bluuebunny/crossref_metadata_2025 huggingface dataset:
HIV, violence, blame and shame: pathways of risk to internalized HIV stigma among South African adolescents living with HIV
Authors: Pantelic Marija , Boyes Mark , Cluver Lucie , Meinck Franziska
Published: August 2017

Introduction: Internalized HIV stigma is a key risk factor for negative outcomes amongst adolescents living with HIV (ALHIV), including non‐adherence to anti‐retroviral treatment, loss‐to‐follow‐up and morbidity. This study tested a theoretical model of multi‐level risk pathways to internalized HIV stigma among South African ALHIV.

Methods: From 2013 to 2015, a survey using total population sampling of ALHIV who had ever initiated anti‐retroviral treatment (ART) in 53 public health facilities in the Eastern Cape, South Africa was conducted. Community‐tracing ensured inclusion of ALHIV who were defaulting from ART or lost to follow‐up. 90.1% of eligible ALHIV were interviewed (n = 1060, 55% female, mean age = 13.8, 21% living in rural locations). HIV stigma mechanisms (internalized, enacted, and anticipated), HIV‐related disability, violence victimization (physical, emotional, sexual abuse, bullying victimization) were assessed using well‐validated self‐report measures. Structural equation modelling was used to test a theoretically informed model of risk pathways from HIV‐related disability to internalized HIV stigma. The model controlled for age, gender and urban/rural address.

Results: Prevalence of internalized HIV stigma was 26.5%. As hypothesized, significant associations between internalized stigma and anticipated stigma, as well as depression were obtained. Unexpectedly, HIV‐related disability, victimization, and enacted stigma were not directly associated with internalized stigma. Instead significant pathways were identified via anticipated HIV stigma and depression. The model fitted the data well (RMSEA = .023; CFI = .94; TLI = .95; WRMR = 1.070).

Conclusions: These findings highlight the complicated nature of internalized HIV stigma. Whilst it is seemingly a psychological process, indirect pathways suggest multi‐level mechanisms leading to internalized HIV stigma. Findings suggest that protection from violence within homes, communities and schools may interrupt risk pathways from HIV‐related health problems to psychological distress and internalized HIV stigma. This highlights the potential for interventions that do not explicitly target adolescents living with HIV but are sensitive to their needs.
A lncRNA fine tunes the dynamics of a cell state transition involving Lin28, let-7 and de novo DNA methylation
Authors: Li Meng Amy , Amaral Paulo P , Cheung Priscilla , Bergmann Jan H , Kinoshita Masaki , Kalkan Tüzer , Ralser Meryem , Robson Sam , von Meyenn Ferdinand , Paramor Maike , Yang Fengtang , Chen Caifu , Nichols Jennifer , Spector David L , Kouzarides Tony , He Lin , Smith Austin
Published: August 2017

Execution of pluripotency requires progression from the naïve status represented by mouse embryonic stem cells (ESCs) to a state capacitated for lineage specification. This transition is coordinated at multiple levels. Non-coding RNAs may contribute to this regulatory orchestra. We identified a rodent-specific long non-coding RNA (lncRNA) linc1281, hereafter Ephemeron (Eprn), that modulates the dynamics of exit from naïve pluripotency. Eprn deletion delays the extinction of ESC identity, an effect associated with perduring Nanog expression. In the absence of Eprn, Lin28a expression is reduced which results in persistence of let-7 microRNAs, and the up-regulation of de novo methyltransferases Dnmt3a/b is delayed. Dnmt3a/b deletion retards ES cell transition, correlating with delayed Nanog promoter methylation and phenocopying loss of Eprn or Lin28a. The connection from lncRNA to miRNA and DNA methylation facilitates the acute extinction of naïve pluripotency, a pre-requisite for rapid progression from preimplantation epiblast to gastrulation in rodents. Eprn illustrates how lncRNAs may introduce species-specific network modulations.
A synthetic planar cell polarity system reveals localized feedback on Fat4-Ds1 complexes
Authors: Loza Olga , Heemskerk Idse , Gordon-Bar Nadav , Amir-Zilberstein Liat , Jung Yunmin , Sprinzak David
Published: August 2017

The atypical cadherins Fat and Dachsous (Ds) have been found to underlie planar cell polarity (PCP) in many tissues. Theoretical models suggest that polarity can arise from localized feedbacks on Fat-Ds complexes at the cell boundary. However, there is currently no direct evidence for the existence or mechanism of such feedbacks. To directly test the localized feedback model, we developed a synthetic biology platform based on mammalian cells expressing the human Fat4 and Ds1. We show that Fat4-Ds1 complexes accumulate on cell boundaries in a threshold-like manner and exhibit dramatically slower dynamics than unbound Fat4 and Ds1. This suggests a localized feedback mechanism based on enhanced stability of Fat4-Ds1 complexes. We also show that co-expression of Fat4 and Ds1 in the same cells is sufficient to induce polarization of Fat4-Ds1 complexes. Together, these results provide direct evidence that localized feedbacks on Fat4-Ds1 complexes can give rise to PCP.
Live calcium and mitochondrial imaging in the enteric nervous system of Parkinson patients and controls
Authors: Desmet An-Sofie , Cirillo Carla , Tack Jan , Vandenberghe Wim , Vanden Berghe Pieter
Published: August 2017

Parkinson's disease (PD) is a neurodegenerative disease with motor and non-motor symptoms, including constipation. Therefore, several studies have investigated the gastrointestinal tract, and more specifically the enteric nervous system (ENS), in search of an early biomarker of PD. Besides α-synuclein aggregation, mitochondrial dysfunction and dysregulation of intracellular Ca2+ concentration probably contribute to the pathogenesis of PD. Here we assessed neuronal and mitochondrial functioning in primary enteric neurons of PD patients and their healthy partners as controls. Using a unique combination of live microscopy techniques, applied to routine duodenum biopsies, we were able to record neuronal Ca2+ responses and mitochondrial membrane potential in these nerve tissues. We found that submucous neurons were not affected in PD patients, which suggests that these neurons are not involved in the pathogenesis or the gastrointestinal symptoms of PD. Our study provides for the first time functional information on live neurons in PD patients.
Blockade of the LRP16-PKR-NF-κB signaling axis sensitizes colorectal carcinoma cells to DNA-damaging cytotoxic therapy
Authors: Li Xiaolei , Wu Zhiqiang , An Xiaojing , Mei Qian , Bai Miaomiao , Hanski Leena , Li Xiang , Ahola Tero , Han Weidong
Published: August 2017

Acquired therapeutic resistance by tumors is a substantial impediment to reducing the morbidity and mortality that are attributable to human malignancies. The mechanisms responsible for the dramatic shift between chemosensitivity and chemoresistance in colorectal carcinoma have not been defined. Here, we report that LRP16 selectively interacts and activates double-stranded RNA-dependent kinase (PKR), and also acts as scaffolds to assist the formation of a ternary complex of PKR and IKKβ, prolonging the polymers of ADP-ribose (PAR)-dependent nuclear factor kappa B (NF-κB) transactivation caused by DNA-damaging agents and confers acquired chemoresistance. We also identified a small molecule, MRS2578, which strikingly abrogated the binding of LRP16 to PKR and IKKβ, converting LRP16 into a death molecule and forestalling colon tumorigenesis. Inclusion of MRS2578 with etoposide, versus each drug alone, exhibited synergistic antitumor cytotoxicity in xenografts. Our combinatorial approach introduces a strategy to enhance the efficacy of genotoxicity therapies for the treatment of tumors.
A comprehensive analysis of coregulator recruitment, androgen receptor function and gene expression in prostate cancer
Authors: Liu Song , Kumari Sangeeta , Hu Qiang , Senapati Dhirodatta , Venkadakrishnan Varadha Balaji , Wang Dan , DePriest Adam D , Schlanger Simon E , Ben-Salem Salma , Valenzuela Malyn May , Willard Belinda , Mudambi Shaila , Swetzig Wendy M , Das Gokul M , Shourideh Mojgan , Koochekpour Shahriah , Falzarano Sara Moscovita , Magi-Galluzzi Cristina , Yadav Neelu , Chen Xiwei , Lao Changshi , Wang Jianmin , Billaud Jean-Noel , Heemers Hannelore V
Published: August 2017

Standard treatment for metastatic prostate cancer (CaP) prevents ligand-activation of androgen receptor (AR). Despite initial remission, CaP progresses while relying on AR. AR transcriptional output controls CaP behavior and is an alternative therapeutic target, but its molecular regulation is poorly understood. Here, we show that action of activated AR partitions into fractions that are controlled preferentially by different coregulators. In a 452-AR-target gene panel, each of 18 clinically relevant coregulators mediates androgen-responsiveness of 0–57% genes and acts as a coactivator or corepressor in a gene-specific manner. Selectivity in coregulator-dependent AR action is reflected in differential AR binding site composition and involvement with CaP biology and progression. Isolation of a novel transcriptional mechanism in which WDR77 unites the actions of AR and p53, the major genomic drivers of lethal CaP, to control cell cycle progression provides proof-of-principle for treatment via selective interference with AR action by exploiting AR dependence on coregulators.
Temporal network analysis identifies early physiological and transcriptomic indicators of mild drought in Brassica rapa
Authors: Greenham Kathleen , Guadagno Carmela Rosaria , Gehan Malia A , Mockler Todd C , Weinig Cynthia , Ewers Brent E , McClung C Robertson
Published: August 2017

The dynamics of local climates make development of agricultural strategies challenging. Yield improvement has progressed slowly, especially in drought-prone regions where annual crop production suffers from episodic aridity. Underlying drought responses are circadian and diel control of gene expression that regulate daily variations in metabolic and physiological pathways. To identify transcriptomic changes that occur in the crop Brassica rapa during initial perception of drought, we applied a co-expression network approach to associate rhythmic gene expression changes with physiological responses. Coupled analysis of transcriptome and physiological parameters over a two-day time course in control and drought-stressed plants provided temporal resolution necessary for correlation of network modules with dynamic changes in stomatal conductance, photosynthetic rate, and photosystem II efficiency. This approach enabled the identification of drought-responsive genes based on their differential rhythmic expression profiles in well-watered versus droughted networks and provided new insights into the dynamic physiological changes that occur during drought.
Small molecule inhibition of apicomplexan FtsH1 disrupts plastid biogenesis in human pathogens
Authors: Amberg-Johnson Katherine , Hari Sanjay B , Ganesan Suresh M , Lorenzi Hernan A , Sauer Robert T , Niles Jacquin C , Yeh Ellen
Published: August 2017

The malaria parasite Plasmodium falciparum and related apicomplexan pathogens contain an essential plastid organelle, the apicoplast, which is a key anti-parasitic target. Derived from secondary endosymbiosis, the apicoplast depends on novel, but largely cryptic, mechanisms for protein/lipid import and organelle inheritance during parasite replication. These critical biogenesis pathways present untapped opportunities to discover new parasite-specific drug targets. We used an innovative screen to identify actinonin as having a novel mechanism-of-action inhibiting apicoplast biogenesis. Resistant mutation, chemical-genetic interaction, and biochemical inhibition demonstrate that the unexpected target of actinonin in P. falciparum and Toxoplasma gondii is FtsH1, a homolog of a bacterial membrane AAA+ metalloprotease. PfFtsH1 is the first novel factor required for apicoplast biogenesis identified in a phenotypic screen. Our findings demonstrate that FtsH1 is a novel and, importantly, druggable antimalarial target. Development of FtsH1 inhibitors will have significant advantages with improved drug kinetics and multistage efficacy against multiple human parasites.
Total lipids, cholesterol and plasmatic riglycerides in California sea lion pups (Zalophus californianus)
Authors: Castro-González MI , Aurioles-Gamboa D , Montaño-Benavides S , Gil-Romo FP , López-Orea N
Published: August 2017

The concentrations of total lipids, cholesterol and plasmatic triglycerides of breeding pups of Zalophus californianus from Los Islotes (Baja California Sur, Mexico) were quantified during the summer of 1999. The contents of total lipids and cholesterol were similar between females and males, with a range of 0.056–0.061 mg/dL and 108–240 mg/dL, respectively. The maximum value of cholesterol found in males belonged to those with smaller weight (240 mg/dL: 8.1 kg); in females, the opposite occurred (112 mg/dL: 14.1 kg). A similar behavior was observed when cholesterol was compared to the thickness of the fat layer. Triglyceride values were very heterogeneous in both females and males, since these values are strongly influenced by the different fasting periods of the pups and because these levels rise during the nutritious lipemia, ranging from 11 to 306 mg/dL in females and from 15 to 232 mg/dL in males. The correlation between morphometric measurements and the clinical parameters was very low. A greater correlation was detected between cholesterol and weight in females; in males it was almost null. No correlation was detected between triglycerides and the morphometric measurements studied. The population at Los Islotes has shown good status during the last four breeding seasons (steady pup production, high pup body condition, stable female fecundity), and during the 1999 sampling, pup body conditions were within the normal values estimated for the Gulf of California in regard to axillary girth, sculp thickness and Fulton´ s condition factor. For these reasons, we consider that triglycerides and cholesterol in pup plasma circa two months old could provide a reference framework for subsequent comparative studies, particularly during periods of environmental stress, such as El Niño.
Histology of the oocytes of Lutjanus peru (Nichols and Murphy, 1922) (Pisces: Lutjanidae)
Authors: Lucano-Ramírez G , Villagrán-SantaCruz M , Ruiz-Ramírez S , López-Murillo T
Published: August 2017

The distinctive characteristics found in each of the development stages of the oocyte in the ovary of Lutjanus peru (Pacific red snapper) are described. The histological technique was used to identify the development stages of the oocytes and the averages of the diameters of the oocytes were obtained for these stages. Stage I, chromatin nucleolus oocyte: average diameter of 52.89 µm. Stage II, perinucleolus oocyte: average diameter of 117.78 µm. Stage III, yolk vesicle oocyte: average diameter of 166.18 µm. Stage IV, primary vitellogenesis oocyte: average diameter of 221.73 µm. Stage V, secondary vitellogenesis oocyte: average diameter of 333.7 µm. Stage VI, tertiary vitellogenesis oocyte: average diameter of 340.17 µm. Stage VII, mature oocyte: average diameter of 340.17 µm. With the identification of these stages, the observation of the process of the oogenesis in L. peru has been completed.
Influence of benthic regeneration on the biogeochemical cycle of CO2 in littoral ecosystems
Authors: Forja JM , Ortega T , Del-Valls TA , Gómez-Parra A
Published: August 2017

The benthic fluxes of inorganic carbon were measured in the Bay of Cádiz, located in the SW of the Iberian Peninsula (Southern Europe). The values measured ranged between 74 and 224 mmol m–2 d–1, which are higher than most reported fluxes. They were linearly correlated with the organic carbon content in surface sediments. For the Bay of Cádiz, a carbon budget is proposed. It was determined that 53% of the benthic inorganic carbon production is used by the phytoplankton of the area, and 43% is exported by tides to other littoral areas. The rest of the benthic production, together with direct emission of CO2 from intertidal sediments to the atmosphere, yielded a maximum net flux of 5.6 · 108 mol C y–1. If extrapolated to coastal areas globally, these values are particularly significant. Taking 44 mmol m–2 d–1 as an average value for benthic fluxes of dissolved inorganic carbon, it is estimated that the benthic CO2 production by coastal ecosystems is about 4.2 · 1014 mol y–1, similar to the estimated annual CO2 emissions to the atmosphere from the burning of fossil fuels.
Comparison of the digestibility of diets based on fish meal and soybean meal in Litopenaeus Vannamei Boone 1931, using different temperatures and salinities for culture
Authors: Cabanillas-Beltrán H , Ponce-Palafox JT , Martínez-Palacios CA , Chávez-Sánchez MC , Ross LG
Published: August 2017

The digestibility of fish meal and soybean meal by Litopenaeus vannamei was determined at different temperatures (22ºC and 28ºC) and salinities (16‰ and 35‰) using practical diets based on ingredients available in Mexico. The digestibility of soybean meal was consistently higher compared to that of fish meal, in terms of the apparent digestibilities of dry matter, crude protein and aminoacids, suggesting that soybean meal proteins are more readily digested. For fish meal, the apparent digestibility of the dry matter was reduced by high salinity at 28ºC, and the carbohydrate apparent digestibility was reduced by high salinity at both temperatures. The high salinity also reduced the digestibility of dry-matter, lipids and carbohydrates in soybean meal at 28°C, but had no effect on crude protein digestibility. This may have implications for the role of carbohydrates as source of energy in practical diets for shrimp. The results also suggest that the fish meal used might have been of reduced quality.
Relationships between environmental variables and the abundance of Peracarid fauna in Algeciras Bay (Southern Iberian peninsula)
Authors: Conradi M , López-Gonzaléz PJ
Published: August 2017

The distribution and abundance of peracaridean fauna associated with the bryozoan Bugula neritina have been analysed according to their possible relationships with environmental stress on the coastline of Algeciras Bay. The spatial environmental variability along this bay has been established based on the analysis of five abiotic variables (hydrodynamism, siltation, suspended solids, and organic matter content) at six stations over a 12-month period. The temporal variability of these abiotic variables was not taken into account due to the method used in collecting the samples. The abundance and beta diversity of the peracarid fauna were also calculated monthly. Hydrodynamism was the only abiotic variable significantly correlated with beta diversity, with a linear regression model between the two variables (r = 0.81). The distributional pattern of the peracarids (based on the abundance matrix) was correlated with the environmental variables by matching samples' similarities using the Spearman rank correlation. This analysis showed that the combination of variables that best explains the patterns of distribution is hydrodynamism and siltation (ρs = 0.665). Of the species considered the amphipods Ischyrocerus inexpectatus, Jassa marmorata and Podocerus variegatus were negatively correlated with hydrodynamism and positively with temperature. The caprellidea Phtisica marina was also negatively correlated with hydrodynamism. On the other hand, the amphipods Cressa mediterranea and Stenothoe dollfusi preferred environments with high hydrological forces and low sedimentation rate. Due to the particular environmental conditions where they live and their requirements, Gammaropsis maculata, Corophium acutum, J. marmorata, I. inexpectatus, and P. variegatus were categorised as good indicator species in port environments. Others such as Aora spinicornis, Microjassa cumbrensis, and C. mediterranea were categorised as species well adapted to high hydrological forces.
Changes in the macrobenthos of a sandy beach during "El Niño" 1997-98 in the Malaga Bay, Colombian Pacific
Authors: Riascos JM
Published: August 2017

Changes in the macrobenthic community of a sandy-beach were studied during the "El Niño" 1997-98 event at the Malaga Bay, in the central Colombian Pacific. Species composition was recorded monthly from October 1997 to May 1998 at four tidal levels, and species diversity (Shannon-Wienner, H') and richness were calculated. In order to analyze community structure changes, multivariate ordinations were performed (non-metric multidimensional scaling) and species responsible for the observed temporal changes were discriminated using a dissimilarity index. Differences in species diversity and richness were related to a seriation pattern in vertical species distribution . A common pattern of structure change was found at four tidal levels on the beach. Population reduction or increase of some species and vertical modifications of the spatial distribution patterns were the main source of temporal community change.
Characterization of the carrageenan of Chondracanthus pectinatus (Rhodophyta: Gigartinales)
Authors: López-Acuña LM , Pacheco-Ruíz I , Hernández-Garibay E , Zertuche-González JA
Published: August 2017

The extraction as well as the chemical and physical characterization of the carrageenan of the red algae Chondracanthus pectinatus (Dawson) L. Aguilar and R. Aguilar was performed from field samples collected in three seasons of the year and three reproductive phases. The highest yield of carrageenan was in winter (72%) while the lowest was in summer (66%). Tetrasporic plants showed the lower percentages of 3,6 anhydrogalactose (9%), whereas the maximum was obtained from sterile spring plants (26%). An inverse relationship was observed in the sulfate content. The infrared spectrum showed that the carrageenan of C. pectinatus belongs to the hybrid kappa-iota (κ-ι) in carposporic and sterile samples but to lambda type (λ) in tetrasporic ones.
Uniform surface‐to‐line integral reduction of physical optics for curved surfaces by modified edge representation with higher‐order correction
Authors: Lyu Pengfei , Ando Makoto
Published: August 2017

The modified edge representation is one of the equivalent edge currents approximation methods for calculating the physical optics surface radiation integrals in diffraction analysis. The Stokes' theorem is used in the derivation of the modified edge representation from the physical optics for the planar scatterer case, which implies that the surface integral is rigorously reduced into the line integral of the modified edge representation equivalent edge currents, defined in terms of the local shape of the edge. On the contrary, for curved surfaces, the results of radiation integrals depend upon the global shape of the scatterer. The physical optics surface integral consists of two components, from the inner stationary phase point and the edge. The modified edge representation is defined independently from the orientation of the actual edge, and therefore, it could be available not only at the edge but also at the arbitrary points on the scatterer except the stationary phase point where the modified edge representation equivalent edge currents becomes infinite. If stationary phase point exists inside the illuminated region, the physical optics surface integration is reduced into two kinds of the modified edge representation line integrations, along the edge and infinitesimally small integration around the inner stationary phase point, the former and the latter give the diffraction and reflection components, respectively. The accuracy of the latter has been discussed for the curved surfaces and published. This paper focuses on the errors of the former and discusses its correction. It has been numerically observed that the modified edge representation works well for the physical optics diffraction in flat and concave surfaces; errors appear especially for the observer near the reflection shadow boundary if the frequency is low for the convex scatterer. This paper gives the explicit expression of the higher‐order correction for the modified edge representation.
Improving representation of canopy temperatures for modeling subcanopy incoming longwave radiation to the snow surface
Authors: Webster Clare , Rutter Nick , Jonas Tobias
Published: August 2017

A comprehensive analysis of canopy surface temperatures was conducted around a small and large gap at a forested alpine site in the Swiss Alps during the 2015 and 2016 snowmelt seasons (March–April). Canopy surface temperatures within the small gap were within 2–3°C of measured reference air temperature. Vertical and horizontal variations in canopy surface temperatures were greatest around the large gap, varying up to 18°C above measured reference air temperature during clear‐sky days. Nighttime canopy surface temperatures around the study site were up to 3°C cooler than reference air temperature. These measurements were used to develop a simple parameterization for correcting reference air temperature for elevated canopy surface temperatures during (1) nighttime conditions (subcanopy shortwave radiation is 0 W m−2) and (2) periods of increased subcanopy shortwave radiation >400 W m−2 representing penetration of shortwave radiation through the canopy. Subcanopy shortwave and longwave radiation collected at a single point in the subcanopy over a 24 h clear‐sky period was used to calculate a nighttime bulk offset of 3°C for scenario 1 and develop a multiple linear regression model for scenario 2 using reference air temperature and subcanopy shortwave radiation to predict canopy surface temperature with a root‐mean‐square error (RMSE) of 0.7°C. Outside of these two scenarios, reference air temperature was used to predict subcanopy incoming longwave radiation. Modeling at 20 radiometer locations throughout two snowmelt seasons using these parameterizations reduced the mean bias and RMSE to below 10 W m s−2 at all locations.
Reproducibility of Ba/Ca variations recorded by northeast Pacific bamboo corals
Authors: Serrato Marks G. , LaVigne M. , Hill T. M. , Sauthoff W. , Guilderson T. P. , Roark E. B. , Dunbar R. B. , Horner T. J.
Published: August 2017

Trace elemental ratios preserved in the calcitic skeleton of bamboo corals have been shown to serve as archives of past ocean conditions. The concentration of dissolved barium (BaSW), a bioactive nutrientlike element, is linked to biogeochemical processes such as the cycling and export of nutrients. Recent work has calibrated bamboo coral Ba/Ca, a new BaSW proxy, using corals spanning the oxygen minimum zone beneath the California Current System. However, it was previously unclear whether Ba/Cacoral records were internally reproducible. Here we investigate the accuracy of using laser ablation inductively coupled plasma mass spectrometry for Ba/Cacoral analyses and test the internal reproducibility of Ba/Ca among replicate radial transects in the calcite of nine bamboo corals collected from the Gulf of Alaska (643–720 m) and the California margin (870–2054 m). Data from replicate Ba/Ca transects were aligned using visible growth bands to account for nonconcentric growth; smoothed data were reproducible within ~4% for eight corals (n = 3 radii/coral). This intracoral reproducibility further validates using bamboo coral Ba/Ca for BaSW reconstructions. Sections of the Ba/Ca records that were potentially influenced by noncarbonate bound Ba phases occurred in regions where elevated Mg/Ca or Pb/Ca and coincided with anomalous regions on photomicrographs. After removing these regions of the records, increased Ba/Cacoral variability was evident in corals between ~800 and 1500 m. These findings support additional proxy validation to understand BaSW variability on interannual timescales, which could lead to new insights into deep sea biogeochemistry over the past several centuries.
Improving ecosystem‐scale modeling of evapotranspiration using ecological mechanisms that account for compensatory responses following disturbance
Authors: Millar David J. , Ewers Brent E. , Mackay D. Scott , Peckham Scott , Reed David E. , Sekoni Adewale
Published: August 2017

Mountain pine beetle outbreaks in western North America have led to extensive forest mortality, justifiably generating interest in improving our understanding of how this type of ecological disturbance affects hydrological cycles. While observational studies and simulations have been used to elucidate the effects of mountain beetle mortality on hydrological fluxes, an ecologically mechanistic model of forest evapotranspiration (ET) evaluated against field data has yet to be developed. In this work, we use the Terrestrial Regional Ecosystem Exchange Simulator (TREES) to incorporate the ecohydrological impacts of mountain pine beetle disturbance on ET for a lodgepole pine‐dominated forest equipped with an eddy covariance tower. An existing degree‐day model was incorporated that predicted the life cycle of mountain pine beetles, along with an empirically derived submodel that allowed sap flux to decline as a function of temperature‐dependent blue stain fungal growth. The eddy covariance footprint was divided into multiple cohorts for multiple growing seasons, including representations of recently attacked trees and the compensatory effects of regenerating understory, using two different spatial scaling methods. Our results showed that using a multiple cohort approach matched eddy covariance‐measured ecosystem‐scale ET fluxes well, and showed improved performance compared to model simulations assuming a binary framework of only areas of live and dead overstory. Cumulative growing season ecosystem‐scale ET fluxes were 8 – 29% greater using the multicohort approach during years in which beetle attacks occurred, highlighting the importance of including compensatory ecological mechanism in ET models.
Direct measurements of lift and drag on shallowly submerged cobbles in steep streams: Implications for flow resistance and sediment transport
Authors: Lamb Michael P. , Brun Fanny , Fuller Brian M.
Published: August 2017

Steep mountain streams have higher resistance to flow and lower sediment transport rates than expected by comparison with low gradient rivers, and often these differences are attributed to reduced near‐bed flow velocities and stresses associated with form drag on channel forms and immobile boulders. However, few studies have directly measured drag and lift forces acting on bed sediment for shallow flows over coarse sediment, which ultimately control sediment transport rates and grain‐scale flow resistance. Here we report on particle lift and drag force measurements in flume experiments using a planar, fixed cobble bed over a wide range of channel slopes (0.004 < S < 0.3) and water discharges. Drag coefficients are similar to previous findings for submerged particles (CD ∼ 0.7) but increase significantly for partially submerged particles. In contrast, lift coefficients decrease from near unity to zero as the flow shallows and are strongly negative for partially submerged particles, indicating a downward force that pulls particles toward the bed. Fluctuating forces in lift and drag decrease with increasing relative roughness, and they scale with the depth‐averaged velocity squared rather than the bed shear stress. We find that, even in the absence of complex bed topography, shallow flows over coarse sediment are characterized by high flow resistance because of grain drag within a roughness layer that occupies a significant fraction of the total flow depth, and by heightened critical Shields numbers and reduced sediment fluxes because of reduced lift forces and reduced turbulent fluctuations.
Visualizing and quantifying the crossover from capillary fingering to viscous fingering in a rough fracture
Authors: Chen Yi‐Feng , Fang Shu , Wu Dong‐Sheng , Hu Ran
Published: August 2017

Immiscible fluid‐fluid displacement in permeable media is important in many subsurface processes, including enhanced oil recovery and geological CO2 sequestration. Controlled by capillary and viscous forces, displacement patterns of one fluid displacing another more viscous one exhibit capillary and viscous fingering, and crossover between the two. Although extensive studies investigated viscous and capillary fingering in porous media, a few studies focused on the crossover in rough fractures, and how viscous and capillary forces affect the crossover remains unclear. Using a transparent fracture‐visualization system, we studied how the two forces impact the crossover in a horizontal rough fracture. Drainage experiments of water displacing oil were conducted at seven flow rates (capillary number log10Ca ranging from −7.07 to −3.07) and four viscosity ratios (M=1/1000,1/500,1/100 and 1/50). We consistently observed lower invading fluid saturations in the crossover zone. We also proposed a phase diagram for the displacement patterns in a rough fracture that is consistent with similar studies in porous media. Based on real‐time imaging and statistical analysis of the invasion morphology, we showed that the competition between capillary and viscous forces is responsible for the saturation reduction in the crossover zone. In this zone, finger propagation toward the outlet (characteristic of viscous fingering) as well as void‐filling in the transverse/backward directions (characteristic of capillary fingering), are both suppressed. Therefore, the invading fluid tends to occupy larger apertures with higher characteristic front velocity, promoting void‐filling toward the outlet with thinner finger growth and resulting in a larger volume of defending fluid left behind.
Limits of heat as a tracer to quantify transient lateral river‐aquifer exchanges
Authors: Xie Yueqing , Batlle‐Aguilar Jordi
Published: August 2017

The application of heat as a tracer for assessing river‐aquifer exchanges has been mainly limited to vertical flow through the riverbed. Lateral river‐aquifer exchanges become more important than vertical riverbed exchanges if the river is deeply incised into an aquifer. Few studies have examined lateral river‐aquifer exchanges and the ability of heat to constrain such exchanges. This study aims to perform a robust assessment of the limits of heat as a tracer to quantify lateral river‐aquifer exchanges. The study is based on a section of the Meuse River in Belgium, a river predominantly gaining in the studied area and becoming intermittently losing in the winter time. A calibrated transect model shows that river temperature can affect groundwater temperature up to 9 m into the aquifer. An accompanying synthetic modeling investigation using Monte Carlo simulation shows that heat data for distances between 4 and 9 m from the river can reduce the uncertainty of river‐aquifer exchanges for conditions similar to those of the transect model. The ability of heat to reduce the river‐aquifer exchange uncertainty improves with distance from the river because of the reduction in the number of acceptable model realizations. The optimal distance is 8 m from the river where the groundwater temperature is no longer affected by the river temperature. The synthetic modeling also indicates that heat alone cannot constrain river‐aquifer exchanges better than the commonly used hydraulic head. However, when combined with hydraulic head, heat can significantly reduce the uncertainty of river‐aquifer lateral exchanges under gaining conditions.
Embedded Spheroids as Models of the Cancer Microenvironment
Authors: Tevis Kristie M. , Colson Yolonda L. , Grinstaff Mark W.
Published: August 2017

To more accurately study the complex mechanisms behind cancer invasion, progression, and response to treatment, researchers require models that replicate both the multicellular nature and 3D stromal environment present in an in vivo tumor. Multicellular aggregates (i.e., spheroids) embedded in an extracellular matrix mimic are a prevalent model. Recently, quantitative metrics that fully utilize the capability of spheroids are described along with conventional experiments, such as invasion into a matrix, to provide additional details and insights into the underlying cancer biology. The article begins with a discussion of the salient features of the tumor microenvironment, introduces the early work on non‐embedded spheroids as tumor models, and then concentrates on the successes achieved with the study of embedded spheroids. Examples of studies include cell movement, drug response, tumor cellular heterogeneity, stromal effects, and cancer progression. Additionally, new methodologies and those borrowed from other research fields (e.g., vascularization and tissue engineering) are highlighted that expand the capability of spheroids to aid future users in designing their cancer‐related experiments. The convergence of spheroid research among the various fields catalyzes new applications and leads to a natural synergy. Finally, the article concludes with a reflection and future perspectives for cancer spheroid research.
Cancer Cell Membrane‐Biomimetic Oxygen Nanocarrier for Breaking Hypoxia‐Induced Chemoresistance
Authors: Tian Hao , Luo Zhenyu , Liu Lanlan , Zheng Mingbin , Chen Ze , Ma Aiqing , Liang Ruijing , Han Zhiqun , Lu Chengyu , Cai Lintao
Published: August 2017

The inadequate oxygen supply in solid tumor causes hypoxia, which leads to drug resistance and poor chemotherapy outcomes. To solve this problem, a cancer cell membrane camouflaged nanocarrier is developed with a polymeric core encapsulating hemoglobin (Hb) and doxorubicin (DOX) for efficient chemotherapy. The designed nanoparticles (DHCNPs) retain the cancer cell adhesion molecules on the surface of nanoparticles for homologous targeting and possess the oxygen‐carrying capacity of Hb for O2‐interfered chemotherapy. The results show that DHCNPs not only achieve higher tumor specificity and lower toxicity by homologous targeting but also significantly reduce the exocytosis of DOX via suppressing the expressions of hypoxia‐inducible factor‐1α, multidrug resistance gene 1, and P‐glycoprotein, thus resulting in safe and high‐efficient chemotherapy. This work presents a new paradigm for targeted oxygen interference therapy by conquering hypoxia‐involved therapeutic resistance and achieves effective treatment of solid tumors.
Intermolecular Tandem Addition/Esterification Reaction of Alkenes with Malonates Leading to γ‐Lactones Mediated by Molecular Iodine under Visible Light Irradiation
Authors: Maejima Saki , Yamaguchi Eiji , Itoh Akichika
Published: August 2017

The iodine‐mediated intermolecular C−C bond‐forming/esterification reaction of various alkenes including α‐olefins with malonates under irradiation using a compact fluorescent lamp has been developed to synthesize γ‐lactones in moderate to excellent yields. The method developed in this research shows broad substrate scope and moderate diastereoselectivity and constructs valuable polyfunctionalized γ‐lactones. Furthermore, the developed methodology was comprehensively studied by performing several control experiments, radical trapping, and radical clock experiments. These experiments showed that sequential iodination by an iodine radical is triggered for the following C−C bond‐forming reaction.γ

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Liquid‐Gated Organic Electronic Devices Based on High‐Performance Solution‐Processed Molecular Semiconductor
Authors: Di Lauro Michele , Berto Marcello , Giordani Martina , Benaglia Simone , Schweicher Guillaume , Vuillaume Dominique , Bortolotti Carlo A. , Geerts Yves H. , Biscarini Fabio
Published: August 2017

High‐mobility organic semiconductors such as [1]benzothieno[3,2‐b]benzothiophene (BTBT) derivatives are potential candidates for ultrasensitive biosensors. Here 2,7‐dioctyl BTBT (C8‐BTBT‐C8)‐based liquid‐gated organic electronic devices are demonstrated with two device architectures, viz. electrolyte‐gated organic field‐effect transistor (EGOFET) and electrolyte‐gated organic synapstor (EGOS), and different electrode materials, viz. gold and poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). EGOFETs exhibit a mean transconductance of about 45 µS, on a par with literature, and a max value up to 256 µS at the state‐of‐the‐art in aqueous electrolyte, with a mean product of charge mobility and effective capacitance of about 0.112 and 0.044 µS V−1 for gold and PEDOT:PSS electrodes, respectively. EGOSs exhibit a dynamic response with 15 ms characteristic timescale with Au electrodes and about twice with PEDOT:PSS electrodes. These results demonstrate a promising route for sensing applications in physiological environment based on fully solution‐processed whole‐organic electronic devices featuring ultrahigh sensitivity and fast response.
Synergistic effects of polymer and bentonite clay on rheology and thermal stability of foam fluid developed for hydraulic fracturing
Authors: Verma Amit , Chauhan Geetanjali , Ojha Keka
Published: August 2017

Demand for foam fracturing fluids is ever‐increasing because of its nondamaging characteristics, less water requirement, combined with efficient proppant carrying capacity. The present study reported the synergistic effects of bentonite clay and polymer (guar) on rheology and stability of the foam prepared with surfactant (sodium dodecyl sulfate). Bentonite clay, which is never considered so far for improving quality of foam fracturing fluid, was found to provide improved foam rheology at reduced polymer concentration. Static and dynamic rheology with microscopic study showed the improvement of apparent viscosity, viscoelasticity, thermal stability, and morphology of foam on addition of bentonite clay. Addition of bentonite reduced the doses of polymer with similar proppant suspension capacity, which could be preferred over conventional gelled foam to reduce formation damage incurred by insoluble guar in the very low permeability unconventional reservoirs like shale gas, coal bed methane, or water‐sensitive formations. © 2017 Curtin University and John Wiley & Sons, Ltd.
Wide σ Orionis binaries resolved by UKIDSS
Authors: Caballero J. A. , Novalbos I. , Tobal T. , Miret F. X.
Published: August 2017

In spite of its importance for the study of star formation at all mass domains, the nearby young σ Orionis cluster still lacks a comprehensive survey for multiplicity. We try to fill that observational gap by looking for wide resolved binaries with angular separations between 0.4 and 4.0 arcsec. We search for companions to 331 cataloged cluster stellar members and candidates in public K‐band UKIDSS images outside the innermost 1 arcmin, which is affected by the glare of the bright, eponymous σ Ori multiple system, and investigate their cluster membership with color–magnitude diagrams and previous knowledge of youth features. Of the 18 identified pairs, 10 have very low individual probabilities of chance alignment (< 1%) and are considered here as physical pairs. Four of them are new, while the other six had been discovered previously but never investigated homogeneously and in detail. Projected physical separations and magnitude differences of the 10 probably bound pairs range from 180 to 1220 au, and from 0.0 to 3.4 mag in K, respectively. Besides, we identify two cluster stars with elongated point spread functions. We determine the minimum frequency of wide multiplicity in the interval of projected physical separations s = 160–1600 au in σ Orionis at 3.0%. We discover a new Lindroos system, find that massive and X‐ray stars tend to be in pairs or trios, conclude that multiplicity truncates circumstellar disks and enhances X‐ray emission, and ascribe a reported lithium depletion in a young star to unresolved binarity in spectra of moderate resolution. When accounting for all known multiples, including spectroscopic binaries, the minimum frequency of multiplicity increases to about 10%, which implies that of the order of 80–100 unknown multiple systems still await discovery in σ Orionis.
Mesenchymal Stem Cells Relevance in Multicellular Bioengineered 3D In Vitro Tumor Models
Authors: Ferreira Luís P. , Gaspar Vítor M. , Henrique Rui , Jerónimo Carmen , Mano João F.
Published: August 2017

In vitro 3D tumor microenvironment mimicking models are gathering momentum as alternatives to traditional 2D flat monolayer cultures due to their potential for recapitulating major cancer hallmarks. To fulfill such potential, it is crucial that 3D tumor testing platforms completely emulate in vitro the complex in vivo tumor niche and its cellular constituents. Mesenchymal stem cells (MSCs) are recognized to play a pivotal multi‐modulatory role in cancer, generating interest as biological targets and as key tumor suppressing, or tumor promoting effectors. This review discusses the biological influence of different types of MSCs in the tumor microenvironment and showcases recent studies that engineer 3D MSCs‐cancer cells co‐cultures as advanced in vitro therapy testing platforms. A special focus is given to MSCs‐cancer 3D co‐culture set‐up parameters, challenges, and future opportunities. Understanding cancer‐MSCs crosstalk and their underlying effects is envisioned to support the development of advanced 3D in vitro disease models for discovery of forefront cancer treatments.
The discussion of t(1;17)(p11;q21) translocation in acute promyelocytic leukemia patient on molecular remission
Authors: Jia Yannan , Li Chengwen , Zhao Jiawei , Song Yang , Wang Juan , Mi Yingchang
Published: August 2017

Key Clinical Message

Some chromosomal aberrations emerging in the course of treatment are probably not related to disease progression, but attribute to the germline alteration. Therefore, the dynamic genetic tests should be performed during the whole treatment process, which is significantly essential for efficacy evaluation and treatment decision‐ making.
Esterification of Palm Fatty Acid Distillate Using a Sulfonated Mesoporous CuO‐ZnO Mixed Metal Oxide Catalyst
Authors: Soltani Soroush , Rashid Umer , Nehdi Imededdine Arbi , Al-Resayes Saud Ibrahim
Published: August 2017

A nanocrystalline mesoporous CuO‐ZnO hollow sphere was successfully fabricated by the hydrothermal method. The nanocomposite was formed in the presence of polyethylene glycol as a dispersant and D‐glucose as a template. The mesoporous CuO‐ZnO catalyst was further functionalized with benzenesulfonic acid to catalyze the esterification of palm fatty acid distillate (PFAD). The physicochemical, textural, structural, and thermal properties of the mesoporous CuO‐ZnO mixed‐oxide catalysts were evaluated. The modified mesoporous catalyst possessed unique textural properties. With a Cu/Zn atomic ratio of 1.0 the best catalytic activity through PFAD esterification was achieved. The optimum reaction conditions in terms of methanol/PFAD molar ratio, catalyst concentration, reaction temperature, and reaction time were determined.