bluuebunny/crossref_metadata_2025_split huggingface dataset:
Partial flocculation for spray drying of spherical mixed metal oxide particles
Authors: Ehrhart Brian D. , Ward Barbara J. , Richardson Benjamin M. , Anseth Kristi S. , Weimer Alan W. 
Published: May 2018

AbstractParticles are an important design consideration for many proposed solar thermochemical water splitting reactor concepts. These particles must maintain physical integrity and chemical performance at very high temperatures (>900°C) while flowing within a system. Spray drying is a commonly used, scalable method to produce solid spherical particles that have the best opportunity to meet these requirements. Spray drying is used to produce hercynite (FeAl2O4) particles using pH‐modification of a charge‐stabilized sol. This process involves inducing partial flocculation in nanoparticle suspensions to yield larger particles that are spherical and structurally robust. A commercial boehmite suspension is characterized along with a mixture of the boehmite suspension with an iron oxide suspension. Zeta potential near zero and peak yield stress measurements at the same pH indicate flocculation, but associated sedimentation behavior is not observed. The behavior of both the boehmite‐only and mixed suspensions both seem to be driven by the behavior of the boehmite suspension alone. Spray dried particles from the mixed suspension at the critical pH gave significantly larger and more spherical particles, which also indicates flocculation. This relatively simple technique shows promise for new mixed‐metal material formulations and scalable applications.
Excavating New Constructs for Family Stress Theories in the Context of Everyday Life Experiences of Black American Families
Authors: Murry Velma McBride , Butler‐Barnes Sheretta T. , Mayo‐Gamble Tilicia L. , Inniss‐Thompson Misha N. 
Published: May 2018

AbstractMuch of what happens inside Black families involves spillover effects and consequences of macro‐level stressors. Racism is a major stressor that cascades through Black families' lives, with detrimental consequences for their everyday life experiences. To understand ways in which Black families successfully navigate social, environment, and cultural pressures and constraints, we sought to gain insight into these processes by conducting a systematic, deep excavation, in order to (a) critically examine the adequacy and accuracy of traditional frameworks used to study stress in Black American families, (b) determine whether the studies of stress in Black families in the era of the first Black family in the White House stimulated new areas of research, and (c) advance the field of stress research in general and for Black Americans, in particular, by proposing a heuristic model anchored in a historical, contextual, life‐span perspective, with emphasis on culturally specific strengths‐based coping adaptation.
The Cultural Lens Approach to Bowen Family Systems Theory: Contributions of Family Change Theory
Authors: Erdem Gizem , Safi Ommay Aiman 
Published: May 2018

AbstractAn accumulation of theoretical and empirical work focuses on expanding Bowen family systems theory (BFST) to be more culturally expansive by including gender, ethnicity, race, social class, and sexual orientation, as well as family history, values, and rituals. In the current article, we contribute to the discussion of culture in BFST and move the question of diversity from how family processes are different to why they are different. Utilizing Hardin and colleagues' cultural lens approach, we discuss the cultural validity of BFST, more specifically the concept of differentiation of self and its premises, in five steps. Further, we propose the integration of Kağıtçıbaşı's family change theory and Carter and McGoldrick's multicultural perspective with BFST and offer cultural examples. Potential contributions and limitations of the cultural lens approach in expanding our understanding BFST are discussed, as are implications for research and clinical practice.
Integrating Life Course, Globalization, and the Study of Racial and Ethnic Families
Authors: Trask Bahira Sherif 
Published: May 2018

AbstractDespite the proliferation of studies that specifically employ life course perspectives for contemporary families, an important omission, with only a few exceptions, has been critical inquiry into how race, ethnicity, cultural diversity, and global processes affect individual and family development. Furthermore, this perspective has been seriously underutilized for understanding the diversity of human experiences in global contexts. A focus on these issues should help move the study of families away from the inherent ethnocentric lens that undergirds so much of the discipline. The life course perspective, with its focus on the interplay of micro and macro factors, is a critical theoretical tool in expanding our understanding of context, vantage point, pluralism, and power relationships. New approaches to understanding and incorporating a life course perspective may spur fresh pathways for researchers and policy makers as they attempt to make sense of complex social phenomena.
Toward a Better Understanding of African American Families: Development of the Sociocultural Family Stress Model
Authors: McNeil Smith Shardé , Landor Antoinette M. 
Published: May 2018

AbstractFamily stress models have a long and rich history in family science research and are useful frameworks for understanding multicultural families. Although these models add greatly to research on diverse families in general, we believe that the almost exclusive focus on cross‐cultural replications may come at the cost of a more culturally and contextually informed understanding of specific groups such as African Americans. In this article, we expand current family stress models using two key extensions that challenge some of the underlying assumptions and situate constructs within intersectionality and mundane extreme environmental stress (MEES) perspectives. In addition, we introduce an integrative theoretical framework, the sociocultural family stress (SFS) model, which includes explicit considerations of both the culture and heterogeneity of African Americans and their families. Suggestions for future research are discussed.
Terpenes associated with resistance against the gall wasp, Leptocybe invasa, in Eucalyptus grandis
Authors: Naidoo Sanushka , Christie Nanette , Acosta Juan J. , Mphahlele Makobatjatji M. , Payn Kitt G. , Myburg Alexander A. , Külheim Carsten 
Published: May 2018

AbstractLeptocybe invasa is an insect pest causing gall formation on oviposited shoot tips and leaves of Eucalyptus trees leading to leaf deformation, stunting, and death in severe cases. We previously observed different constitutive and induced terpenes, plant specialized metabolites that may act as attractants or repellents to insects, in a resistant and susceptible clone of Eucalyptus challenged with L. invasa. We tested the hypothesis that specific terpenes are associated with pest resistance in a Eucalyptus grandis half‐sib population. Insect damage was scored over 2 infestation cycles, and leaves were harvested for near‐infrared reflectance (NIR) and terpene measurements. We used Bayesian model averaging for terpene selection and obtained partial least squares NIR models to predict terpene content and L. invasa infestation damage. In our optimal model, 29% of the phenotypic variation could be explained by 7 terpenes, and the monoterpene combination, limonene, α‐terpineol, and 1,8‐cineole, could be predicted with an NIR prediction ability of .67. Bayesian model averaging supported α‐pinene, γ‐terpinene, and iso‐pinocarveol as important for predicting L. invasa infestation. Susceptibility was associated with increased γ‐terpinene and α‐pinene, which may act as a pest attractant, whereas reduced susceptibility was associated with iso‐pinocarveol, which may act to recruit parasitoids or have direct toxic effects.
The Derivative Yajima–Oikawa System: Bright, Dark Soliton and Breather Solutions
Authors: Chen Junchao , Feng Bao‐Feng , Maruno Ken‐ichi , Ohta Yasuhiro 
Published: May 2018

AbstractIn this paper, we study the derivative Yajima–Oikawa (YO) system which describes the interaction between long and short waves (SWs). It is shown that the derivative YO system is classified into three types which are similar to the ones of the derivative nonlinear Schrödinger equation. The general N‐bright and N‐dark soliton solutions in terms of Gram determinants are derived by the combination of the Hirota's bilinear method and the Kadomtsev–Petviashvili hierarchy reduction method. Particularly, it is found that for the dark soliton solution of the SW component, the magnitude of soliton can be larger than the nonzero background for some parameters, which is usually called anti‐dark soliton. The asymptotic analysis of two‐soliton solutions shows that for both kinds of soliton only elastic collision exists and each soliton results in phase shifts in the long and SWs. In addition, we derive two types of breather solutions from the different reduction, which contain the homoclinic orbit and Kuznetsov–Ma breather solutions as special cases. Moreover, we propose a new (2+1)‐dimensional derivative Yajima–Oikawa system and present its soliton and breather solutions.
The real peso–dollar rate and US–Mexico industry trade: an asymmetric analysis
Authors: Bahmani‐Oskooee Mohsen , Harvey Hanafiah , Hegerty Scott W. 
Published: May 2018

AbstractIn an attempt to improve upon previous analyses and find further evidence for exchange rate theories such as the ‘J‐curve', numerous studies have introduced novel econometric approaches that might help uncover significant results through disaggregation and nonlinearity. This study applies the nonlinear cointegration method of Shin et al. () to US–Mexican trade balances in 91 individual industries. While the linear model yields support for the ‘J‐curve' effect in 16 industries, the nonlinear model raises this number to 29 which includes the two largest industries that engage in 35% of the trade between two countries. Furthermore, while the short‐run asymmetric effects of exchange rate changes were discovered in almost all industries, short‐run effects translated to significant long‐run asymmetric effects in 52 industries.
The force and stiffness of myosin motors in the isometric twitch of a cardiac trabecula and the effect of the extracellular calcium concentration
Authors: Pinzauti Francesca , Pertici Irene , Reconditi Massimo , Narayanan Theyencheri , Stienen Ger J. M. , Piazzesi Gabriella , Lombardi Vincenzo , Linari Marco , Caremani Marco 
Published: May 2018

Key points
Fast sarcomere‐level mechanics in intact trabeculae, which allows the definition of the mechano‐kinetic properties of cardiac myosin in situ, is a fundamental tool not only for understanding the molecular mechanisms of heart performance and regulation, but also for investigating the mechanisms of the cardiomyopathy‐causing mutations in the myosin and testing small molecules for therapeutic interventions.
The approach has been applied to measure the stiffness and force of the myosin motor and the fraction of motors attached during isometric twitches of electrically paced trabeculae under different extracellular Ca2+ concentrations.
Although the average force of the cardiac myosin motor (∼6 pN) is similar to that of the fast myosin isoform of skeletal muscle, the stiffness (1.07 pN nm–1) is 2‐ to 3‐fold smaller.
The increase in the twitch force developed in the presence of larger extracellular Ca2+ concentrations is fully accounted for by a proportional increase in the number of attached motors.
AbstractThe mechano‐kinetic properties of the cardiac myosin were studied in situ, in trabeculae dissected from the right ventricle of the rat heart, by measuring the stiffness of the half‐sarcomere both at the twitch force peak (Tp) of an electrically paced intact trabecula at different extracellular Ca2+ concentrations ([Ca2+]o), and in the same trabecula after skinning and induction of rigor. Taking into account the contribution of filament compliance to half‐sarcomere compliance and the lattice geometry, we found that the stiffness of the cardiac myosin motor is 1.07 ± 0.09 pN nm–1, which is slightly larger than that of the slow myosin isoform of skeletal muscle (0.6‐0.8 pN nm–1) and 2‐ to 3‐fold smaller than that of the fast skeletal muscle isoform. The increase in Tp from 61 ± 4 kPa to 93 ± 9 kPa, induced by raising [Ca2+]o from 1 to 2.5 mm at sarcomere length ∼2.2 μm, is accompanied by an increase of the half‐sarcomere stiffness that is explained by an increase of the fraction of actin‐attached motors from 0.08 ± 0.01 to 0.12 ± 0.02, proportional to Tp. Consequently, each myosin motor bears an average force of 6.14 ± 0.52 pN independently of Tp and [Ca2+]o. The application of fast sarcomere‐level mechanics to intact trabeculae to define the mechano‐kinetic properties of the cardiac myosin in situ represents a powerful tool for investigating cardiomyopathy‐causing mutations in the myosin motor and testing specific therapeutic interventions.
Emergence of High-Level Colistin Resistance in an Acinetobacter baumannii Clinical Isolate Mediated by Inactivation of the Global Regulator H-NS
Authors: Deveson Lucas Deanna , Crane Bethany , Wright Amy , Han Mei-Ling , Moffatt Jennifer , Bulach Dieter , Gladman Simon L. , Powell David , Aranda Jesus , Seemann Torsten , Machado Diana , Pacheco Teresa , Marques Teresa , Viveiros Miguel , Nation Roger , Li Jian , Harper Marina , Boyce John D. 
Published: May 2018

ABSTRACT

Colistin is a crucial last-line drug used for the treatment of life-threatening infections caused by multidrug-resistant strains of the Gram-negative bacterium
Acinetobacter baumannii
. However, colistin-resistant
A. baumannii
isolates can still be isolated following failed colistin therapy. Resistance is most often mediated by the addition of phosphoethanolamine (pEtN) to lipid A by PmrC, following missense mutations in the
pmrCAB
operon encoding PmrC and the two-component signal transduction system PmrA/PmrB. We recovered a pair of
A. baumannii
isolates from a single patient before (6009-1) and after (6009-2) failed colistin treatment. These strains displayed low and very high levels of colistin resistance (MICs, 8 to 16 μg/ml and 128 μg/ml), respectively. To understand how increased colistin resistance arose, we sequenced the genome of each isolate, which revealed that 6009-2 had an extra copy of the insertion sequence element IS
Aba125
within a gene encoding an H-NS family transcriptional regulator. To confirm the role of H-NS in colistin resistance, we generated an
hns
deletion mutant in 6009-1 and showed that colistin resistance increased upon the deletion of
hns
. We also provided 6009-2 with an intact copy of
hns
and showed that the strain was no longer resistant to high concentrations of colistin. Transcriptomic analysis of the clinical isolates identified more than 150 genes as being differentially expressed in the colistin-resistant
hns
mutant 6009-2. Importantly, the expression of
eptA
, encoding a second lipid A-specific pEtN transferase but not
pmrC
, was increased in the
hns
mutant. This is the first time an H-NS family transcriptional regulator has been associated with a pEtN transferase and colistin resistance.
Terminal Olefin Profiles and Phylogenetic Analyses of Olefin Synthases of Diverse Cyanobacterial Species
Authors: Zhu Tao , Scalvenzi Thibault , Sassoon Nathalie , Lu Xuefeng , Gugger Muriel 
Published: May 2018

ABSTRACT

Cyanobacteria can synthesize alkanes and alkenes, which are considered to be infrastructure-compatible biofuels. In terms of physiological function, cyanobacterial hydrocarbons are thought to be essential for membrane flexibility for cell division, size, and growth. The genetic basis for the biosynthesis of terminal olefins (1-alkenes) is a modular type I polyketide synthase (PKS) termed olefin synthase (Ols). The modular architectures of Ols and structural characteristics of alkenes have been investigated only in a few species of the small percentage (approximately 10%) of cyanobacteria that harbor putative Ols pathways. In this study, investigations of the domains, modular architectures, and phylogenies of Ols in 28 cyanobacterial strains suggested distinctive pathway evolution. Structural feature analyses revealed 1-alkenes with three carbon chain lengths (C
15
, C
17
, and C
19
). In addition, the total cellular fatty acid profile revealed the diversity of the carbon chain lengths, while the fatty acid feeding assay indicated substrate carbon chain length specificity of cyanobacterial Ols enzymes. Finally,
in silico
analyses suggested that the N terminus of the modular Ols enzyme exhibited characteristics typical of a fatty acyl-adenylate ligase (FAAL), suggesting a mechanism of fatty acid activation via the formation of acyl-adenylates. Our results shed new light on the diversity of cyanobacterial terminal olefins and a mechanism for substrate activation in the biosynthesis of these olefins.

IMPORTANCE
Cyanobacterial terminal olefins are hydrocarbons with promising applications as advanced biofuels. Despite the basic understanding of the genetic basis of olefin biosynthesis, the structural diversity and phylogeny of the key modular olefin synthase (Ols) have been poorly explored. An overview of the chemical structural traits of terminal olefins in cyanobacteria is provided in this study. In addition, we demonstrated by
in vivo
fatty acid feeding assays that cyanobacterial Ols enzymes might exhibit substrate carbon chain length specificity. Furthermore, by performing bioinformatic analyses, we observed that the substrate activation domain of Ols exhibited features typical of a fatty acyl-adenylate ligase (FAAL), which activates fatty acids by converting them to fatty acyl-adenylates. Our results provide further insight into the chemical structures of terminal olefins and further elucidate the mechanism of substrate activation for terminal olefin biosynthesis in cyanobacteria.
Susceptibility of Methicillin-Resistant and -Susceptible Staphylococcus aureus Isolates of Various Clonal Lineages from Germany to Eight Biocides
Authors: Kernberger-Fischer Isa Adriana , Krischek Carsten , Strommenger Birgit , Fiegen Ulrike , Beyerbach Martin , Kreienbrock Lothar , Klein Günter , Kehrenberg Corinna 
Published: May 2018

ABSTRACT

Few studies have been conducted on the susceptibility of bacteria to biocides. A total of 182 methicillin-resistant and -susceptible
Staphylococcus aureus
isolates collected from healthy or diseased humans and animals in Germany were included in the present study. Sixty-three isolates of animal origin and 119 human isolates were tested for their MICs to eight biocides or heavy metals by the broth microdilution method. The MIC
50
and MIC
90
values of human and animal isolates were equal or differed by not more than 1 dilution step, and statistical analysis revealed that differences between MICs of human and animal isolates were not significant. However, when taking into account the multilocus sequence type (MLST), a strong tendency (
P
= 0.054) to higher MICs of silver nitrate was detected for clonal complex 398 (CC398) isolates from humans compared to those from animals. Furthermore, a comparison of MIC values from isolates belonging to different clonal lineages revealed that important human lineages such as CC22 and CC5 exhibited significantly (
P
< 0.05) higher MICs for the biocides chlorhexidine, benzethonium chloride, and acriflavine than the main animal lineage sequence type 398 (ST398). Isolates with elevated MIC values were tested for the presence of biocide and heavy metal tolerance-mediating genes by PCR assays, and the following genes were detected:
mepA
(
n
[no. of isolates containing the gene] = 44),
lmrS
(
n
= 36),
norA
(
n
= 35),
sepA
(
n
= 22),
mco
(
n
= 5),
czrC
(
n
= 3),
smr
(
n
= 2),
copA
(
n
= 1),
qacA
and/or -
B
(
n
= 1),
qacG
(
n
= 2), and
qacJ
(
n
= 1). However, only for some compounds was a correlation between the presence of a biocide tolerance gene and the level of MIC values detected.

IMPORTANCE
Biocides play an essential role in controlling the growth of microorganisms and the dissemination of nosocomial pathogens. In this study, we determined the susceptibility of methicillin-resistant and -susceptible
S. aureus
isolates from humans and animals to various biocides and heavy metal ions and analyzed differences in susceptibilities between important clonal lineages. In addition, the presence of biocide or heavy metal tolerance-mediating genes was investigated. We demonstrated that important human lineages such as CC22 and CC5 had significantly higher MIC values for chlorhexidine, benzethonium chloride, and acriflavine than the main farm animal lineage, ST398. In addition, it was shown that for some combinations of biocides and tolerance genes, significantly higher MICs were detected for carriers. These findings provide new insights into
S. aureus
biocide and heavy metal tolerance.
Conductive Particles Enable Syntrophic Acetate Oxidation between
Geobacter
and
Methanosarcina
from Coastal Sediments
Authors: Rotaru Amelia-Elena , Calabrese Federica , Stryhanyuk Hryhoriy , Musat Florin , Shrestha Pravin Malla , Weber Hannah Sophia , Snoeyenbos-West Oona L. O. , Hall Per O. J. , Richnow Hans H. , Musat Niculina , Thamdrup Bo 
Published: May 2018

ABSTRACT

Coastal sediments are rich in conductive particles, possibly affecting microbial processes for which acetate is a central intermediate. In the methanogenic zone, acetate is consumed by methanogens and/or syntrophic acetate-oxidizing (SAO) consortia. SAO consortia live under extreme thermodynamic pressure, and their survival depends on successful partnership. Here, we demonstrate that conductive particles enable the partnership between SAO bacteria (i.e.,
Geobacter
spp.) and methanogens (
Methanosarcina
spp.) from the coastal sediments of the Bothnian Bay of the Baltic Sea. Baltic methanogenic sediments were rich in conductive minerals, had an apparent isotopic fractionation characteristic of CO
2
-reductive methanogenesis, and were inhabited by
Geobacter
and
Methanosarcina
. As long as conductive particles were delivered,
Geobacter
and
Methanosarcina
persisted, whereas exclusion of conductive particles led to the extinction of
Geobacter
. Baltic
Geobacter
did not establish a direct electric contact with
Methanosarcina
, necessitating conductive particles as electrical conduits. Within SAO consortia,
Geobacter
was an efficient [
13
C]acetate utilizer, accounting for 82% of the assimilation and 27% of the breakdown of acetate.
Geobacter
benefits from the association with the methanogen, because in the absence of an electron acceptor it can use
Methanosarcina
as a terminal electron sink. Consequently, inhibition of methanogenesis constrained the SAO activity of
Geobacter
as well. A potential benefit for
Methanosarcina
partnering with
Geobacter
is that together they competitively exclude acetoclastic methanogens like
Methanothrix
from an environment rich in conductive particles. Conductive particle-mediated SAO could explain the abundance of acetate oxidizers like
Geobacter
in the methanogenic zone of sediments where no electron acceptors other than CO
2
are available.

IMPORTANCE
Acetate-oxidizing bacteria are known to thrive in mutualistic consortia in which H
2
or formate is shuttled to a methane-producing
Archaea
partner. Here, we discovered that such bacteria could instead transfer electrons via conductive minerals. Mineral SAO (syntrophic acetate oxidation) could be a vital pathway for CO
2
-reductive methanogenesis in the environment, especially in sediments rich in conductive minerals. Mineral-facilitated SAO is therefore of potential importance for both iron and methane cycles in sediments and soils. Additionally, our observations imply that agricultural runoff or amendments with conductive chars could trigger a significant increase in methane emissions.