bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation Mechanism of Atmospheric Ammonium Bisulfate: Hydrogen‐Bond‐Promoted Nearly Barrierless Reactions of SO3 with NH3 and H2O
Authors: Chen Shunwei , Zhao Yanling , Zhang Ruiqin
Published: February 2018

Particulate matter (PM) air pollution threatens the health of people and ecosystems worldwide. As the key component of PM, ammonium sulfate plays a critical role in the formation of aerosol particles; thus, there is an urgent need to know the detailed mechanisms for its formation in the atmosphere. Through a quantum chemistry study, we reveal a series of nearly barrierless reactions that may occur in clusters/droplets in the atmosphere leading to the formation of ammonium bisulfate (NH4HSO4), the precursor of ammonium sulfate. In this mechanism, NH4HSO4 is directly formed through one‐step reactions of SO3 with H2O and NH3 promoted by surrounding molecule(s) that substantially lower the reaction activation barrier to ≈0 kcal mol−1. The promoters of these reactions are found to be various common atmospheric molecules, such as water, ammonia, and sulfuric acid, which can form relatively strong hydrogen bonds with the reaction center. Our results suggest many more similar pathways that can be facilitated by other ambient molecules. Due to its one‐step and barrierless reaction characteristics and the great abundance of potential reactions, this mechanism has great implications on the formation of atmospheric ammonium sulfate as well as on the growth of aerosol particles.
Evaluation of the benefit and use of the new terminology in endometrial cytology reporting system
Authors: Shinagawa Akiko , Kurokawa Tetsuji , Yamamoto Makoto , Onuma Toshimichi , Tsuyoshi Hideaki , Chino Yoko , Iwasaki Kazumi , Mori Masaki , Imamura Yoshiaki , Yoshio Yoshida
Published: February 2018

Objective

The introduction and establishment of a new classification system for endometrial cytology, the “New Terminology in Endometrial Cytology (NTEMC) system,” which is based on the Bethesda System for uterine cervical cytology, has recently been reported. However, the clinical management for new categories in the NTEMC system, particularly atypical endometrial cells (ATEC), has not been clarified. The objective of the present study is to determine how the ATEC category should be treated and whether the introduction of the system has decreased the number of unnecessary endometrial biopsies.

Methods

Fifty‐nine cases were diagnosed as “suspicious positive” according to the three‐tier reporting (TTR) system, which was adopted in Japan. The specimens were re‐evaluated according to the NTEMC system. Thirty‐seven of the 59 patients underwent endometrial biopsy. We correlated the pathological diagnosis with the NTEMC system category.

Results

The 59 cases were classified according to the NTEMC system as follows: 36 cases were classified as ATEC of undetermined significance (ATEC‐US), 21 cases were classified as ATEC for which atypical endometrial hyperplasia or worse cannot be excluded (ATEC‐A), and 2 cases were classified as endometrial hyperplasia. The ratio of atypical endometrial hyperplasia or malignancy in ATEC‐US category was significantly lower than that in ATEC‐A category. Fifteen cases in ATEC‐US category did not show atypical endometrial hyperplasia lesions or malignancy after 3 months.

Conclusions

These data suggest that patients with ATEC‐US results can be followed up for at least three months, and the introduction of the NTEMC system decreased the number of unnecessary endometrial biopsies.
Differential expression of various clones of estrogen receptor in cell block preparation of lung adenocarcinoma
Authors: Hakima Laleh , Schlesinger Kathie , Sunkara Jaya , Karabakhtsian Rouzan G.
Published: February 2018

Background

Women treated for breast cancer are at increased risk of developing pulmonary nodules which could represent new primary lung carcinomas or metastatic breast carcinoma. The FNA biopsy is frequently the first diagnostic choice in determining the primary site of the tumor. Estrogen receptor (ER) positivity in diagnostic tissue is generally used to favor breast over lung primary. However, the recent studies have shown a wide range of ER antibody cross reactivity with lung adenocarcinoma. We studied the frequency of ER expression in cytology samples of lung adenocarcinoma using antibodies to three different ER clones.

Methods

Cytology cell block preparations, including 22 lung FNAs and 19 malignant pleural effusions (PE) from 41 patients, with clinically documented primary lung adenocarcinomas were selected for this study. All cases were stained with monoclonal antibodies to ER clones 6F11 and 1D5. Twenty nine cases with remaining available material (15 FNA and 14 PE) were stained with a third antibody to ER clone SP1. The extent of ER nuclear staining was scored as 3+ (50%–100% of tumor cells), 2+ (11%–49%), and 1+ (≤10%).

Results

Positivity for ER‐6F11 clone was present in 4 of 22 lung FNAs (18.2%, 2+ staining). Two of the four 6F11 positive FNAs also co‐expressed ER‐1D5 (9.1%, 2+ staining). No immunoreactivity was observed for ER clones 6F11 and 1D5 in all 19 malignant PEs. In addition, none of the remaining 15 FNAs and 14 PEs showed immunoreactivity for ER‐SP1 clone.

Conclusions

A small subset of pulmonary adenocarcinomas shows immunoreactivity for ER clones 6F11 and 1D5 in FNA samples (18.2% and 9.1%, respectively). The absence of immunoreactivity for ER‐SP1 clone indicates higher specificity of this clone in non‐breast tissue. The differential diagnostic value of all ER clones in malignant PEs appears to be secure. Larger studies are necessary to validate this observation.
Lessons learned from the 1‐hour post‐load glucose level during OGTT: Current screening recommendations for dysglycaemia should be revised
Authors: Bergman Michael , Jagannathan Ram , Buysschaert Martin , Pareek Manan , Olsen Michael H. , Nilsson Peter M. , Medina José Luis , Roth Jesse , Chetrit Angela , Groop Leif , Dankner Rachel
Published: February 2018

This perspective covers a novel area of research describing the inadequacies of current approaches for diagnosing dysglycaemia and proposes that the 1‐hour post‐load glucose level during the 75‐g oral glucose tolerance test may serve as a novel biomarker to detect dysglycaemia earlier than currently recommended screening criteria for glucose disorders. Considerable evidence suggests that a 1‐hour post‐load plasma glucose value ≥155 mg/dl (8.6 mmol/L) may identify individuals with reduced β‐cell function prior to progressing to prediabetes and diabetes and is highly predictive of those likely to progress to diabetes more than the HbA1c or 2‐hour post‐load glucose values. An elevated 1‐hour post‐load glucose level was a better predictor of type 2 diabetes than isolated 2‐hour post‐load levels in Indian, Japanese, and Israeli and Nordic populations. Furthermore, epidemiological studies have shown that a 1‐hour PG ≥155 mg/dl (8.6 mmol/L) predicted progression to diabetes as well as increased risk for microvascular disease and mortality when the 2‐hour level was <140 mg/dl (7.8 mmol/L). The risk of myocardial infarction or fatal ischemic heart disease was also greater among subjects with elevated 1‐hour glucose levels as were risks of retinopathy and peripheral vascular complications in a Swedish cohort. The authors believe that the considerable evidence base supports redefining current screening and diagnostic recommendations with the 1‐hour post‐load level. Measurement of the 1‐hour PG level would increase the likelihood of identifying a larger, high‐risk group with the additional practical advantage of potentially replacing the conventional 2‐hour oral glucose tolerance test making it more acceptable in a clinical setting.
Males prefer virgin females, even if parasitized, in the terrestrial isopod Armadillidium vulgare
Authors: Fortin Margot , Debenest Catherine , Souty‐Grosset Catherine , Richard Freddie‐Jeanne
Published: February 2018

In many species, males increase their reproductive success by choosing high‐quality females. In natural populations, they interact with both virgin and mated females, which can store sperm in their spermatheca. Therefore, males elaborate strategies to avoid sperm competition. In the terrestrial isopod Armadillidium vulgare, females can store sperm and produce several clutches. Moreover, this species can be parasitized by Wolbachia, which feminizes genetic males, transforming them into functional females. Our study compared attractiveness and mate choice when a male is exposed to both virgin and experienced females (i.e., females who have produced offspring and rested for 6 months), with or without Wolbachia. Our results revealed that males are more attracted to virgin females than experienced females, even if these virgin females are parasitized. Moreover, the chemical analysis highlighted different odors in females according to their reproductive and infection (Wolbachia‐free or vertically Wolbachia‐infected) status. Males attempted copulation more frequently and for longer with virgin females, even if Wolbachia‐infected, while experienced females refused further copulation. The evolutionary consequences of both male choice and female resistance on their fitness are discussed in this study.
Hydrological gradients and functional diversity of plants drive ecosystem processes inPoyang Lakewetland
Authors: Fu Hui , Lou Qian , Dai Taotao , Yuan Guixiang , Huang Zhenrong , Ge Dabing , Zou Dongsheng , Li Wei , Liu Qiaolin , Wu Aiping , Guo Chunjing , Zhong Jiayou , Fang Shaowen , Hu Jianmin
Published: February 2018

Functional trait approaches have greatly improved the mechanistic understanding of the impacts of biodiversity in ecosystem. We evaluated how hydrological gradients (i.e., soil water content and elevation) affected the taxonomic diversity, functional identity, and functional diversity and assessed how changes in these measures of diversity ultimately drove variations in above‐ground biomass (AGB). Results showed that a combination of hydrological gradients and functional trait composition (i.e., the community weighted means, the single‐trait functional diversity and the multiple‐trait functional diversity) better explained variations (40.8%) of AGB. No significant relationships between taxonomic diversity and AGB were observed. The dominant species became taller with thicker stem, and co‐occurring species showed greater divergent distribution of stem diameter towards higher soil water content. As elevation increased, the dominant plant had thinner leaves with later onset of flowering and longer flowering duration, and co‐occurring species showed less divergent distribution of lamina thickness and leaf dry‐mass content. Our results highlighted that the positive biodiversity–ecosystem functioning relations were largely attributed to the co‐operations of selection and complementary effects, as evidences showed that the dominant trait values (i.e., community weighted mean of shoot height) and trait diversity (i.e., functional evenness) improved biomass production of wetland plants.
It takes a few to tango: changing climate and fire regimes can cause regeneration failure of two subalpine conifers
Authors: Hansen Winslow D. , Braziunas Kristin H. , Rammer Werner , Seidl Rupert , Turner Monica G.
Published: February 2018

Environmental change is accelerating in the 21st century, but how multiple drivers may interact to alter forest resilience remains uncertain. In forests affected by large high‐severity disturbances, tree regeneration is a resilience linchpin that shapes successional trajectories for decades. We modeled stands of two widespread western U.S. conifers, Douglas‐fir (Pseudotsuga menziesii var. glauca), and lodgepole pine (Pinus contorta var. latifolia), in Yellowstone National Park (Wyoming, USA) to ask (1) What combinations of distance to seed source, fire return interval, and warming‐drying conditions cause postfire tree‐regeneration failure? (2) If postfire tree regeneration was successful, how does early tree density differ under future climate relative to historical climate? We conducted a stand‐level (1 ha) factorial simulation experiment using the individual‐based forest process model iLand to identify combinations of fire return interval (11–100 yr), distance to seed source (50–1,000 m), and climate (historical, mid‐21st century, late‐21st century) where trees failed to regenerate by 30‐yr postfire. If regeneration was successful, we compared stand densities between climate periods. Simulated postfire regeneration were surprisingly resilient to changing climate and fire drivers. Douglas‐fir regeneration failed more frequently (55%) than lodgepole pine (28% and 16% for non‐serotinous and serotinous stands, respectively). Distance to seed source was an important driver of regeneration failure for Douglas‐fir and non‐serotinous lodgepole pine; regeneration never failed when stands were 50 m from a seed source and nearly always failed when stands were 1 km away. Regeneration of serotinous lodgepole pine only failed when fire return intervals were ≤20 yr and stands were far (1 km) from a seed source. Warming climate increased regeneration success for Douglas‐fir but did not affect lodgepole pine. If regeneration was successful, postfire density varied with climate. Douglas‐fir and serotinous lodgepole pine regeneration density both increased under 21st‐century climate but in response to different climate variables (growing season length vs. cold limitation). Results suggest that, given a warmer future with larger and more frequent fires, a greater number of stands that fail to regenerate after fires combined with increasing density in stands where regeneration is successful could produce a more coarse‐grained forest landscape.
Exploring Synthetic Routes to Heteroleptic UIII, UIV, and ThIV Bulky Bis(silyl)amide Complexes
Authors: Goodwin Conrad A. P. , Tuna Floriana , McInnes Eric J. L. , Mills David P.
Published: February 2018

The bis(silyl)amide {N(SiMe3)2} (N′′) has supported spectacular actinide (An) chemistry for over 40 years, yet surprisingly there are only a handful of An complexes containing larger bis(silyl)amides, for example [U(N**)3] [N** = {N(SiMe2tBu)2}, 1]. Herein we report the structural characterization of the UIII complexes [U(N**)2(µ‐I)]2 (2), [U(N†′)2(µ‐I)]2 [N†′ = {N(SiiPr3)(SiMe3)}, 3], [U(N††)(I)2(THF)2] [N†† = {N(SiiPr3)2}, 4], [U(N††)2(I)] (5), and [U(N†′)2(I)(THF)] (6), and the AnIV complexes [An(N**){N(SiMe2tBu)(SiMetBuCH2‐κ2‐N,C)}(µ‐Cl)]2 (7‐An, An = U, Th) and [Th(N**)2{N(SiMe2tBu)(SiMetBuCH2‐κ2‐N,C)}] (8). Low crystalline yields were obtained in all cases, presumably due to facile cyclometallation. Although this precluded full characterization of UIII 4 and 6, and AnIV 7 and 8, for UIII complexes 2, 3, and 5 yields were high enough to perform NMR, EPR, NIR/UV/Vis, and FTIR spectroscopy, elemental analysis, and magnetic measurements.
Establishing a sensitive capillary electrophoresis‐UV method for direct determination of amino acids to evaluate vinegar quality
Authors: Luo Tian , Dong Yue , He Shujuan , Yang Jing , Dong Yuming
Published: February 2018

In this study, the capillary electrophoresis method with ultraviolet detection was established to directly determine amino acids in vinegar, according to the coordination interaction between amino acids (AAs) and copper ions. The online sweeping technique was combined to improve the detection sensitivity. The quality of vinegar was evaluated with AAs as parameters by United Nations Food Agriculture Organization/Word Health Organization AAs model and principal component analysis. Optimum conditions were obtained under 50 mM CuSO4 and adjusted pH 4.40 with 8 mM acetate, 70 s injection time, 22.5 kV separation voltage, and 254 nm detected wavelength. Method validation, indicating good linearity (R2 > 0.9989), precision with an RSD less than 8.0% (n = 5), LOD (0.13–0.25 μg/mL), LOQ (0.43–0.83 μg/mL) and recovery (80.5–112.6%). Under the optimal conditions, AAs in vinegar can be directly separated which is propitious for the quality evaluation of vinegar.
Experimental Study of MgCl2 ⋅ 6 H2O as Thermochemical Energy Storage Material
Authors: Kohler Tobias , Biedermann Thomas , Müller Karsten
Published: February 2018

Hydrates of magnesium chloride are interesting as a thermochemical energy storage material. An open storage system was set‐up, which enables the reaction of water vapor with the salt hydrate at a given relative humidity. It is demonstrated that hydrates of magnesium chloride are only suited if the relative humidity is below 30 %. Otherwise the hygroscopic salt will cause the formation of an aqueous, liquid phase. This liquid inhibits mass transport and leads to the agglomeration of particles. As a consequence of the low partial pressure of the water, the reaction is very slow. Therefore, rather low effective energy densities of around 300 kJ kg−1 were measured. A way to enable higher humidities is to use a solid support like zeolite 13X. However, the adsorption of water vapor on the zeolite, without magnesium chloride, reached higher energy densities even at low relative humidity. Thus, it must be concluded that hydration of magnesium chloride for thermochemical energy storage cannot be recommended for most technical applications.
Experimental design and 4E (energy, exergy, emission, and economical) analysis of a fixed bed advanced microgasifier stove
Authors: Sakthivadivel D. , Iniyan S.
Published: February 2018

In this article, an attempt has been made to design a new updraft fixed bed advanced microgasifier cookstove (ACS). The newly developed ACS stove has been tested with a Tamarind seed pellet as fuel. Results have been analyzed in terms of energy and exergy efficiency, emissions and economics (4E). The testing practice adopted for evaluation of the performance of the ACS stove is as per the standard protocol WBT 4.2.3. The energy efficiency of an advanced cookstove was found to be 35% and the exergy efficiency of 17.3%. Experiments have also been performed to provide data for investigation of the emission characteristics of the new stove. Eventually, the simple payback period has been determined as 2 months for four members of a family. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018
Seismic performance of buildings retrofitted with nonlinear viscous dampers and adjacent reaction towers
Authors: Impollonia Nicola , Palmeri Alessandro
Published: February 2018

An effective strategy of seismic retrofitting consists of installing nonlinear viscous dampers between the existing building, with insufficient lateral resistance, and some auxiliary towers, specially designed and erected as reaction structures. This allows improving the seismic performance of the existing building without any major alteration to its structural and nonstructural elements, which makes this approach particularly appealing for buildings with heritage value. In this paper, the nonlinear governing equations of the coupled lateral‐torsional seismic motion are derived from first principles for the general case of a multistory building connected at various locations in plan and in elevation to an arbitrary number of multistory towers. This formulation is then used to assess the performance of the proposed retrofitting strategy for a real case study, namely, a 5‐story student hall of residence in the city of Messina, Italy. The results of extensive time‐history analyses highlight the key design considerations associated with the stiffness of the reaction towers and the mechanical parameters of the nonlinear viscous dampers, confirming the validity of this approach.
A well‐preserved Eemian incised‐valley fill in the southern North Sea Basin, Belgian Continental Shelf ‐ Coastal Plain: Implications for northwest European landscape evolution
Authors: De Clercq M. , Missiaen T. , Wallinga J. , Zurita Hurtado O. , Versendaal A. , Mathys M. , De Batist M.
Published: February 2018

This paper demonstrates that the Belgian Continental Shelf and coastal plain occupy a key position between the depositional North Sea Basin and the erosional area of the Dover Strait as it is an area where erosional landforms and fragmented sedimentary sequences provide new evidence on northwest European landscape evolution. The study area hosts 20–30 m thick penultimate to last glacial sand‐dominated sequences that are preserved within the buried palaeo‐Scheldt Valley. Here, we build on the results of previous seismo‐ and lithostratigraphical studies, and present new evidence from biostratigraphical analysis, OSL dating and depth‐converted structure maps, together revealing a complex history of deposition and landscape evolution controlled by climate change, sea‐level fluctuations and glacio‐isostasy. This study presents strong new supportive evidence on the development of the incised palaeo‐Scheldt Valley landform that became established towards the end of the penultimate glacial period (MIS 6; Saalian) as a result of glacio‐isostatic forebulge updoming, proglacial lake drainage and subsequent collapse of a forebulge between East Anglia and Belgium following ice‐sheet growth, disintegration and retreat in areas to the north. The majority of the incised‐valley fill is of estuarine to shallow marine depositional context deposited during the transgression and high‐stand of the last interglacial (MIS 5e: Eemian). A thin upper part of the valley fill consists of last glacial (MIS 5d‐2: Weichselian) fluvial sediments that show a gradual decrease and retreat of fluvial activity to inland, upstream reaches of the valley system until finally the valley ceases to exist as the combined result of climate‐driven aeolian activity and possibly also glacio‐isostatic adjustment. Thus, strong contrasts exist between the palaeo‐Scheldt Valley and estuary systems of the penultimate glacial maximum to Last Interglacial (Saalian, Eemian), the beginning of the Last Glacial (Weichselian Early Glacial and Early‐Middle Pleniglacial), and the Last Glacial Maximum to Holocene. Copyright © 2018 John Wiley & Sons, Ltd.
Performance analysis of SFBC‐OFDM system with channel estimation error over generalized fading channels
Authors: Singh Daljeet , Joshi Hem Dutt
Published: February 2018

In this paper, the performance of space‐frequency block code orthogonal frequency‐division multiplexing (SFBC‐OFDM) system is analyzed over different fading channels using a generalized approach. General closed‐form expressions of average bit error rate (ABER) are derived for SFBC‐OFDM system. Both M‐ary phase‐shift keying and M‐ary quadrature amplitude modulation techniques have been considered in this analysis. The effect of imperfect channel estimation on ABER is included while deriving the ABER expression. The derived expressions are applicable under any given fading conditions provided that the moment‐generating function of fading channel is known. Simulation results are provided to verify the numerical results obtained from the derived expressions.
An SPH multi‐fluid model based on quasi buoyancy for interface stabilization up to high density ratios and realistic wave speed ratios
Authors: Kruisbrink A.C.H. , Pearce F.R. , Yue T. , Morvan H.P.
Published: February 2018

We introduce a smoothed particle hydrodynamics (SPH) concept for the stabilization of the interface between 2 fluids. It is demonstrated that the change in the pressure gradient across the interface leads to a force imbalance. This force imbalance is attributed to the particle approximation implicit to SPH. To stabilize the interface, a pressure gradient correction is proposed. In this approach, the multi‐fluid pressure gradients are related to the (gravitational and fluid) accelerations. This leads to a quasi‐buoyancy correction for hydrostatic (stratified) flows, which is extended to nonhydrostatic flows. The result is a simple density correction that involves no parameters or coefficients. This correction is included as an extra term in the SPH momentum equation. The new concept for the stabilization of the interface is explored in 5 case studies and compared with other multi‐fluid models. The first case is the stagnant flow in a tank: The interface remains stable up to density ratios of 1:1000 (typical for water and air), in combination with artificial wave speed ratios up to 1:4. The second and third cases are the Rayleigh‐Taylor instability and the rising bubble, where a reasonable agreement between SPH and level‐set models is achieved. The fourth case is an air flow across a water surface up to density ratios of 1:100, artificial wave speed ratios of 1:4, and high air velocities. The fifth case is about the propagation of internal gravity waves up to density ratios of 1:100 and artificial wave speed ratios of 1:4. It is demonstrated that the quasi‐buoyancy model may be used to stabilize the interface between 2 fluids up to high density ratios, with real (low) viscosities and more realistic wave speed ratios than achieved by other weakly compressible SPH multi‐fluid models. Real wave speed ratios can be achieved as long as the fluid velocities are not very high. Although the wave speeds may be artificial in many cases, correct and realistic wave speed ratios are essential in the modelling of heat transfer between 2 fluids (eg, in engineering applications such as gas turbines).
Linking the Qinling Orogeny with the Chang 7 shale (Triassic Yanchang Formation) deposition: Evidence from major, trace, and rare earth element geochemistry
Authors: Yuan Wei , Chen Ruiqian , Liu Guangdi , Shang Fei , Xu Liming , Niu Xiaobing
Published: February 2018

The lacustrine organic‐rich shale of Triassic Chang 7 Member is an unconventional shale oil reservoir that is a major hydrocarbon target in the Ordos Basin, northern China. This study uses major, trace, and rare earth element (REE) abundance documented through a 115‐m‐thick core obtained from the western part of the Ordos Basin to assess dominant controls on temporal variations in total organic carbon in the Chang 7 shale. Our results suggest that total organic carbon trends in the Chang 7 can be directly linked with the tectonic and magmatic evolution of Qinling orogen. The Chang 73 and Chang 72 submembers of the lower part of the Chang 7 were likely deposited in association with heighted tectonic and magmatic activity of the Qinling Orogeny. Sediments derived from these submembers display light REE and trace element compositions similar to the Tianshui rhyolites suggesting deposition contemporaneous with magmatic and/or volcanic activity of the Qinling Orogeny. Higher nutrient concentrations introduced by volcanic eruptions would have stimulated primary productivity in the surface water enhancing the organic carbon flux to the lake bottom. In addition, higher rates of mountain building in the Qinling Orogeny may have been responsible for increasing subsidence rate of the southern Ordos Basin, also favourable for the establishment of anoxic bottom‐water conditions. In contrast, lower light REE and trace element abundances of the Chang 71 submember at the top of the Chang 7 suggest deposition during a tectonically and magmatic quiescent period of the Qinling Orogeny. The diminished volcanic flux could have lowered the rate of primary productivity. Moreover, a reduced rate of mountain building would have decreased the rate of foredeep subsidence favouring shallower water and oxic/suboxic bottom‐water conditions. Thus, the hydrography of the lake during accumulation of the Chang 71 was not conducive for organic carbon accumulation. Together, the correlation of the Qinling mountain building and magmatism and deposition of the Chang 7 shale provide evidence for the role of tectonism in the accumulation of organic carbon enriched sediment.
Spatial elongation of population receptive field profiles revealed by model‐free fMRI back‐projection
Authors: Merkel Christian , Hopf Jens‐Max , Schoenfeld Mircea Ariel
Published: February 2018

Estimates of visual field topographies in human visual cortex obtained through fMRI traveling wave techniques usually provide the parameters of population receptive field (pRF) location (polar angle, eccentricity) and receptive field size. These parameters are obtained by fitting the recorded data to a standard model population receptive field. In this work, pRF profiles are measured directly by back‐projecting preprocessed fMRI time‐series to sweeps of a bar across the visual field in different angles. The current data suggest that the model‐free pRF profiles contain information not only about receptive field location and size but also about the pRF shape characteristics. The elongation (ellipticity) of pRFs decreases along the early visual hierarchy to a different degree for the ventral and the dorsal stream. Furthermore, ellipticity changes as a function of eccentricity. pRF orientation shows a high degree of collinearity with its angular position within the visual field. Using model‐free pRF measurements, the traveling wave technique provides additional characteristics of pRF topographies that are not restricted to size and provide robust measures within the single subject.
Exploring the rationale for combining ionizing radiation and immune checkpoint blockade in head and neck cancer
Authors: Morisada Megan , Chamberlin Michael , Allen Clint
Published: February 2018

Background

The ability of radiation to enhance antitumor immunity under specific experimental conditions is well established. Here, we explore preclinical data and the rationale for combining different radiation doses and fractions with immune checkpoint blockade immunotherapy.

Methods

We conducted a review of the literature.

Results

The ability of high‐dose or hypofractionated radiation to enhance antitumor immunity resulting in additive or synergistic tumor control when combined with checkpoint blockade is well studied. Whether low‐dose daily fractionated radiation does the same is less well studied and available data suggests it may be immunosuppressive.

Conclusion

Although daily fractionated radiation is well established as the standard of care for the treatment of patients with head and neck cancer, how this radiation schema alters antitumor immunity needs further study. If the radiation doses and fractions alter antitumor immunity differently can have profound implications in the rational design of clinical trials investigating whether radiation can enhance response rates to immune checkpoint blockade.
Surface and subsurface water contributions to streamflow from a mesoscale watershed in complex mountain terrain
Authors: Zhang Qinghuan , Knowles John F. , Barnes Rebecca T. , Cowie Rory M. , Rock Nathan , Williams Mark W.
Published: February 2018

An understanding of surface and subsurface water contributions to streamflow is essential for accurate predictions of water supply from mountain watersheds that often serve as water towers for downstream communities. As such, this study used the end‐member mixing analysis technique to investigate source water contributions and hydrologic flow paths of the 264 km2 Boulder Creek Watershed, which drains the Colorado Front Range, USA. Four conservative hydrochemical tracers were used to describe this watershed as a 3 end‐member system, and tracer concentration reconstruction suggested that the application of end‐member mixing analysis was robust. On average from 2009 to 2011, snowmelt and rainwater from the subalpine zone and groundwater sampled from the upper montane zone contributed 54%, 22%, and 24% of the annual streamflow, respectively. These values demonstrate increased rainwater and decreased snow water contributions to streamflow relative to area‐weighted mean values derived from previous work at the headwater scale. Young water (2.3 ± 0.8 months) fractions of streamflow decreased from 18–22% in the alpine catchment to 8–10% in the lower elevation catchments and the watershed outlet with implications for subsurface storage and hydrological connectivity. These results contribute to a process‐based understanding of the seasonal source water composition of a mesoscale watershed that can be used to extrapolate headwater streamflow generation predictions to larger spatial scales.
Immune checkpoint blockade combined with IL‐6 and TGF‐β inhibition improves the therapeutic outcome of mRNA‐based immunotherapy
Authors: Bialkowski Lukasz , Van der Jeught Kevin , Bevers Sanne , Tjok Joe Patrick , Renmans Dries , Heirman Carlo , Aerts Joeri L. , Thielemans Kris
Published: February 2018

Improved understanding of cancer immunology has provided insight into the phenomenon of frequent tumor recurrence after initially successful immunotherapy. A delicate balance exists between the capacity of the immune system to control tumor growth and various resistance mechanisms that arise to avoid or even counteract the host's immune system. These resistance mechanisms include but are not limited to (i) adaptive expression of inhibitory checkpoint molecules in response to the proinflammatory environment and (ii) amplification of cancer stem cells, a small fraction of tumor cells possessing the capacity for self‐renewal and mediating treatment resistance and formation of metastases after long periods of clinical remission. Several individual therapeutic agents have so far been developed to revert T‐cell exhaustion or disrupt the cross‐talk between cancer stem cells and the tumor‐promoting microenvironment. Here, we demonstrate that a three‐arm combination therapy—consisting of an mRNA‐based vaccine to induce antigen‐specific T‐cell responses, monoclonal antibodies blocking inhibitory checkpoint molecules (PD‐1, TIM‐3, LAG‐3), and antibodies targeting IL‐6 and TGF‐β—improves the therapeutic outcome in subcutaneous TC‐1 tumors and significantly prolongs survival of treated mice. Our findings point to a need for a rational development of multidimensional anticancer therapies, aiming at the induction of tumor‐specific immunity and simultaneously targeting multiple resistance mechanisms.
A novel multimodal medical image fusion using sparse representation and modified spatial frequency
Authors: Aishwarya N. , Bennila Thangammal C.
Published: February 2018

Fusion of multimodal imaging data supports medical experts with ample information for better disease diagnosis and further clinical investigations. Recently, sparse representation (SR)‐based fusion algorithms has been gaining importance for their high performance. Building a compact, discriminative dictionary with reduced computational effort is a major challenge to these algorithms. Addressing this key issue, we propose an adaptive dictionary learning approach for fusion of multimodal medical images. The proposed approach consists of three steps. First, zero informative patches of source images are discarded by variance computation. Second, the structural information of remaining image patches is evaluated using modified spatial frequency (MSF). Finally, a selection rule is employed to separate the useful informative patches of source images for dictionary learning. At the fusion step, batch‐OMP algorithm is utilized to estimate the sparse coefficients. A novel fusion rule which measures the activity level in both spatial domain and transform domain is adopted to reconstruct the fused image with the sparse vectors and trained dictionary. Experimental results of various medical image pairs and clinical data sets reveal that the proposed fusion algorithm gives better visual quality and competes with existing methodologies both visually and quantitatively.
Effects of cell state and staining on femtosecond laser nanosurgery
Authors: Hagenah Dorian , Heisterkamp Alexander , Kalies Stefan
Published: February 2018

Femtosecond laser nanosurgery enables precise manipulation of subcellular elements to study regeneration. However, currently it is not frequently employed—probably because of its unknown consequences on the whole cell level. To better understand the associated biological response of the cell, especially in the context of different cell states and cell staining, we manipulated C2C12 myoblasts and myotubes, which were either unstained (nicotinamide adenine dinucleotide signal) or stained with MitoTracker Red. Both signals overlap well and stain similar areas in untreated cells. We chose 3 different cutting lengths and performed surgery in the cytosol along the major cell axis. The cuts resealed within several minutes independent of the cutting length. We analyzed cell area, perimeter, major and minor axis on long term. We observed significant changes in the cell area and perimeter, dependent on the staining and more pronounced in differentiated myotubes. We conclude, that laser parameters must be chosen carefully, depending on the staining of the cell, its (differentiation) state, and the extent of the cut region, such that unwanted cell responses can be avoided. Laser manipulation of C2C12 myotubes with small ablation (0.8 μm) and large ablation (3.0 μm). While small damages recover, larger damages lead to elimination from the syncytium. Scale bar: 20 μm.
Live Imaging of Type I Collagen Assembly Dynamics in Osteoblasts Stably Expressing GFP and mCherry-Tagged Collagen Constructs
Authors: Lu Yongbo , Kamel-El Sayed Suzan A , Wang Kun , Tiede-Lewis LeAnn M , Grillo Michael A , Veno Patricia A , Dusevich Vladimir , Phillips Charlotte L , Bonewald Lynda F , Dallas Sarah L
Published: February 2018

Type I collagen is the most abundant extracellular matrix protein in bone and other connective tissues and plays key roles in normal and pathological bone formation as well as in connective tissue disorders and fibrosis. Although much is known about the collagen biosynthetic pathway and its regulatory steps, the mechanisms by which it is assembled extracellularly are less clear. We have generated GFPtpz and mCherry-tagged collagen fusion constructs for live imaging of type I collagen assembly by replacing the α2(I)-procollagen N-terminal propeptide with GFPtpz or mCherry. These novel imaging probes were stably transfected into MLO-A5 osteoblast-like cells and fibronectin-null mouse embryonic fibroblasts (FN-null-MEFs) and used for imaging type I collagen assembly dynamics and its dependence on fibronectin. Both fusion proteins co-precipitated with α1(I)-collagen and remained intracellular without ascorbate but were assembled into α1(I) collagen-containing extracellular fibrils in the presence of ascorbate. Immunogold-EM confirmed their ultrastuctural localization in banded collagen fibrils. Live cell imaging in stably transfected MLO-A5 cells revealed the highly dynamic nature of collagen assembly and showed that during assembly the fibril networks are continually stretched and contracted due to the underlying cell motion. We also observed that cell-generated forces can physically reshape the collagen fibrils. Using co-cultures of mCherry- and GFPtpz-collagen expressing cells, we show that multiple cells contribute collagen to form collagen fiber bundles. Immuno-EM further showed that individual collagen fibrils can receive contributions of collagen from more than one cell. Live cell imaging in FN-null-MEFs expressing GFPtpz-collagen showed that collagen assembly was both dependent upon and dynamically integrated with fibronectin assembly. These GFP-collagen fusion constructs provide a powerful tool for imaging collagen in living cells and have revealed novel and fundamental insights into the dynamic mechanisms for the extracellular assembly of collagen. © 2018 American Society for Bone and Mineral Research.
Suppression of microRNA‐144‐3p attenuates oxygen–glucose deprivation/reoxygenation‐induced neuronal injury by promoting Brg1/Nrf2/ARE signaling
Authors: Li Yanru , Zhao Yongli , Cheng Mingkun , Qiao Yingjie , Wang Yongtao , Xiong Wancheng , Yue Wei
Published: February 2018

Accumulating evidence has reported that microRNA‐144‐3p (miR‐144‐3p) is highly related to oxidative stress and apoptosis. However, little is known regarding its role in cerebral ischemia/reperfusion‐induced neuronal injury. Herein, our results showed that miR‐144‐3p expression was significantly downregulated in neurons following oxygen–glucose deprivation and reoxygenation (OGD/R) treatment. Overexpression of miR‐144‐3p markedly reduced cell viability, promoted cell apoptosis, and increased oxidative stress in neurons with OGD/R treatment, whereas downregulation of miR‐144‐3p protected neurons against OGD/R‐induced injury. Brahma‐related gene 1 (Brg1) was identified as a potential target gene of miR‐144‐3p. Moreover, downregulation of miR‐144‐3p promoted the nuclear translocation of nuclear factor erythroid 2‐related factor 2 (Nrf2) and increased antioxidant response element (ARE) activity. However, knockdown of Brg1 significantly abrogated the neuroprotective effects of miR‐144‐3p downregulation. Overall, our results suggest that miR‐144‐3p contributes to OGD/R‐induced neuronal injury in vitro through negatively regulating Brg1/Nrf2/ARE signaling.
Molecular dynamics coupled with a virtual system for effective conformational sampling
Authors: Hayami Tomonori , Kasahara Kota , Nakamura Haruki , Higo Junichi
Published: February 2018

An enhanced conformational sampling method is proposed: virtual‐system coupled canonical molecular dynamics (VcMD). Although VcMD enhances sampling along a reaction coordinate, this method is free from estimation of a canonical distribution function along the reaction coordinate. This method introduces a virtual system that does not necessarily obey a physical law. To enhance sampling the virtual system couples with a molecular system to be studied. Resultant snapshots produce a canonical ensemble. This method was applied to a system consisting of two short peptides in an explicit solvent. Conventional molecular dynamics simulation, which is ten times longer than VcMD, was performed along with adaptive umbrella sampling. Free‐energy landscapes computed from the three simulations mutually converged well. The VcMD provided quicker association/dissociation motions of peptides than the conventional molecular dynamics did. The VcMD method is applicable to various complicated systems because of its methodological simplicity. © 2018 Wiley Periodicals, Inc.
A framework of Afrocentric hope: Rural South African children's conceptualizations of hope
Authors: Cherrington Avivit M.
Published: February 2018

There is a growing need to explore and understand indigenous knowledge and subjective experiences around hope from children raised in rural African communities. This engagement sought to address the question: What are rural South African primary school children's conceptualizations of hope? A visual participatory methodology (using collage‐making, drawing, Mmogo method, and photovoice) enabled an exploration of hope with 12 children (9‐13 years) attending an aftercare center in rural QwaQwa region of South Africa. Using evidence generated from the study, and drawing on Scioli's theory of integrated hope, this article posits a framework of Afrocentric hope that develops along four interdependent and interrelated levels: contextual, personal, relational, and collective. These interactions are mediated by the spiritual/cultural worldview dimension. Understanding rural South African children's perspectives of hope contributes toward engagements aimed at nurturing, shaping, and strengthening hope in collective‐oriented communities.
Comparability and repeatability of three commonly used methods for measuring endurance capacity
Authors: Baxter‐Gilbert James , Mühlenhaupt Max , Whiting Martin J.
Published: February 2018

Measures of endurance (time to exhaustion) have been used to address a wide range of questions in ecomorphological and physiological research, as well as being used as a proxy for survival and fitness. Swimming, stationary (circular) track running, and treadmill running are all commonly used methods for measuring endurance. Despite the use of these methods across a broad range of taxa, how comparable these methods are to one another, and whether they are biologically relevant, is rarely examined. We used Australian water dragons (Intellagama lesueurii), a species that is morphologically adept at climbing, swimming, and running, to compare these three methods of endurance and examined if there is repeatability within and between trial methods. We found that time to exhaustion was not highly repeatable within a method, suggesting that single measures or a mean time to exhaustion across trials are not appropriate. Furthermore, we compared mean maximal endurance times among the three methods, and found that the two running methods (i.e., stationary track and treadmill) were similar, but swimming was distinctly different, resulting in lower mean maximal endurance times. Finally, an individual's endurance rank was not repeatable across methods, suggesting that the three endurance trial methods are not providing similar information about an individual's performance capacity. Overall, these results highlight the need to carefully match a measure of performance capacity with the study species and the research questions being asked so that the methods being used are behaviorally, ecologically, and physiologically relevant.
Bis‐dihydropyrimidines: Catalyst‐free, Microwave‐assisted Organic Synthesis, Characterization and In Vitro Biological Screenings
Authors: Bhatia Sumeet Kaur , Samdhian Varsha , Kaur Balbir
Published: February 2018

In present research, we aim to afford the catalyst‐free, greener synthesis of diethyl 2,2′‐(1,2‐phenylenebis(methylene))bis(sulfanediyl)bis(6‐methyl‐4‐substitutedphenyl‐1,4‐dihydropyrimidine‐5‐carboxylate)derivatives via microwave irradiations. The reactions were also performed under conventional heating. The reaction times and yields thus obtained of the isolated desired products were compared too, and hence explaining the significance of using microwave irradiations. The structural elucidation of the synthesized moieties was carried out by modern sophisticated spectral techniques. The prepared bis‐heterocycles were screened for their in vitro anti‐microbial activities. Samples that possessed electron‐releasing group on the phenyl ring showed anti‐bacterial activities while those that carry electron‐withdrawing group exhibited anti‐fungal activities.
An Exceedingly Mild, Green Synthesis of Substituted N‐3‐diaryl‐1,8‐naphthyridin‐2‐amine Derivatives and Their Antimicrobial Activity
Authors: Ravi Dharavath , Rambabu Sirgamalla , Ashok Kommakula , Madhu Palithapu , Sakram Boda
Published: February 2018

An exceedingly and highly efficient procedure has been described for the synthesis of substituted N‐3‐diaryl‐1,8‐naphthyridin‐2‐amines by the reaction of 2‐chloro‐3‐aryl‐1,8‐naphthyridines with various anilines in the presence of N‐methyl‐2‐pyrrolidone and K2CO3 under thermal green solvent‐free conditions. The significant features of this green reaction include very good yields in purity, simple experimental, short reaction time, easy workability, and avoidance of toxic solvents. All synthesized compounds have been evaluated for their antibacterial activity.