bluuebunny/crossref_metadata_2025 huggingface dataset:
The RCPA Quality Assurance Program in Dermatopathology: A Retrospective Review
Authors: Peck Martyn , Beer Trevor W. , Badrick Tony , Wood Benjamin A.
Published: September 2017

Aims:

To review the Royal College of Pathologists of Australasia (RCPA) Quality Assurance Program Dermatopathology module from 2005 to 2016 to assess diagnostic performance, changes over time, and areas of diagnostic difficulty.

Methods:

The computerized records of the RCPA Dermatopathology subspecialist module were reviewed. Cases were categorized into groups including nonneoplastic disorders, neoplasms, and cases with multiple diagnoses. The performance of participants over time in each of these categories and in more specific areas (including melanocytic and adnexal neoplasms) was assessed. Cases which showed high rates of discordant responses were specifically reviewed.

Results:

One hundred sixteen cases circulated over 10 years were evaluated. The overall concordance rate was 77%, with a major discordance rate of 7%. There was a slightly higher concordance rate for neoplasms compared with nonneoplastic lesions (80% vs. 74%). Specific areas associated with lower concordance rates included classification of adnexal tumors and identification of multiple pathologies. A spindle cell nevus of Reed yielded a 40% discordance rate, with most misclassifications indicating melanoma.

Conclusions:

The RCPA quality assurance program module has circulated a wide range of common and uncommon cases to participants over the 12 years studied, highlighting a low but important rate of major discordant responses. Melanocytic lesions, hematolymphoid infiltrates, adnexal tumors, and identification of multiple pathologies are identified as areas worthy of particular attention in quality improvement activities.
Novel Double-Needle System That Can Prevent Intravascular Injection of Any Filler
Authors: Huang Hsiang , Lin Yu-Shan
Published: September 2017

A new type of needle system combines 2 parts, an inner needle and an outer needle. The inner needle is used for filler injection and the outer needle acts as a guiding needle that can observe blood reflow when inserting into the vessel lumen during injection process. This new needle system can be used for all kinds of filler, providing real time monitoring for physician and preventing intravascular injection of any filler.
Spontaneous Regression of Lymphangiomas in a Single Center Over 34 Years
Authors: Kato Motoi , Watanabe Shoji , Kato Reiko , Kawashima Hiroshi , Iida Takuya , Watanabe Azusa
Published: September 2017

Background:

A lymphangioma, also called a lymphatic malformation, is a congenital condition that frequently occurs in young children. It is classified into 3 groups depending on the size of the cysts (macrocystic, microcystic, and mixed). Spontaneous regression occurs in some cases; however, the characteristics of patients who show regression have not been studied previously. Furthermore, the types and the timing of the initial treatment are still controversial. Therefore, we statistically analyzed the occurrence of short-term spontaneous regression, patient age at original occurrence, cyst types, cyst sizes, and cyst locations in patients diagnosed with peripheral localized lymphangiomas in a single children center over 34 years.

Methods:

We retrospectively collected the data of 153 patients and reviewed the medical charts.

Results:

Spontaneous regression occurred only in macrocystic or mixed type; regression was most frequent in patients who, at the time of onset, were more than 2 years old.

Conclusions:

We concluded that elderly patients with macrocystic or mixed type lymphangioma may have to wait for treatment for over 3 months from the initial onset. Conversely, microcystic type could not be expected to show regression in a short period, and prompt initiation of the treatments may be required. The difference of the regression or not may depend on the characteristics of the lymph flow.
Nucleus accumbens mediates the pronociceptive effect of sleep deprivation: the role of adenosine A2A and dopamine D2 receptors
Authors: Sardi Natalia Fantin , Tobaldini Glaucia , Morais Rosana Nogueira , Fischer Luana
Published: September 2017

Sleep disorders increase pain sensitivity and the risk of developing painful conditions; however, the underlying mechanisms are poorly understood. It has been suggested that nucleus accumbens (NAc) influences sleep-wake cycle by means of a balance between adenosine activity at A2A receptors and dopamine activity at D2 receptors. Because the NAc also plays an important role in pain modulation, we hypothesized that the NAc and its A2A and D2 receptors mediate the pronociceptive effect of rapid eye movement (REM) sleep deprivation (SD). We found that 24 hours of REM-SD induced an intense pronociceptive effect in Wistar rats, which decreases progressively over a sleep rebound period. Although the level of fecal glucocorticoid metabolites increased with SD within group, it did not differ between sleep-deprived group and control group, indicating a stress response with similar magnitude between groups. The pronociceptive effect of REM-SD was prevented by excitotoxic lesion (N-Methyl-D-aspartate, 5.5 μg) of NAc and reverted by its acute blockade (Qx-314, 2%). The administration of an A2A receptor antagonist (SCH-58261, 7 ng) or a D2 receptor agonist (piribedil, 6 μg) into the NAc increased home cage activity and blocked the pronociceptive effect of REM-SD. Complementarily, an A2A receptor agonist (CGS-21680, 24 ng) impaired the reversal of the pronociceptive effect and decreased home cage activity, as it did a D2 receptor antagonist (raclopride, 5 μg). Rapid eye movement SD did not affect the expression of c-Fos protein in NAc. These data suggest that SD increases pain by increasing NAc adenosinergic A2A activity and by decreasing NAc dopaminergic D2 activity.
Protein Digestion and Quality of Goat and Cow Milk Infant Formula and Human Milk Under Simulated Infant Conditions
Authors: Maathuis Annet , Havenaar Robert , He Tao , Bellmann Susann
Published: September 2017

Objective:

The aim of this study was to determine the kinetics of true ileal protein digestion and digestible indispensable amino acid score (DIAAS) of a goat milk-based infant formula (GIF), a cow milk-based infant formula (CIF), and human milk (HM).

Methods:

The GIF, CIF, and HM were investigated in an in vitro gastrointestinal model simulating infant conditions. Digested compounds were dialyzed from the intestinal compartment as bioaccessible fraction. Dialysate was collected in 15 to 60-minute periods for 4 hours. True ileal protein digestibility and DIAAS were determined as bioaccessible nitrogen (N) and amino acids.

Results:

N bioaccessibility from the GIF showed similar kinetics to that of HM. The CIF showed a delay in N bioaccessibility versus the GIF and HM. In the 1st hour of digestion, N bioaccessibility was 19.9% ± 3.5% and 23.3% ± 1.3% for the GIF and HM, respectively, and 11.2% ± 0.6% for CIF (P < 0.05 vs HM). In the 3rd hour of digestion, the N bioaccessibility was higher (P < 0.05) for the CIF (28.9% ± 1.2%) than for the GIF (22.5% ± 1.6%) and HM (20.6% ± 1.0%). After 4 hours, the true ileal protein digestibility of the GIF, CIF, and HM was 78.3% ± 3.7%, 73.4% ± 2.7%, and 77.9% ± 4.1%, respectively. The DIAAS for the GIF, CIF, and HM for 0- to 6-month-old infants was 83%, 75%, and 77% for aromatic AA.

Conclusion:

The protein quality is not different between the GIF, CIF, and HM, but the kinetics of protein digestion of the GIF is more comparable to that of HM than that of the CIF.
Interventions for Gait Training in Children With Spinal Cord Impairments: A Scoping Review
Authors: Funderburg Sarah E. , Josephson Hannah E. , Price Ashlee A. , Russo Maredith A. , Case Laura E.
Published: September 2017

Purpose:

This is a scoping review of the literature on interventions for gait in individuals with pediatric spinal cord impairments.

Summary of Key Points:

Four categories of interventions were identified: orthoses/assistive devices, electrical stimulation, treadmill training, and infant treadmill stepping.

Conclusions:

Studies on orthotic intervention, electrical stimulation, and treadmill training reported benefits for various components of gait. The majority of articles (77%) were classified as levels of evidence III and IV.

Clinical Recommendations:

Each intervention targeted specific outcomes; therefore, it is important to identify individual patient characteristics and goals appropriate for each intervention to guide clinical practice. Determining the appropriate orthotic support for each child, and incorporating treadmill training or electrical stimulation, is recommended.
Determining Need for School-Based Physical Therapy Under IDEA: Commonalities Across Practice Guidelines
Authors: Vialu Carlo , Doyle Maura
Published: September 2017

Background and Purpose:

The Individuals with Disabilities Education Act (IDEA) includes physical therapy (PT) as a related service that may be provided to help students with disabilities benefit from their education. However, the IDEA does not provide specific guidance for the provision of school-based PT, resulting in variations in practice across the United States. The authors examined 22 state and local education agency guidelines available online to find commonalities related to the determination of a student's need for PT.

Results and Conclusions:

Seven commonalities found: educational benefit, team decision, need for PT expertise, establishment of Individualized Education Program (IEP) goal before determining need for PT, distinction between medical and educational PT, the student's disability adversely affects education, and the student's potential for improvement. These commonalities are discussed in relation to current PT and special education literature. This article suggests applying these commonalities as procedural requirements and questions for discussion during an IEP team meeting.
Qualitative Methodologies as an Intervention: Beyond Program Planning and Implementation
Authors: Farb Heather , Brown Lisanne , Priebe Alexandra
Published: September 2017

The Primary Care Capacity Project (PCCP), implemented by the Louisiana Public Health Institute, systematically and rigorously applied qualitative methodologies beyond simple interviews and focus groups to develop the project areas of focus, evaluate clinical transformation interventions in selected heath centers along the Gulf Coast, and provide data and support to foster ongoing quality improvement approaches. Qualitative methodologies were utilized for formative, implementation, and summative evaluation. During the early formative stages of PCCP, community prioritization meetings were conducted in Louisiana, Mississippi, Alabama, and Florida, in which key stakeholders were asked to brainstorm and prioritize major health issues and recommendations in their communities. Findings from these meetings were then used to inform PCCP clinic funding and other community priorities. During project implementation, dyadic interviews were facilitated around specific PCCP areas of focus. These dyadic interviews were valuable in that they uncovered stories, successes, and challenges of clinical transformation. Moreover, they promoted peer-to-peer learning among diverse health centers. The relationships between interview participants are likely to continue past the grant period and further promote innovation and efficiency. Finally case studies were conducted to inform actionable recommendations tailored to each health center. These data also provided value add back to the health centers as they used the information to guide programming and quality improvement efforts. Qualitative methods are critical tools for public health practitioners to support project planning and improvement as well as community change.
Engagement Strategies to Advance Community-Centered Primary Care
Authors: Brown Lisanne , Clesi Giepert Jamie , Black Amanda “Barrie” , Farb Heather
Published: September 2017

The Louisiana Public Health Institute designed and implemented the Primary Care Capacity Project (PCCP) with the purpose of expanding access to high-quality, integrated, and sustainable community-based primary care, including linkages to behavioral health services, as well as environmental and occupational health services. With a primary focus to invest in community health centers across 17 Gulf Coast counties and parishes, PCCP engaged stakeholders, including 4 primary care organizations, over 20 federally qualified health centers, public health institutes, health information exchanges, national experts, academic organizations, and health departments along with their relevant community partners. This article examines the strategies PCCP used to engage stakeholders and partners throughout the project in order to strengthen sustainable primary care systems. The PCCP team fostered trusted partnerships with a wide range of stakeholders to not only understand the need of the communities but to also identify ways to complement and not duplicate already existing efforts. Specifically, community prioritization convenings, peer-to-peer learning through the Regional Care Collaborative, and dyadic interviews were instrumental in linking stakeholders and maximizing capacity-building efforts. Health partners across the 4 states are now better positioned to collaborate on future regional opportunities including continued knowledge transfer through special interest groups, ongoing engagement with an annual regional convening, continued efforts to advance emergency management and resiliency, and potential development of group purchasing and other shared services. The PCCP experience suggests that in disaster-prone areas the sustainability of integrated primary care and behavioral health services is enhanced when cross-jurisdiction collaborations are established.
Trends, Frequency, and Nature of Surgeon-Reported Conflicts of Interest in Plastic Surgery
Authors: Lopez Joseph , Musavi Leila , Quan Amy , Calotta Nicholas , Juan Ilona , Park Angela , Tufaro Anthony P. , May James W. , Dorafshar Amir H.
Published: September 2017

Background:

The purpose of this study was to identify types and trends in industry sponsorship of plastic surgery research since the establishment of conflict-of-interest reporting policies in plastic surgery.

Methods:

The authors analyzed the frequency and types of self-reported conflicts of interest in the plastic surgery literature since the adoption of reporting policies in 2007. All original articles that met the authors’ inclusion criteria and were published in the following three journals from 2008 to 2013 were included: Annals of Plastic Surgery, Plastic and Reconstructive Surgery, and Journal of Plastic, Reconstructive & Aesthetic Surgery. A multivariate regression analysis was performed to determine what study-specific variables were associated with conflict-of-interest disclosures.

Results:

A total of 3722 articles were analyzed. The incidence of conflicts of interest increased from 14 percent in 2008 to 24 percent in 2009. However, thereafter, the incidence of conflicts of interest decreased steadily from 21 percent in 2010 to 9 percent in 2013. Furthermore, the authors’ analysis revealed that from 2008 to 2013, industry decreased direct research support but steadily increased the rate of consultantships (p < 0.001). A multivariate regression analysis revealed that, after adjusting for potential confounders, self-reported conflicts of interest have decreased since 2008 (p = 0.03) and the prevalence of conflicts of interest differs by plastic surgery subspecialty (p < 0.0001), country of origin (p < 0.0001), and journal of publication (p = 0.05).

Conclusions:

If self-reporting of conflicts of interest is assumed to be accurate, the number of surgeon-reported conflicts of interest in plastic surgery declined overall. Although the absolute number of consultantships did not change, the rate of consultantships rather than direct research support increased over this period.
The Ethics of Sharing Plastic Surgery Videos on Social Media: Systematic Literature Review, Ethical Analysis, and Proposed Guidelines
Authors: Dorfman Robert G. , Vaca Elbert E. , Fine Neil A. , Schierle Clark F.
Published: September 2017

Recent videos shared by plastic surgeons on social media applications such as Snapchat, Instagram, and YouTube, among others, have blurred the line between entertainment and patient care. This has left many in the plastic surgery community calling for the development of more structured oversight and guidance regarding video sharing on social media. To date, no official guidelines exist for plastic surgeons to follow. Little is known about the ethical implications of social media use by plastic surgeons, especially with regard to video sharing. A systematic review of the literature on social media use in plastic surgery was performed on October 31, 2016, with an emphasis on ethics and professionalism. An ethical analysis was conducted using the four principles of medical ethics. The initial search yielded 87 articles. Thirty-four articles were included for analyses that were found to be relevant to the use of social media in plastic surgery. No peer-reviewed articles were found that mentioned Snapchat or addressed the ethical implications of sharing live videos of plastic surgery on social media. Using the four principles of medical ethics, it was determined that significant ethical concerns exist with broadcasting these videos. This analysis fills an important gap in the plastic surgery literature by addressing the ethical issues concerning live surgery broadcasts on social media. Plastic surgeons may use the guidelines proposed here to avoid potential pitfalls.
“Internet of Things” Real-Time Free Flap Monitoring
Authors: Kim Sang Hun , Shin Ho Seong , Lee Sang Hwan
Published: September 2017

Background:

Free flaps are a common treatment option for head and neck reconstruction in plastic reconstructive surgery, and monitoring of the free flap is the most important factor for flap survival. In this study, the authors performed real-time free flap monitoring based on an implanted Doppler system and “internet of things” (IoT)/wireless Wi-Fi, which is a convenient, accurate, and efficient approach for surgeons to monitor a free flap.

Methods:

Implanted Doppler signals were checked continuously until the patient was discharged by the surgeon and residents using their own cellular phone or personal computer. If the surgeon decided that a revision procedure or exploration was required, the authors checked the consumed time (positive signal-to-operating room time) from the first notification when the flap's status was questioned to the determination for revision surgery according to a chart review. To compare the efficacy of real-time monitoring, the authors paired the same number of free flaps performed by the same surgeon and monitored the flaps using conventional methods such as a physical examination.

Results:

The total survival rate was greater in the real-time monitoring group (94.7% versus 89.5%). The average time for the real-time monitoring group was shorter than that for the conventional group (65 minutes versus 86 minutes).

Conclusions:

Based on this study, real-time free flap monitoring using IoT technology is a method that surgeon and reconstruction team can monitor simultaneously at any time in any situation.
Melanotic Neuroectodermal Tumor of Infancy in the Maxilla
Authors: Ünsal Haluk Yener , Yalçin Mustafa
Published: September 2017

Melanotic neuroectodermal tumor of infancy is uncommon and has rapid expansile growth. Melanotic neuroectodermal tumor of infancy is a very rare and benign but locally aggressive neoplasm that originates from neural crest and is composed of relatively primitive pigment-producing cells. The lesion commonly affects the maxilla of infants during the first year of life. Common treatment methods include surgical excision and resection of the tumor. The aim of this article is to present the diagnosis and treatment of a patient with melanotic neuroectodermal tumor that occurred in the anterior maxilla of a 6-month-old male baby.
A Novel Reverse Periauricular Flap Reconstruction Method That Uses Additional Anastomosis to Avoid Venous Congestion for Periorbital Defects
Authors: Xiao Hui , Wang Haiping
Published: September 2017

The aim of this study was to introduce and evaluate a method to prevent venous congestion in periauricular flap pedicled on the frontal branch of the superficial temporal artery (STA). Flaps based on the STA are therefore extremely versatile in reconstruction of the face and scalp. The literature on reconstructive possibilities provided by temporal flaps describes venous congestion, but there are currently no methods for preventing this problem. In this brief report, we describe a method to anastomose the parietal branch of superficial temporal vein and the middle temporal vein to ensure venous flow when a concomitant vein of the frontal branch of the STA is unavailable. The flap survived without venous congestion and donor sites healed with satisfactory outcomes. Color and texture match of the flap were excellent and morbidity at the donor site was usually minimal.

Level of Evidence: IV
Postradiotherapy Prosthetic Management of Mandible Reconstructed With Fibular Graft
Authors: Kharade Pankaj , Dholam Kanchan , Bhirangi Pravin
Published: September 2017

Intraoral defects secondary to resection of mandible leading to mandibular discontinuity are very complicated to treat as the muscles exert forces on the residual portion of the mandible. Primarily this leads to disfigurement of the face. These forces also make mastication difficult due to imbalance. Ultimately it leads to poor quality of life for the patient. Apart from that the clinical outcome and prognosis of prosthetic rehabilitation of such patients is very poor. The composite fibular flap is the preferred donor site for reconstruction of most complex orofacial-mandibular defects. The addition of a skin island allows for absolute tension-free intraoral closure that enhances tongue mobility. After reconstruction with free fibula graft, planning for prosthodontic rehabilitation by various methods can be carried out. Treatment strategy is dependent on the intraoral situation and patient's acceptance. This article reports various treatment considerations for implant retained prosthetic rehabilitation in a patient who had undergone mandibular reconstruction with free fibula flap.
Secondary Maxillary and Orbital Floor Reconstruction With a Free Scapular Flap Using Cutting and Fixation Guides Created by Computer-Aided Design/Computer-Aided Manufacturing
Authors: Morita Daiki , Numajiri Toshiaki , Tsujiko Shoko , Nakamura Hiroko , Yamochi Ryo , Sowa Yoshihiro , Yasuda Makoto , Hirano Shigeru
Published: September 2017

Computer-aided design/computer-aided manufacturing (CAD/CAM) guides are now widely used in maxillofacial reconstruction. However, there are few reports of CAD/CAM guides being used for scapular flaps. The authors performed the secondary maxillary and orbital floor reconstruction using a free latissimus dorsi muscle, cutaneous tissue, and scapular flap designed using CAD/CAM techniques in a 72-year-old man who had undergone partial maxillectomy four years previously. The patient had diplopia, the vertical dystopia of eye position, and a large oral-nasal-cutaneous fistula. After the operation, the authors confirmed that the deviation between the postoperative and preoperative planning three-dimensional images was less than 2 mm. Because scapular guides require 3 cutting surfaces, the shape of the scapular guide is more complex than that of a conventional fibular guide. In orbital floor reconstruction, the use of a CAM technique such as that used to manufacture the authors’ fixation guide is as necessary for accurate, safe, and easy reconstruction as is preoperative CAD planning. The production of a fixation guide as well as a cutting guide is particularly useful because it is difficult to determine the angle for reconstructing the orbital floor by freehand techniques. In this case, the orbital floor was reconstructed based on a mirror image of the healthy side to avoid overcompression of the orbital tissue. Although the patient's vertical dystopia of eye position was improved, diplopia was not improved because, for greater safety, the authors did not plan overcorrection of the orbital volume.
Intraoral Observation of the Mentalis and Incisivus Labii Inferioris Muscles
Authors: Iwanaga Joe , He Puhan , Watanabe Koichi , Kamura Yasuhiko , Oskouian Rod J. , Tubbs R. Shane
Published: September 2017

The mentalis (MT) and the incisivus labii inferioris (ILI), which are accessory muscles of the orbicularis oris (OO) muscle, form an intertwined and three-dimensionally related complex. The purpose of this study is to clarify the relationship between the MT, ILI, and OO muscles via intraoral dissection. Twenty-two sides from 11 fresh adult Caucasian cadaveric heads were used, and the MT, ILI, and OO dissected under the surgical microscope. Next, measurements of the bony attachment were carried out on another 12 sides. The fibers of the MT were separated into 2 parts: a superior and an inferior part with the former coursing anteromedially and joining the inferior part of the OO. The latter coursed anteroinferiorly to the skin of the chin. The ILI traveled anterolaterally and joined the inferior part of the OO. Inferior labial branches of the mental nerves ran on the OO. There was a significant difference (P = 0.0001) between specimens that were edentulous or had severe periodontitis with regard to the distance from the alveolar ridge to the upper side of the quadrangle when compared with specimens with mild periodontitis. However, there was no significant difference (P > 0.05) between specimens that were edentulous or had severe periodontitis specimens with mild periodontitis with regard to the distance from the inferior border of the mandible to the lower side of the quadrangle. We believe that the observations of this study could help surgeons better understand the anatomy of the chin and minimize complications following surgical and other invasive procedures in this area.
Human X chromosome inactivation and reactivation: implications for cell reprogramming and disease
Authors: Cantone Irene , Fisher Amanda G.
Published: September 2017

X-chromosome inactivation (XCI) is an exemplar of epigenetic regulation that is set up as pluripotent cells differentiate. Once established, XCI is stably propagated, but can be reversed
in vivo
or by pluripotent reprogramming
in vitro
. Although reprogramming provides a useful model for inactive X (Xi) reactivation in mouse, the relative instability and heterogeneity of human embryonic stem (ES) cells and induced pluripotent stem cells hampers comparable progress in human. Here we review studies aimed at reactivating the human Xi using different reprogramming strategies. We outline our recent results using mouse ES cells to reprogramme female human fibroblasts by cell–cell fusion. We show that pluripotent reprogramming induces widespread and rapid chromatin remodelling in which the human Xi loses
XIST
and H3K27m3 enrichment and selected Xi genes become reactivated, ahead of mitotic division. Using RNA sequencing to map the extent of human Xi reactivation, and chromatin-modifying drugs to potentiate reactivation, we outline how this approach could be used to better design strategies to re-express human X-linked loci. As cell fusion induces the expression of human pluripotency genes that represent both the ‘primed’ and ‘naive’ states, this approach may also offer a fresh opportunity to segregate human pluripotent states with distinct Xi expression profiles, using single-cell-based approaches.

This article is part of the themed issue ‘X-chromosome inactivation: a tribute to Mary Lyon’.
X-chromosome dosage as a modulator of pluripotency, signalling and differentiation?
Authors: Schulz Edda G.
Published: September 2017

Already during early embryogenesis, before sex-specific hormone production is initiated, sex differences in embryonic development have been observed in several mammalian species. Typically, female embryos develop more slowly than their male siblings. A similar phenotype has recently been described in differentiating murine embryonic stem cells, where a double dose of the X-chromosome halts differentiation until dosage-compensation has been achieved through X-chromosome inactivation. On the molecular level, several processes associated with early differentiation of embryonic stem cells have been found to be affected by X-chromosome dosage, such as the transcriptional state of the pluripotency network, the activity pattern of several signal transduction pathways and global levels of DNA-methylation. This review provides an overview of the sex differences described in embryonic stem cells from mice and discusses a series of X-linked genes that are associated with pluripotency, signalling and differentiation and their potential involvement in mediating the observed X-dosage–dependent effects.

This article is part of the themed issue ‘X-chromosome inactivation: a tribute to Mary Lyon’.
Progress in understanding the molecular mechanism of
Xist
RNA function through genetics
Authors: Monfort Asun , Wutz Anton
Published: September 2017

The
Xist
gene produces a long noncoding RNA that initiates chromosome-wide gene repression on the inactive X chromosome in female mammals. Recent progress has advanced the understanding of
Xist
function at the molecular level. This review provides an overview of insights from genetic approaches and puts the new data in the context of an emerging mechanistic model as well as the existing literature. Some consideration is given on how independent biochemical studies on X inactivation help to advance on the wider question of chromatin regulation in the mammalian dosage compensation system.

This article is part of the themed issue ‘X-chromosome inactivation: a tribute to Mary Lyon’.
Polycomb complexes in X chromosome inactivation
Authors: Brockdorff Neil
Published: September 2017

Identifying the critical RNA binding proteins (RBPs) that elicit
Xist
mediated silencing has been a key goal in X inactivation research. Early studies implicated the Polycomb proteins, a family of factors linked to one of two major multiprotein complexes, PRC1 and PRC2 (Wang 2001
Nat. Genet.
28
, 371–375 (
doi:10.1038/ng574
); Silva 2003
Dev. Cell
4
, 481–495 (
doi:10.1016/S1534-5807(03)00068-6
); de Napoles 2004
Dev. Cell
7
, 663–676 (
doi:10.1016/j.devcel.2004.10.005
); Plath 2003
Science
300
, 131–135 (
doi:10.1126/science.1084274
)). PRC1 and PRC2 complexes catalyse specific histone post-translational modifications (PTMs), ubiquitylation of histone H2A at position lysine 119 (H2AK119u1) and methylation of histone H3 at position lysine 27 (H3K27me3), respectively, and accordingly, these modifications are highly enriched over the length of the inactive X chromosome (Xi). A key study proposed that PRC2 subunits bind directly to
Xist
RNA A-repeat element, a region located at the 5′ end of the transcript known to be required for
Xist
mediated silencing (Zhao 2008
Science
322
, 750–756 (
doi:10.1126/science.1163045
)). Subsequent recruitment of PRC1 was assumed to occur via recognition of PRC2 mediated H3K27me3 by the CBX subunit of PRC1, as has been shown to be the case at other Polycomb target loci (Cao 2002
Science
298
, 1039–1043 (
doi:10.1126/science.1076997
)). More recently, several reports have questioned aspects of the prevailing view, both in relation to the mechanism for Polycomb recruitment by
Xist
RNA and the contribution of the Polycomb pathway to
Xist
mediated silencing. In this article I provide an overview of our recent progress towards resolving these discrepancies.

This article is part of the themed issue ‘X-chromosome inactivation: a tribute to Mary Lyon’.
Phylogenetic comparative methods on phylogenetic networks with reticulations
Authors: Bastide Paul , Solís-Lemus Claudia , Kriebel Ricardo , Sparks K. William , Ané Cécile
Published: September 2017

The goal of Phylogenetic Comparative Methods (PCMs) is to study the distribution of quantitative traits among related species. The observed traits are often seen as the result of a Brownian Motion (BM) along the branches of a phylogenetic tree. Reticulation events such as hybridization, gene flow or horizontal gene transfer, can substantially affect a species’ traits, but are not modeled by a tree.Phylogenetic networkshave been designed to represent reticulate evolution. As they become available for downstream analyses, new models of trait evolution are needed, applicable to networks. One natural extension of the BM is to use a weighted average model for the trait of a hybrid, at a reticulation point. We develop here an efficient recursive algorithm to compute the phylogenetic variance matrix of a trait on a network, in only one preorder traversal of the network. We then extend the standard PCM tools to this new framework, including phylogenetic regression with covariates (or phylogenetic ANOVA), ancestral trait reconstruction, and Pagel’s λ test of phylogenetic signal. The trait of a hybrid is sometimes outside of the range of its two parents, for instance because of hybrid vigor or hybrid depression. These two phenomena are rather commonly observed in present-day hybrids. Transgressive evolution can be modeled as a shift in the trait value following a reticulation point. We develop a general framework to handle such shifts, and take advantage of the phylogenetic regression view of the problem to design statistical tests for ancestral transgressive evolution in the evolutionary history of a group of species. We study the power of these tests in several scenarios, and show that recent events have indeed the strongest impact on the trait distribution of present-day taxa. We apply those methods to a dataset ofXiphophorusfishes, to confirm and complete previous analysis in this group. All the methods developed here are available in theJuliapackagePhyloNetworks.
Interactions between immunotoxicants and parasite stress: implications for host health
Authors: Booton Ross D. , Yamaguchi Ryo , Marshall James A. R. , Childs Dylan Z. , Iwasa Yoh
Published: September 2017

Many organisms face a wide variety of biotic and abiotic stressors which reduce individual survival, interacting synergistically to further reduce fitness. Here we studied the effects of two such synergistically interacting stressors; immunotoxicant exposure and parasite infection. We model the dynamics of a within-host infection and the associated immune response of an individual. We consider both the indirect sub-lethal effects on immunosuppression and the direct effects on health and mortality of individuals exposed to toxicants. We demonstrate that sub-lethal exposure to toxicants can promote infection through the suppression of the immune system. This happens through the depletion of the immune response which causes rapid proliferation in parasite load. In addition, high toxicant exposure can alter cellular regulation and cause the breakdown of normal healthy tissue, from which we infer higher mortality risk of the host. We classify this breakdown into three phases of increasing toxicant stress, and demonstrate the range of conditions under which toxicant exposure causes failure at the within-host level. These phases are determined by the relationship between the immunity status, overall cellular health and the level of toxicant exposure. We discuss the implications of our model in the context of individual honey bee health. Our model provides an assessment of how pesticide stress and infection interact to cause the synergistic breakdown of the within-host dynamics of individual honey bees.
Insights into cerebral haemodynamics and oxygenation utilising in vivo mural cell imaging and mathematical modelling
Authors: Sweeney Paul W. , Walker-Samuel Simon , Shipley Rebecca J.
Published: September 2017

The neurovascular mechanisms underpinning the local regulation of cerebral blood flow (CBF) and oxygen transport remain elusive. In this study we have combined novel in vivo imaging of cortical microvascular and mural cell architecture with mathematical modelling of blood flow and oxygen transport, to provide new insights into CBF regulation that would be inaccessible in a conventional experimental context. Our study implicates vasomotion of smooth muscle actin-covered vessels, rather than pericyte-covered capillaries, as the main mechanism for modulating tissue oxygenation. We also resolve seemingly paradoxical observations in the literature around reduced blood velocity in response to arteriolar constrictions and deduce the cause to be propagation of constrictions to upstream penetrating arterioles. We provide support for pericytes acting as signalling conduits for upstream smooth muscle activation, and erythrocyte deformation as a complementary regulatory mechanism. Finally, we caution against the use of blood velocity as a proxy measurement for flow. Our combined imaging-modelling platform complements conventional experimentation allowing cerebrovascular physiology to be probed in unprecedented detail.
3-(Pyridin-4-yl)acetylacetone: a donor ligand towards mercury(II) halides and a versatile linker for complex materials
Authors: Truong Khai-Nghi , Merkens Carina , Englert Ulli
Published: September 2017

The ditopic organic molecule 3-(pyridin-4-yl)acetylacetone (HacacPy) acts as a pyridine-type ligand towards HgX
2 (X = Cl, Br, I). The nature of the anion and the ligand-to-cation ratio dominate the outcome of the reaction. Two different coordination compounds form with HgCl2, namely a ligand-rich mononuclear complex, HgCl2(HacacPy)2, and a ligand-deficient one-dimensional chain polymer, [Hg(μ-Cl)2(HacacPy)]1
∞, with five-coordinated HgII cations. Two compounds are also observed for HgBr2, a molecular complex isomorphous to the chloride derivative and a chain polymer with the composition [Hg(μ-Br)Br(HacacPy)]1
∞, in which the cations are four-coordinated. The ligand-rich mononuclear and ligand-deficient polymeric chloride and bromide complexes may be interconverted via thermal degradation and mechanochemical synthesis. In contrast to the chloride and bromide compounds, the reaction product with HgI2 does not depend on the ligand-to-cation ratio but corresponds to [Hg(μ-I)I(HacacPy)]1
∞, isomorphous to the bromide derivative. The N-coordinated HacacPy complexes could not be deprotonated and further crosslinked with a second cation. Synthesis of mixed-metal products could be achieved, however, by deprotonation of the acetylacetone moiety in HacacPy and formation of tris-chelated Fe(acacPy)3 and Al(acacPy)3 complexes in the first step. These mononuclear building blocks act as bridging poly(pyridine) ligands towards HgII halides and form two structure types. The first represents a one-dimensional ladder, with the tris(ligand) complexes acting as triconnected nodes and the HgII halides acting as linkers. In the alternative unprecedented product, both the tris(ligand) complexes and the [HgX
2(μ-X)HgX] groups act as equivalent triconnected nodes. They form a uninodal two-dimensional coordination network with vertex symbol 4.82 and fes topology.
Hydroxytropylium chloride: the first crystal structure of an unfunctionalized hydroxytropylium ion
Authors: Jandl Christian , Pöthig Alexander
Published: September 2017

The crystal structure of hydroxytropylium chloride, C7H6OH+·Cl−, the hydrochloride salt of tropone, is described, which represents the first crystallographic characterization of an unfunctionalized hydroxytropylium ion. Crystals were obtained serendipitously from a sample of chlorotropylium chloride after partial hydrolysis. This highlights the role of hydroxytropylium ions as an intermediate in the hydrolytic decomposition of halotropylium halides to tropone. The solid-state structure consists of layers, in which the hydroxytropylium and chloride ions interact via both strong hydrogen bonds formed by the hydroxy protons and weaker hydrogen bonds formed by the tropylium protons to produce a two-dimensional network.
Crystal structure of a twisted-ribbon type double-stranded AgIcoordination polymer:catena-poly[[silver(I)-μ3-bis(pyridin-3-ylmethyl)sulfane-κ3N:N′:S] nitrate]
Authors: Moon Suk-Hee , Kang Youngjin , Park Ki-Min
Published: September 2017

The asymmetric unit in the title compound, {[Ag(C12H12N2S)]·NO3}nor {[AgL]·NO3}n,L= bis(pyridin-3-ylmethyl)sulfane, consists of an AgIcation bound to a pyridine N atom of anLligand and an NO3−anion that is disordered over two orientations in an 0.570 (17):0.430 (17) occupancy ratio. Each AgIcation is coordinated by two pyridine N atoms from adjacentLligands to form an infinite zigzag chain along [110]. In addition, each AgIion binds to an S donor from a thirdLligand in an adjacent parallel chain, resulting in the formation of a twisted-ribbon type of double-stranded chain propagating along the [110] or [1-10] directions. The AgIatom is displaced out of the trigonal N2S coordination plane by 0.371 (3) Å because of interactions between the AgIcation and O atoms of the disordered nitrate anions. Intermolecular π–π stacking interactions [centroid-to-centroid distance = 3.824 (3) Å] occur between one pair of corresponding pyridine rings in the double-stranded chain. In the crystal, the double-stranded chains are alternately stacked along thecaxis with alternate stacks linked by intermolecular π–π stacking interactions [centroid-to-centroid distance = 3.849 (3) Å], generating a three-dimensional supramolecular architecture. Weak intermolecular C—H...O hydrogen bonds between the polymer chains and the O atoms of the nitrate anions also occur.
FlexED8: the first member of a fast and flexible sample-changer family for macromolecular crystallography
Authors: Papp Gergely , Felisaz Franck , Sorez Clement , Lopez-Marrero Marcos , Janocha Robert , Manjasetty Babu , Gobbo Alexandre , Belrhali Hassan , Bowler Matthew W. , Cipriani Florent
Published: September 2017

Automated sample changers are now standard equipment for modern macromolecular crystallography synchrotron beamlines. Nevertheless, most are only compatible with a single type of sample holder and puck. Recent work aimed at reducing sample-handling efforts and crystal-alignment times at beamlines has resulted in a new generation of compact and precise sample holders for cryocrystallography: miniSPINE and NewPin [see the companion paper by Pappet al.(2017,Acta Cryst., D73, 829–840)]. With full data collection now possible within seconds at most advanced beamlines, and future fourth-generation synchrotron sources promising to extract data in a few tens of milliseconds, the time taken to mount and centre a sample is rate-limiting. In this context, a versatile and fast sample changer, FlexED8, has been developed that is compatible with the highly successful SPINE sample holder and with the miniSPINE and NewPin sample holders. Based on a six-axis industrial robot, FlexED8 is equipped with a tool changer and includes a novel open sample-storage dewar with a built-in ice-filtering system. With seven versatile puck slots, it can hold up to 112 SPINE sample holders in uni-pucks, or 252 miniSPINE or NewPin sample holders, with 36 samples per puck. Additionally, a double gripper, compatible with the SPINE sample holders and uni-pucks, allows a reduction in the sample-exchange time from 40 s, the typical time with a standard single gripper, to less than 5 s. Computer vision-based sample-transfer monitoring, sophisticated error handling and automatic error-recovery procedures ensure high reliability. The FlexED8 sample changer has been successfully tested under real conditions on a beamline.
Reconciling activity-based descriptions of competence with professional work
Authors: Lester Stan
Published: September 2017

Purpose

The purpose of this paper is to discuss the problems of applying competence standards to professional-level work, noting limitations in functional approaches and drawing on developments in professions and on a recent Erasmus+ project to propose a more adequate alternative.

Design/methodology/approach

An approach to describing competence based on previously reported developments in some self-governing, principally British professions was used to inform an Erasmus+ project that created competence standards for five higher-level occupations in different European countries.

Findings

The original developments in professions and further work through the project both endorse a model of competence that is based on standards of practice, applies holistically to professional or occupational fields rather than focusing on work roles and functions, respects contextual factors in defining competent action, and necessitates situational interpretation and judgement.

Practical implications

Descriptions of professional competence need to avoid being overly constrained by assumptions about the roles that practitioners might perform or the context in which practice takes place. They need to reflect the ethos and ethics of the field as well as more transversal aspects of professionalism. Descriptions of this type are likely to reflect factors that are also valued in higher education.

Originality/value

The model of competence that is proposed appears to have a good level of validity for high-level professional work, and provides an approach to describing practice that is not limited to particular national contexts.
Work-integrated learning (WIL) in information technology
Authors: Jones Faye R. , Mardis Marcia A. , McClure Charles R. , Ma Jinxuan , Ambavarapu Chandrahasa , Spears Laura I.
Published: September 2017

Purpose

The purpose of this paper is to analyze 86 information technology (IT) internship postings to discern the extent to which the intended outcomes matched professional standards for four-year IT programs.

Design/methodology/approach

The researchers text mined specified skills from 86 internship postings and compared them to the competencies outlined in the ACM/IEEE Body of Knowledge.

Findings

Results indicated that students can expect to gain experience and exposure to both technical and general competencies. Though research and policy relating to technical fields have emphasized professional competencies such as teamwork, communication, and professionalism, this analysis suggested that the internship postings greatly emphasized technical skills at the expense of general competencies.

Research limitations/implications

The most frequently occurring competencies suggest future research opportunities for considering contextual factors of internship sites. The researchers conclude with implications for using text mining as a tool for comparing internship intent vs outcomes as well as suggestions for policies, standards, and curricula worthy of further exploration.

Originality/value

Employers, educators, and professionals agree that internships offer a promising means to link course content and practical workplace skills, especially in technical fields like IT. However, less clear are the ingredients of effective IT internships.