 1). One transmembrane stretch was shown by trypsin cleavage to be situated between lysine-4 and lysine-41 with the N-terminal on the lumenal side of the membrane. The active site is located on the cytoplasmic side of the endoplasmic reticulum.
ATP-Dependent Conformational Changes and Translocation of Substrates in Clpap Protease as Revealed by Cryo-Electron Microscopy
Authors: Ishikawa Takashi , Beuron Fabienne , Kessel Martin , Wickner Sue , Maurizi Michael R , Steven Alasdair C 
Published: July 2020

Abstract
ClpAP, an ATP-dependent protease of E. coli, recognizes and unfolds protein substrates via ClpA, its chaperonelike ATPase component, and digests them in ClpP, its protease component. ClpA forms hexameric rings with a two-layered structure, and stacks axially on either face of the double heptameric rings of ClpP. Protein substrates can bind to ClpAP in the presence of ATPγS, which is not hydrolyzed by ClpA, but are not degraded unless ATP is added. This property makes it possible to synchronize degradation in vitro by forming enzymesubstrate complexes in the presence of ATPγS and then adding ATP to trigger subsequent steps. We have used image averaging of electron micrographs of frozen hydrated and negatively stained specimens to characterize interactions of ClpA and ClpAP complexes with the model substrate, bacteriophage P1 protein, RepA.
Quaternary Polymorphism in Helicases and the DnaB.DnaC Complex
Authors: Donate LE , Bárcena M , Llorca O , Dixon N , Carazo JM 
Published: July 2020

Abstract
Strand separation in double stranded DNA is achieved in vivo by a class of enzymes called helicases in a process fuelled by hydrolysis of nucleoside triphosphates. DnaB is the major replicative helicase in E.coli. For chromosomal replication to initiate, DnaB needs to interact with a partner protein, namely DnaC, which after properly loading DnaB onto the DNA template at the origin of replication is subsequently released from the complex. DnaB turns to be functionally active as a helicase only after DnaC has been released from the complex. The native DnaB is a homohexamer of molecular weight 318 kD. In the presence of ATP and Mg2+, the hexameric DnaB has been shown to form a complex with six molecules of DnaC (total molecular weight of the complex: 480 kD).
The reconstructed 3D volume of the DnaB hexamer obtained from frozen-hydrated specimens showed the DnaB oligomer as a particle possessing three-fold rather than six-fold symmetry, despite DnaB being made up by six identical subunits.
Three Dimensional Immuno-Localization of Green Fluorescent Protein Chimeras Using Rapid Freezing and Freeze-Substitution
Authors: Morphew Mary , Mastronarde David , O'Toole Eileen , Ladinsky Mark , Marsh Brad , Kahana Jason , Richard Mcintosh J 
Published: July 2020

Abstract
All microscopy is limited by the quality of the specimen under study. Three-dimensional (3-D) visualization of antigen localization using the electron microscope (EM) is particularly challenging due to the need to maintain the activity of some epitopes while preserving cellular ultrastructure. We have used rapid freezing to immobilize all cellular constituents almost instantaneously. Freeze-substitution of the frozen samples was used to stabilize the specimen and to accomplish low-temperature dehydration, minimizing perturbation of cellular structure. We have found that high pressure freezing, double jet freezing and plunge freezing are all useful for achieving high quality structural preservation for some cell types or for particular applications. For immunolocalization, we have had most success freeze-substituting into acetone containing 0.2% glutaraldehyde and 0.1 % uranyl acetate. We have utilized low-temperature acrylic embedding resins, Lowicryl HM20 and LRGold, to further maintain structure and decrease protein insolubility. Both of these resins have proven suitable for cutting serial thin sections.
Oxidative Stress and Lipid Peroxides in the Retina of the BBZ/WOR Diabetic Rat: An Ultrastructural Cytochemical Study
Authors: Ann Ellis E , Guberski Dennis L , Grant Maria B , Armstrong Donald 
Published: July 2020

Abstract
Biochemical studies have documented a role for oxidative stress in complications of diabetes. Our previous cytochemical and immunocytochemical studies demonstrated increased levels of NADH oxidase in retinal endothelial cells and pericytes of the BBZ/Wor diabetic rat which coincided with disruption of the blood retinal barrier. Lipid peroxidation and damage to outer segments was demonstrated in retinas of a streptozotocin-induced rat model of diabetes. Xanthine oxidase has been proposed as a source of superoxide and hydrogen peroxide (H2O2) in oxidative stress mediated complications of diabetes; however, there are no studies which confirm the role and cellular sites of xanthine oxidase in complications of diabetes. In addition, cellular sites of lipid peroxides have not been documented in diabetic retinopathy.
Xanthine oxidase was localized in retinas of BBZ/Wor diabetic rat by cerium based histochemistry using hypoxanthine and NADH as substrates.
Microstructure of Plasma-Nitrided 316 Austenitic Stainless Steel
Authors: Jiang JC , Meletis EI 
Published: July 2020

Abstract
Austenitic stainless steels plasma-nitrided at low temperature can have a tremendously improved surface hardness without affecting their excellent corrosion resistance. The surface layer of these nitrided materials was considered to be composed of an uncharacterized, so called “S-phase”. During the past decade, several research groups have studied “S” phase using X-ray diffraction and transmission electron microscopy (TEM), but its microstructure is not yet well understood and is still a topic of debate. In this paper, we characterize the microstructure of 316 stainless steel nitrided by intensified plasma-assisted processing (IPAP) using cross-sectional TEM.
Samples of 316 austenitic stainless steel were nitrided for 1 hour by IPAP at a temperature of ∼ 400 °C. Plasma-nitrided samples were cross-sectioned and glued face-to-face by joining the nitrided surface. Crosssectional specimens for TEM observations were prepared by mechanical grinding, polishing and dimpling followed by Ar+ milling. TEM studies were carried out in a newly installed JEOL JEM 2010 electron microscope in the Materials Characterization Facility at the Louisiana State University.
3D-Morphometry of the Microvascular Architecture in Normal Human Tissues, Precanceroses, and Primary Tumors: Quantitative Corrosion Casting Studies
Authors: Konerding M A , Malkusch W , Fait E , Gaumann A 
Published: July 2020

Abstract
The important question as to whether the vascular architecture of an individual tumor is tumor type specific has been controversial. We have recently shown using a simple and accurate technique for 3D-measurements in microcorrosion casts that at least experimental tumors develop a characteristic vascular network. There is strong evidence that the basic vascular architecture is determined by the tumor cells themselves. However, for human primary tumors and their metastases as well as their possible precanceroses no data are available until today.
Therefore we studied the microvascular architecture of different colorectal carcinomas and adenomas as well as the vascularity of different segments of the colon and rectum. For this, parameters defining the microvascular unit were analysed on 3D reconstructed images as recently described.Comparisons of the quantified parameters within a given segment of the colon as well as group comparisons of all segments did not reveal any significant inter-individual difference.
Identification of Infectious Disease Agents: Unusual and usual Pathogens and the Diagnostic Difficulties they Present
Authors: Humphrey CD 
Published: July 2020

Abstract
“Emergence” of infectious disease agents in humans, domestic animals and wildlife during the past 20 years has been widely described. Perception of emergence derives largely from the application of improved identification methods, including refinements in molecular, serologic, and microscopy technologies that enable researchers to monitor species migration with greater sensitivity. The reality of emergence comes from shifts in genetic profiles and from influences of ecological changes often brought about by human interventions designed for economic or quality-of-life gains, and ecologic management. CDC has frequent involvement with many outbreaks caused by various infectious disease agents, some of which may be considered emerging. Notable unusual agents include filoviruses (Fig. 1) and hantaviruses (Fig. 2). More typically encountered agents include caliciviruses (Fig. 3) and influenza viruses (Fig. 4). Recently, threats of national and international bioterrorism have added to CDC's responsibilities for prompt identification of infectious agents.
Use of Cryosem and Confocal LSM to Study Pathogenesis: The Septoria Tritici Blotch Pathosystem
Authors: Duncan Keith E , Howard Richard J 
Published: July 2020

Abstract
Low temperature, low voltage field emission scanning electron microscopy (cryoSEM) allows brilliant imaging of superbly preserved biological material without suffering the specimen destruction inherent in conventional SEM techniques. Confocal laser scanning microscopy (CLSM) allows observation of fluorescence-labeling within host tissues, utilizing the optical sectioning capability of the CLSM to construct composite stereo images of specimens in three dimensions. These technologies were invaluable in elucidating the septoria tritici blotch infection process on wheat, caused by Mycosphaerella graminicola (anamorph Septoria tritici).
Seedlings inoculated with M. graminicola were incubated for the first 48 h in a dew chamber with constant misting, 20°C days and 16°C nights, then transferred to a growth chamber under the same temperature conditions at 90% RH until development of mature pycnidia, visible macroscopically at 11 days post-inoculation. Samples for cryoSEM were attached to specimen blocks with Histo Prep (Fischer Scientific, Orangeburg, NY) and frozen by plunging blocks into liquid nitrogen slush.
Identification of a Crystalline Drug Metabolite in Tissue Sections using Microscopy and Maldi-MS
Authors: Fagerland J , Miesbauer L , Burton R , Seiler F , Neilly J , Hickman D , Buko A , Leal J 
Published: July 2020

Abstract
Development of a potential drug candidate was discontinued when rats treated with the compound developed severe renal toxicity after one week of daily dosing. Tubular degeneration in the kidney was accompanied by deposition of large amounts of crystalline material, which was also present in spleen and pancreas (Fig. 1). It was presumed that the crystals were precipitated parent drug or one of its metabolites. Using microscopy and mass spectrometry, it was confirmed that the crystals were indeed derived from the drug and not endogenously formed; in addition, the precise metabolite that had precipitated in the tissues was identified, providing clues to the metabolic pathways involved.
Frozen sections of phosphate-buffered formaldehyde-fixed kidney, pancreas, and spleen were evaluated by polarized light microscopy (PLM), scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDXS), and matrix assisted laser desorption ionization-mass spectrometry (MALDI-MS). For reference, crystals of the trifluoroacetate salt of the parent drug were also analyzed using these methods.
Self-Organized Sb-Based Quantum Dots Studied by Means of AFM, TEM and PL
Authors: Möck P , Booker GR , Alphandery E , Mason NJ , Nicholas RJ 
Published: July 2020

Abstract
There is currently an increasing interest in the growth and characterisation of semiconductor quantum dots (QDs) for potential use in opto-electronic devices. Heteroepitaxy in the Stranski-Krastanow growth mode is thought to be one of the most promising routes towards the fabrication of such QDs. Little work has been done so far to extend the range of wavelength at which potential QD based opto-electronic devises might work into the middle infrared region of the electromagnetic spectrum. The aim of this paper is to expand on our previous reports on such work and to present new experimental observations concerning the formation of InSb rich QDs in GaSb and InAs matrices. Preliminary results on GaSb rich islands on GaAs are also given for comparison purposes. All samples were grown by metal-organic vapour phase epitaxy on nominal (001) GaAs and GaSb substrates at susceptor temperatures ranging from 460 to 545 °C.
X-Ray Microscopy of Polymer Blends Compatibilized with Clay Nanocomposites
Authors: Winesett DA , Ade H , Rafailovich M , Sokolov J , Zhang W 
Published: July 2020

Abstract
Multi-component polymer films are important for numerous technological applications such as paint systems, adhesives, photographic material, and index-matched optical coatings. Unfortunately, different polymer components are often incompatible so they will phase-separate and create large agglomerations of like phases, which has adverse effects on the structural integrity of thin films. Stabilizing polymer blends usually requires the addition of a third component which is often an expensive emulsifying agent such as a block copolymer. Recent studies have shown the emulsifying benefits of less expensive clay additives in oil-water mixtures [1] but the effect on stabilizing polymer blends is not entirely understood.
We are systematically examining the effects of clay additives on polymer thin film blends using Near Edge Xray Absorption Fine Structure (NEXAFS) Microscopy. We present results from films composed of a 50/50 weight percent blend of polystyrene (PS) and poly(methyl methacrylate) (PMMA) (Mw=62k, 25k, respectively) spun cast from toluene onto Si3N4 membranes.
Use of the Low Voltage Transmission Electron Microscope with Biological Specimens: A Feasibility Study
Authors: Sharp William P , Coufalova Eva , Delong Armin , Kolarik Vladimir , Roberson Robert W , Tsong IST 
Published: July 2020

Abstract
Biological transmission electron microscopy (TEM) has evolved over the past 50 to 60 years in concert with the instrumentation available. As beam acceleration energies have increased to 100-200 keV, specimen preparation protocols have been modified and tailored to fit the capabilities and constraints of new TEMs. Higher voltage allows improved resolution, (Fig. 1) but as acceleration voltage increases, contrast decreases. Vacuum levels required for conventional TEM prevent specimen contamination which protects specimen details from being obscured, but lower contrast requires heavy metal post staining which may lead to specimen contamination. Specimen thickness can increase with higher voltage (up to lOOnm at 200keV) because penetration is much increased, however, the chance of specimen - electron interaction of the type that causes heat build-up and specimen damage increases rapidly with thickness. It seems that these limitations and others must be tolerated in order to enjoy the obvious advantages of TEM.
Longer Duration of the Weak Stratospheric Vortex During Extreme El Niño Events Linked to Spring Eurasian Coldness
Authors: Zhou Xin , Chen Quanliang , Wang Zhenglin , Xu Mian , Zhao Sen , Cheng Zhigang , Feng Fan 
Published: July 2020

AbstractThe stratosphere is a key link between El Niño and Eurasian surface climate in winter. Instead of the amplitude of the stratospheric response discussed by many previous studies, we focus on the persistence of wintertime extreme El Niño impacts through the stratospheric pathway to midlatitude Eurasia in spring. A novel approach is used by running WACCM4 with El Niño forcing imposed only during winter to isolate the stratospheric role in the following spring. We show that a descending signal with a strong deceleration of zonal wind throughout the atmosphere could reach the surface and persist in spring during extreme El Niño events, whereas during moderate El Niño events the signal is generally confined to the stratosphere. Two different mechanisms are involved in maintaining the tropospheric signal of extreme El Niño. Under the westerly regime, the planetary Rossby waves from the wave centers over East Asia and the North Pacific transmit the signals from the stratosphere to the troposphere; and under the easterly regime, strong tropospheric eddy feedback over the midlatitude Atlantic favors the persistence of tropospheric responses during extreme El Niño events. The prolonged stratospheric pathway of extreme El Niño events amplifies and extends the equatorward shift of the midlatitude jet, allowing southward intrusions of cold polar air into Eurasia. Such circulation changes induced by a prolonged stratospheric pathway can cause springtime coldness and daily cold extremes in midlatitude Eurasia.
Biochemical and nutritional overview of diet-induced metabolic syndrome models in rats: what is the best choice?
Authors: Rodríguez-Correa Eduardo , González-Pérez Imelda , Clavel-Pérez Pedro Isauro , Contreras-Vargas Yolanda , Carvajal Karla 
Published: July 2020

AbstractMetabolic syndrome (MS) is a condition that includes obesity, insulin resistance, dyslipidemias among other, abnormalities that favors type 2 Diabetes Mellitus (T2DM) and cardiovascular diseases development. Three main diet-induced metabolic syndrome models in rats exist: High carbohydrate diet (HCHD), high fat diet (HFD), and high carbohydrate-high fat diet (HCHHFD). We analyzed data from at least 35 articles per diet, from different research groups, to determine their effect on the development of the MS, aimed to aid researchers in choosing the model that better suits their research question; and also the best parameter that defines obesity, as there is no consensus to determine this condition in rats. For the HCHD we found a mild effect on body weight gain and fasting blood glucose levels (FBG), but significant increases in triglycerides, fasting insulin, insulin resistance and visceral fat accumulation. HFD had the greater increase in the parameters previously mentioned, followed by HCHHFD, which had a modest effect on FBG levels. Therefore, to study early stages of MS a HCHD is recommended, while HFD and HCHHFD better reproduce more severe stages of MS. We recommend the assessment of visceral fat accumulation as a good estimate for obesity in the rat.