PeerJ
type: channel
link: https://peerj.com/articles/
description: Articles published in PeerJ
publisher: PeerJ Inc.
publication name: PeerJ
issn: 2167-8359
items: Sex differences in pacing during ‘Ultraman Hawaii’
items: A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum
items: Evolution history of duplicated smad3 genes in teleost: insights from Japanese flounder, Paralichthys olivaceus
items: Enzymatically crosslinked gelatin hydrogel promotes the proliferation of adipose tissue-derived stromal cells
items: Reproductive ecology and isolation of Psittacanthus calyculatus and P. auriculatus mistletoes (Loranthaceae)
items: Genetic diversity of Poa pratensis L. depending on geographical origin and compared with genetic markers
items: Continuum beliefs in the stigma process regarding persons with schizophrenia and depression: results of path analyses
items: Formal modeling and analysis of the hexosamine biosynthetic pathway: role of O-linked N-acetylglucosamine transferase in oncogenesis and cancer progression
items: Effects of grip force on median nerve deformation at different wrist angles
items: Self-rated mental health and race/ethnicity in the United States: support for the epidemiological paradox

Sex differences in pacing during ‘Ultraman Hawaii’
type: item
type: AcademicArticle
description: Background To date, little is known for pacing in ultra-endurance athletes competing in a non-stop event and in a multi-stage event, and especially, about pacing in a multi-stage event with different disciplines during the stages. Therefore, the aim of the present study was to examine the effect of age, sex and calendar year on triathlon performance and variation of performance by events (i.e., swimming, cycling 1, cycling 2 and running) in ‘Ultraman Hawaii’ held between 1983 and 2015. Methods Within each sex, participants were grouped in quartiles (i.e., Q1, Q2, Q3 and Q4) with Q1 being the fastest (i.e., lowest overall time) and Q4 the slowest (i.e., highest overall time). To compare performance among events (i.e., swimming, cycling 1, cycling 2 and running), race time in each event was converted in z score and this value was used for further analysis. Results A between-within subjects ANOVA showed a large sex × event (p = 0.015, η2 = 0.014) and a medium performance group × event interaction (p = 0.001, η2 = 0.012). No main effect of event on performance was observed (p = 0.174, η2 = 0.007). With regard to the sex × event interaction, three female performance groups (i.e., Q2, Q3 and Q4) increased race time from swimming to cycling 1, whereas only one male performance group (Q4) revealed a similar trend. From cycling 1 to cycling 2, the two slower female groups (Q3 and Q4) and the slowest male group (Q4) increased raced time. In women, the fastest group decreased (i.e., improved) race time from swimming to cycling 1 and thereafter, maintained performance, whereas in men, the fastest group decreased race time till cycling 2 and increased it in the running. Conclusion In summary, women pace differently than men during ‘Ultraman Hawaii’ where the fastest women decreased performance on day 1 and could then maintain on day 2 and 3, whereas the fastest men worsened performance on day 1 and 2 but improved on day 3.
format: application/pdf
format: text/html
creator: Beat Knechtle
creator: Pantelis T. Nikolaidis
subject: Kinesiology
description: doi:10.7717/peerj.2509
publisher: PeerJ Inc.
rights: © 2016 Knechtle and Nikolaidis
abstract: Background To date, little is known for pacing in ultra-endurance athletes competing in a non-stop event and in a multi-stage event, and especially, about pacing in a multi-stage event with different disciplines during the stages. Therefore, the aim of the present study was to examine the effect of age, sex and calendar year on triathlon performance and variation of performance by events (i.e., swimming, cycling 1, cycling 2 and running) in ‘Ultraman Hawaii’ held between 1983 and 2015. Methods Within each sex, participants were grouped in quartiles (i.e., Q1, Q2, Q3 and Q4) with Q1 being the fastest (i.e., lowest overall time) and Q4 the slowest (i.e., highest overall time). To compare performance among events (i.e., swimming, cycling 1, cycling 2 and running), race time in each event was converted in z score and this value was used for further analysis. Results A between-within subjects ANOVA showed a large sex × event (p = 0.015, η2 = 0.014) and a medium performance group × event interaction (p = 0.001, η2 = 0.012). No main effect of event on performance was observed (p = 0.174, η2 = 0.007). With regard to the sex × event interaction, three female performance groups (i.e., Q2, Q3 and Q4) increased race time from swimming to cycling 1, whereas only one male performance group (Q4) revealed a similar trend. From cycling 1 to cycling 2, the two slower female groups (Q3 and Q4) and the slowest male group (Q4) increased raced time. In women, the fastest group decreased (i.e., improved) race time from swimming to cycling 1 and thereafter, maintained performance, whereas in men, the fastest group decreased race time till cycling 2 and increased it in the running. Conclusion In summary, women pace differently than men during ‘Ultraman Hawaii’ where the fastest women decreased performance on day 1 and could then maintain on day 2 and 3, whereas the fastest men worsened performance on day 1 and 2 but improved on day 3.
bibliographic citation: Knechtle et al. (2016) Sex differences in pacing during ‘Ultraman Hawaii’. PeerJ 4:e2509 https://doi.org/10.7717/peerj.2509
date submitted: 2016-07-05
date accepted: 2016-08-31
issued: 2016-09-27
is part of: PeerJ
license: http://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Knechtle
  given name: Beat
author list: Agent
  family name: Nikolaidis
  given name: Pantelis T.
doi: 10.7717/peerj.2509
volume: 4
issn: 2167-8359
publication name: PeerJ
publication date: 2016-09-27
copyright: ©2016 Knechtle and Nikolaidis
attribution name: Knechtle and Nikolaidis

A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum
type: item
type: AcademicArticle
description: Most ocean acidification (OA) experimental systems rely on pH as an indirect way to control CO2. However, accurate pH measurements are difficult to obtain and shifts in temperature and/or salinity alter the relationship between pH and pCO2. Here we describe a system in which the target pCO2 is controlled via direct analysis of pCO2 in seawater. This direct type of control accommodates potential temperature and salinity shifts, as the target variable is directly measured instead of being estimated. Water in a header tank is permanently re-circulated through an air-water equilibrator. The equilibrated air is then routed to an infrared gas analyzer (IRGA) that measures pCO2 and conveys this value to a Proportional-Integral-Derivative (PID) controller. The controller commands a solenoid valve that opens and closes the CO2 flush that is bubbled into the header tank. This low-cost control system allows the maintenance of stabilized levels of pCO2 for extended periods of time ensuring accurate experimental conditions. This system was used to study the long term effect of OA on the coralline red algae Phymatolithon lusitanicum. We found that after 11 months of high CO2 exposure, photosynthesis increased with CO2 as opposed to respiration, which was positively affected by temperature. Results showed that this system is adequate to run long-term OA experiments and can be easily adapted to test other relevant variables simultaneously with CO2, such as temperature, irradiance and nutrients.
format: application/pdf
format: text/html
creator: Laura Sordo
creator: Rui Santos
creator: Joao Reis
creator: Alona Shulika
creator: Joao Silva
subject: Biochemistry
subject: Ecology
subject: Ecosystem Science
subject: Environmental Sciences
subject: Marine Biology
description: doi:10.7717/peerj.2503
publisher: PeerJ Inc.
rights: © 2016 Sordo et al.
abstract: Most ocean acidification (OA) experimental systems rely on pH as an indirect way to control CO2. However, accurate pH measurements are difficult to obtain and shifts in temperature and/or salinity alter the relationship between pH and pCO2. Here we describe a system in which the target pCO2 is controlled via direct analysis of pCO2 in seawater. This direct type of control accommodates potential temperature and salinity shifts, as the target variable is directly measured instead of being estimated. Water in a header tank is permanently re-circulated through an air-water equilibrator. The equilibrated air is then routed to an infrared gas analyzer (IRGA) that measures pCO2 and conveys this value to a Proportional-Integral-Derivative (PID) controller. The controller commands a solenoid valve that opens and closes the CO2 flush that is bubbled into the header tank. This low-cost control system allows the maintenance of stabilized levels of pCO2 for extended periods of time ensuring accurate experimental conditions. This system was used to study the long term effect of OA on the coralline red algae Phymatolithon lusitanicum. We found that after 11 months of high CO2 exposure, photosynthesis increased with CO2 as opposed to respiration, which was positively affected by temperature. Results showed that this system is adequate to run long-term OA experiments and can be easily adapted to test other relevant variables simultaneously with CO2, such as temperature, irradiance and nutrients.
bibliographic citation: Sordo et al. (2016) A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum. PeerJ 4:e2503 https://doi.org/10.7717/peerj.2503
date submitted: 2016-05-05
date accepted: 2016-08-30
issued: 2016-09-27
is part of: PeerJ
license: http://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Sordo
  given name: Laura
author list: Agent
  family name: Santos
  given name: Rui
author list: Agent
  family name: Reis
  given name: Joao
author list: Agent
  family name: Shulika
  given name: Alona
author list: Agent
  family name: Silva
  given name: Joao
doi: 10.7717/peerj.2503
volume: 4
issn: 2167-8359
publication name: PeerJ
publication date: 2016-09-27
copyright: © 2016 Sordo et al.
attribution name: Sordo et al.

Evolution history of duplicated smad3 genes in teleost: insights from Japanese flounder, Paralichthys olivaceus
type: item
type: AcademicArticle
description: Following the two rounds of whole-genome duplication (WGD) during deuterosome evolution, a third genome duplication occurred in the ray-fined fish lineage and is considered to be responsible for the teleost-specific lineage diversification and regulation mechanisms. As a receptor-regulated SMAD (R-SMAD), the function of SMAD3 was widely studied in mammals. However, limited information of its role or putative paralogs is available in ray-finned fishes. In this study, two SMAD3 paralogs were first identified in the transcriptome and genome of Japanese flounder (Paralichthys olivaceus). We also explored SMAD3 duplication in other selected species. Following identification, genomic structure, phylogenetic reconstruction, and synteny analyses performed by MrBayes and online bioinformatic tools confirmed that smad3a/3b most likely originated from the teleost-specific WGD. Additionally, selection pressure analysis and expression pattern of the two genes performed by PAML and quantitative real-time PCR (qRT-PCR) revealed evidence of subfunctionalization of the two SMAD3 paralogs in teleost. Our results indicate that two SMAD3 genes originate from teleost-specific WGD, remain transcriptionally active, and may have likely undergone subfunctionalization. This study provides novel insights to the evolution fates of smad3a/3b and draws attentions to future function analysis of SMAD3 gene family.
format: application/pdf
format: text/html
creator: Xinxin Du
creator: Yuezhong Liu
creator: Jinxiang Liu
creator: Quanqi Zhang
creator: Xubo Wang
subject: Aquaculture, Fisheries and Fish Science
subject: Evolutionary Studies
subject: Genetics
subject: Marine Biology
subject: Molecular Biology
description: doi:10.7717/peerj.2500
publisher: PeerJ Inc.
rights: © 2016 Du et al.
abstract: Following the two rounds of whole-genome duplication (WGD) during deuterosome evolution, a third genome duplication occurred in the ray-fined fish lineage and is considered to be responsible for the teleost-specific lineage diversification and regulation mechanisms. As a receptor-regulated SMAD (R-SMAD), the function of SMAD3 was widely studied in mammals. However, limited information of its role or putative paralogs is available in ray-finned fishes. In this study, two SMAD3 paralogs were first identified in the transcriptome and genome of Japanese flounder (Paralichthys olivaceus). We also explored SMAD3 duplication in other selected species. Following identification, genomic structure, phylogenetic reconstruction, and synteny analyses performed by MrBayes and online bioinformatic tools confirmed that smad3a/3b most likely originated from the teleost-specific WGD. Additionally, selection pressure analysis and expression pattern of the two genes performed by PAML and quantitative real-time PCR (qRT-PCR) revealed evidence of subfunctionalization of the two SMAD3 paralogs in teleost. Our results indicate that two SMAD3 genes originate from teleost-specific WGD, remain transcriptionally active, and may have likely undergone subfunctionalization. This study provides novel insights to the evolution fates of smad3a/3b and draws attentions to future function analysis of SMAD3 gene family.
bibliographic citation: Du et al. (2016) Evolution history of duplicated smad3 genes in teleost: insights from Japanese flounder, Paralichthys olivaceus. PeerJ 4:e2500 https://doi.org/10.7717/peerj.2500
date submitted: 2016-05-18
date accepted: 2016-08-29
issued: 2016-09-27
is part of: PeerJ
license: http://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Du
  given name: Xinxin
author list: Agent
  family name: Liu
  given name: Yuezhong
author list: Agent
  family name: Liu
  given name: Jinxiang
author list: Agent
  family name: Zhang
  given name: Quanqi
author list: Agent
  family name: Wang
  given name: Xubo
doi: 10.7717/peerj.2500
volume: 4
issn: 2167-8359
publication name: PeerJ
publication date: 2016-09-27
copyright: © 2016 Du et al.
attribution name: Du et al.

Enzymatically crosslinked gelatin hydrogel promotes the proliferation of adipose tissue-derived stromal cells
type: item
type: AcademicArticle
description: Gelatin hydrogel crosslinked by microbial transglutaminase (mTG) exhibits excellent performance in cell adhesion, proliferation, and differentiation. We examined the gelation time and gel strength of gelatin/mTG hydrogels in various proportions to investigate their physical properties and tested their degradation performances in vitro. Cell morphology and viability of adipose tissue-derived stromal cells (ADSCs) cultured on the 2D gel surface or in 3D hydrogel encapsulation were evaluated by immunofluorescence staining. Cell proliferation was tested via Alamar Blue assay. To investigate the hydrogel effect on cell differentiation, the cardiac-specific gene expression levelsof Nkx2.5, Myh6, Gja1, and Mef2c in encapsulated ADSCs with or without cardiac induction medium were detected by real-time RT-PCR. Cell release from the encapsulated status and cell migration in a 3D hydrogel model were assessed in vitro. Results show that the gelatin/mTG hydrogels are not cytotoxic and that their mechanical properties are adjustable. Hydrogel degradation is related to gel concentration and the resident cells. Cell growth morphology and proliferative capability in both 2D and 3D cultures were mainly affected by gel concentration. PCR result shows that hydrogel modulus together with induction medium affects the cardiac differentiation of ADSCs. The cell migration experiment and subcutaneous implantation show that the hydrogels are suitable for cell delivery.
format: application/pdf
format: text/html
creator: Gang Yang
creator: Zhenghua Xiao
creator: Xiaomei Ren
creator: Haiyan Long
creator: Hong Qian
creator: Kunlong Ma
creator: Yingqiang Guo
subject: Biotechnology
subject: Cell Biology
description: doi:10.7717/peerj.2497
publisher: PeerJ Inc.
rights: © 2016 Yang et al.
abstract: Gelatin hydrogel crosslinked by microbial transglutaminase (mTG) exhibits excellent performance in cell adhesion, proliferation, and differentiation. We examined the gelation time and gel strength of gelatin/mTG hydrogels in various proportions to investigate their physical properties and tested their degradation performances in vitro. Cell morphology and viability of adipose tissue-derived stromal cells (ADSCs) cultured on the 2D gel surface or in 3D hydrogel encapsulation were evaluated by immunofluorescence staining. Cell proliferation was tested via Alamar Blue assay. To investigate the hydrogel effect on cell differentiation, the cardiac-specific gene expression levelsof Nkx2.5, Myh6, Gja1, and Mef2c in encapsulated ADSCs with or without cardiac induction medium were detected by real-time RT-PCR. Cell release from the encapsulated status and cell migration in a 3D hydrogel model were assessed in vitro. Results show that the gelatin/mTG hydrogels are not cytotoxic and that their mechanical properties are adjustable. Hydrogel degradation is related to gel concentration and the resident cells. Cell growth morphology and proliferative capability in both 2D and 3D cultures were mainly affected by gel concentration. PCR result shows that hydrogel modulus together with induction medium affects the cardiac differentiation of ADSCs. The cell migration experiment and subcutaneous implantation show that the hydrogels are suitable for cell delivery.
bibliographic citation: Yang et al. (2016) Enzymatically crosslinked gelatin hydrogel promotes the proliferation of adipose tissue-derived stromal cells. PeerJ 4:e2497 https://doi.org/10.7717/peerj.2497
date submitted: 2016-05-10
date accepted: 2016-08-27
issued: 2016-09-27
is part of: PeerJ
license: http://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Yang
  given name: Gang
author list: Agent
  family name: Xiao
  given name: Zhenghua
author list: Agent
  family name: Ren
  given name: Xiaomei
author list: Agent
  family name: Long
  given name: Haiyan
author list: Agent
  family name: Qian
  given name: Hong
author list: Agent
  family name: Ma
  given name: Kunlong
author list: Agent
  family name: Guo
  given name: Yingqiang
doi: 10.7717/peerj.2497
volume: 4
issn: 2167-8359
publication name: PeerJ
publication date: 2016-09-27
copyright: ©2016 Yang et al.
attribution name: Yang et al.

Reproductive ecology and isolation of Psittacanthus calyculatus and P. auriculatus mistletoes (Loranthaceae)
type: item
type: AcademicArticle
description: Background Relationships between floral biology and pollinator behavior are important to understanding species diversity of hemiparasitic Psittacanthus mistletoes (c. 120 species). We aimed to investigate trait divergence linked to pollinator attraction and reproductive isolation (RI) in two hummingbird-pollinated and bird-dispersed Psittacanthus species with range overlap. Methods We investigated the phylogenetic relationships, floral biology, pollinator assemblages, seed dispersers and host usage, and the breeding system and female reproductive success of two sympatric populations of P. calyculatus and P. auriculatus, and one allopatric population of P. calyculatus. Flowers in sympatry were also reciprocally pollinated to assess a post-mating component of RI. Results Hummingbird assemblages differed between calyculatus populations, while allopatric plants of calyculatus opened more but smaller flowers with longer lifespans and produced less nectar than those in sympatry. Bayesian-based phylogenetic analysis indicated monophyly for calyculatus populations (i.e. both populations belong to the same species). In sympatry, calyculatus plants opened more and larger flowers with longer lifespans and produced same nectar volume than those of auriculatus; populations shared pollinators but seed dispersers and host usage differed between species. Nectar standing crops differed between sympatric populations, with lower visitation in calyculatus. Hand pollination experiments indicated a predominant outcrossing breeding system, with fruit set after interspecific pollination two times higher from calyculatus to auriculatus than in the opposite direction. Conclusions Given the low genetic differentiation between calyculatus populations, observed trait divergence could have resulted from changes regarding the local communities of pollinators and, therefore, expected divergence for peripheral, allopatric populations. Using RI estimates, there were fewer heterospecific matings than…
format: application/pdf
format: text/html
creator: Sergio Díaz Infante
creator: Carlos Lara
creator: María del Coro Arizmendi
creator: Luis E. Eguiarte
creator: Juan Francisco Ornelas
subject: Biodiversity
subject: Ecology
subject: Evolutionary Studies
subject: Genetics
subject: Plant Science
description: doi:10.7717/peerj.2491
publisher: PeerJ Inc.
rights: © 2016 Díaz Infante et al.
abstract: Background Relationships between floral biology and pollinator behavior are important to understanding species diversity of hemiparasitic Psittacanthus mistletoes (c. 120 species). We aimed to investigate trait divergence linked to pollinator attraction and reproductive isolation (RI) in two hummingbird-pollinated and bird-dispersed Psittacanthus species with range overlap. Methods We investigated the phylogenetic relationships, floral biology, pollinator assemblages, seed dispersers and host usage, and the breeding system and female reproductive success of two sympatric populations of P. calyculatus and P. auriculatus, and one allopatric population of P. calyculatus. Flowers in sympatry were also reciprocally pollinated to assess a post-mating component of RI. Results Hummingbird assemblages differed between calyculatus populations, while allopatric plants of calyculatus opened more but smaller flowers with longer lifespans and produced less nectar than those in sympatry. Bayesian-based phylogenetic analysis indicated monophyly for calyculatus populations (i.e. both populations belong to the same species). In sympatry, calyculatus plants opened more and larger flowers with longer lifespans and produced same nectar volume than those of auriculatus; populations shared pollinators but seed dispersers and host usage differed between species. Nectar standing crops differed between sympatric populations, with lower visitation in calyculatus. Hand pollination experiments indicated a predominant outcrossing breeding system, with fruit set after interspecific pollination two times higher from calyculatus to auriculatus than in the opposite direction. Conclusions Given the low genetic differentiation between calyculatus populations, observed trait divergence could have resulted from changes regarding the local communities of pollinators and, therefore, expected divergence for peripheral, allopatric populations. Using RI estimates, there were fewer heterospecific matings than…
bibliographic citation: Díaz Infante et al. (2016) Reproductive ecology and isolation of Psittacanthus calyculatus and P. auriculatus mistletoes (Loranthaceae). PeerJ 4:e2491 https://doi.org/10.7717/peerj.2491
date submitted: 2016-06-01
date accepted: 2016-08-25
issued: 2016-09-27
is part of: PeerJ
license: http://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Díaz Infante
  given name: Sergio
author list: Agent
  family name: Lara
  given name: Carlos
author list: Agent
  family name: Arizmendi
  given name: María del Coro
author list: Agent
  family name: Eguiarte
  given name: Luis E.
author list: Agent
  family name: Ornelas
  given name: Juan Francisco
doi: 10.7717/peerj.2491
volume: 4
issn: 2167-8359
publication name: PeerJ
publication date: 2016-09-27
copyright: © 2016 Díaz Infante et al.
attribution name: Díaz Infante et al.

Genetic diversity of Poa pratensis L. depending on geographical origin and compared with genetic markers
type: item
type: AcademicArticle
description: Background Poa pratensis is one of the most common species of meadow grass in Europe. Most cultivars of the species found in Poland were originally derived from its ecotypes. We compared the effectiveness of the RAPD and ISSR methods in assessing the genetic diversity of the selected populations of P. pratensis. We examined whether these methods could be useful for detecting a possible link between the geographical origin of a given population and its assessed genetic variation. Methods The molecular markers RAPD and ISSR were used and their efficiency compared using, inter alia, statistical multivariate methods (UPGMA and PCA). Results The low value of Dice’s coefficient (0.369) along with the significantly high percentage of polymorphic products indicates a substantial degree of genetic diversity among the studied populations. Our results found a correlation between the geographical origin of the studied populations and their genetic variations. For ISSR, which proved to be the more effective method in that respect, we selected primers with the greatest differentiating powers correlating to geographical origin. Discussion The populations evaluated in this study were characterized by a high genetic diversity. This seems to confirm the hypothesis that ecotypes of P. pratensis originating from different regions of Central Europe with different terrain structures and habitat conditions can be a source of great genetic variability.
format: application/pdf
format: text/html
creator: Magdalena Szenejko
creator: Przemysław Śmietana
creator: Edyta Stępień
subject: Biodiversity
subject: Ecology
subject: Ecosystem Science
subject: Molecular Biology
subject: Plant Science
description: doi:10.7717/peerj.2489
publisher: PeerJ Inc.
rights: © 2016 Szenejko et al.
abstract: Background Poa pratensis is one of the most common species of meadow grass in Europe. Most cultivars of the species found in Poland were originally derived from its ecotypes. We compared the effectiveness of the RAPD and ISSR methods in assessing the genetic diversity of the selected populations of P. pratensis. We examined whether these methods could be useful for detecting a possible link between the geographical origin of a given population and its assessed genetic variation. Methods The molecular markers RAPD and ISSR were used and their efficiency compared using, inter alia, statistical multivariate methods (UPGMA and PCA). Results The low value of Dice’s coefficient (0.369) along with the significantly high percentage of polymorphic products indicates a substantial degree of genetic diversity among the studied populations. Our results found a correlation between the geographical origin of the studied populations and their genetic variations. For ISSR, which proved to be the more effective method in that respect, we selected primers with the greatest differentiating powers correlating to geographical origin. Discussion The populations evaluated in this study were characterized by a high genetic diversity. This seems to confirm the hypothesis that ecotypes of P. pratensis originating from different regions of Central Europe with different terrain structures and habitat conditions can be a source of great genetic variability.
bibliographic citation: Szenejko et al. (2016) Genetic diversity of Poa pratensis L. depending on geographical origin and compared with genetic markers. PeerJ 4:e2489 https://doi.org/10.7717/peerj.2489
date submitted: 2016-05-02
date accepted: 2016-08-25
issued: 2016-09-27
is part of: PeerJ
license: http://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Szenejko
  given name: Magdalena
author list: Agent
  family name: Śmietana
  given name: Przemysław
author list: Agent
  family name: Stępień
  given name: Edyta
doi: 10.7717/peerj.2489
volume: 4
issn: 2167-8359
publication name: PeerJ
publication date: 2016-09-27
copyright: ©2016 Szenejko et al.
attribution name: Szenejko et al.

Continuum beliefs in the stigma process regarding persons with schizophrenia and depression: results of path analyses
type: item
type: AcademicArticle
description: Background Individuals with mental illness often experience stigmatization and encounter stereotypes such as being dangerous or unpredictable. To further improve measures against psychiatric stigma, it is of importance to understand its components. In this study, we attend to the step of separation between “us” and “them” in the stigma process as conceptualized by Link and Phelan. In using the belief in continuity of mental illness symptoms as a proxy for separation, we explore its associations with stereotypes, emotional responses and desire for social distance in the stigma process. Methods Analyses are based on a representative survey in Germany. Vignettes with symptoms suggestive of schizophrenia (n = 1,338) or depression (n = 1,316) were presented to the respondents, followed by questions on continuum belief, stereotypes, emotional reactions and desire for social distance. To examine the relationship between these items, path models were computed. Results Respondents who endorsed the continuum belief tended to show greater prosocial reactions (schizophrenia: 0.07; p < 0.001, depression: 0.09; p < 0.001) and less desire for social distance (schizophrenia: −0.13; p < 0.001, depression: −0.14; p < 0.001) toward a person with mental illness. In both cases, agreement with the stereotypes of unpredictability and dangerousness was positively associated with feelings of anger and fear as well as desire for social distance. There were no statistically significant relations between stereotypes and continuum beliefs. Discussion Assumptions regarding continuum beliefs in the stigma process were only partially confirmed. However, there were associations of continuum beliefs with less stigmatizing attitudes toward persons affected by either schizophrenia or depression. Including information on continuity of symptoms, and thus oppose perceived separation, could prove helpful in future anti-stigma campaigns.
format: application/pdf
format: text/html
creator: Anna C. Makowski
creator: Eva E. Mnich
creator: Matthias C. Angermeyer
creator: Olaf von dem Knesebeck
subject: Neurology
subject: Psychiatry and Psychology
description: doi:10.7717/peerj.2360
publisher: PeerJ Inc.
rights: © 2016 Makowski et al.
abstract: Background Individuals with mental illness often experience stigmatization and encounter stereotypes such as being dangerous or unpredictable. To further improve measures against psychiatric stigma, it is of importance to understand its components. In this study, we attend to the step of separation between “us” and “them” in the stigma process as conceptualized by Link and Phelan. In using the belief in continuity of mental illness symptoms as a proxy for separation, we explore its associations with stereotypes, emotional responses and desire for social distance in the stigma process. Methods Analyses are based on a representative survey in Germany. Vignettes with symptoms suggestive of schizophrenia (n = 1,338) or depression (n = 1,316) were presented to the respondents, followed by questions on continuum belief, stereotypes, emotional reactions and desire for social distance. To examine the relationship between these items, path models were computed. Results Respondents who endorsed the continuum belief tended to show greater prosocial reactions (schizophrenia: 0.07; p < 0.001, depression: 0.09; p < 0.001) and less desire for social distance (schizophrenia: −0.13; p < 0.001, depression: −0.14; p < 0.001) toward a person with mental illness. In both cases, agreement with the stereotypes of unpredictability and dangerousness was positively associated with feelings of anger and fear as well as desire for social distance. There were no statistically significant relations between stereotypes and continuum beliefs. Discussion Assumptions regarding continuum beliefs in the stigma process were only partially confirmed. However, there were associations of continuum beliefs with less stigmatizing attitudes toward persons affected by either schizophrenia or depression. Including information on continuity of symptoms, and thus oppose perceived separation, could prove helpful in future anti-stigma campaigns.
bibliographic citation: Makowski et al. (2016) Continuum beliefs in the stigma process regarding persons with schizophrenia and depression: results of path analyses. PeerJ 4:e2360 https://doi.org/10.7717/peerj.2360
date submitted: 2016-05-05
date accepted: 2016-07-22
issued: 2016-09-27
is part of: PeerJ
license: http://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Makowski
  given name: Anna C.
author list: Agent
  family name: Mnich
  given name: Eva E.
author list: Agent
  family name: Angermeyer
  given name: Matthias C.
author list: Agent
  family name: von dem Knesebeck
  given name: Olaf
doi: 10.7717/peerj.2360
volume: 4
issn: 2167-8359
publication name: PeerJ
publication date: 2016-09-27
copyright: © 2016 Makowski et al.
attribution name: Makowski et al.

Formal modeling and analysis of the hexosamine biosynthetic pathway: role of O-linked N-acetylglucosamine transferase in oncogenesis and cancer progression
type: item
type: AcademicArticle
description: The alteration of glucose metabolism, through increased uptake of glucose and glutamine addiction, is essential to cancer cell growth and invasion. Increased flux of glucose through the Hexosamine Biosynthetic Pathway (HBP) drives increased cellular O-GlcNAcylation (hyper-O-GlcNAcylation) and contributes to cancer progression by regulating key oncogenes. However, the association between hyper-O-GlcNAcylation and activation of these oncogenes remains poorly characterized. Here, we implement a qualitative modeling framework to analyze the role of the Biological Regulatory Network in HBP activation and its potential effects on key oncogenes. Experimental observations are encoded in a temporal language format and model checking is applied to infer the model parameters and qualitative model construction. Using this model, we discover step-wise genetic alterations that promote cancer development and invasion due to an increase in glycolytic flux, and reveal critical trajectories involved in cancer progression. We compute delay constraints to reveal important associations between the production and degradation rates of proteins. O-linked N-acetylglucosamine transferase (OGT), an enzyme used for addition of O-GlcNAc during O-GlcNAcylation, is identified as a key regulator to promote oncogenesis in a feedback mechanism through the stabilization of c-Myc. Silencing of the OGT and c-Myc loop decreases glycolytic flux and leads to programmed cell death. Results of network analyses also identify a significant cycle that highlights the role of p53-Mdm2 circuit oscillations in cancer recovery and homeostasis. Together, our findings suggest that the OGT and c-Myc feedback loop is critical in tumor progression, and targeting these mediators may provide a mechanism-based therapeutic approach to regulate hyper-O-GlcNAcylation in human cancer.
format: application/pdf
format: text/html
creator: Muhammad Tariq Saeed
creator: Jamil Ahmad
creator: Shahzina Kanwal
creator: Andreana N. Holowatyj
creator: Iftikhar A. Sheikh
creator: Rehan Zafar Paracha
creator: Aamir Shafi
creator: Amnah Siddiqa
creator: Zurah Bibi
creator: Mukaram Khan
creator: Amjad Ali
subject: Computational Biology
subject: Oncology
description: doi:10.7717/peerj.2348
publisher: PeerJ Inc.
rights: © 2016 Saeed et al.
abstract: The alteration of glucose metabolism, through increased uptake of glucose and glutamine addiction, is essential to cancer cell growth and invasion. Increased flux of glucose through the Hexosamine Biosynthetic Pathway (HBP) drives increased cellular O-GlcNAcylation (hyper-O-GlcNAcylation) and contributes to cancer progression by regulating key oncogenes. However, the association between hyper-O-GlcNAcylation and activation of these oncogenes remains poorly characterized. Here, we implement a qualitative modeling framework to analyze the role of the Biological Regulatory Network in HBP activation and its potential effects on key oncogenes. Experimental observations are encoded in a temporal language format and model checking is applied to infer the model parameters and qualitative model construction. Using this model, we discover step-wise genetic alterations that promote cancer development and invasion due to an increase in glycolytic flux, and reveal critical trajectories involved in cancer progression. We compute delay constraints to reveal important associations between the production and degradation rates of proteins. O-linked N-acetylglucosamine transferase (OGT), an enzyme used for addition of O-GlcNAc during O-GlcNAcylation, is identified as a key regulator to promote oncogenesis in a feedback mechanism through the stabilization of c-Myc. Silencing of the OGT and c-Myc loop decreases glycolytic flux and leads to programmed cell death. Results of network analyses also identify a significant cycle that highlights the role of p53-Mdm2 circuit oscillations in cancer recovery and homeostasis. Together, our findings suggest that the OGT and c-Myc feedback loop is critical in tumor progression, and targeting these mediators may provide a mechanism-based therapeutic approach to regulate hyper-O-GlcNAcylation in human cancer.
bibliographic citation: Saeed et al. (2016) Formal modeling and analysis of the hexosamine biosynthetic pathway: role of O-linked N-acetylglucosamine transferase in oncogenesis and cancer progression. PeerJ 4:e2348 https://doi.org/10.7717/peerj.2348
date submitted: 2016-03-01
date accepted: 2016-07-19
issued: 2016-09-27
is part of: PeerJ
license: http://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Saeed
  given name: Muhammad Tariq
author list: Agent
  family name: Ahmad
  given name: Jamil
author list: Agent
  family name: Kanwal
  given name: Shahzina
author list: Agent
  family name: Holowatyj
  given name: Andreana N.
author list: Agent
  family name: Sheikh
  given name: Iftikhar A.
author list: Agent
  family name: Zafar Paracha
  given name: Rehan
author list: Agent
  family name: Shafi
  given name: Aamir
author list: Agent
  family name: Siddiqa
  given name: Amnah
author list: Agent
  family name: Bibi
  given name: Zurah
author list: Agent
  family name: Khan
  given name: Mukaram
author list: Agent
  family name: Ali
  given name: Amjad
doi: 10.7717/peerj.2348
volume: 4
issn: 2167-8359
publication name: PeerJ
publication date: 2016-09-27
copyright: ©2016 Saeed et al.
attribution name: Saeed et al.

Effects of grip force on median nerve deformation at different wrist angles
type: item
type: AcademicArticle
description: The present study investigated the effects of grip on changes in the median nerve cross-sectional area (MNCSA) and median nerve diameter in the radial-ulnar direction (D1) and dorsal-palmar direction (D2) at three wrist angles. Twenty-nine healthy participants (19 men [mean age, 24.2 ± 1.6 years]; 10 women [mean age, 24.0 ± 1.6 years]) were recruited. The median nerve was examined at the proximal carpal tunnel region in three grip conditions, namely finger relaxation, unclenched fist, and clenched fist. Ultrasound examinations were performed in the neutral wrist position (0°), at 30°wrist flexion, and at 30°wrist extension for both wrists. The grip condition and wrist angle showed significant main effects (p < 0.01) on the changes in the MNCSA, D1, and D2. Furthermore, significant interactions (p < 0.01) were found between the grip condition and wrist angle for the MNCSA, D1, and D2. In the neutral wrist position (0°), significant reductions in the MNCSA, D1, and D2 were observed when finger relaxation changed to unclenched fist and clenched fist conditions. Clenched fist condition caused the highest deformations in the median nerve measurements (MNCSA, approximately −25%; D1, −13%; D2, −12%). The MNCSA was significantly lower at 30°wrist flexion and 30°wrist extension than in the neutral wrist position (0°) at unclenched fist and clenched fist conditions. Notably, clenched fist condition at 30°wrist flexion showed the highest reduction of the MNCSA (−29%). In addition, 30°wrist flexion resulted in a lower D1 at clenched fist condition. In contrast, 30°wrist extension resulted in a lower D2 at both unclenched fist and clenched fist conditions. Our results suggest that unclenched fist and clenched fist conditions cause reductions in the MNCSA, D1, and D2. More importantly, unclenched fist and clenched fist conditions at 30°wrist flexion and 30°wrist extension can lead to further deformation of the median nerve.
format: application/pdf
format: text/html
creator: Ping Yeap Loh
creator: Hiroki Nakashima
creator: Satoshi Muraki
subject: Kinesiology
subject: Neurology
subject: Orthopedics
description: doi:10.7717/peerj.2510
publisher: PeerJ Inc.
rights: © 2016 Loh et al.
abstract: The present study investigated the effects of grip on changes in the median nerve cross-sectional area (MNCSA) and median nerve diameter in the radial-ulnar direction (D1) and dorsal-palmar direction (D2) at three wrist angles. Twenty-nine healthy participants (19 men [mean age, 24.2 ± 1.6 years]; 10 women [mean age, 24.0 ± 1.6 years]) were recruited. The median nerve was examined at the proximal carpal tunnel region in three grip conditions, namely finger relaxation, unclenched fist, and clenched fist. Ultrasound examinations were performed in the neutral wrist position (0°), at 30°wrist flexion, and at 30°wrist extension for both wrists. The grip condition and wrist angle showed significant main effects (p < 0.01) on the changes in the MNCSA, D1, and D2. Furthermore, significant interactions (p < 0.01) were found between the grip condition and wrist angle for the MNCSA, D1, and D2. In the neutral wrist position (0°), significant reductions in the MNCSA, D1, and D2 were observed when finger relaxation changed to unclenched fist and clenched fist conditions. Clenched fist condition caused the highest deformations in the median nerve measurements (MNCSA, approximately −25%; D1, −13%; D2, −12%). The MNCSA was significantly lower at 30°wrist flexion and 30°wrist extension than in the neutral wrist position (0°) at unclenched fist and clenched fist conditions. Notably, clenched fist condition at 30°wrist flexion showed the highest reduction of the MNCSA (−29%). In addition, 30°wrist flexion resulted in a lower D1 at clenched fist condition. In contrast, 30°wrist extension resulted in a lower D2 at both unclenched fist and clenched fist conditions. Our results suggest that unclenched fist and clenched fist conditions cause reductions in the MNCSA, D1, and D2. More importantly, unclenched fist and clenched fist conditions at 30°wrist flexion and 30°wrist extension can lead to further deformation of the median nerve.
bibliographic citation: Loh et al. (2016) Effects of grip force on median nerve deformation at different wrist angles. PeerJ 4:e2510 https://doi.org/10.7717/peerj.2510
date submitted: 2016-05-17
date accepted: 2016-08-31
issued: 2016-09-22
is part of: PeerJ
license: http://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Loh
  given name: Ping Yeap
author list: Agent
  family name: Nakashima
  given name: Hiroki
author list: Agent
  family name: Muraki
  given name: Satoshi
doi: 10.7717/peerj.2510
volume: 4
issn: 2167-8359
publication name: PeerJ
publication date: 2016-09-22
copyright: ©2016 Loh et al.
attribution name: Loh et al.

Self-rated mental health and race/ethnicity in the United States: support for the epidemiological paradox
type: item
type: AcademicArticle
description: This paper evaluates racial/ethnic differences in self-rated mental health for adults in the United States, while controlling for demographic and socioeconomic characteristics as well as length of stay in the country. Using data from the 2010 National Health Interview Survey Cancer Control Supplement (NHIS-CCS), binomial logistic regression models are fit to estimate the association between race/ethnicity and poor/fair self-reported mental health among US Adults. The size of the analytical sample was 22,844 persons. Overall prevalence of poor/fair self-rated mental health was 7.72%, with lower prevalence among Hispanics (6.93%). Non-Hispanic blacks had the highest prevalence (10.38%). After controls for socioeconomic characteristics are incorporated in the models, Hispanics were found to have a lower probability of reporting poor/fair self-rated mental health in comparison to non-Hispanic whites (OR = 0.70; 95% CI [0.55–0.90]). No difference was found for other minority groups when compared to the reference group in the final model. Contrary to global self-rated health, Hispanics were found to have a lower probability of reporting poor/fair self-rated mental health in comparison to non-Hispanic whites. No difference was found for non-Hispanic blacks when they were compared to non-Hispanic whites. Self-rated mental health is therefore one case of a self-rating of health in which evidence supporting the epidemiological paradox is found among adults in the United States.
format: application/pdf
format: text/html
creator: Alexis R. Santos-Lozada
subject: Epidemiology
subject: Public Health
subject: Statistics
description: doi:10.7717/peerj.2508
publisher: PeerJ Inc.
rights: © 2016 Santos-Lozada
abstract: This paper evaluates racial/ethnic differences in self-rated mental health for adults in the United States, while controlling for demographic and socioeconomic characteristics as well as length of stay in the country. Using data from the 2010 National Health Interview Survey Cancer Control Supplement (NHIS-CCS), binomial logistic regression models are fit to estimate the association between race/ethnicity and poor/fair self-reported mental health among US Adults. The size of the analytical sample was 22,844 persons. Overall prevalence of poor/fair self-rated mental health was 7.72%, with lower prevalence among Hispanics (6.93%). Non-Hispanic blacks had the highest prevalence (10.38%). After controls for socioeconomic characteristics are incorporated in the models, Hispanics were found to have a lower probability of reporting poor/fair self-rated mental health in comparison to non-Hispanic whites (OR = 0.70; 95% CI [0.55–0.90]). No difference was found for other minority groups when compared to the reference group in the final model. Contrary to global self-rated health, Hispanics were found to have a lower probability of reporting poor/fair self-rated mental health in comparison to non-Hispanic whites. No difference was found for non-Hispanic blacks when they were compared to non-Hispanic whites. Self-rated mental health is therefore one case of a self-rating of health in which evidence supporting the epidemiological paradox is found among adults in the United States.
bibliographic citation: Santos-Lozada (2016) Self-rated mental health and race/ethnicity in the United States: support for the epidemiological paradox. PeerJ 4:e2508 https://doi.org/10.7717/peerj.2508
date submitted: 2016-06-15
date accepted: 2016-08-26
issued: 2016-09-22
is part of: PeerJ
license: http://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Santos-Lozada
  given name: Alexis R.
doi: 10.7717/peerj.2508
volume: 4
issn: 2167-8359
publication name: PeerJ
publication date: 2016-09-22
copyright: ©2016 Santos-Lozada
attribution name: Santos-Lozada

PeerJ
type: Periodical
uri: PeerJ
issn: 2167-8359