bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphoproteomic analysis of protease-activated receptor-1 biased signaling reveals unique modulators of endothelial barrier function
Authors: Lin Ying , Wozniak Jacob M. , Grimsey Neil J. , Girada Sravan , Patwardhan Anand , Molinar-Inglis Olivia , Smith Thomas H. , Lapek John D. , Gonzalez David J. , Trejo JoAnn
Published: February 2020

Thrombin, a procoagulant protease, cleaves and activates protease-activated receptor-1 (PAR1) to promote inflammatory responses and endothelial dysfunction. In contrast, activated protein C (APC), an anticoagulant protease, activates PAR1 through a distinct cleavage site and promotes anti-inflammatory responses, prosurvival, and endothelial barrier stabilization. The distinct tethered ligands formed through cleavage of PAR1 by thrombin versus APC result in unique active receptor conformations that bias PAR1 signaling. Despite progress in understanding PAR1 biased signaling, the proteins and pathways utilized by thrombin versus APC signaling to induce opposing cellular functions are largely unknown. Here, we report the global phosphoproteome induced by thrombin and APC signaling in endothelial cells with the quantification of 11,266 unique phosphopeptides using multiplexed quantitative mass spectrometry. Our results reveal unique dynamic phosphoproteome profiles of thrombin and APC signaling, an enrichment of associated biological functions, including key modulators of endothelial barrier function, regulators of gene transcription, and specific kinases predicted to mediate PAR1 biased signaling. Using small interfering RNA to deplete a subset of phosphorylated proteins not previously linked to thrombin or APC signaling, a function for afadin and adducin-1 actin binding proteins in thrombin-induced endothelial barrier disruption is unveiled. Afadin depletion resulted in enhanced thrombin-promoted barrier permeability, whereas adducin-1 depletion completely ablated thrombin-induced barrier disruption without compromising p38 signaling. However, loss of adducin-1 blocked APC-induced Akt signaling. These studies define distinct thrombin and APC dynamic signaling profiles and a rich array of proteins and biological pathways that engender PAR1 biased signaling in endothelial cells.
Bisphenol A and bisphenol S disruptions of the mouse placenta and potential effects on the placenta–brain axis
Authors: Mao Jiude , Jain Ashish , Denslow Nancy D. , Nouri Mohammad-Zaman , Chen Sixue , Wang Tingting , Zhu Ning , Koh Jin , Sarma Saurav J. , Sumner Barbara W. , Lei Zhentian , Sumner Lloyd W. , Bivens Nathan J. , Roberts R. Michael , Tuteja Geetu , Rosenfeld Cheryl S.
Published: February 2020

Placental trophoblast cells are potentially at risk from circulating endocrine-disrupting chemicals, such as bisphenol A (BPA). To understand how BPA and the reputedly more inert bisphenol S (BPS) affect the placenta, C57BL6J mouse dams were fed 200 μg/kg body weight BPA or BPS daily for 2 wk and then bred. They continued to receive these chemicals until embryonic day 12.5, whereupon placental samples were collected and compared with unexposed controls. BPA and BPS altered the expression of an identical set of 13 genes. Both exposures led to a decrease in the area occupied by spongiotrophoblast relative to trophoblast giant cells (GCs) within the junctional zone, markedly reduced placental serotonin (5-HT) concentrations, and lowered 5-HT GC immunoreactivity. Concentrations of dopamine and 5-hydroxyindoleacetic acid, the main metabolite of serotonin, were increased. GC dopamine immunoreactivity was increased in BPA- and BPS-exposed placentas. A strong positive correlation between 5-HT+GCs and reductions in spongiotrophoblast to GC area suggests that this neurotransmitter is essential for maintaining cells within the junctional zone. In contrast, a negative correlation existed between dopamine+GCs and reductions in spongiotrophoblast to GC area ratio. These outcomes lead to the following conclusions. First, BPS exposure causes almost identical placental effects as BPA. Second, a major target of BPA/BPS is either spongiotrophoblast or GCs within the junctional zone. Third, imbalances in neurotransmitter-positive GCs and an observed decrease in docosahexaenoic acid and estradiol, also occurring in response to BPA/BPS exposure, likely affect the placental–brain axis of the developing mouse fetus.
Sexually dimorphic role of oxytocin in medaka mate choice
Authors: Yokoi Saori , Naruse Kiyoshi , Kamei Yasuhiro , Ansai Satoshi , Kinoshita Masato , Mito Mari , Iwasaki Shintaro , Inoue Shuntaro , Okuyama Teruhiro , Nakagawa Shinichi , Young Larry J. , Takeuchi Hideaki
Published: February 2020

Oxytocin is a central neuromodulator required for facilitating mate preferences for familiar individuals in a monogamous rodent (prairie vole), irrespective of sex. While the role of oxytocin in mate choice is only understood in a few monogamous species, its function in nonmonogamous species, comprising the vast majority of vertebrate species, remains unclear. To address this issue, we evaluated the involvement of an oxytocin homolog (isotocin, referred herein as oxt) in mate choice in medaka fish (
Oryzias latipes
). Female medaka prefer to choose familiar mates, whereas male medaka court indiscriminately, irrespective of familiarity. We generated mutants of the oxt ligand (
oxt
) and receptor genes (
oxtr1
and
oxtr2
) and revealed that the oxt-oxtr1 signaling pathway was essential for eliciting female mate preference for familiar males. This pathway was also required for unrestricted and indiscriminate mating strategy in males. That is, either
oxt
or
oxtr1
mutation in males decreased the number of courtship displays toward novel females, but not toward familiar females. Further, males with these mutations exhibited enhanced mate-guarding behaviors toward familiar females, but not toward novel females. In addition, RNA-sequencing (seq) analysis revealed that the transcription of genes involved in gamma-amino butyric acid metabolism as well as those encoding ion-transport ATPase are up-regulated in both
oxt
and
oxtr1
mutants only in female medaka, potentially explaining the sex difference of the mutant phenotype. Our findings provide genetic evidence that oxt-oxtr1 signaling plays a role in the mate choice for familiar individuals in a sex-specific manner in medaka fish.
Climate and plant community diversity in space and time
Authors: Harrison Susan , Spasojevic Marko J. , Li Daijiang
Published: February 2020

Climate strongly shapes plant diversity over large spatial scales, with relatively warm and wet (benign, productive) regions supporting greater numbers of species. Unresolved aspects of this relationship include what causes it, whether it permeates to community diversity at smaller spatial scales, whether it is accompanied by patterns in functional and phylogenetic diversity as some hypotheses predict, and whether it is paralleled by climate-driven changes in diversity over time. Here, studies of Californian plants are reviewed and new analyses are conducted to synthesize climate–diversity relationships in space and time. Across spatial scales and organizational levels, plant diversity is maximized in more productive (wetter) climates, and these consistent spatial relationships are mirrored in losses of taxonomic, functional, and phylogenetic diversity over time during a recent climatic drying trend. These results support the tolerance and climatic niche conservatism hypotheses for climate–diversity relationships, and suggest there is some predictability to future changes in diversity in water-limited climates.
Latinxs’ bilingualism at work in the US
Authors: Alonso Lara , Villa Laura
Published: February 2020

In the current context of a globalized economy, bilingualism is
increasingly portrayed as a resource for corporations and for workers competing
for jobs in today’s slim market. In this paper we analyze the economic value of
languages other than English in the US, Spanish in particular. Working from a
political economy perspective and drawing from current theoretical approaches to
language and labor under neoliberalism, we examine the reproduction of the
discursive trope of language profit in the corporate world and educational
spaces, and then analyze the narratives and trajectories of young Latinx workers
in New York. The marginalized position of Latinxs in the social structure and
the racialization of their linguistic practices result in a linguistic
exploitation that remains unchallenged in the US. We conclude that today’s
celebrations of bilingualism, which follow a capitalist logic, perpetuate a
hierarchy of languages and speakers that is detrimental to racialized
minorities.
USP22 controls iNKT immunity through MED1 suppression of histone H2A monoubiquitination
Authors: Zhang Yana , Wang Yajun , Gao Beixue , Sun Yueqi , Cao Liang , Genardi Samantha M. , Wang Chyung-Ru , Li HuaBin , Sun Zhaolin , Yang Yanjie , Fang Deyu
Published: February 2020

The ubiquitin pathway has been shown to regulate iNKT cell immunity, but the deubiquitinase involved in this process has not been identified. Herein we found that ubiquitin-specific peptidase 22 (USP22) is highly expressed in iNKT cells during their early developmental stage 1. USP22 deficiency blocked the transition from stage 1 to 2 during iNKT cell development in a cell-intrinsic manner. USP22 suppression also diminishes iNKT17 and iNKT1 differentiation but favors iNKT2 polarization without altering conventional T cell activation and differentiation. USP22 interacts with the Mediator complex subunit 1 (MED1), a transcription coactivator involved in iNKT cell development. Interestingly, while interacting with MED1, USP22 does not function as a deubiquitinase to suppress MED1 ubiquitination for its stabilization. Instead, USP22 enhances MED1 functions for IL-2Rβ and T-bet gene expression through deubiquitinating histone H2A but not H2B monoubiquitination. Therefore, our study revealed USP22-mediated histone H2A deubiquitination fine-tunes MED1 transcriptional activation as a previously unappreciated molecular mechanism to control iNKT development and functions.
Microswimmers in an axisymmetric vortex flow
Authors: Arguedas-Leiva José-Agustín , Wilczek Michael
Published: February 2020

Microswimmers are encountered in a wide variety of biophysical settings. When interacting with flow fields, they show interesting dynamical features such as hydrodynamic trapping, clustering, and preferential orientation. One important step towards the understanding of such features is to clarify the interplay of hydrodynamic flows with microswimmer motility and shape. Here, we study the dynamics of ellipsoidal microswimmers in a two-dimensional axisymmetric vortex flow. Despite this simple setting, we find surprisingly rich dynamics, which can be comprehensively characterized in the framework of dynamical systems theory. By classifying the fixed-point structure of the underlying phase space as a function of motility and microswimmer shape, we uncover the topology of the phase space and determine the conditions under which microswimmers are trapped in the vortex. For spherical microswimmers, we identify Hamiltonian dynamics, which are broken for microswimmers of a different shape. We find that prolate ellipsoidal microswimmers tend to align parallel to the velocity field, while oblate microswimmers tend to remain perpendicular to it. Additionally, we find that rotational noise allows microswimmers to escape the vortex with an enhanced escape rate close to the system’s saddle point. Our results clarify the role of shape and motility on the occurrence of preferential concentration and clustering and provide a starting point to understand the dynamics in more complex flows.
Nonlocal solitons supported by non-parity-time-symmetric complex potentials
Authors: Zhu Xing , Peng Xi , Qiu Yunli , Wang Hongcheng , He Yingji
Published: February 2020

We report on the existence and stability of fundamental and out-of-phase dipole solitons in nonlocal focusing Kerr media supported by one-dimensional non-parity-time (PT)-symmetric complex potentials. These fundamental and dipole solitons bifurcate from different discrete eigenvalues in the linear spectra. Below the phase transition of the non-PT-symmetric complex potentials, these solitons are stable in the low power region. While above the phase transition, they are stable in the moderate power region. The eigenvalues in linear-stability spectra of solitons appear as conjugation pairs (δ, δ
*). The transverse power flow and the nonlinear contribution to refractive index are asymmetric functions. Moreover, the degree of nonlocality can also influence the stability of these solitons.
Investigation of active-region doping on InAs/GaSb long wave infrared detectors*
Authors: Cui Su-Ning , Jiang Dong-Wei , Sun Ju , Jia Qing-Xuan , Li Nong , Zhang Xuan , Li Yong , Chang Fa-Ran , Wang Guo-Wei , Xu Ying-Qiang , Niu Zhi-Chuan
Published: February 2020

The eight-band
k
⋅
p
model is used to establish the energy band structure model of the type-II InAs/GaSb superlattice detectors with a cut-off wavelength of 10.5 μm, and the best composition of M-structure in this type of device is calculated theoretically. In addition, we have also experimented on the devices designed with the best performance to investigate the effect of the active region p-type doping temperature on the quantum efficiency of the device. The results show that the modest active region doping temperature (Be: 760 °C) can improve the quantum efficiency of the device with the best performance, while excessive doping (Be: > 760 °C) is not conducive to improving the photo response. With the best designed structure and an appropriate doping concentration, a maximum quantum efficiency of 45% is achieved with a resistance–area product of 688 Ω ⋅cm2, corresponding to a maximum detectivity of 7.35 × 1011cm ⋅ Hz1/2/W.
Generating Kerr nonlinearity with an engineered non-Markovian environment*
Authors: Xiong Fei-Lei , Yang Wan-Li , Feng Mang
Published: February 2020

Kerr nonlinearity is an important resource for creating squeezing and entanglement in quantum technology. Here we propose a scheme for generating Kerr nonlinearity originated from an engineered non-Markovian environment, which is different from the previous efforts using nonlinear media or quantum systems with special energy structures. In the present work, the generation of Kerr nonlinearity depends on the system–environment interaction time, the energy spectrum of the environment, and the system–environment coupling strength, regardless of the environmental initial state. The scheme can be realized in systems originally containing no Kerr interaction, such as superconducting circuit systems, optomechanical systems, and cavity arrays connected by transmission lines.
Molecular dynamics simulation of thermal conductivity of silicone rubber*
Authors: Xu Wenxue , Wu Yanyan , Zhu Yuan , Liang Xin-Gang
Published: February 2020

Silicone rubber is widely used as a kind of thermal interface material (TIM) in electronic devices. However few studies have been carried out on the thermal conductivity mechanism of silicone rubber. This paper investigates the thermal conductivity mechanism by non-equilibrium molecular dynamics (NEMD) in three aspects: chain length, morphology, and temperature. It is found that the effect of chain length on thermal conductivity varies with morphologies. In crystalline state where the chains are aligned, the thermal conductivity increases apparently with the length of the silicone-oxygen chain, the thermal conductivity of 79 nm-long crystalline silicone rubber could reach 1.49 W/(m⋅K). The thermal conductivity of amorphous silicone rubber is less affected by the chain length. The temperature dependence of thermal conductivity of silicone rubbers with different morphologies is trivial. The phonon density of states (DOS) is calculated and analyzed. The results indicate that crystalline silicone rubber with aligned orientation has more low frequency phonons, longer phonon MFP, and shorter conducting path, which contribute to a larger thermal conductivity.
Two-step processed efficient perovskite solar cells via improving perovskite/PTAA interface using solvent engineering in PbI2 precursor*
Authors: Long Cao-Yu , Wang Ning , Huang Ke-Qing , Li Heng-Yue , Liu Biao , Yang Jun-Liang
Published: February 2020

The morphology and interface of perovskite film are very important for the performance of perovskite solar cells (PSCs). The quality of perovskite film, fabricated via two-step spin-coating process, is significantly influenced by the morphology and crystallinity of PbI2 film. With the addition of additive dimethyl sulfoxide (DMSO) into the PbI2 precursor, the roughness and trap-state density of perovskite film have been significantly reduced, leading to the excellent contact between perovskite layer and subsequent deposited carrier transport layer. Accordingly, the planar heterojunction PSCs with an architecture of ITO/SnO2/perovskite/PTAA/Ag show an efficiency up to 19.02%. Furthermore, PSCs exhibit promising stability in air with a humidity of ∼ 45%, and retain 80% of initial efficiency after being exposed to air for 400 h without any encapsulation.
Major factors of global and regional monsoon rainfall changes: natural versus anthropogenic forcing
Authors: Ha Kyung-Ja , Kim Byeong-Hee , Chung Eui-Seok , Chan Johnny C L , Chang Chih-Pei
Published: February 2020

A number of studies have investigated the mechanisms that determine changes in precipitation, including how a wet region gets wetter. However, not all monsoon areas get wetter—there is a need to understand the major factors behind changes in regional monsoon precipitation, in terms of external forcing and internal variabilities in the last six decades by a combination of different observed datasets and model runs. We have found that time of emergence of anthropogenic signals is robustly detected in the northern African monsoon before the 1990s with the use of the CESM Large Ensemble Project. From CMIP5 model runs and three reanalysis datasets, the results found are that the change in rainfall over African monsoon (AFM) is mainly due to anthropogenic forcing and that over Asian-Australian monsoon (AAM) is affected by internal variability. Moreover, the cause of American monsoon (AMM) rainfall change cannot be known due to a discrepancy among observed datasets. Here we show that the asymmetry between Northern Hemisphere (NH) and Southern Hemisphere (SH) parts by green-house gas (GHG) is detected over the AFM and AAM regions. However, the land monsoon rainfall in the northern AMM is decreased by a combination of GHG and aerosol forcing. In general, the aerosol forcing causes a decreasing rainfall over the monsoon regions. In future projection, the land rainfall over the AAM and AMM are expected to increase and decrease in the future from most models’ results. The asymmetry between an increase in NH and a decrease in SH is dominant in the future from most models’ future simulation results, which is well shown over the AFM and AAM. This study suggests that the physical process of GHG and aerosol effects in rainfall should be explored in the context of regional aspects.
‘Mbare Musika is ours’: An analysis of a fresh produce market in Zimbabwe
Authors: Chikulo Shiela , Hebinck Paul , Kinsey Bill
Published: February 2020

The functioning of markets is premised on the creation of collaborative relationships and networks. Food markets in Zimbabwe are evolving in response to state interventions that aim to restructure the marketplace and the flow of produce. This article explores Mbare Musika, the oldest and largest marketplace in Harare supplying the city with fresh fruit and vegetables. We analyse Mbare Musika from the perspective of the interactions among farmers and retailers, vendors, transporters, intermediaries, officials, and customers, in creating and sustaining a specific enduring market. We use actor narratives to understand the ordering and (re)ordering of people and produce in the context of informalization, shifting polycentric relationships, and market infrastructure to sustain livelihoods anchored on the circulation of large volumes of diverse fresh produce. The market is overtly economic in outlook but, intrinsically, it is a social arena where discourses are continuously reconstructed, reproduced, and expressed through daily interactions. We situate Mbare Musika in past and present sociopolitical processes of transformation in Zimbabwe.
RFPR-IDP: reduce the false positive rates for intrinsically disordered protein and region prediction by incorporating both fully ordered proteins and disordered proteins
Authors: Liu Yumeng , Wang Xiaolong , Liu Bin
Published: February 2020

As an important type of proteins, intrinsically disordered proteins/regions (IDPs/IDRs) are related to many crucial biological functions. Accurate prediction of IDPs/IDRs is beneficial to the prediction of protein structures and functions. Most of the existing methods ignore the fully ordered proteins without IDRs during training and test processes. As a result, the corresponding predictors prefer to predict the fully ordered proteins as disordered proteins. Unfortunately, these methods were only evaluated on datasets consisting of disordered proteins without or with only a few fully ordered proteins, and therefore, this problem escapes the attention of the researchers. However, most of the newly sequenced proteins are fully ordered proteins in nature. These predictors fail to accurately predict the ordered and disordered proteins in real-world applications. In this regard, we propose a new method called RFPR-IDP trained with both fully ordered proteins and disordered proteins, which is constructed based on the combination of convolution neural network (CNN) and bidirectional long short-term memory (BiLSTM). The experimental results show that although the existing predictors perform well for predicting the disordered proteins, they tend to predict the fully ordered proteins as disordered proteins. In contrast, the RFPR-IDP predictor can correctly predict the fully ordered proteins and outperform the other 10 state-of-the-art methods when evaluated on a test dataset with both fully ordered proteins and disordered proteins. The web server and datasets of RFPR-IDP are freely available at http://bliulab.net/RFPR-IDP/server.
DIMERBOW: exploring possible GPCR dimer interfaces
Authors: García-Recio Adrián , Navarro Gemma , Franco Rafael , Olivella Mireia , Guixà-González Ramon , Cordomí Arnau
Published: February 2020

Motivation

G protein-coupled receptors (GPCRs) can form homo-, heterodimers and larger order oligomers that exert different functions than monomers. The pharmacological potential of such complexes is hampered by the limited information available on the type of complex formed and its quaternary structure. Several GPCR structures in the Protein Data Bank display crystallographic interfaces potentially compatible with physiological interactions.

Results

Here, we present DIMERBOW, a database and web application aimed to visually browse the complete repertoire of potential GPCR dimers present in solved structures. The tool is suited to help finding the best possible structural template to model GPCR homomers.

Availability and implementation

DIMERBOW is available at http://lmc.uab.es/dimerbow/.

Supplementary information

Supplementary data are available at Bioinformatics online.
High levels of androgens cause chondrocyte accumulation and loss of smooth muscle in the mouse penile body†
Authors: Hiremath Deepak S , Geerling Elizabeth C , Hai Lan , Narayan Prema
Published: February 2020

Androgens are essential for penile development and for maintaining penile structural and functional integrity. Loss of androgen levels or function results in a decrease in smooth muscle content, accumulation of adipocytes in the corpora cavernosa, and inhibition of erectile function. Our previous studies with a mouse model (KiLHRD582G) of constitutive luteinizing hormone receptor activity also showed structural abnormalities in the penis caused by a decrease in smooth muscle content, accumulation of chondrocytes, and sexual dysfunction. As KiLHRD582G mice exhibit very high levels of testosterone at all postnatal ages, the goal of this study was to determine if the elevated androgen levels were responsible for the morphological changes in the penis. Implantation of testosterone capsules in wild-type mice at neonatal (2 weeks) and postpubertal (5 weeks) ages resulted in the accumulation of chondrocytes in the corpora cavernosa of the adult animals. Mice implanted with testosterone capsules at 2 weeks of age exhibited a 4-fold increase in serum testosterone with a 1.5-fold loss of smooth muscle at 24 weeks of age. Collagen content was unchanged. Only 57% of testosterone implanted mice were fertile at 24 weeks of age. Mice implanted with testosterone capsules at 5 weeks of age showed no decrease in smooth muscle content at 24 weeks, although serum testosterone levels were elevated 5-fold. Implantation with dihydrotestosterone also resulted in chondrocyte accumulation and a 2-fold loss in smooth muscle content. Together, these studies demonstrate that supraphysiological levels of androgens cause structural changes in the penile corpora cavernosa and impair fertility.
Qualification and Clinical Validation of an Immunodiagnostic Assay for Detecting 11 Additional Streptococcus pneumoniae Serotype–specific Polysaccharides in Human Urine
Authors: Kalina Warren V , Souza Victor , Wu Kangjian , Giardina Peter , McKeen Andrew , Jiang Qin , Tan Charles , French Roger , Ren Yanhua , Belanger Kelly , McElhiney Susan , Unnithan Manu , Cheng Huiming , Mininni Terri , Giordano-Schmidt Donna , Gessner Bradford D , Jansen Kathrin U , Pride Michael W
Published: February 2020

Background

Identifying Streptococcus pneumoniae serotypes by urinary antigen detection (UAD) assay is the most sensitive way to evaluate the epidemiology of nonbacteremic community-acquired pneumonia (CAP). We first described a UAD assay to detect the S. pneumoniae serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F, covered by the licensed 13-valent S. pneumoniae conjugate vaccine. To assess the substantial remaining pneumococcal disease burden after introduction of several pneumococcal vaccines, a UAD-2 assay was developed to detect 11 additional serotypes (2, 8, 9N, 10A, 11A, 12F, 15B, 17F, 20, 22F, and 33F) in individuals with radiographically confirmed CAP.

Methods

The specificity of the UAD-2 assay was achieved by capturing pneumococcal polysaccharides with serotype-specific monoclonal antibodies, using Luminex technology. Assay qualification was used to assess accuracy, precision, and sample linearity. Serotype positivity was based on cutoffs determined by nonparametric statistical evaluation of urine samples from individuals without pneumococcal disease. The sensitivity and specificity of the positivity cutoffs were assessed in a clinical validation, using urine samples obtained from a large study that measured the proportion of radiographically confirmed CAP caused by S. pneumoniae serotypes in hospitalized US adults.

Results

The UAD-2 assay was shown to be specific and reproducible. Clinical validation demonstrated assay sensitivity and specificity of 92.2% and 95.9% against a reference standard of bacteremic pneumonia. In addition, the UAD-2 assay identified a S. pneumoniae serotype in 3.72% of nonbacteremic CAP cases obtained from hospitalized US adults. When combined with bacteremic CAP cases, the proportion of pneumonias with a UAD-2 serotype was 4.33%.

Conclusions

The qualified/clinically validated UAD-2 method has applicability in understanding the epidemiology of nonbacteremic S. pneumoniae CAP and for assessing the efficacy of future pneumococcal conjugate vaccines that are under development.
Vascular endothelial S1pr1 ameliorates adverse cardiac remodelling via stimulating reparative macrophage proliferation after myocardial infarction
Authors: Kuang Yashu , Li Xiaolin , Liu Xiuxiang , Wei Lu , Chen Xiaoli , Liu Jie , Zhuang Tao , Pi Jingjiang , Wang Yanfang , Zhu Chenying , Gong Xin , Hu Hao , Yu Zuoren , Li Jiming , Yu Ping , Fan Huimin , Zhang Yuzhen , Liu Zhongmin , Zhang Lin
Published: February 2020

Aims 

Endothelial cell (EC) homoeostasis plays an important role in normal physiological cardiac functions, and its dysfunction significantly influences pathological cardiac remodelling after myocardial infarction (MI). It has been shown that the sphingosine 1-phosphate receptor 1 (S1pr1) was highly expressed in ECs and played an important role in maintaining endothelial functions. We thus hypothesized that the endothelial S1pr1 might be involved in post-MI cardiac remodelling.

Methods and results 

Our study showed that the specific loss of endothelial S1pr1 exacerbated post-MI cardiac remodelling and worsened cardiac dysfunction. We found that the loss of endothelial S1pr1 significantly reduced Ly6clow macrophage accumulation, which is critical for the resolution of inflammation and cardiac healing following MI. The reduced reparative macrophages in post-MI myocardium contributed to the detrimental effects of endothelial S1pr1 deficiency on post-MI cardiac remodelling. Further investigations showed that the loss of endothelial S1pr1-reduced Ly6clow macrophage proliferation, while the pharmacological activation of S1pr1-enhanced Ly6clow macrophage proliferation, thereby ameliorated cardiac remodelling after MI. A mechanism study showed that S1P/S1pr1 activated the ERK signalling pathway and enhanced colony-stimulating factor 1 (CSF1) expression, which promoted Ly6clow macrophage proliferation in a cell-contact manner. The blockade of CSF1 signalling reversed the enhancing effect of S1pr1 activation on Ly6clow macrophage proliferation and worsened post-MI cardiac remodelling.

Conclusion 

This study reveals that cardiac microvascular endothelium promotes reparative macrophage proliferation in injured hearts via the S1P/S1PR1/ERK/CSF1 pathway and thus ameliorates post-MI adverse cardiac remodelling.
Nitrogen concentration affects amphotericin B and fluconazole tolerance of pathogenic cryptococci
Authors: Bosch Caylin , Toplis Barbra , Vreulink Jo-Marie , Volschenk Heinrich , Botha Alfred
Published: February 2020

Environmental stress often causes phenotypic changes among pathogenic cryptococci, such as altered antifungal susceptibility, changes in capsule and melanin formation, as well as altered levels of the membrane sterol and antifungal target, ergosterol. We therefore hypothesised that nitrogen limitation, a prevalent environmental stress in the natural habitat of these yeasts, might affect virulence and antifungal susceptibility. We tested the effect of different nitrogen concentrations on capsule, melanin and ergosterol biosynthesis, as well as amphotericin B (AmB) and fluconazole (FLU) susceptibility. This was achieved by culturing cryptococcal strains representing Cryptococcus neoformans and Cryptococcus gattii in media with high (0.53 g/l), control (0.42 g/l) and low (0.21 g/l) NH4Cl concentrations. India ink staining was used to determine capsule thickness microscopically, while melanin and ergosterol content were determined spectrophotometrically. We found that lower nitrogen concentrations enhanced both ergosterol and capsule biosynthesis, while a variable effect was observed on melanisation. Evaluation of drug tolerance using time-kill methodology, as well as tests for FLU heteroresistance, revealed that the low nitrogen cultures had the highest survival percentages in the presence of both AmB and FLU, and showed the highest frequency of FLU heteroresistance, suggesting that nitrogen concentration may indeed influence drug tolerance.
On the generation and segregation of helicity in geodynamo simulations
Authors: Ranjan A , Davidson P A , Christensen U R , Wicht J
Published: February 2020

Helicity, the inner product of velocity and vorticity, is considered an important ingredient for the maintenance of a dipolar magnetic field in the geodynamo. Outside the tangent cylinder—an imaginary cylinder which circumscribes the inner core—a spatial segregation of helicity has been observed in several simulations, being negative in the north and positive in the south. Such a segregation pattern is important for a dynamo that relies on the α-effect. However, the origin of this pattern in these simulations is poorly understood. In this paper, we use three strongly forced numerical dynamo solutions to study the various sources of helicity, including those due to buoyancy $({H_T})$, Coriolis, Lorentz and viscous forces. We find a strong spatial correlation between the segregation pattern of helicity and ${H_T}$ both in the instantaneous and the time-averaged results. Our results show that, outside the tangent cylinder, ${H_T}$ is dominated by the product $- {u_z}\partial T/\partial \varphi $, where ${u_z}$ is the vertical velocity component and T is the temperature perturbation. It is known that when inertial waves are launched from a localized buoyant anomaly, ${H_T}$ takes the same sign as the local helicity. We conjecture that this is the reason for the spatial correlation between ${H_T}$ and helicity in our simulation results. The flow in our simulations being strongly turbulent, this effect seems to be a statistical one and manifests itself most clearly in the averaged quantities.
Effects of salinity and pH on the spectral induced polarization signals of graphite particles
Authors: Wu Yuxin , Peruzzo Luca
Published: February 2020

The electrical property of micrometre-sized graphite particles was investigated under different particle concentration, particle size, fluid conductivity and pH conditions. Due to its large internal electronic conductivity and ability to polarize under external potential field, significant enhancement of its spectral induced polarization (SIP) responses is observed when graphite is included in sand mixtures. While a small amount of graphite inclusion significantly increases the SIP response of its mixtures with sand, further concentration increase does not necessarily lead to a proportional increase of the SIP response. This is shown to be related to the formation of graphite aggregates at higher concentrations. Changes of fluid salinity have a significant effect on graphite's SIP behaviour. This includes a positive impact on normalized chargeability and imaginary conductivity, but a negative impact on chargeability and relaxation time constant. The effect of pH on the SIP response of graphite is small but shows consistent trend, where pH increase leads to a decrease of both the chargeability and relaxation time constant. The underlying cause of this effect is not clear.
On the influence of different misfit functions for attenuation estimation in viscoelastic full-waveform inversion: synthetic study
Authors: Pan Wenyong , Wang Yanfei
Published: February 2020

Estimating subsurface attenuation distribution is essential to compensate the amplitude and phase distortions in seismic imaging and characterize attenuative reservoirs. Full-waveform inversion (FWI) methods represent promising techniques to invert for both velocity and attenuation models with arbitrary spatial distributions. However, simultaneously determining velocity and attenuation properties introduces the problem of interparameter trade-off in viscoelastic FWI. Ignoring attenuation effects can result in inaccurate velocity estimations. Velocity errors may produce significant parameter crosstalk artefacts in the inverted attenuation models. An appropriate misfit function measuring specific seismic attribute is essential to capture the influence of attenuation on the seismic data and thus is expected to reduce the influences of velocity errors for attenuation estimation. In this study, we evaluate the performances of different misfit functions for attenuation estimation in viscoelastic FWI accompanied with a two-stage sequential inversion strategy. Synthetic examples with different acquisition surveys are given to show that in the presence of strong velocity errors, the amplitude-based misfit functions, including envelope-difference, root-mean-square amplitude-ratio and spectral amplitude-ratio, can invert for the attenuation models more reliably, compared to the waveform-difference and instantaneous phase misfit functions. With the two-stage inversion approach, more reliable velocity and attenuation models can be obtained using viscoelastic FWI.
Longitudinal measures of RNA expression and disease activity in FSHD muscle biopsies
Authors: Wong Chao-Jen , Wang Leo H , Friedman Seth D , Shaw Dennis , Campbell Amy E , Budech Chris B , Lewis Leann M , Lemmers Richard J F L , Statland Jeffrey M , van der Maarel Silvère M , Tawil Rabi N , Tapscott Stephen J
Published: February 2020

Advances in understanding the pathophysiology of facioscapulohumeral dystrophy (FSHD) have led to the discovery of candidate therapeutics, and it is important to identify markers of disease activity to inform clinical trial design. For drugs that inhibit DUX4 expression, measuring DUX4 or DUX4-target gene expression might be an interim measure of drug activity; however, only a subset of FHSD muscle biopsies shows evidence of DUX4 expression. Our prior study showed that MRI T2-STIR-positive muscles had a higher probability of showing DUX4 expression than muscles with normal MRI characteristics. In the current study, we performed a 1-year follow-up assessment of the same muscle with repeat MRI and muscle biopsy. There was little change in MRI characteristics over the 1-year period and, similar to the initial evaluation, MRI T2-STIR-postive muscles had a higher expression of DUX4-regulated genes, as well as genes associated with inflammation, extracellular matrix and cell cycle. Compared to the initial evaluation, overall the level of expression in these gene categories remained stable over the 1-year period; however, there was some variability for each individual muscle biopsied. The pooled data from both the initial and 1-year follow-up evaluations identified several FSHD subgroups based on gene expression, as well as a set of genes—composed of DUX4-target genes, inflammatory and immune genes and cell cycle control genes—that distinguished all of the FSHD samples from the controls. These candidate markers of disease activity need to be replicated in independent datasets and, if validated, may provide useful measures of disease progression and response to therapy.
Simultaneous Determination of Vitamins B1 and B6 by Nuclear Magnetic Resonance Spectrometry
Authors: Hassan Saad S M
Published: February 2020

A new, simple, and rapid quantitative nuclear magnetic resonance method has been developed for simultaneous determination of vitamins B1 and B6 in mixtures in the presence of vitamin B2 without prior separation. The peak areas of 2 resonance lines at δ2.55 and 2.65 ppm are used. Maleic acid (δ = 6.6 ppm) is used as a reference standard, and the integral peak areas are referred to it. The method was tested with synthetically prepared mixtures containing from 0.05 to 1.5mM of each vitamin and was applied to the analysis of some pharmaceutical preparations. The results show an average recovery of 98% of both vitamins. Vitamin B2 does not interfere, if present.
Analysis of Fat-Soluble Vitamins. XVII. Comparison of Chemical and Biological Assays of Vitamin D
Authors: Mulder Frits J , Strik Roel
Published: February 2020

Two methods, the chemical assay using maleic anhydride addition and the British Standard Institution chick bioassay, were used to analyze samples from vitamin D3 resin batches manufactured over a period of about 4 years. Statistical analysis of data obtained for vitamin D shows that (1) the reproducibility of the chemical assay has a coefficient of variation of 0.7% ; (2) the chemical assay is suitable for controlling the dilution procedure of resins in oil, the product variability being represented by a coefficient of variation of 1.7% ; (3) the agreement between the average values obtained by the bioassay and the chemical method is satisfactory (geometric mean ratio = 99.7%, n = 39); (4) the chick bioassay has 95% limits of variation of about ±30% for single results.
Multiple Internal Standard Technique for the Gas-Liquid Chromatographic Determination of Indole in Shrimp
Authors: Staruszkiewicz Walter F , Bond John F
Published: February 2020

A multiple internal standard technique has been developed for the official first action gas-liquid chromatographic (GLC) method for determining indole in shrimp. The modification was developed because interfering GLC peaks are occasionally observed when 2-methylindole is used as the internal standard. An internal standard solution containing 1-methylindole, 2- methylindole, and diphenylamine was added to extracts of shrimp before silica gel cleanup and separation by GLC. All of the compounds were quantitatively recovered and were separated on the GLC column under identical experimental conditions. Extracts of acceptable shrimp to which indole was added at levels of 3–10 μg/ 100 g and extracts of decomposed shrimp were stored at room temperature for 2 weeks. Average and maximum changes (μg indole/100 g) during storage were, respectively, for each internal standard: average 0.6, 0.4, and 1.1; maximum 1.7, 0.9, and 2.9.
Collaborative Study of Three Methods for the Determination of Fluoride in Vegetation
Authors: Jacobson Jay S , Heller Laurence I
Published: February 2020

A procedure is described for determining Kepone (decachlorooctahydro-l,3,4-metheno-2ffcyclobuta[ cd]pentalene-2-one) residues in avian egg, liver, and tissue. Samples were extracted with benzene-isopropanol, and the extract was cleaned up with fuming H2S04-concentrated H2SO4. Kepone was separated from organochlorine pesticides and polychlorinated biphenyls on a Florisil column and analyzed by electron capture gas-liquid chromatography (GLC). The average recovery from spiked tissues was 86%. The analyses performed on 14 bald eagle carcasses and livers, 3 bald eagle eggs, and 14 osprey eggs show measurable levels which indicate that Kepone accumulates in the tissues of fish-eating birds. Residues were confirmed by GLC-mass spectrometry
Foam-Charcoal Chromatography for Analysis of Polychlorinated Dibenzodioxins in Herbicide Orange
Authors: Huckins James N , Stalling David L , Smith William A
Published: February 2020

Herbicide Orange (HO) is a mixture of n-butyl esters of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). The 2,4,5-T is known to contain 2,3, 7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and other chlorinated aromatic contaminants. Adsorption of TCDD from HO on small amounts of powdered charcoal results in sample cleanup adequate for electron capture gas-liquid chromatographic (GLC) analysis. Column flow restrictions with powdered charcoal are overcome by using polyurethane foams as a dispersive support, HO is dissolved in chloroform and percolated through a column containing a mixture of PX-21 activated carbon suspended on clean polyurethane foam (14.9% charcoal/ 85.1% foam, w/w). Subsequently, the column is washed with benzene, and TCDD is recovered with toluene-benzene (1+1). Samples containing less than 1 μg TCDD/ml required additional sample cleanup on activated alumina prior to GLC analysis. The average recovery of TCDD determined from 4 replicate radiometric measurements was 91.4% (standard error = 4.0). TCDD residues greater than 0.02 μg/ml in HO samples were quantitated by electron capture GLC after cleanup. The presence of TCDD and pentachlorodibenzo-p-dioxin was confirmed by GLC-mass spectroscopy. In addition, tetrachloro- and pentachlorodibenzofurans were inferred by GLC-mass spectrometry.
Automated Determination of Phosphorus in Fertilizers Collaborative Study
Authors: Johnson Frank J
Published: February 2020

An automated method for determining total and direct available P2O5 in fertilizers was compared to the official final action gravimetric quinolinium molybdophosphate and spectrophotometric molybdovanadate methods in a collaborative study. Ten samples were sent to 10 collaborators for analysis. Eight complete sets of data were returned, and the ninth collaborator returned data for direct available phosphorus by the automated method only. The data were statistically analyzed by the technique of closely matched pairs. No significant overall difference was found between methods or among collaborators. The automated method has been adopted as official first action for phosphorus.
Simple Derivatization Procedure for Gas-Liquid Chromatographic Analysis of Diflubenzuron in Pond Water and for Analysis of Its Trifluoromethyl Analog Penfluron in Boll Weevils
Authors: DeMilo Albert B , Terry Paul H , Rains Diane M
Published: February 2020

A simple and convenient gas-liquid chromatographic procedure involving electron capture detection is described for determining diflubenzuron (N- [[(4-chlorophenyl) amino] carbonyl] - 2,6-difluorobenzamide) in pond water and for determining the uptake of penfluron (trifluoromethyl analog of diflubenzuron) by boll weevils sexually sterilized by this compound. Both compounds were quantitatively converted to their respective N-(trifluoroacetyl) anilines by treatment with trifluoroacetic anhydride and pyridine in benzene at 50–60 °C. In boll weevil analyses, the procedure was quantitative for penfluron at concentrations involving microgram quantities (10–35 ≧g/weevil) without the necessity of a cleanup step. However, at submicrogram quantities, background interference necessitated a thin layer chromatographic cleanup prior to derivatization. This modification enabled the determination of 100 ng/ weevil. Analysis for diflubenzuron in natural pond water gave excellent results. For example, diflubenzuron at 2, 0.2, and 0.02 ppm in pond water was recovered at 95, 82, and 98%, respectively. A mechanism describing the reaction is proposed.
High Pressure Liquid Chromatographic Method for Probenecid in Flavored Oral Suspensions Containing Ampicillin: Collaborative Studies
Authors: Vollmer Paul J , Alexander Thomas G , Haneke Carol
Published: February 2020

A high pressure liquid chromatographic method for determining probenecid in oral suspensions of amoxicillin was applied to the determination of probenecid in oral suspensions of ampicillin. Three preparations containing various known amounts of probenecid in synthetic mixtures of ampicillin oral suspensions were analyzed by 5 chemists in an intralaborastory study, with satisfactory results. Blind duplicates of 3 prepared oral suspensions were sent to 12 collaborators, who were instructed to analyze the samples in a fixed random order. The standards showed a satisfactory linear response. Average recoveries of probenecid in the interlaboratory study for the 6 mixtures ranged from 95.2 to 99.1%, and the coefficients of variation ranged from 1.63 to 4.9%.
Gas-Liquid Chromatographic Determination of T-2 Toxin and Diacetoxyscirpenol in Corn and Mixed Feeds
Authors: Romer Thomas R , Boling Tamara M , Macdonald John L
Published: February 2020

A gas-liquid chromatographic method has been developed for the simultaneous determination of the T-2 toxin and diacetoxyscirpenol (DAS) in corn and mixed feeds. The analytes are extracted with aqueous methanol. Ammonium sulfate is used to denature and precipitate proteinaceous compounds and to salt out low polar compounds. The analytes are selectively concentrated into chloroform, which is washed with aqueous potassium hydroxide to remove acidic compounds. Residual interferences are removed by silica gel column chromatography. Heptafluorobutrylimidazole (HFBI) is added to form esters of the analytes. The HFB-esters are separated on an SE-30 glass column and measured with a 63Ni electron capture detector, using methoxychlor as an internal standard. The method has been applied to corn, livestock feeds, and pet food. The limit of detection is 100 ng T-2 toxin and 25 ng DAS/g. Average recoveries of 105 and 97% and coefficients of variation of 17 and 10% were obtained for T-2 toxin and DAS, respectively.