bluuebunny/crossref_metadata_2025 huggingface dataset:
Nutritional quality of snacks for preschoolers recommended on the internet
Authors: Santos Vanessa Fernandes Amadei , Neves Felipe Silva , Binoti Mirella Lima , Mendes Larissa Loures
Published: April 2017

Introduction: Concerns about proper nutrition in childhood have been highlighted by the media. This is accompanied by an ongoing increase in the number of Internet pages, including those on social networks, channeled toward providing health information. Objective: To analyze the nutritional quality of snack recipes presented on web pages, aimed at preschoolers and described as healthy. Methods: a cross-sectional study carried out in 2015. A search was made for Brazilian web pages aimed at the lay public, and that contained snacks for children between 2 and 6 years of age. The first 20 URLs located by the search engine were selected and 10% of the recipes were set apart. The snacks were checked for compliance with steps 6, 7, and 8 of the Food Guide. Subsequently, nutritional labels were made for the preparations that met the three pre-established steps. Results: 85% of the pages were sites, 5% were blogs, and the rest were identified as sites/blogs. It was found that all were readable/comprehensible and 40% provided author identification. Of the 35 preparations initially observed, 31.4% met all three steps for healthy eating. In the qualitative analysis, seven were considered hypocaloric; only one of the snacks came close to the proposed carbohydrate content; two had excess protein. In general, the recipes had low quantities of: lipids, calcium, iron, sodium, and fiber. Conclusions: less than half of the addresses consulted identified the author. In addition, the recipes were predominantly misleading, as most had inadequacies in macronutrient and micronutrient content.
Growth and puberty in a prospective cohort of patients with sickle-cell anaemia: an assessment over ten years abstract
Authors: Gomes Ingrid Cristiane Pereira , Melo Hugo Nivaldo , Melo Suyaluane Italla Amana , Menezes Nelmo Vasconcelos de , Dantas Tulio Vinicius Paes , Cipolotti Rosana
Published: April 2017

Introduction: Hereditary haemoglobinopathies are the most common group of monogenic hereditary diseases in the world. Erythrocytes in sickle form, cellular expression of polymerization of deoxygenated HbS, cause intermittent vascular obstruction, leading to tissue ischaemia and consequent chronic damage in organs and endocrine glands. Objective: The evaluation of the growth pattern and pubertal development of a group of patients with sickle-cell anaemia (SCA) from childhood to adulthood. Method: Thirty patients with SCA between the ages of 10 and 23 years were evaluated in a prospective longitudinal study at three points in time (Te1: 2005; Te2: 2010 and Te3: 2015) and compared with controls. Anthropometric, pubertal and hormonal evaluations were carried out. Age- and gender-specific Z-scores for weight, height and BMI (body mass index) were calculated according to the reference growth standards. Results: Thirty patients with SCA (mean age = 13.93 years) were evaluated at Te1 and 26 patients (mean age = 25.08 years) at Te3. The SCA group lower showed Z-scores for weight (p = 0.0002), height (p = 0.0184) and BMI (p = 0.0011) than the control group at Te1. At Te3, there was no difference in height, but weight (p = <0.0001) and BMI (p = <0.0001) were lower in the SCA group. Men showed greater weight commitment than women at the three study times (Te1: p = 0.0340, Te2: p = 0.0426 and Te3: p = 0.0387) and lower BMI in Te3 (p = 0.0155) in the SCA group. There was a significant increase in weight when comparing Te1 with Te3 (p = 0.0009) and in height when comparing Te1 with Te2 (p = 0.0292) and with Te3 (p = 0.0003) in the SCA group. There was a significant increase in weight when comparing Te1 and Te3 (p = 0.0009) and in height when comparing Te1 and Te2 (p = 0.0292) and Te3 (p = 0.0003) in the SCA group. At Te1, 14 cases and 2 controls were prepubertal. Bone age was delayed in 12 patients. Age at menarche was delayed and lower in the SCA group (mean = 15 years). Five patients had gestated, but no patient had experienced fatherhood. At Te1, TSH levels were higher (p = 0.0080) and T3 levels were lower (p = 0.0020) in the SCA group. At Te3, LH and FSH levels were higher in men with SCA (p = 0.0014; p; 0.0002). IGF-I levels were lower in cases both at Te1 (p = 0.0002) and at Te3 (p = 0.0032). Conclusions: Patients with SCA showed growth impairment and pubertal delay compared with healthy controls. However, albeit belatedly, they reached normal sexual maturation and height in adulthood. Women with SCA showed no fertility problems. The findings highlight the need to investigate the intention of paternity and fertility among men with SCA.
Vulnerability in adolescence: a case report of attempted abortion and sexual violence
Authors: Silva Adna Thaysa Marcial da , Sousa Guilherme Dias de , Lohmann Camila Menezes , Ferreira Filho Edson Santos , Pinheiro Walter Da Silva , Soares Júnior José Maria , Baracat Edmund Chada , Sorpreso Isabel Cristina Esposito
Published: April 2017

Background: Abortion, even when provided by law in cases of sexual violence, continues to be practiced in an insecure way, since women who suffer violence are not reported or guarded by social, institutional or age vulnerability, as in adolescence. Objective: Describe the clinical consequences of unsafe abortion, report this experience as well as sexual violence in situations of social and age vulnerability. Method: It is a clinical case report, with the consent of the patient, in the year 2016, of a 16-year-old female adolescent with a personal history of sexual violence by an intimate aggressor. Admitted to the health service with diagnosis of acute abdomen and induced abortion using antibiotic therapy. Results: Laboratory tests revealed altered C reactive protein and presence of leukocytosis, ultrasound showed heterogenic mass, computed tomography showed presence of cylindrical foreign body in vaginal cavity, surgical interventions, sepsis, clinical complications (pulmonary thromboembolism) and prolonged hospitalization. Conclusion: The history of violence portrayed in this study reveals an attempt of abortion with self harm, revealing negative clinical repercussions and the health problems of the adolescent. This person has committed an abortion that does not fit into the abortion criteria provided by law. It also revealed the need for further discussion on the topic, highlighting health promotion practices against unsafe abortion.
Lissencephaly-1 is a context-dependent regulator of the human dynein complex
Authors: Baumbach Janina , Murthy Andal , McClintock Mark A , Dix Carly I , Zalyte Ruta , Hoang Ha Thi , Bullock Simon L
Published: April 2017

The cytoplasmic dynein-1 (dynein) motor plays a central role in microtubule organisation and cargo transport. These functions are spatially regulated by association of dynein and its accessory complex dynactin with dynamic microtubule plus ends. Here, we elucidate in vitro the roles of dynactin, end-binding protein-1 (EB1) and Lissencephaly-1 (LIS1) in the interaction of end tracking and minus end-directed human dynein complexes with these sites. LIS1 promotes dynactin-dependent tracking of dynein on both growing and shrinking plus ends. LIS1 also increases the frequency and velocity of processive dynein movements that are activated by complex formation with dynactin and a cargo adaptor. This stimulatory effect of LIS1 contrasts sharply with its documented ability to inhibit the activity of isolated dyneins. Collectively, our findings shed light on how mammalian dynein complexes associate with dynamic microtubules and help clarify how LIS1 promotes the plus-end localisation and cargo transport functions of dynein in vivo.
SIRT6 regulates Ras-related protein R-Ras2 by lysine defatty-acylation
Authors: Zhang Xiaoyu , Spiegelman Nicole A , Nelson Ornella D , Jing Hui , Lin Hening
Published: April 2017

The Ras family of GTPases are important in cell signaling and frequently mutated in human tumors. Understanding their regulation is thus important for studying biology and human diseases. Here, we report that a novel posttranslational mechanism, reversible lysine fatty acylation, regulates R-Ras2, a member of the Ras family. SIRT6, a sirtuin with established tumor suppressor function, regulates the lysine fatty acylation of R-Ras2. In mouse embryonic fibroblasts (MEFs), Sirt6 knockout (KO) increased R-Ras2 lysine fatty acylation. Lysine fatty acylation promotes the plasma membrane localization of R-Ras2 and its interaction with phosphatidylinositol 3-kinase PI3K, leading to activated Akt and increased cell proliferation. Our study establishes lysine fatty acylation as a previously unknown mechanism that regulates the Ras family of GTPases and provides an important mechanism by which SIRT6 functions as a tumor suppressor.
Susceptibility of Human Oral Squamous Cell Carcinoma (OSCC) H103 and H376 cell lines to Retroviral OSKM mediated reprogramming
Authors: Verusingam Nalini Devi , Yeap Swee Keong , Ky Huynh , Paterson Ian C. , Khoo Suan Phaik , Cheong Soon Keng , Ong Alan H.K. , Kamarul Tunku
Published: April 2017

Although numbers of cancer cell lines have been shown to be successfully reprogrammed into induced pluripotent stem cells (iPSCs), reprogramming Oral Squamous Cell Carcinoma (OSCC) to pluripotency in relation to its cancer cell type and the expression pattern of pluripotent genes under later passage remain unexplored. In our study, we reprogrammed and characterised H103 and H376 oral squamous carcinoma cells using retroviral OSKM mediated method. Reprogrammed cells were characterized for their embryonic stem cells (ESCs) like morphology, pluripotent gene expression via quantitative real-time polymerase chain reaction (RT-qPCR), immunofluorescence staining, embryoid bodies (EB) formation and directed differentiation capacity. Reprogrammed H103 (Rep-H103) exhibited similar ESCs morphologies with flatten cells and clear borders on feeder layer. Reprogrammed H376 (Rep-H376) did not show ESCs morphologies but grow with a disorganized morphology. Critical pluripotency genes Oct4, Sox2 and Nanog were expressed higher in Rep-H103 against the parental counterpart from passage 5 to passage 10. As for Rep-H376, Nanog expression against its parental counterpart showed a significant decrease at passage 5 and although increased in passage 10, the level of expression was similar to the parental cells. Rep-H103 exhibited pluripotent signals (Oct4, Sox2, Nanog and Tra-1-60) and could form EB with the presence of three germ layers markers. Rep-H103 displayed differentiation capacity into adipocytes and osteocytes. The OSCC cell line H103 which was able to be reprogrammed into an iPSC like state showed high expression of Oct4, Sox2 and Nanog at late passage and may provide a potential iPSC model to study multi-stage oncogenesis in OSCC.
Rates of morphological evolution in Captorhinidae: an adaptive radiation of Permian herbivores
Authors: Brocklehurst Neil
Published: April 2017

The evolution of herbivory in early tetrapods was crucial in the establishment of terrestrial ecosystems, although it is so far unclear what effect this innovation had on the macro-evolutionary patterns observed within this clade. The clades that entered this under-filled region of ecospace might be expected to have experienced an “adaptive radiation”: an increase in rates of morphological evolution and speciation driven by the evolution of a key innovation. However such inferences are often circumstantial, being based on the coincidence of a rate shift with the origin of an evolutionary novelty. The conclusion of an adaptive radiation may be made more robust by examining the pattern of the evolutionary shift; if the evolutionary innovation coincides not only with a shift in rates of morphological evolution, but specifically in the morphological characteristics relevant to the ecological shift of interest, then one may more plausibly infer a causal relationship between the two.

Here I examine the impact of diet evolution on rates of morphological change in one of the earliest tetrapod clades to evolve high-fibre herbivory: Captorhinidae. Using a method of calculating heterogeneity in rates of discrete character change across a phylogeny, it is shown that a significant increase in rates of evolution coincides with the transition to herbivory in captorhinids. The herbivorous captorhinids also exhibit greater morphological disparity than their faunivorous relatives, indicating more rapid exploration of new regions of morphospace. As well as an increase in rates of evolution, there is a shift in the regions of the skeleton undergoing the most change; the character changes in the herbivorous lineages are concentrated in the mandible and dentition. The fact that the increase in rates of evolution coincides with increased change in characters relating to food acquisition provides stronger evidence for a causal relationship between the herbivorous diet and the radiation event.
Comparison of Diagnostic Accuracy for the Low‐Type Imperforate Anus Between Prone Cross‐Table Radiography and Sonography
Authors: Hosokawa Takahiro , Hosokawa Mayumi , Tanami Yutaka , Hattori Shinya , Sato Yumiko , Tanaka Yujiro , Kawashima Hiroshi , Oguma Eiji , Yamada Yoshitake
Published: April 2017

Objectives

To compare the diagnostic accuracy for the low‐type imperforate anus between prone cross‐table radiography and sonography.

Methods

We included 20 neonates with imperforate anus: 13 with a surgically proven low type and 7 with an intermediate or high type. The distance between the distal rectal pouch and the perineum (pouch‐perineum distance) was measured by both sonography and prone cross‐table radiography. A previously established pouch‐perineum distance of 10 mm was used as the cutoff for diagnosis of a low‐type imperforate anus. The fistula location was also determined with sonography. We then compared the diagnostic accuracy of the imaging methods for a low‐type imperforate anus using the cutoff value of the pouch‐perineum distance alone and both the cutoff value of the pouch‐perineum distance and fistula location. The McNemar test was used for statistical analysis.

Results

With the use of only the pouch‐perineum distance, the diagnostic accuracy for the low‐type imperforate anus based on sonographic measurements was comparable with the accuracy achieved by prone cross‐table radiographic measurements (60.0% [12 of 20] versus 45.0% [9 of 20]; P = .625). With the use of the pouch‐perineum distance and fistula location, the diagnostic accuracy of sonography was significantly better than the accuracy of prone cross‐table radiography (90.0% [18 of 20] versus 45% [9 of 20]; P = .012).

Conclusions

The diagnostic accuracy of sonography for the low‐type imperforate anus based on both the pouch‐perineum distance and fistula location is better than that of prone cross‐table radiography. If the pouch‐perineum distance on prone cross‐table radiography is greater than 10 mm, a sonographic examination to determine the fistula location could be recommended.
Acoustic Radiation Force Impulse Imaging for Assessing Liver Fibrosis Preoperatively in Infants With Biliary Atresia: Comparison With Liver Fibrosis Biopsy Pathology
Authors: Gao Fen , Chen Ya‐Qing , Fang Jing , Gu Sheng‐Li , Li Luan , Wang Xiao‐Ying
Published: April 2017

Objectives

The purpose of this study was to investigate the diagnostic performance of acoustic radiation force impulse (ARFI) in assessing liver fibrosis preoperatively in infants with biliary atresia (BA).

Methods

A total of 50 consecutive infants with BA and 50 healthy infants who underwent ARFI examination were recruited. Siemens Acuson S2000 in Virtual Touch Quantification mode (Siemens Medical Solutions, Mountain View, CA) was used to measure shear wave speeds (SWSs). All infants with BA underwent a liver biopsy within 3 days after ARFI imaging. The liver fibrosis stages of specimens were defined according to the Batts‐Ludwig scoring system. The correlation analysis was performed between SWSs and pathological findings. Cut‐off values were determined using receiver operating characteristic (ROC) curves.

Results

The mean SWS in the BA group was significantly higher than controls (mean ± standard deviation): 1.89 ± 0.45 versus 1.12 ± 0.06 m/s; P < .001). A significant correlation was found between the SWSs and fibrosis stages (r = 0.719, P < .001). The cut‐off value for predicting significant fibrosis (F ≥ 2), severe fibrosis (F ≥ 3), and cirrhosis (F = 4) was 1.53, 1.80 and 2.16 m/s, respectively, and the area under the ROC curve was 0.823, 0.884 and 0.917, respectively.

Conclusions

Acoustic radiation force impulse imaging showed significant correlation with the severity of liver fibrosis by comparing it with liver fibrosis biopsy pathology. It may be an effective method for liver fibrosis assessment, prognosis prediction, and clinical management in infants with BA.
Recurrence of Thrombin‐Injected Pseudoaneurysms Under Ultrasound Guidance: A 10‐Year Retrospective Analysis
Authors: Esterson Yonah B. , Pellerito John S.
Published: April 2017

Objectives

Ultrasound‐guided thrombin injection has become standard treatment for extremity pseudoaneurysms. Our specific aims were to determine the procedural success rate, the procedural complication rate, and the factors associated with pseudoaneurysm recurrence.

Methods

A total of 262 consecutive cases of ultrasound‐guided thrombin repair of pseudoaneurysms were identified between January 1, 2006, and March 20, 2016. The procedural and follow‐up ultrasound studies were reviewed. Outcomes of interest included procedural success (defined as complete thrombosis at the time of injection and on a follow‐up examination), incomplete pseudoaneurysm thrombosis, and postprocedural recurrence. Postprocedural pseudoaneurysm recurrences were compared to procedural successes with regard to patient demographics, pseudoaneurysm characteristics, amount of thrombin injected, and periprocedural laboratory values.

Results

Procedural success occurred in 85.7% of cases. Complications occurred in 3.0% of cases. The mean patient age ± SD was 72.3 ± 11.3 years. The median amount of thrombin injected was 500 U (interquartile range, 400 U). The median follow‐up time was 1 day (interquartile range, 0 days). A pseudoaneurysm size of 2 cm or larger and thrombocytopenia were significant independent predictors of pseudoaneurysm recurrence (P = .003 and .03, respectively). The odds ratios for pseudoaneurysm recurrence were 2.29 for pseudoaneurysm size of 2 cm or larger (P = .03) and 1.04 for thrombocytopenia (P = .04).

Conclusions

Thrombin injection of pseudoaneurysms is an off‐label procedure with few complications and a high success rate. Follow‐up imaging is recommended in all pseudoaneurysms that are 2 cm or larger and in patients with thrombocytopenia.
Far‐field connectivity of the UK's four largest marine protected areas: Four of a kind?
Authors: Robinson J. , New A. L. , Popova E. E. , Srokosz M. A. , Yool A.
Published: April 2017

Marine Protected Areas (MPAs) are established to conserve important ecosystems and protect marine species threatened in the wider ocean. However, even MPAs in remote areas are not wholly isolated from anthropogenic impacts. “Upstream” activities, possibly thousands of kilometers away, can influence MPAs through ocean currents that determine their connectivity. Persistent pollutants, such as plastics, can be transported from neighboring shelf regions to MPAs, or an ecosystem may be affected if larval dispersal is reduced from a seemingly remote upstream area. Thus, improved understanding of exactly where upstream is, and on what timescale it is connected, is important for protecting and monitoring MPAs. Here, we use a high‐resolution (1/12°) ocean general circulation model and Lagrangian particle tracking to diagnose the connectivity of four of the UK's largest MPAs: Pitcairn; South Georgia and Sandwich Islands; Ascension; and the British Indian Ocean Territory (BIOT). We introduce the idea of a circulation “connectivity footprint”, by which MPAs are connected to upstream areas. Annual connectivity footprints were calculated for the four MPAs, taking into account seasonal and inter‐annual variability. These footprints showed that, on annual timescales, Pitcairn was not connected with land, whereas there was increasing connectivity for waters reaching South Georgia, Ascension, and, especially, BIOT. BIOT also had a high degree of both seasonal and inter‐annual variability, which drastically changed its footprint, year‐to‐year. We advocate that such connectivity footprints are an inherent property of all MPAs, and need to be considered when MPAs are first proposed or their viability as refuges evaluated.
A comprehensive overview of the climatological composition of the Asian summer monsoon anticyclone based on 10 years of Aura Microwave Limb Sounder measurements
Authors: Santee M. L. , Manney G. L. , Livesey N. J. , Schwartz M. J. , Neu J. L. , Read W. G.
Published: April 2017

Intense deep convection associated with the Asian summer monsoon (ASM) lofts surface pollutants to the upper troposphere/lower stratosphere (UTLS), where strong winds and long chemical lifetimes allow intercontinental transport, affecting atmospheric composition around the globe. The Aura Microwave Limb Sounder (MLS), launched in 2004, makes simultaneous colocated measurements of trace gases and cloud ice water content (a proxy for deep convection) in the UTLS on a daily basis. Here we exploit the dense spatial and temporal coverage, long‐term data record, extensive measurement suite, and insensitivity to aerosol and most clouds of Aura MLS to characterize the climatological (2005–2014) composition of the ASM anticyclone throughout its annual life cycle. We use version 4 MLS data to quantify spatial and temporal variations in both tropospheric (H2O, CO, CH3Cl, CH3CN, CH3OH) and stratospheric (O3, HNO3, HCl) tracers on four potential temperature surfaces (350–410 K). Inside the mature anticyclone, all species exhibit substantial changes, not only from their premonsoon distributions in the ASM region but also from their summertime distributions in the rest of the hemisphere. Different tracers exhibit dissimilar seasonal evolution, and the exact location and timing of their extreme values vary. Although individual aspects of the anticyclone have been described previously, we present a uniquely comprehensive overview of the climatological seasonal evolution of the ASM and its impact on UTLS composition. This work provides valuable context for planned in situ measurements as well as a benchmark for model evaluation and future investigations of interannual variability and long‐term changes in monsoon processes.
The climatic significance of Late Ordovician‐early Silurian black shales
Authors: Pohl A. , Donnadieu Y. , Le Hir G. , Ferreira D.
Published: April 2017

The Ordovician‐Silurian transition (∼455–430 Ma) is characterized by repeated climatic perturbations, concomitant with major changes in the global oceanic redox state best exemplified by the periodic deposition of black shales. The relationship between the climatic evolution and the oceanic redox cycles, however, remains largely debated. Here using an ocean‐atmosphere general circulation model accounting for ocean biogeochemistry (MITgcm), we investigate the mechanisms responsible for the burial of organic carbon immediately before, during, and right after the latest Ordovician Hirnantian (445–444 Ma) glacial peak. Our results are compared with recent sedimentological and geochemical data. We show that the late Katian time slice (∼445 Ma), typified by the deposition of black shales at tropical latitudes, represents an unperturbed oceanic state, with regional organic carbon burial driven by the surface primary productivity. During the Hirnantian, our experiments predict a global oxygenation event, in agreement with the disappearance of the black shales in the sedimentary record. This suggests that deep‐water burial of organic matter may not be a tenable triggering factor for the positive carbon excursion reported at that time. Our simulations indicate that the perturbation of the ocean circulation induced by the release of freshwater, in the context of the post‐Hirnantian deglaciation, does not sustain over sufficiently long geological periods to cause the Rhuddanian (∼444 Ma) oceanic anoxic event. Input of nutrients to the ocean, through increased continental weathering and the leaching of newly exposed glaciogenic sediments, may instead constitute the dominant control on the spread of anoxia in the early Silurian.
Implementation of a physiographic complexity‐based multiresolution snow modeling scheme
Authors: Baldo Elisabeth , Margulis Steven A.
Published: April 2017

Using a uniform model resolution over a domain is not necessarily the optimal approach for simulating hydrologic processes when considering both model error and computational cost. Fine‐resolution simulations at 100 m or less can provide fine‐scale process representation, but can be costly to apply over large domains. On the other hand, coarser spatial resolutions are more computationally inexpensive, but at the expense of fine‐scale model accuracy. Defining a multiresolution (MR) grid spanning from fine resolutions over complex mountainous areas to coarser resolutions over less complex regions can conceivably reduce computational costs, while preserving the accuracy of fine‐resolution simulations on a uniform grid. A MR scheme was developed using a physiographic complexity metric (CM) that combines surface heterogeneity in forested fraction, elevation, slope, and aspect. A data reduction term was defined as a metric (relative to a uniform fine‐resolution grid) related to the available computational resources for a simulation. The focus of the effort was on the snowmelt season where physiographic complexity is known to have a significant signature. MR simulations were run for different data reduction factors to generate melt rate estimates for three representative water years over a test headwater catchment in the Colorado River Basin. The MR approach with data reductions up to 47% led to negligible cumulative snowmelt differences compared to the fine‐resolution baseline case, while tests with data reductions up to 60% showed differences lower than 2%. Large snow‐dominated domains could therefore benefit from a MR approach to be more efficiently simulated while mitigating error.
Time‐dependent velocity‐field controls on anomalous chemical transport in porous media
Authors: Nissan Alon , Dror Ishai , Berkowitz Brian
Published: April 2017

Temporal variations in the subsurface velocity field are often (if not always) present in the real world to at least some degree. However, an accounting of their effects on chemical transport has been largely neglected. Here we demonstrate experimentally the effects of a time‐varying velocity field on conservative chemical tracer transport in porous media, as compared to constant velocity conditions. We find that velocity‐field fluctuations increase chemical tracer spreading and residence time, which intensify the anomalous nature of the transport. This behavior is modeled by a continuous time random walk particle tracking method formulated to account for time‐dependent velocity fields. The model matches the experimental results with a parsimonious and consistent set of parameters. The model is then applied to study the effects of different magnitudes in velocity‐field fluctuations, as well as different degrees of porous media heterogeneity, on 1‐D and 2‐D spatiotemporal propagation of an injected, point‐source, chemical plume. Increased intensity of velocity‐field fluctuations, and increased porous medium heterogeneity, each serve to increase the extent of chemical spreading and anomalous behavior.
Picoplankton contribution to biogenic silica stocks and production rates in the Sargasso Sea
Authors: Krause Jeffrey W. , Brzezinski Mark A. , Baines Stephen B. , Collier Jackie L. , Twining Benjamin S. , Ohnemus Daniel C.
Published: April 2017

Picocyanobacteria in the Sargasso Sea accumulate significant amounts of Si, a finding which questions how we interpret previous regional measurements of biogenic silica (bSi) production and the role of diatoms in the open ocean. The picoplankton (<3 μm cells) contributed a measurable, and at times significant, proportion of both the total bSi standing stock and its rate of production. The 100 m integrated bSi stock and bSi production rate in the <3 μm size fraction averaged 14% and 16%, respectively, of the total. At some stations, specific rates of bSi production in the <3 μm cells were up to threefold higher than for larger cells. But among all stations and depths, the two size fractions had statistically indistinguishable specific production rates (~0.35 day−1). The estimated contributions of Synechococcus alone to the 100 m integrated bSi stock and bSi production in cells <3 μm were 15% and 55%, respectively, suggesting that half of bSi production in this small size fraction could be sustained by Synechococcus, but a majority of the bSi was not associated with living Synechococcus. Our results suggest that picoplankton have a small but persistent regional contribution to bSi stocks, which is masked by a dynamic bSi pool driven by larger cells. While a significant fraction of bSi production is attributable to picoplankton, their contributions are likely to have been included in previous analyses, making prior regional budgets still relevant. However, our understanding of the factors controlling regional bSi production and our interpretations of particulate matter elemental ratios (e.g., Si:C) may require revision.
Climate impacts of the Atlantic Multidecadal Oscillation simulated in the CMIP5 models: A re‐evaluation based on a revised index
Authors: Lyu Kewei , Yu Jin‐Yi
Published: April 2017

The Atlantic Multidecadal Oscillation (AMO) has pronounced influences on weather and climate across the globe. This study provides a direct comparison of the observed AMO‐related surface temperature and precipitation anomalies to those simulated in the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. It is found that the model‐simulated AMO‐related features are obscured by the global signal in some key regions if the North Atlantic sea surface temperature (SST) itself is used to represent the AMO as in previous studies. After the global mean SST is removed from the North Atlantic SST, the CMIP5 models show substantially better agreement with the observations in terms of the AMO‐related worldwide impacts, such as the Pacific SST and the rainfall over the United States and India. These results suggest the removal of the global signal or signals originating in other ocean basins is a necessary procedure to uncover the AMO features in climate model simulations.
Close packing effects on clean and dirty snow albedo and associated climatic implications
Authors: He Cenlin , Takano Yoshi , Liou Kuo‐Nan
Published: April 2017

Previous modeling of snow albedo, a key climate feedback parameter, follows the independent scattering approximation (ISA) such that snow grains are considered as a number of separate units with distances longer than wavelengths. Here we develop a new snow albedo model for widely observed close‐packed snow grains internally mixed with black carbon (BC) and demonstrate that albedo simulations match closer to observations. Close packing results in a stronger light absorption for clean and BC‐contaminated snow. Compared with ISA, close packing reduces pure snow albedos by up to ~0.05, whereas it enhances BC‐induced snow albedo reduction and associated surface radiative forcing by up to 15% (20%) for fresh (old) snow, with larger enhancements for stronger structure packing. Finally, our results suggest that BC‐snow albedo forcing and snow albedo feedback (climate sensitivity) are underestimated in previous modeling studies, making snow close packing consideration a necessity in climate modeling and analysis.
Decadal dynamics and predictability of oxygen and subsurface tracers in the California Current System
Authors: Pozo Buil Mercedes , Di Lorenzo Emanuele
Published: April 2017

The oxygen of the source waters that feed the upwelling in the California Current System shows prominent multidecadal fluctuations that are not significantly correlated with the dominant modes of Pacific climate variability. By combining observations and ocean reanalysis products between 1950 and 2010, we show that decadal changes in oxygen are linked to subsurface salinity variability and primarily controlled by ocean circulation dynamics. We find that subsurface anomalies in the core of the North Pacific Current propagate the oxygen signal downstream into the coastal upwelling system following the path of the mean gyre circulation with a time scale of 10 years. These results suggest that decadal variability in the ocean subsurface is a key process for understanding, and potentially predicting, hypoxia and other biogeochemical tracers in upwelling systems. According to the current sign of the subsurface tracer anomalies in the gyre, California may experience a new period of strong decline in oxygen by 2020.
Air‐Sea exchange of biogenic volatile organic compounds and the impact on aerosol particle size distributions
Authors: Kim Michelle J. , Novak Gordon A. , Zoerb Matthew C. , Yang Mingxi , Blomquist Byron W. , Huebert Barry J. , Cappa Christopher D. , Bertram Timothy H.
Published: April 2017

We report simultaneous, underway eddy covariance measurements of the vertical flux of isoprene, total monoterpenes, and dimethyl sulfide (DMS) over the Northern Atlantic Ocean during fall. Mean isoprene and monoterpene sea‐to‐air vertical fluxes were significantly lower than mean DMS fluxes. While rare, intense monoterpene sea‐to‐air fluxes were observed, coincident with elevated monoterpene mixing ratios. A statistically significant correlation between isoprene vertical flux and short wave radiation was not observed, suggesting that photochemical processes in the surface microlayer did not enhance isoprene emissions in this study region. Calculations of secondary organic aerosol production rates (PSOA) for mean isoprene and monoterpene emission rates sampled here indicate that PSOA is on average <0.1 μg m−3 d−1. Despite modest PSOA, low particle number concentrations permit a sizable role for condensational growth of monoterpene oxidation products in altering particle size distributions and the concentration of cloud condensation nuclei during episodic monoterpene emission events from the ocean.
The role of uplift and erosion in the persistence of saline groundwater in the shallow subsurface
Authors: Yager R. M. , McCoy K. J. , Voss C. I. , Sanford W. E. , Winston R. B.
Published: April 2017

In many regions of the world, the shallow (<300 m) subsurface is replenished with meteoric recharge within a few centuries or millennia, but in some regions saline groundwater persists despite abundant rainfall. Analyses of the flushing rate of shallow groundwater usually consider the permeability and recharge rate and a static landscape. The influence of landscape evolution can become important over millions of years, however. Here we present numerical simulations of fluid flow and transport in the top 1 km of a sedimentary foreland basin dominated by aquitards, where the rate of uplift and erosion (20 m Ma−1) balances that of meteoric flushing. Paleozoic age saline groundwater and brine persist at shallow depths that might otherwise have contained potable water. Similar hydrogeologic conditions, and uplift and erosion rates, likely exist in many other regions of the world, where a moving landscape has probably never been considered as an important contributor to groundwater quality.
Slow and fast responses of mean and extreme precipitation to different forcing in CMIP5 simulations
Authors: Sillmann Jana , Stjern Camilla Weum , Myhre Gunnar , Forster Piers M.
Published: April 2017

We are investigating the fast and slow responses of changes in mean and extreme precipitation to different climate forcing mechanisms, such as greenhouse gas and solar forcing, to understand whether rapid adjustments are important for extreme precipitation. To disentangle the effect of rapid adjustment to a given forcing on the overall change in extreme precipitation, we use a linear regression method that has been previously applied to mean precipitation. Equilibrium experiments with preindustrial CO2 concentrations and reduced solar constant were compared with a four times CO2 concentration experiment for 10 state‐of‐the‐art climate models. We find that the two forcing mechanisms, greenhouse gases and solar, impose clearly different rapid adjustment signals in the mean precipitation, while such difference is difficult to discern for extreme precipitation due to large internal variability. In contrast to mean precipitation, changes in extreme precipitation scale with surface temperature trends and do not seem to depend on the forcing mechanism.
On the relationship between the meridional overturning circulation, alongshore wind stress, and United States East Coast sea level in the Community Earth System Model Large Ensemble
Authors: Little Christopher M. , Piecuch Christopher G. , Ponte Rui M.
Published: April 2017

By the late twenty‐first century, climate models project enhanced dynamic sea level (DSL) rise along the western boundary of the North Atlantic associated with a decline in the Atlantic meridional overturning circulation (AMOC). In contrast, coastal DSL variability over the last few decades has been driven largely by local winds, with limited evidence for coupling to AMOC strength. The unclear forcing‐dependence and timescale‐dependence of relationships between local winds, AMOC strength, and DSL obscures: (1) the validity of tide gauge‐derived DSL gradients as a proxy of AMOC strength and (2) the assessment of climate model reliability. Here we analyze these relationships in the Community Earth System Model Large Ensemble (CESM‐LE) over the 1920–2100 period. In CESM‐LE, the amplitude of interannual to multidecadal DSL variability and its along‐coast correlation are comparable to detrended annual mean tide gauge records. A “crossover timescale” of approximately 5–15 years partitions a local wind‐driven coastal DSL regime from an overturning‐related regime. Processes unrelated to either AMOC strength or local winds are important at interannual to decadal timescales. As external forcing increases in strength over the twenty‐first century, DSL variability associated with the overturning circulation becomes dominant. While the largely externally forced, AMOC‐associated, component explains only 29 ± 12% of DSL variance over the 1920–2010 period, it explains 89 ± 3% of the variance in the 2011–2100 period. We discuss the implications of these results on the reliability of climate model projections of regional DSL, the use of coastal DSL as a proxy for AMOC, and the origins of multidecadal DSL variability.
Strongly nonlinear internal solitons: Models and applications
Authors: Ostrovsky L. A. , Irisov V. G.
Published: April 2017

A strongly nonlinear evolution equation based on an approximate Hamiltonian is suggested and applied to the description of nonstationary processes of formation and evolution of strong internal solitons and their groups (solibores). Comparison with experimental data shows that such a simplified approach can be effectively applied to the description and prediction of strong internal waves’ evolution in the upper ocean.
Revised transport estimates of the Denmark Strait overflow
Authors: Jochumsen Kerstin , Moritz Martin , Nunes Nuno , Quadfasel Detlef , Larsen Karin M. H. , Hansen Bogi , Valdimarsson Hedinn , Jonsson Steingrimur
Published: April 2017

The major export route of dense water from the Nordic Seas into the North Atlantic is in the deep channel in Denmark Strait. Here currents have been monitored with one or two moored Acoustic Doppler Current Profilers (ADCPs) since 1996. Volume transport estimates of the Denmark Strait Overflow Water (DSOW) so far were based on these data, which were regressed to the total transport of dense water in a numerical model. The resulting transport has been used in many publications. Here we present results from an extended five‐mooring array deployed in 2014/2015, which included measurements outside the swift overflow core. This array provided the basis for new calculations to estimate the DSOW transports. Furthermore, a correction is proposed for biases detected on some ADCPs, which led to earlier underestimation of the flow in the lower part of the plume. Using the new method, the mean DSOW transport is estimated to be 3.2 Sv in the period 1996–2016, without a significant trend. Uncertainties are typically ±0.5 Sv. Beyond variations on the eddy scale, an empirical orthogonal functions (EOF) analysis of the velocity field reveals three dominant modes of variability: the first mode is roughly barotropic and corresponds to pulsations of the plume, the second mode represents the laterally shifting component of the plume's core position, and the third mode indicates the impact of the varying overflow thickness. Finally, DSOW transports are compared to the Faroe Bank Channel overflow transports, but no clear relationship is found.
Dosimetric impacts of endorectal balloon in CyberKnife stereotactic body radiation therapy (SBRT) for early‐stage prostate cancer
Authors: Xiang Hong F. , Lu Hsiao‐Ming , Efstathiou Jason A. , Zietman Anthony L. , De Armas Ricardo , Harris Kathryn , Bloch B. Nicolas , Qureshi Muhammad Mustafa , Keohan Sean , Hirsch Ariel E.
Published: April 2017

Purpose

In SBRT for prostate cancer, higher fractional dose to the rectum is a major toxicity concern due to using smaller PTV margin and hypofractionation. We investigate the dosimetric impact on rectum using endorectal balloon (ERB) in prostate SBRT.

Materials and Methods

Twenty prostate cancer patients were included in a retrospective study, ten with ERB and 10 without ERB. Optimized SBRT plans were generated on CyberKnife MultiPlan for 5 × 7.25 Gy to PTV under RTOG‐0938 protocol for early‐stage prostate cancer. For the rectum and the anterior half rectum, mean dose and percentage of volumes receiving 50%, 80%, 90%, and 100% prescription dose were compared.

Results

Using ERB, mean dose to the rectum was 62 cGy (P = 0.001) lower per fraction, and 50 cGy (P = 0.024) lower per fraction for the anterior half rectum. The average V50%, V80%, V90%, and V100% were lower by 9.9% (P = 0.001), 5.3% (P = 0.0002), 3.4% (P = 0.0002), and 1.2% (P = 0.005) for the rectum, and lower by 10.4% (P = 0.009), 8.3% (P = 0.0004), 5.4% (P = 0.0003), and 2.1% (P = 0.003) for the anterior half rectum.

Conclusions

Significant reductions of dose to the rectum using ERB were observed. This may lead to improvement of the rectal toxicity profiles in prostate SBRT.
Optimization of the Photo‐Electrochemical Performance of Mo‐Doped BiVO4 Photoanode by Controlling the Metal–Oxygen Bond State on (020) Facet
Authors: Bu Yuyu , Tian Jing , Chen Zhiwei , Zhang Qiang , Li Weibing , Tian FengHui , Ao Jin‐Ping
Published: April 2017

Oxygen vacancy on semiconductor has been usually considered as donor contributor which can improve the charge transfer capacity of the photoanode. However, oxygen vacancy has also been found to perform as recombination center for the photogenerated charges. Herein, electrochemical reduction method is employed to treat the surface of Mo‐doped BiVO4 (BiMoVO) photoanode. Experimental data indicate that when the reduction potential is located at −0.8 V (vs Ag/AgCl), quasioxygen vacancy is formed on the (020) facet (only BiO bonds crack), the electron mobility and photo‐electrochemical (PEC) current density of the BiMoVO photoanode are increased dramatically. However, with the reduction potential increasing to −1.2 V, oxygen vacancy is formed on the surface of (020) facet (both BiO and VO bonds crack simultaneously), the PEC current density is decreased obviously. Further density functional theory calculation data point out that a moderate level of reduction is a key factor for the adjustment of photoanode performance. Thus, these results demonstrate first that oxygen vacancy actually is not the positive factor to improve the PEC performance of a BiVO4 photoelectrode, but the quasioxygen vacancy forming on the surface of the active facet is.
Anisotropic Wetting of Water on Patterned Asymmetric Nanostructure Arrays
Authors: Ge Peng , Wang Shuli , Liu Wendong , Wang Tieqiang , Yu Nianzuo , Xue Peihong , Chen Hongxu , Shen Huaizhong , Zhang Junhu , Yang Bai
Published: April 2017

This paper reports the directional wetting behavior of water on a patterned heterogeneous surface, which is integrated by two asymmetric nanostructures with different directions. The asymmetric nanostructures are Janus silicon cylinder arrays (Si‐CAs) modified by molecules with distinct surface energies on two sides. Through a photolithography process, the two asymmetric nanostructures are integrated in a single surface to form chessboard patterns with different directions. When water is injected onto the patterned surface, water droplets wet in a unidirectional manner, and the wetting direction is along resultant direction of the two wetting directions of water on the two asymmetric patterns. This paper investigates the factors which may influence the wetting behavior of water on the surface, experimental results show that patterned asymmetric surfaces prepared from different chessboard pattern size, Si‐CAs with different diameters, and different morphology‐symmetric structures do not affect the wetting property, but the molecules modified on two sides do. Larger surface energy difference between the modified molecules improves the ability of the surfaces induce water moving. It is believed that the patterned asymmetric nanostructure arrays provide a new strategy to modulate the wetting behavior of water, which will show potential applications in microfluidics and others involving unidirectional liquid manipulation.
Filled Skutterudites for Broadband Saturable Absorbers
Authors: Lee Junsu , Yu Byung‐Kyu , Jhon Young In , Koo Joonhoi , Kim Sung Jin , Jhon Young Min , Lee Ju Han
Published: April 2017

Filled skutterudites (FSs), which are known to be good thermoelectric materials, have been intensively investigated in the field of condensed matter physics in the past decades, due to their large variety of electronic and magnetic properties. However, to the best of the authors' knowledge, there has been no previous investigation of the optical properties of FSs. The nonlinear optical saturable absorption property of FSs is investigated in this work for the first time, and the results are reported here. More specifically, Co4Sb12 is chosen as a binary skutterudite system, and indium ions are added as a filling element to form a FS of In0.2Co4Sb12. The material properties are systematically investigated using a series of measurements. Density functional theory calculations of the electronic band structures of InCo4Sb12 and In0.25Co4Sb12 are conducted for better understanding of their energy band structures. It is also demonstrated that a broadband saturable absorber (SA) that can simultaneously operate at 1.5 and 1.9 µm can readily be implemented by depositing particles of In0.2Co4Sb12 onto fiber ferrules. The efficacy of the prepared SA is tested by incorporating the device into rare earth ion‐doped fiber ring cavities, to show its capability for both 1.5 and 1.9 µm operation.