bluuebunny/crossref_metadata_2025 huggingface dataset:
Ecological engineers’ nests benefit plant recovery following fire in a semiarid grassland, New Mexico, USA
Authors: Nicolai Nancy
Published: April 2019

Questions

Ants and rodents are recognized as ecosystem engineers worldwide creating soil‐modified nests and adjacent edges with superior resources. The influence of Dipodomys spectabilis (rat) and Pogonomyrmex rugosus (ant) on nests and edges would be similar in burned and unburned habitat on functional groups’ cover, density, number of inflorescences and species number. We hypothesize that annual and perennial dicots would recover faster on rat patches than on burned grassland, dicots and grasses would recover faster on ant patches than on burned grassland, and annual dicots would recover faster on rat than on ant patches, whereas grasses would recover faster on ant than on rat patches.

Location

Semiarid grassland, Sevilleta National Wildlife Refuge, New Mexico, USA.

Methods

We analyzed annual and perennial dicots, grasses and subshrubs in burned and unburned plots at 80 nests during cool‐ and warm‐seasons two years post‐fire. Data were collected at nest top (mound), edge, and 20 m (control) from the edge.

Results

Cover, density and species richness of different functional groups were low on animal mounds in unburned and burned plots. Ant edges had greater perennial dicot cover, grass cover and richness while rat edges had lower grass density and richness than control sites at unburned and burned plots. Perennial dicot density and richness recovered faster at rat mounds and edges than control. Ant edges yielded faster recovery of grass inflorescences than control. Dicots recovered faster on rat than ant mounds whereas grasses grew faster on ant edges.

Conclusions

Rats create nests enhancing density of recovering dicots and ant edges facilitate reproduction of recovering grasses. Equal regeneration between animal nests and grassland occurred commonly when fire reduced grass competition. Dysochory, granivory and fire intensity may influence recovery. Nests may be sources of reestablishment and seed dispersal. Recovery of grassland may be amplified as plants infill from engineered nests.
Linking diet quality and energy demand in free‐living guanacos: an eco‐physiological innovative approach
Authors: Gregorio P. F. , Panebianco A. , Ovejero Aguilar R. , Taraborelli P. A. , Moreno P. G. , Schroeder N. M. , Leggieri L. R. , Marozzi A. A. , Carmanchahi P. D.
Published: April 2019

In adaptive terms, animals are subject to challenges imposed by their environment. To address physiological patterns in wild mammals, the non‐invasive study of glucocorticoid hormones has become the main approach through two well‐defined conceptual frameworks: one is related to stress responses, whereas another refers to the glucocorticoids as physiological mediators of the allostatic load, necessary for the maintenance of homeostasis. A key factor to analyse the physiology of wild animals is to understand the relationship between energetic demands and nutritional attributes. The objective of this study was to assess the influence of diet quality on physiological mediators of energy mobilization in two populations of wild guanacos (Lama guanicoe) from Northern Patagonia. In order to evaluate energy mobilization and its relationship with diet quality, we quantified nitrogen content and cortisol metabolite concentrations in fresh faeces. Samples were collected in two contrasting seasons (summer and winter, representing the breeding and non‐breeding seasons respectively). Summer was identified as the period of highest diet quality and energy mobilization, in both sexes and populations. We found quadratic relationships between cortisol levels and nitrogen percentage, which we hypothesize corresponds to two different factors: one of an energetic‐nutritional nature (during winter, the non‐reproductive season), and the other of an energetic‐reproductive nature (during summer, the reproductive season). Our evidence suggests variation in the administration of energy resources in guanacos in response to internal and external stimuli, giving rise to a novel Biphasic Model of energy demand. Our results reinforce the knowledge of the adaptive eco‐physiological attributes of guanaco, and we describe a new conceptual model which explains the energy management patterns for this species and possibly for other ungulates, within the breeding and non‐breeding seasons.
Accuracy and precision of age determination using growth layer groups for California sea lions (Zalophus californianus) with known ages
Authors: Rust Lauren B. , Danil Kerri , Melin Sharon R. , Wilkerson Brent
Published: April 2019

Age determination from counts of growth layer groups (GLGs) in tooth dentine is a common method for aging marine mammals. Using known‐aged animals, we validated this method for acid etched teeth of California sea lions (CSLs), Zalophus californianus. Between 1991 and 2013, the upper left canine (n = 33) was collected opportunistically during necropsy from animals tagged or branded as pups that later died. Overall, 55%–61% of age estimates by GLG counting were within 1 yr of the known‐age in the sample of 1–30‐yr‐old CSLs. Accuracy of age estimates was found to be dependent on age of the CSLs, however. 71%–79% of age estimates were within 1 yr of the known‐age in CSLs <10 yr old. These findings support the validity of counting GLGs to estimate age for CSLs <10 yr old to within 1 yr of accuracy.
White matter changes in the perforant path area in patients with amyotrophic lateral sclerosis
Authors: Mollink J. , Hiemstra M. , Miller K. L. , Huszar I. N. , Jenkinson M. , Raaphorst J. , Wiesmann M. , Ansorge O. , Pallebage‐Gamarallage M. , van Cappellen van Walsum A. M.
Published: April 2019

Objective

The aim of this study was to test the hypothesis that white matter degeneration of the perforant path – as part of the Papez circuit – is a key feature of amyotrophic lateral sclerosis (ALS), even in the absence of frontotemporal dementia (FTD) or deposition of pTDP‐43 inclusions in hippocampal granule cells.

Methods

We used diffusion Magnetic Resonance Imaging (dMRI), polarized light imaging (PLI) and immunohistochemical analysis of post mortem hippocampus specimens from controls (n = 5) and ALS patients (n = 14) to study white matter degeneration in the perforant path.

Results

diffusion Magnetic Resonance Imaging demonstrated a decrease in fractional anisotropy (P = 0.01) and an increase in mean diffusivity (P = 0.01) in the perforant path in ALS compared to controls. PLI‐myelin density was lower in ALS (P = 0.05) and correlated with fractional anisotropy (r = 0.52, P = 0.03). These results were confirmed by immunohistochemistry; both myelin (proteolipid protein, P = 0.03) and neurofilaments (SMI‐312, P = 0.02) were lower in ALS. Two out of the fourteen ALS cases showed pTDP‐43 pathology in the dentate gyrus, but with comparable myelination levels in the perforant path to other ALS cases.

Conclusion

We conclude that degeneration of the perforant path occurs in ALS patients and that this may occur before, or independent of, pTDP‐43 aggregation in the dentate gyrus of the hippocampus. Future research should focus on correlating the degree of cognitive decline to the amount of white matter atrophy in the perforant path.
Developing a new intelligent system for the diagnosis of oral medicine with case‐based reasoning approach
Authors: Ehtesham Hamideh , Safdari Reza , Mansourian Arash , Tahmasebian Shahram , Mohammadzadeh Niloofar , Pourshahidi Sara
Published: April 2019

Objective

Since the clinical manifestations of many oral diseases can be quite similar despite the wide variety in etiology and pathology, the differential diagnosis of oral diseases is a complex and challenging process. Intelligent system for differential diagnosis of oral medicine using the artificial intelligence (AI) capabilities helps specialists in achieving differential diagnosis in a wide range of oral diseases.

Materials and Methods

First, the essential data elements to design and develop an intelligent system were identified in a cross‐sectional descriptive study. The case‐based reasoning method was selected to design and implement the system, which consists of three stages: collect the clinical data, construct the cases database, and case‐based reasoning cycle. The problem is solved by CBR method in a cycle consisting of four main stages of retrieval, reuse, review, and retention. The evaluation process was conducted in a pilot‐based way through the evaluation of the system's performance in the clinical setting and also using the usability assessment questionnaire.

Results

The output of the present project is a web‐based intelligent information system, which is developed using the Visual Studio 2015 software. The database of this system is the Microsoft SQL Server version 2012, which has been programmed based on Net framework (version 4.5 or higher) using Visual Basic language. The results of the system evaluation by specialists in clinical settings showed that the system's diagnosis power in different aspects of the disease is influenced by their prevalence and incidence.

Conclusions

System development using the artificial intelligence capabilities and through the clinical data analysis has potential to help specialists to determine the best diagnostic strategy to achieve a differential diagnosis of a wide range of oral diseases. The results of evaluation present the potential of the system to improve the quality and efficiency of patient care.
The mind in psychotherapy: An interpersonal neurobiology framework for understanding and cultivating mental health
Authors: Siegel Daniel J.
Published: April 2019

In this brief overview, I offer a conceptual approach to the mind that can support whatever clinical, research, public policy, or other approach you may be involved with. It seeks to help both the understanding and cultivating of mental health and well‐being in our world, and may be especially important in encouraging future psychotherapists to be systems‐oriented and multidisciplinary in their work. As the ideas of this framework have been published in a number of texts, I will simply have a brief listing of those and other selected publications at the end of this article and outline the main ideas and factual points as we move along.

Practitioner points

Consilience across wide range of disciplines leads to an integrated framework defining the mind, mental health, and the strategies of intervention to cultivate well‐being.
Psychology across cultures: Challenges and opportunities
Authors: Edge Dawn , Lemetyinen Henna
Published: April 2019

Large variations of inequalities in rates of mental health disorders and access to mental health care exist within and between countries. Globally, disparities range from countries where there is little provision to those where, despite the availability of evidence‐based mental health care, service access and outcomes are mediated by social factors such as socio‐economic status, race/ethnicity, and culture. This is salient because increasingly diverse populations are inevitably created with globalization. We posit that in multicultural contexts, effective therapeutic engagement requires therapists who are competent and confident to work with diversity and difference, utilizing insights into their own as well as their clients’ internal and external worlds. Although there are many reasons why psychotherapies can be insensitive and harmful, for example, the inherent power imbalance in therapeutic relationships, a lack of awareness of cultural and ethnic variation and needs are among them. Acquisition of ‘cultural competence’ and increasing availability of culturally‐adapted interventions should, in theory, enable practitioners to work with a range of individuals with whom they might have little in common. However, whilst cultural adaptation appears promising, there are concerns regarding its viability as a strategy for tackling disparities in access to psychological care. Evidence for cultural competency is patchy at best. We show how and why delivering effective psychotherapy in the twenty‐first century requires a paradigm shift from current approaches to truly integrated models, developed in collaboration with recipients of care. Coproducing interventions, training, and means of evaluating them with clients necessitates taking into consideration social contexts, alternative conceptualizations of mental health and disorders and difficulties, and what constitutes appropriate helpful interventions for psychological distress.

Practitioner points

Upskilling therapists to work with diversity and difference is essential for effective delivery of psychological treatments.

Increasing the availability of culturally‐adapted interventions together with therapists who are sufficiently competent and confident to deliver them should enable practitioners to work with a range of individuals with whom they might have little in common.

Coproducing culturally appropriate means of responding to mental health difficulties, staff training and development, and service evaluation methods with clients necessitates taking into consideration social contexts, alternative explanatory models of mental health and ‘illness’, and what constitutes helpful interventions for psychological distress.
A novel CDKN2A variant (p16L117P) in a patient with familial and multiple primary melanomas
Authors: Li Christopher , Liu Tong , Liu Bin , Hernandez Rolando , Facelli Julio C. , Grossman Douglas
Published: April 2019

Germline mutations in CDKN2A (p16) are commonly found in patients with family history of melanoma or personal history of multiple primary melanomas. The p16 tumor suppressor gene regulates cell cycle progression and senescence through binding of cyclin‐dependent kinases (CDK) and also regulates cellular oxidative stress independently of cell cycle control. We identified a germline missense (c.350T>C, p.Leu117Pro) CDKN2A mutation in a patient who had history of four primary melanomas, numerous nevi, and self‐reported family history of melanoma. This particular CDKN2A mutation has not been previously reported in prior large studies of melanoma kindreds or patients with multiple primary melanomas. Compared with wild‐type p16, the p16L117P mutant largely retained binding capacity for CDK4 and CDK6 but exhibited impaired capacity for repressing cell cycle progression and inducing senescence, while retaining its ability to reduce mitochondrial reactive oxygen species. Structural modeling predicted that the Leu117Pro mutation disrupts a putative adenosine monophosphate (AMP) binding pocket involving residue 117 in the fourth ankyrin domain. Identification of this new likely pathogenic variant extends our understanding of CDKN2A in melanoma susceptibility and implicates AMP as a potential regulator of p16.
Autonomic correlates of lifetime suicidal thoughts and behaviors among adolescents with a history of depression
Authors: Yang Xiao , Daches Shimrit , George Charles J. , Kiss Enikő , Kapornai Krisztina , Baji Ildikó , Kovacs Maria
Published: April 2019

Suicidal thoughts and behaviors (STBs) have been associated with emotion dysregulation and atypical responses to affective and stressful stimuli. To investigate the psychophysiology involved, we measured changes in respiratory sinus arrhythmia (RSA) and cardiac pre‐ejection period (PEP; indexing parasympathetic and sympathetic functioning, respectively) in response to stressful‐ and sadness‐eliciting laboratory probes. Our sample included adolescents with a history of depression and STBs (n = 177), adolescents with a history of depression but no history of STBs (n = 47), and healthy controls (n = 175). The outcome of interest was the most severe form of clinician‐rated STBs across the subject’s lifetime. In partial support of our hypotheses, during the stressful task, adolescents with a history of depression and STBs did not evidence the RSA decrease that was exhibited by controls and displayed greater PEP shortening compared to ever‐depressed adolescents with no lifetime STBs. No group differences were found in either RSA or PEP reactivity to the sadness‐eliciting stimulus. As expected, severity of STBs was positively correlated with the extent of PEP shortening during the stressful task. The results suggest that adolescents with a history of depression and STBs experience blunted parasympathetic responses to stress along with compensatory efforts. Our findings contribute to a better understanding of STBs among youths and underscore that future studies should examine physiological risk factors for these psychopathological outcomes.
Home deaths of children under 5 years in rural South Africa: a population‐based longitudinal study
Authors: Price Jessica , Willcox Merlin , Kabudula Chodziwadziwa Whiteson , Herbst Kobus , Kahn Kathleen , Harnden Anthony
Published: April 2019

Objectives

To determine the proportion of under‐5 deaths that occurred at home in rural South Africa, whether care was sought prior to death, and determinants of home deaths amongst those who sought care.

Methods

Verbal autopsy data were used for all under‐5 deaths, 2000–2015, in two health and demographic surveillance system sites. Trends in place of death and care‐seeking were assessed. Associations between sociodemographic factors and home death despite seeking care were assessed by multivariate logistic regressions.

Results

There were 3760 under‐5 deaths; 1954 (53%) at home and 1510 (41%) in health facilities. Eighty‐four per cent of children who died at home accessed healthcare during their final illness. Amongst neonates for whom care was sought, those who were 8–27 days old were more likely to die at home than those who were 0–7 days old (OR = 5.56, 95%CI 2.69–11.55, P < 0.001). Factors associated with home death of infants and young children despite seeking care included low maternal education (OR = 1.71, 95%CI 1.31–2.24, P < 0.001), larger household size (OR = 1.56, 95%CI 1.17–2.06, P = 0.002), traditional medicine use (OR = 2.33, 95%CI 1.75–3.12, P < 0.001) and Mozambican descent (OR = 1.47, 95%CI 1.06–2.03, P = 0.020). The proportion of HIV‐related deaths that occurred at home fell from 60% in 2008–2011 to 39% in 2012–2015 ( χ2 = 13.86, P < 0.001).

Conclusion

More than half of under‐5 deaths in rural South Africa occurred at home although healthcare was sought for most children, highlighting that home deaths are not simply a function of poor care‐seeking. Interventions should target high‐risk sociodemographic groups.
Population genomics reveals a fine‐scale recombination landscape for genetic improvement of cotton
Authors: Shen Chao , Wang Nian , Huang Cong , Wang Maojun , Zhang Xianlong , Lin Zhongxu
Published: April 2019

Recombination breaks up ancestral linkage disequilibrium, creates combinations of alleles, affects the efficiency of natural selection, and plays a major role in crop domestication and improvement. However, there is little knowledge regarding the variation in the population‐scaled recombination rate in cotton. We constructed recombination maps and characterized the difference in the genomic landscape of the population‐scaled recombination rate between Gossypium hirsutum and G. arboreum and sub‐genomes based on the 381 sequenced G. hirsutum and 215 G. arboreum accessions. Comparative genomics identified large structural variations and syntenic genes in the recombination regions, suggesting that recombination was related to structural variation and occurred preferentially in the distal chromosomal regions. Correlation analysis indicated that recombination was only slightly affected by geographical distribution and breeding period. A genome‐wide association study (GWAS) was performed with 15 agronomic traits using 267 cotton accessions and identified 163 quantitative trait loci (QTL) and an important candidate gene (Ghir_COL2) for early maturity traits. Comparative analysis of recombination and a GWAS revealed that the QTL of fibre quality traits tended to be more common in high‐recombination regions than were those of yield and early maturity traits. These results provide insights into the population‐scaled recombination landscape, suggesting that recombination contributed to the domestication and improvement of cotton, which provides a useful reference for studying recombination in other species.
Reexamination of the chromium‐51–labeled posttransfusion red blood cell recovery method
Authors: Francis Richard O. , Mahajan Sonia , Rapido Francesca , La Carpia Francesca , Soffing Mark , Divgi Chaitanya , Yeh Randy , Mintz Akiva , Leslie Lenhurst , Agrest Irina , Karafin Matthew S. , Ginzburg Yelena , Shaz Beth H. , Spitalnik Steven L. , Schwartz Joseph , Thomas Tiffany , Fu Xiaoyun , Amireault Pascal , Buffet Pierre , Zimring James C. , D'Alessandro Angelo , Hod Eldad A.
Published: April 2019

BACKGROUND

The chromium‐51–labeled posttransfusion recovery (PTR) study has been the gold‐standard test for assessing red blood cell (RBC) quality. Despite guiding RBC storage development for decades, it has several potential sources for error.

METHODS

Four healthy adult volunteers each donated an autologous, leukoreduced RBC unit, aliquots were radiolabeled with technetium‐99m after 1 and 6 weeks of storage, and then infused. Subjects were imaged by single‐photon‐emission computed tomography immediately and 4 hours after infusion. Additionally, from subjects described in a previously published study, adenosine triphosphate levels in transfusates infused into 52 healthy volunteers randomized to a single autologous, leukoreduced, RBC transfusion after 1, 2, 3, 4, 5, or 6 weeks of storage were correlated with PTR and laboratory parameters of hemolysis.

RESULTS

Evidence from one subject imaged after infusion of technetium‐99m–labeled RBCs suggests that, in some individuals, RBCs may be temporarily sequestered in the liver and spleen immediately following transfusion and then subsequently released back into circulation; this could be one source of error leading to PTR results that may not accurately predict the true quantity of RBCs cleared by intra‐ and/or extravascular hemolysis. Indeed, adenosine triphosphate levels in the transfusates correlated more robustly with measures of extravascular hemolysis in vivo (e.g., serum iron, indirect bilirubin, non–transferrin‐bound iron) than with PTR results or measures of intravascular hemolysis (e.g., plasma free hemoglobin).

CONCLUSIONS

Sources of measurement error are inherent in the chromium‐51 PTR method. Transfusion of an entire unlabeled RBC unit, followed by quantifying extravascular hemolysis markers, may more accurately measure true posttransfusion RBC recovery.
Reducing ethnic disparity in access to high‐quality HLA‐matched cord blood units for transplantation: analysis of the Canadian Blood Services' Cord Blood Bank inventory
Authors: Allan David , Kiernan Jeffrey , Gragert Loren , Dibdin Nicholas , Bartlett Daniel , Campbell Todd , Mostert Karen , Halpenny Michael , Ganz Kathy , Maiers Martin , Petraszko Tanya , Elmoazzen Heidi
Published: April 2019

BACKGROUND

Launched in 2013, Canadian Blood Services' Cord Blood Bank (CBS' CBB) has built a high‐quality, ethnically diverse cord blood repository that aims to reduce ethnic disparity in accessing suitable units for transplantation.

METHODS AND RESULTS

As of December 2016, 2000 units have been banked. The self‐reported maternal ethnicity was 58% non‐Caucasian. Overall, 26% of units were classified as multi‐ethnicity with Caucasian (84%) most frequently observed in combination with Asian, First Nations (predominant indigenous peoples in Canada south of the Arctic Circle), or African ethnicity. Utilization scores that incorporate total nucleated and CD34+ cell counts in the CBS' CBB were associated with greater likelihood of utilization compared with the international inventory of units (p < 0.05). The distribution of utilization scores was similar for Caucasians compared with non‐Caucasians (p < 0.05). Using HLA genotypes of cord blood units and their mothers, we determined probable ethnic assignments for each haplotype using HaploStats (National Marrow Donor Program). Significant increases in HLA‐match likelihoods are predicted for all ethnicities as the inventory grows to its target of 10,000 units and the gap in HLA‐match likelihoods for Caucasian and non‐Caucasian patients progressively declines.

CONCLUSIONS

The CBS' CBB inventory is predicted to have high HLA‐matching likelihoods across a broad spectrum of ethnic groups, improving access to high‐quality stem cell products for all patients.
Improvements in red blood cell transfusion utilization following implementation of a single‐unit default for electronic ordering
Authors: Warner Matthew A. , Schaefer Kalli K. , Madde Nageswar , Burt Jennifer M. , Higgins Andrew A. , Kor Daryl J.
Published: April 2019

BACKGROUND

The prevention of excessive allogeneic red blood cell (RBC) transfusion is an important component of patient blood management initiatives. In this investigation, changes in transfusion behaviors following modification of computerized physician order entry (CPOE) procedures for RBC transfusions to a single‐unit default quantity were assessed.

STUDY DESIGN AND METHODS

This is an observational cohort study of adults for whom nonemergency allogeneic RBC transfusions were ordered in the 2 years before and 2 years after the date of modification of the CPOE system to a single‐unit default (June 18, 2015). Changes in the frequency of single‐ versus multiunit RBC transfusion orders and other transfusion metrics were compared between preintervention and postintervention cohorts.

RESULTS

A total of 52,773 unique transfusion orders for 61,989 RBC units were included, of which 60,045 (96.9%) were transfused. Single‐unit orders increased annually, from 10,404 (74.1%) in the first year to 11,645 (88.6%) in the last year, while multiunit orders decreased by more than half (p < 0.0001). The number of RBC units transfused decreased by 13.9% from 32,528 in the preintervention cohort to 27,497 in the post intervention cohort (p < 0.0001) with an estimated reduction in transfusion‐related expenditures of nearly $4 million. The percentage of transfusions associated with a posttransfusion hemoglobin of10 g/dL or greater decreased by 34.5% (p < 0.0001).

CONCLUSION

Modification of the CPOE process such that nonemergency RBC transfusion orders were defaulted to a single unit was associated with decreased rates of multiunit RBC transfusion orders, lower transfusion volumes, and substantial cost savings.
Clinical findings associated with development of postoperative reflux and short‐term survival after small intestinal surgery in geriatric and mature nongeriatric horses
Authors: Boorman Sophie , Stefanovski Darko , Southwood Louise L.
Published: April 2019

Objective

To determine risk factors, especially age, associated with postoperative reflux (POR; >2 L of reflux present upon intubation), high‐volume POR (≥20 L in 24 hours), and short‐term outcome after small intestinal (SI) surgery.

Study design

Retrospective case‐control study.

Sample population

Horses aged ≥16 years (geriatric; range, 16–30; n = 44) and <16 years (mature; range, 2–15; n = 39) with an SI surgical lesion that survived general anesthesia and did not have a second exploratory celiotomy during the same visit.

Methods

Medical records (2009–2015) were reviewed; perioperative variables were evaluated for associations with outcomes by using multivariable logistic regression.

Results

Postoperative reflux was associated with an increasing packed cell volume at admission (odds ratio [OR], 1.08; 95% CI, 1.00–1.16;P = .042) and presence of nasogastric reflux at admission (OR, 4.61; 95% CI, 1.3–15.69;P = .014). High‐volume POR was associated with an increasing glycemia at admission (OR, 1.19; 95% CI, 1.01–1.40;P = .041), presence of nasogastric reflux at admission (OR, 10.05; 95% CI, 2.21–45.74;P = .003), and SI resection (OR, 10.52; 95% CI, 1.81–61.25;P = .009). Increasing surgical time (OR, 2.50; 95% CI, 1.16–5.29;P = .019) and high‐volume POR (OR, 6.37; 95% CI, 2.12–19.12;P = .001) were associated with nonsurvival.

Conclusion

Age, considered as both a continuous variable and a categorical variable, was not associated with the development of POR, high‐volume POR, or nonsurvival.

Clinical significance

Age does not influence the occurrence of POR and should not negatively impact an owner's decision to pursue surgery in aged horses.
Intermittent hypoxia impairs uterine artery function in pregnant mice
Authors: Badran Mohammad , Abuyassin Bisher , Ayas Najib , Laher Ismail
Published: April 2019

Key points

Obstructive sleep apnoea (OSA) is a chronic condition characterized by intermittent hypoxia that induces oxidative stress and inflammation leading to cardiovascular disease.

Women can develop OSA during late pregnancy, which is associated with adverse maternal and fetal outcomes. However, the effects of OSA throughout pregnancy on fetoplacental outcomes are unknown.

Using a mouse model of intermittent hypoxia, we evaluated main uterine artery function, spiral artery remodelling, circulating angiogenic and anti‐angiogenic factors, and placental hypoxia and oxidative stress at gestational day 14.5 in pregnant mice.

Gestational intermittent hypoxia increased placental weight but decreased fetal weight, impaired uterine artery function, increased circulating angiogenic and anti‐angiogenic factors, and induced placental hypoxia and oxidative stress, but had no impact on spiral artery remodelling.

Our results suggest that pregnant women experiencing OSA during pregnancy could be at risk of maternal and fetal complications.

Obstructive sleep apnoea (OSA) is characterized by chronic intermittent hypoxia (IH) and is associated with increased inflammation, oxidative stress and endothelial dysfunction. OSA is a common sleep disorder and remains under‐diagnosed; it can increase the risk of adverse maternal and fetal outcomes in pregnant women. We investigated the effects of gestational IH (GIH) on uterine artery function, spiral artery remodelling and placental circulating angiogenic and anti‐angiogenic factors in pregnant female mice. WT C57BL/6 mice (8 weeks) were exposed to either GIH ( 12%) or intermittent air ( 21%) for 14.5 days of gestation. Exposure to GIH reduced fetal weight but increased placental weight. GIH dams had higher plasma levels of oxidative stress (8‐isoprostane) and inflammatory markers (tumour necrosis factor‐α). GIH significantly reduced uterine artery function as indicated by reduced endothelium‐dependent vasodilatation and enhanced vasoconstriction. Plasma levels of placental angiogenic and anti‐angiogenic markers (soluble fms‐like tyrosine kinase‐1, soluble endoglin, angiogenic placental growth factor‐2 and vascular endothelial growth factor) were higher in pregnant mice exposed to GIH. There was no evidence of impaired spiral artery remodelling based on immunostaining with α‐smooth muscle actin and cytokeratin‐7, and also by measurements of lumen area. Immunostaining for markers of hypoxia (pimonidazole) and oxidative stress (4‐hydroxynonenal) were higher in mice exposed to GIH. Our data show that GIH adversely affects uterine vascular function and may be a mechanism by which gestational OSA leads to adverse maternal and fetal outcomes.
Forming Mechanism of Asymmetric Cylinder With Oblique–Straight Flange Spinning
Authors: Jia Z. , Han Z. R. , Xiao Y. , Ji S. D. , Xu B.
Published: April 2019

The asymmetric cylinder with oblique–straight flange spinning has the potential to become a production process for this shape of the aerospace part. This complex shaped part was attempted to be formed by synchronous multipass spinning from a blank disk of 6061-O aluminum alloy with 1.15-mm thickness. The working principle of synchronous multipass spinning focuses on the fact that the radial and axial positions of the roller are synchronized with the spindle rotation to form the roller path. The roller path was calculated by dispersing a pass set into numerous points. The dimensional space between two points from the corresponding curves in a single-pass set was integrated into the trajectory around the circumference. Here, a pass set is the path along which the roller propagates in the two-dimensional space defined by the radial and axial directions. This shape was confirmed to be spun, and the formation mechanism of this spinning process was investigated. Contrastive experiments with paired arcs and pairs of straight lines as roller paths were performed on a spinning machine. The working condition of the cylinder wall with pairs of straight lines roller path was broken because of the higher pull resistance from the remaining part of the flange. The working condition of the flange of the paired arcs follows the law of shear spinning approximately that the cylinder wall forming does not comply. Suitable metal distributions for the flange and an appropriate force state for the cylinder wall are realized by the paired arcs roller path in the spinning process to form the asymmetric cylinder with oblique–straight flange. This provides a theoretical basis for the spinning of the asymmetric cylinder with the oblique–straight flange.
Easy-To-Remove Composite Support Material and Procedure in Additive Manufacturing of Metallic Components Using Multiple Material Laser-Based Powder Bed Fusion
Authors: Wei Chao , Chueh Yuan-Hui , Zhang Xiaoji , Huang Yihe , Chen Qian , Li Lin
Published: April 2019

Support structures are always associated with laser-based powder-bed fusion (L-PBF) processes, particularly for additive manufacturing of metallic components of complex geometry with overhang structures and for reducing component distortion. Existing L-PBF processes use the same material for both built components and support structures. Removing the metallic support structures from L-PBF fabricated components by the traditional post-treatment method is difficult and time-consuming. This paper demonstrates an easy-to-remove composite support material and related processing procedures in an L-PBF process. For additive manufacturing of 316L components, a SiC-316L composite was developed as a support material. This is combined with hybrid powder-bed and point-to-point selective powder deposition for the additive manufacturing of the components. A specific experimental multiple material L-PBF system was developed and employed to produce 316L components with SiC-316L composite as support structures successfully. An interfacial grid structure using 316L steel was used to avoid component contamination and inferior surface roughness of the 316L component. The experimental results demonstrated that the SiC-316L composite with 40 vol. % 320 grit SiC was feasible to be applied as a support material for 316L stainless steel component additive manufacture in a modified PBF system.
Second-Order Contact Kinematics Between Three-Dimensional Rigid Bodies
Authors: Woodruff J. Zachary , Lynch Kevin M.
Published: April 2019

In this discussion, we provide corrections to the second-order kinematic equations describing contact between three-dimensional rigid bodies, originally published in Sarkar et al. (1996) [“Velocity and Acceleration Analysis of Contact Between Three-Dimensional Rigid Bodies,” ASME J. Appl. Mech., 63(4), pp. 974–984].
Low temperature chemical vapor deposition of superconducting vanadium nitride thin films
Authors: Mohimi Elham , Zhang Zhejun V. , Mallek Justin L. , Liu Sumeng , Trinh Brian B. , Shetty Pralav P. , Girolami Gregory S. , Abelson John R.
Published: April 2019

Superconducting thin films of vanadium nitride have been grown by low temperature (250–300 °C) chemical vapor deposition from tetrakis(dimethylamido)vanadium (TDMAV) and ammonia. For example, films grown from TDMAV (1 sccm Ar as carrier gas) and 7 mTorr ammonia at 300 °C are nanocrystalline (cubic δ-phase) with an average crystal size of 20 nm, have relatively low room temperature resistivities of 250 μΩ cm, and are superconducting with critical temperatures as high as 7.6 K (versus a bulk value of 9 K). The films have a V:N ratio of 1:1, with a carbon content of <5 at. % and an oxygen content of <3 at. % (as determined by high resolution XPS). The V 2p3/2 and N 1 s XPS binding energies of 513.5 and 397.3 eV, respectively, are consistent with the presence of a nitride phase. In contrast, films grown at lower temperatures <200 °C show carbon incorporation, have a much higher resistivity of ∼3000 μΩ cm, and are not superconducting. The results suggest that, at low temperatures, the thermally activated transamination reaction with ammonia becomes too slow to remove dimethylamido groups from the surface, resulting in carbon-rich films (10–15 at. % carbon). The conformal step coverage of the VN films depends on the growth conditions. For thermal growth of nonsuperconducting films at 150 °C, the step coverage is >95% in trenches of an aspect ratio of 4:1; for superconducting films grown at 250 °C, the step coverage is 65% for an aspect ratio of 3:1. At 150 °C, near-stoichiometric films with <2 at. % carbon and <3 at. % oxygen can be deposited if the gaseous ammonia is precracked by a remote plasma source; the resulting films have low resistivities of 320 μΩ cm but are not superconducting down to 4 K.
Fabrication of grating coupled GaAs/AlGaAs quantum well infrared photodetector on an Si substrate
Authors: Kim HoSung , Ahn Seung-Yeop , Wasilewski Zbigniew
Published: April 2019

The grating coupled GaAs/AlGaAs quantum well infrared photodetectors (QWIPs) are integrated onto Si substrates using metal wafer bonding and epitaxial lift-off process. The 1 μm depth of hexagonal hole structure of grating was formed. The energy-dispersive x-ray spectroscopy results confirmed that the grating coupled QWIP is successfully mounted on an Si substrate. By evaluating the Raman spectra, PL, and surface roughness of bonded QWIP samples, the authors found that the grating does not induce any change in the optical or structural characteristics of actual QWIP layers. The dark current–voltage characteristics show a nearly identical dark current level between grating coupled QWIP and nongrating QWIP. The photocurrent spectrum shows that the peak photocurrent intensity of grating coupled QWIP is about 16 times higher than that of nongrating QWIP. This indicates that the grating effectively contributes to an increase in the light absorption of QWIP, showing large room for improvement of QWIP performance by further optimization of a grating structure.
On the optimum off-cut angle for the growth on InP(111)B substrates by molecular beam epitaxy
Authors: Sadeghi Ida , Tam Man Chun , Wasilewski Zbigniew Roman
Published: April 2019

InGaAs and InAlAs epilayers were grown on InP(111)B substrates by molecular beam epitaxy. Rather than focusing on a specific off-cut angle, the growths were done on rounded wafer edges, which expose a broad spectrum of vicinal surfaces with varying off-cut angle and off-cut azimuth. The epilayers were grown at several different growth conditions by varying the growth temperature, growth rate, and arsenic (As) overpressure. The epitaxial layers were characterized at the center and the edge of the wafers using Nomarski differential interference contrast microscopy and atomic force microscopy. It was shown that a minimum misorientation angle of ∼0.4° should be used in order to avoid pyramidal hillocks. At higher misorientations, 1.7°–3°, step bunching can lead to surface roughening.
Formation of defects and impurities in MoSx and their effect on electronic properties
Authors: Nie Yifan , Agarwal Ravi , Pandey Sumeet C. , Sandhu Gurtej S.
Published: April 2019

The authors investigate the thermodynamic and electronic properties of few- and monolayer MoS2 using density functional theory. They calculate the formation energies of S vacancies and the doping effect of C and O under various chemical environments which are commonly observed during MoS2 deposition. The results show that in the oxidizing condition, O readily gets incorporated into the MoS2 layer and assists in C doping. They analyze the bandgap and density of states of MoS2 at different concentrations of defect. They find that the bandgap decreases as the defect concentration increases, wherein the ordering of S vacancies has a more significant influence than that of the other two defects. The S vacancy and C dopants generate deep acceptor gap states within the bandgap of MoS2, while O dopant states are delocalized. They also observe that the carbon dopants form penetrative dimers, which lead to shallow acceptor states. This work contributes to the understanding of defect/impurity incorporation during deposition and prediction of electronic behavior of deposited low-quality MoS2 materials.
Rousing the dragon: Polonium production for neutron generators in the Manhattan Project
Authors: Reed B. Cameron
Published: April 2019

During the Manhattan Project, the rare element polonium (Po) was synthesized by neutron bombardment of bismuth in nuclear reactors for use in neutron-generating triggers that were used to initiate the fission chain reactions in the Hiroshima and Nagasaki bombs. In this paper, I explore the physics of why polonium was used, why the triggers contained the amount of polonium that they did, and for how long a given mass of bismuth had to be irradiated in the Oak Ridge X-10 pile or a Hanford plutonium-production pile to generate a given amount of Po. A simple neutron-flux model gives results in reasonable accord with estimates recorded in a 1943 letter written by Robert Oppenheimer.
The candle seesaw
Authors: Tjossem Paul J. H. , Case William B. , Bass Rachel M.
Published: April 2019

A candle skewered transversely near its center of mass by a needle and balanced between two low-friction supports, when lit on both ends, will drip asymmetrically and begin to oscillate like a seesaw; these oscillations grow in time. We examine the onset of instability, and find that the candle does not oscillate quasi-stably until the vertical center of mass is lowered by the symmetrical melting of each end, creating a physical pendulum with a well-defined characteristic period. Additional asymmetric dripping below horizontal drives the pendulum, leading to linear growth in amplitude. The drop release becomes phase locked to the seesaw motion of the candle. We develop a small-angle analytical model that predicts the maximum growth rate when the dripping rate matches the seesaw frequency. Measurements of the motion, droplet phase, and melting rate confirm the validity of the model. We compare our results to earlier studies and make suggestions for the demonstrator.
Ultrasonic wave propagation predictions for polycrystalline materials using three-dimensional synthetic microstructures: Phase velocity variations
Authors: Norouzian Musa , Turner Joseph A.
Published: April 2019

In most theoretical work related to effective properties of polycrystals, the media are assumed to be infinite with randomly oriented grains. Therefore, the bulk material has absolute isotropy because each direction includes an infinite number of grains with infinite possibilities for grain orientation. However, real samples will always include a finite number of grains such that the inspection volume will have some associated anisotropy. Thus, bounds on the bulk properties are expected for a given measurement. Here, the effect of the number of grains on the variations of elastic anisotropy is studied using synthetic polycrystals comprised of equiaxed cubic grains (17 volumes with 100 realizations each). Voigt, Reuss, and self-consistent techniques are used to derive the effective elastic modulus tensor. The standard deviation of the average elastic modulus is then quantified for several materials with varying degrees of single-crystal anisotropy and is shown to be inversely proportional to the square root of the number of grains. Finally, the Christoffel equation is used to study the relevant phase velocities. With appropriate normalization, a master curve is derived with respect to the finite sample size, which shows the expected variations of phase velocity for the longitudinal, fast shear, and slow shear modes.
Autonomous microfluidic actuators for periodic sequential flow generation
Authors: Li Zhenglin , Kim Sung-Jin
Published: April 2019

We report a microfluidic system that generates sequential periodic multiflows only with a constant water head pressure.
Heat flowing from cold to hot without external intervention by using a “thermal inductor”
Authors: Schilling A. , Zhang X. , Bossen O.
Published: April 2019

We show that heat can flow from cold to hot using a thermal inductor, without violating the second law of thermodynamics.
Room temperature polariton lasing in quantum heterostructure nanocavities
Authors: Kang Jang-Won , Song Bokyung , Liu Wenjing , Park Seong-Ju , Agarwal Ritesh , Cho Chang-Hee
Published: April 2019

A room temperature polariton nanolaser is demonstrated using quantum heterostructure nanocavities to boost exciton properties.
Combinatorial optimization by simulating adiabatic bifurcations in nonlinear Hamiltonian systems
Authors: Goto Hayato , Tatsumura Kosuke , Dixon Alexander R.
Published: April 2019

Nonlinear Hamiltonian systems search optimal solutions exploiting their adiabatic and chaotic evolutions.
Origin of giant negative piezoelectricity in a layered van der Waals ferroelectric
Authors: You Lu , Zhang Yang , Zhou Shuang , Chaturvedi Apoorva , Morris Samuel A. , Liu Fucai , Chang Lei , Ichinose Daichi , Funakubo Hiroshi , Hu Weijin , Wu Tom , Liu Zheng , Dong Shuai , Wang Junling
Published: April 2019

Lattice topology and anisotropic chemical bonds underpin unusual negative longitudinal piezoelectricity in van der Waals solids.
Dual-gradient enabled ultrafast biomimetic snapping of hydrogel materials
Authors: Fan Wenxin , Shan Caiyun , Guo Hongyu , Sang Jianwei , Wang Rui , Zheng Ranran , Sui Kunyan , Nie Zhihong
Published: April 2019

We present a new paradigm for designing responsive hydrogel sheets that can exhibit ultrafast snapping deformation.
A Global Deal For Nature: Guiding principles, milestones, and targets
Authors: Dinerstein E. , Vynne C. , Sala E. , Joshi A. R. , Fernando S. , Lovejoy T. E. , Mayorga J. , Olson D. , Asner G. P. , Baillie J. E. M. , Burgess N. D. , Burkart K. , Noss R. F. , Zhang Y. P. , Baccini A. , Birch T. , Hahn N. , Joppa L. N. , Wikramanayake E.
Published: April 2019

The Global Deal for Nature sets an ambitious agenda to protect our biosphere through ecosystem conservation and land restoration.
Searching for hidden earthquakes in Southern California
Authors: Ross Zachary E. , Trugman Daniel T. , Hauksson Egill , Shearer Peter M.
Published: April 2019

Using earthquakes to find earthquakes

Earthquake catalogs elucidate the behavior of faults and allow for rough estimates of when large earthquakes might occur. Cataloging small earthquakes is challenging because the small signal is often indistinguishable from noise. Ross
et al.
used a template-matching algorithm to find almost two million tiny earthquakes previously missed by other earthquake-logging techniques in Southern California (see the Perspective by Brodsky). This more-complete catalog can be used to better understand faults, earthquake reoccurrence, and other geophysical processes.

Science
, this issue p.
767
; see also p.
736
A specific gene-microbe interaction drives the development of Crohn’s disease–like colitis in mice
Authors: Caruso R. , Mathes T. , Martens E. C. , Kamada N. , Nusrat A. , Inohara N. , Núñez G.
Published: April 2019

Combined deficiency of NOD2 and NAPDH oxidase triggers Crohn’s-like disease driven by a mouse pathobiont,
Mucispirillum
.