bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of MODIS and VIIRS cloud properties with ARM ground-based
observations over Finland
Authors: Sporre Moa K. , O'Connor Ewan J. , Håkansson Nina , Thoss Anke , Swietlicki Erik , Petäjä Tuukka
Published: July 2016

Abstract. Cloud retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard the satellites Terra and Aqua and the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard the Suomi-NPP satellite are evaluated using a combination of ground-based instruments providing vertical profiles of clouds. The ground-based measurements are obtained from the Atmospheric Radiation Measurement (ARM) programme mobile facility, which was deployed in Hyytiälä, Finland, between February and September 2014 for the Biogenic Aerosols – Effects on Clouds and Climate (BAECC) campaign. The satellite cloud parameters cloud top height (CTH) and liquid water path (LWP) are compared with ground-based CTH obtained from a cloud mask created using lidar and radar data and LWP acquired from a multi-channel microwave radiometer. Clouds from all altitudes in the atmosphere are investigated. The clouds are diagnosed as single or multiple layer using the ground-based cloud mask. For single-layer clouds, satellites overestimated CTH by 326 m (14 %) on average. When including multilayer clouds, satellites underestimated CTH by on average 169 m (5.8 %). MODIS collection 6 overestimated LWP by on average 13 g m−2 (11 %). Interestingly, LWP for MODIS collection 5.1 is slightly overestimated by Aqua (4.56 %) but is underestimated by Terra (14.3 %). This underestimation may be attributed to a known issue with a drift in the reflectance bands of the MODIS instrument on Terra. This evaluation indicates that the satellite cloud parameters selected show reasonable agreement with their ground-based counterparts over Finland, with minimal influence from the large solar zenith angle experienced by the satellites in this high-latitude location.
Influence of proxy data uncertainty on data assimilation for the past climate
Authors: Matsikaris Anastasios , Widmann Martin , Jungclaus Johann
Published: July 2016

Abstract. Data assimilation (DA) is an emerging topic in palaeoclimatology and one of the key challenges in this field. Assimilating proxy-based continental mean temperature reconstructions into the MPI-ESM model showed a lack of information propagation to small spatial scales . Here, we investigate whether this lack of regional skill is due to the methodology or to errors in the assimilated reconstructions. Error separation is fundamental, as it can lead to improvements in DA methods. We address the question by performing a new set of simulations, using two different sets of target data; the proxy-based PAGES 2K reconstructions (DA-P scheme), and the HadCRUT3v instrumental observations (DA-I scheme). Again, we employ ensemble-member selection DA using the MPI-ESM model, and assimilate Northern Hemisphere (NH) continental mean temperatures; the simulated period is 1850–1949 AD. Both DA schemes follow the large-scale target and observed climate variations well, but the assimilation of instrumental data improves the performance. This improvement cannot be seen for Asia, where the limited instrumental coverage leads to errors in the target data and low skill for the DA-I scheme. No skill on small spatial scales is found for either of the two DA schemes, demonstrating that errors in the assimilated data are not the main reason for the unrealistic representation of the regional temperature variability in Europe and the NH. It can thus be concluded that assimilating continental mean temperatures is not ideal for providing skill on small spatial scales.
Automatic segmentation and classification of seven-segment display digits on auroral images
Authors: Savolainen Tuomas , Whiter Daniel Keith , Partamies Noora
Published: July 2016

Abstract. In this paper we describe a new and fully automatic method for segmenting and classifying digits in seven-segment displays. The method is applied to a dataset consisting of about 7 million auroral all-sky images taken during the time period of 1973–1997 at camera stations centred around Sodankylä observatory in northern Finland. In each image there is a clock display for the date and time together with the reflection of the whole night sky through a spherical mirror. The digitised film images of the night sky contain valuable scientific information but are impractical to use without an automatic method for extracting the date–time from the display. We describe the implementation and the results of such a method in detail in this paper.
The new implementation of a computationally efficient modeling tool (STOPS v1.5) into CMAQ v5.0.2 and its application for a more accurate prediction of Asian dust
Authors: Jeon Wonbae , Choi Yunsoo , Percell Peter , Souri Amir Hossein , Song Chang-Keun , Kim Soon-Tae , Kim Jhoon
Published: July 2016

Abstract. This study suggests a new modeling framework using a hybrid Lagrangian-Eulerian based modeling tool (the Screening Trajectory Ozone Prediction System, STOPS) for a more accurate prediction of Asian dust event in Korea. The new version of STOPS (v1.5) has been implemented into the Community Multi-scale Air Quality (CMAQ) model version 5.0.2. We apply STOPS to PM10 simulations in the East Asia during Asian dust events (22–24 February, 2015). The STOPS modeling system is a moving nest (Lagrangian approach) between the source and the receptor inside a CMAQ structure (Eulerian model). The proposed model generates simulation results that are relatively consistent with those of CMAQ but within a comparatively shorter computational time period. We evaluate the performance of standard CMAQ for the PM10 simulations and investigate the impact of STOPS modeling with constrained PM concentration based on space-derived measurement (by using alternative PM emissions) on the improved accuracy of the PM10 prediction. We find that standard CMAQ generally underestimates PM10 concentrations during the simulation period (February, 2015) and fails to capture PM10 peaks during Asian dust events. Accurately simulated meteorology implies that the underestimated PM10 concentration is not due to the meteorology but to poorly estimated dust emissions for the CMAQ simulation. To improve the underestimated PM10 results from standard CMAQ, we use the STOPS modeling system inside of the CMAQ model, and instead of running the costly, time-consuming Eulerian model, CMAQ, we run several STOPS simulations using constrained PM concentration based on aerosol optical depth (AOD) data from Geostationary Ocean Color Imager (GOCI), reflecting real-time initial and boundary conditions of dust particles near the Korean Peninsula. The STOPS simulations with constrained PM concentration by GOCI-derived AOD show a significant increase in simulated PM10 compared to standard CMAQ. Moreover, the STOPS results were closely matched to surface data. These promising results imply that STOPS could prove to be a useful tool for more accurately predicting Asian dust events in Korea. With additional verification of the capabilities of the methodology on concentration estimations and more STOPS simulations for various time periods, the benefit of STOPS modeling for more accurate predictions of Asian dust could be generalized to the simulation and forecasting of unexpected events such as wildfires and upset emissions events in industrial regions over the East Asia.
Improving together: better science writing through peer learning
Authors: Stiller-Reeve Mathew A. , Heuzé Céline , Ball William T. , White Rachel H. , Messori Gabriele , van der Wiel Karin , Medhaug Iselin , Eckes Annemarie H. , O'Callaghan Amee , Newland Mike J. , Williams Sian R. , Kasoar Matthew , Wittmeier Hella Elisa , Kumer Valerie
Published: July 2016

Abstract. Science, in our case the climate and geosciences, is increasingly interdisciplinary. Scientists must therefore communicate across disciplinary boundaries. For this communication to be successful, scientists must write clearly and concisely, yet the historically poor standard of scientific writing does not seem to be improving. Scientific writing must improve, and the key to long-term improvement lies with the early-career scientist (ECS). Many interventions exist for an ECS to improve their writing, like style guides and courses. However, momentum is often difficult to maintain after these interventions are completed. Continuity is key to improving writing. This paper introduces the ClimateSnack project, which aims to motivate ECSs to develop and continue to improve their writing and communication skills. The project adopts a peer-learning framework where ECSs voluntarily form writing groups at different institutes around the world. The group members learn, discuss, and improve their writing skills together. Several ClimateSnack writing groups have formed. This paper examines why some of the groups have flourished and others have dissolved. We identify the challenges involved in making a writing group successful and effective, notably the leadership of self-organized groups, and both individual and institutional time management. Within some of the groups, peer learning clearly offers a powerful tool to improve writing as well as bringing other benefits, including improved general communication skills and increased confidence.
River water quality changes in New Zealand over 26 years (1989–2014): Response to land use and land disturbance
Authors: Julian Jason P. , de Beurs Kirsten M. , Owsley Braden , Davies-Colley Robert J. , Ausseil Anne-Gaelle E.
Published: July 2016

Abstract. River water quality reflects land use in the catchment (mobilizing diffuse pollution) as well as point source discharges. In New Zealand (NZ) diffuse pollution vastly outweighs point sources which have largely cleaned up over many decades. Because NZ has good geospatial data on physiographic variables, land cover and agricultural statistics, and time series on water quality at the national scale over several decades, the country is a natural laboratory for investigating water quality response to land use/disturbance and associated diffuse pollution "pressures". We interpreted water quality state and trends for the 26 years from 1989 and 2014 in the National Rivers Water Quality Network (NRWQN), consisting of 77 sites on 35 mostly large river systems with an aggregate catchment amounting to half of NZ's land area. To characterize water quality pressures, we used multiple land use datasets spanning 1990–2012, plus recently-developed 8-day land-disturbance datasets using MODIS imagery. Current state and directions of change in visual clarity and nitrate-nitrite-nitrogen provide a particularly valuable summary of impact, respectively from mobilization of fine particulate matter and soluble nutrients. We show that the greatest impact on river water quality in NZ over the 1989–2014 period is high-producing pastures with their high nutrient inputs to support high densities of livestock. While land disturbance was not itself a strong predictor of water quality, it did help explain outliers of land use-water quality relationships, especially those with large areas of plantation forest. Plantation forestry was strongly associated with water quality impacts, particularly on visual clarity and particulate nutrients when land disturbed for harvesting generated sediment runoff and nutrient mobilization. In all, our study demonstrates how interdisciplinary combinations of expertise including geospatial analysis, land management, remote-sensing, and water quality can advance understanding of broad-scale and long-term impacts of land use change on river water quality.
Social Factors and Health: Description of a new Norwegian twin study
Authors: Kutschke Julia , Falch Anina , Brandt Ingunn , Nilsen Thomas S. , Jugessur Astanand , Halekoh Ulrich , Seeman Teresa E. , Harris Jennifer R.
Published: July 2016

A compelling literature substantiates that our social worlds have significant and far-reaching effects onhealth and well-being throughout life. Yet, few studies of social factors and their effects on health have beenembedded within the twin design. Towards this end, we have initiated a new twin study on social factors andhealth which will investigate the genetic and environmental influences on social environments, and explorehow social environments mediate these influences on physical and mental health. Herein, we describe thestudy sample, response rates and measures. Twins born 1935-1960 were invited to complete a questionnaireand these data were supplemented with information on cardiovascular disease and cancer through linkage tonational health registries. Among the 10655 twins who were contacted, responses were received from 5446individuals (1989 pairs and 1468 single responders). The subsample of pairs where both twins responded includes1004 identical (MZ) pairs and 985 fraternal (DZ) pairs. The overall individual and pairwise responserates were 51% and 37%, respectively. The average age is 61.54 years, 56.1% of the responders are femaleand 46.1% are identical twins. MZ twins were more likely to participate than DZ twins. Sex and age effectswere statistically significant for many of the psychosocial measures and for measures of support and strainin the social network. There were no differences in the social networks between twins in pairs where bothtwins responded and twins in pairs where only one twin responded.
Enchondroma of the Hand: Evaluation and Management
Authors: Lubahn John D. , Bachoura Abdo
Published: July 2016

Enchondroma is the most common primary bone tumor of the hand. This benign, cartilaginous tumor often presents as a pathologic fracture. When hand enchondroma is suspected, less common conditions, such as multiple enchondromatosis syndromes and benign and malignant lesions, should be ruled out. Surgical management with curettage is the standard of care for symptomatic lesions. However, controversy surrounds the timing of surgery for pathologic fractures and the use of surgical adjuncts and postcurettage void management. Microscopically distinguishing hand enchondroma from low-grade hand chondrosarcoma is a diagnostic challenge for pathologists, but the primary surgical treatment for both conditions is curettage because the latter has a low metastatic potential. Postoperative complications are typically joint stiffness and soft-tissue‒related deformities, whereas recurrence and malignant degeneration of solitary lesions are much less common. Most patients return to full function after surgery.
A Meta-Analysis of the Financial Participation Impact on Firm Performance
Authors: Aissa Olfa
Published: July 2016

The theme of the financial participation and its relationship with firm performance continue to occupy an important place in the academic and professional literature. However, researches take many different perspectives that it is difficult to define a conceptual framework and results are often different questioning their generalization.

In this research we propose a meta-analytic approach in order to evaluate the impact of the employees’ financial participation on firm performance. The results demonstrated a significant improvement in the economic and social performance of firms that share their profits with their employees.
Challenges Hindering the Accessibility of Tanzania’s Health Service: A Literature Review
Authors: Swere Kelvin Magaka Robert
Published: July 2016

The accessibility of Tanzania’s health service has been challenged with inadequate fund, shortage of fully trained health staff in the hospitals, poor communication and transport infrastructure. These challenges have been hindering the development plans of Tanzania’s health system including The Millennium Development Goal. All of these challenges have been associated with the fact that, Tanzania is still a developing country with a small budget to financing all of the development plans. Therefore, this review article covers these challenges with broader analysis of data and also recommend Tanzania government to take major steps in resolving these challenges.
A Longitudinal Assessment of Tax Reforms and National Income in Nigeria: 1971-2014
Authors: Nwaorgu Innocent Augustine , Herbert Wilson E. , Onyilo Francis
Published: July 2016

This study assesses the impact of tax reforms on Nigeria’s national income over the period, 1971 to 2014. Using a variety of growth indicators signifying tax reforms, our regression model specified growth rate of national income (proxied by GDP) as a function of growth rates in these indicators. Diagnostic tests (F-statistics, Adjusted R-Square and Durbin-Watson) were carried out to ascertain the robustness of the parameter estimates. We found that tax reforms significantly improved national income and economic growth during the period of study, especially growth rates of value added tax and personal income tax. Our results show that growth rate of personal income tax has a positive significant effect on the national income and economic growth, while that of value added tax has a negative significant effect on growth of national income. The growth components of company income tax and petroleum profit tax are positive but not statistically significant. On the other hand, reforms in custom and excise duties were found to yield negative and statistically non-significant effect. The leading conclusions from these findings are: (1) strategic tax reforms significantly influence the behaviour of national income and GDP; (2) tax policy significantly fosters the growth of national income; and (3) policy makers, especially Ministry of Finance and Federal Inland Revenue Service and their state counterparts, should give requisite attention to tax policy issues, in the light of their obvious implications on growth of the national income and economic development.
Reducing the effect of pre-slaughter fasting on the stress response of rainbow trout (Oncorhynchus mykiss)
Authors: Bermejo-Poza R , De la Fuente J , Pérez C , Lauzurica S , de Chávarri E González , Diaz MT , Villarroel M
Published: July 2016

Fasting is commonly used in aquaculture to empty the gut before slaughter, but little is known about how feeding frequency before fasting affects the stress response of trout. To find out more, 240 rainbow trout (Oncorhynchus mykiss) were separated into three groups with different feeding schedules during the final month of fattening, from 26 September to 28 October 2013 (daily, every two days or every four days) and two durations of pre-slaughter fasting (two days of fasting; 24.3 degree days, to nine days of fasting; 102 degree days). After slaughter, a number of stress-related parameters were measured, such as liver glycogen, skin/gill colour and haematological parameters (cortisol, glucose, lactate, triglycerides, lactate dehydrogenase and creatine phosphokinase). Trout given food every two days on the farm had lower levels of cortisol and higher levels of triglycerides and liver glycogen than the other treatments after two days of fasting; indicating that habituating trout to feed once every two days in the final month of fattening lowered their stress response to two days of fasting before slaughter.
Pathogenic shifts in endogenous microbiota impede tissue regeneration via distinct activation of TAK1/MKK/p38
Authors: Arnold Christopher P , Merryman M Shane , Harris-Arnold Aleishia , McKinney Sean A , Seidel Chris W , Loethen Sydney , Proctor Kylie N , Guo Longhua , Sánchez Alvarado Alejandro
Published: July 2016

The interrelationship between endogenous microbiota, the immune system, and tissue regeneration is an area of intense research due to its potential therapeutic applications. We investigated this relationship in Schmidtea mediterranea, a model organism capable of regenerating any and all of its adult tissues. Microbiome characterization revealed a high Bacteroidetes to Proteobacteria ratio in healthy animals. Perturbations eliciting an expansion of Proteobacteria coincided with ectopic lesions and tissue degeneration. The culture of these bacteria yielded a strain of Pseudomonas capable of inducing progressive tissue degeneration. RNAi screening uncovered a TAK1 innate immune signaling module underlying compromised tissue homeostasis and regeneration during infection. TAK1/MKK/p38 signaling mediated opposing regulation of apoptosis during infection versus normal tissue regeneration. Given the complex role of inflammation in either hindering or supporting reparative wound healing and regeneration, this invertebrate model provides a basis for dissecting the duality of evolutionarily conserved inflammatory signaling in complex, multi-organ adult tissue regeneration.
Wireless InGaN–Si/Pt device for photo-electrochemical water splitting
Authors: Sekimoto Takeyuki , Hashiba Hiroshi , Shinagawa Shuichi , Uetake Yusuke , Deguchi Masahiro , Yotsuhashi Satoshi , Ohkawa Kazuhiro
Published: July 2016

We demonstrate a wireless device comprising a gallium nitride (GaN)–silicon-based photo-electrode, and a platinum cathode. Compared with conventional two-electrode photo-electrochemical systems, this wireless monolithic device showed potential for a wider range of applications, and reduced the resistance losses resulting from the wiring and aqueous solution. The efficiency was improved when the electrolyte was changed from KHCO3 to NaOH because water oxidation capability of the surface of the GaN was enhanced. A wider solar spectrum wavelength range was exploited by adopting InGaN as a photo-absorption layer; the improved efficiency for hydrogen generation was 0.90%.
Percentile curves for skinfold thickness for Canadian children and youth
Authors: Kuhle Stefan , Ashley-Martin Jillian , Maguire Bryan , Hamilton David C.
Published: July 2016

Background.Skinfold thickness (SFT) measurements are a reliable and feasible method for assessing body fat in children but their use and interpretation is hindered by the scarcity of reference values in representative populations of children. The objective of the present study was to develop age- and sex-specific percentile curves for five SFT measures (biceps, triceps, subscapular, suprailiac, medial calf) in a representative population of Canadian children and youth.

Methods.We analyzed data from 3,938 children and adolescents between 6 and 19 years of age who participated in the Canadian Health Measures Survey cycles 1 (2007/2009) and 2 (2009/2011). Standardized procedures were used to measure SFT. Age- and sex-specific centiles for SFT were calculated using the GAMLSS method.

Results.Percentile curves were materially different in absolute value and shape for boys and girls. Percentile girls in girls steadily increased with age whereas percentile curves in boys were characterized by a pubertal centered peak.

Conclusions.The current study has presented for the first time percentile curves for five SFT measures in a representative sample of Canadian children and youth.
Non-invasive assessment of phosphate metabolism and oxidative capacity in working skeletal muscle in healthy young Chinese volunteers using31P Magnetic Resonance Spectroscopy
Authors: Li Ming , Chen Fei , Wang Huiting , Wu Wenbo , Zhang Xin , Tian Chuanshuai , Yu Haiping , Liu Renyuan , Zhu Bin , Zhang Bing , Dai Zhenyu
Published: July 2016

Background.Generally, males display greater strength and muscle capacity than females while performing a task. Muscle biopsy is regarded as the reference method of evaluating muscle functions; however, it is invasive and has sampling errors, and is not practical for longitudinal studies and dynamic measurement during excise. In this study, we built an in-house force control and gauge system for quantitatively applying force to quadriceps while the subjects underwent31P Magnetic Resonance Spectroscopy (31P-MRS); our aim was to investigate if there is a sex difference of phosphate metabolite change in working muscles in young heathy Chinese volunteers.

Methods.Volunteers performed knee-extending excises using a force control and gauge system while lying prone in a Philips 3T Magnetic Resonance (MR) scanner. The31P-MRS coil was firmly placed under the middle of the quadriceps .31P-MRS measurements of inorganic phosphate (Pi), phosphocreatine (PCr) and adenosine triphosphate (ATP) were acquired from quadriceps while subjects were in a state of pre-, during- and post-exercise. The PCr, Pi, PCr/Pi, PCr/ATP, pH, work/energy cost ratio (WE), kPCrand oxidative capacity were compared between males and females.

Results.A total of 17 volunteers underwent the study. Males:N= 10,age= 23.30 ± 1.25years; females:N= 7, age = 23.57 ± 0.79 years. In this study, males had significantly greater WE (16.33 ± 6.46 vs. 7.82 ± 2.16,p= 0.002) than females. Among PCr, Pi, PCr/Pi, PCr/ATP, pH, kPCr and oxidative capacity at different exercise status, only PCr/Pi (during-exercise, males = 5.630 ± 1.647, females = 4.014 ± 1.298,p= 0.047), PCr/ATP (during-exercise, males =1.273 ± 0.219, females = 1.523 ± 0.167,p= 0.025), and ATP (post-exercise, males = 24.469 ± 3.911 mmol/kg, females = 18.353 ± 4.818 mmol/kg,p= 0.035) had significant sex differences. Males had significantly greater PCr/Pi, but less PCr/ATP than females during exercise, suggesting males had higher energy transfer efficiency than females. At the post-exercise status, the recovery of PCr did not show sex difference.

Conclusions.Our in-house force control and gauge system quantitatively applied force during the exercise for31P-MRS experiments, and a sex difference of higher energy transfer efficiency and WE was detected in males with mild loaded exercising quadriceps. This noninvasive technology allows us to further study and understand the sex difference of high energy phosphate metabolism in the future.
A study of aerosol properties based on observations of particulate matter from the U.S. Embassy in Beijing, China
Authors: Mukherjee Anondo , Toohey Darin W.
Published: July 2016

The United States Embassy in Beijing, China publicly released a record of mass concentrations of particulate matter 2.5 µm and smaller in aerodynamic diameter (PM2.5), from April 2008 to the present, measured with a beta attenuation monitor (BAM). We compare these measurements with observations of particulate matter recorded at the Beijing Institute of Atmospheric Physics and observations of visibility recorded at the Beijing Capital International Airport (BCIA) to assess their value as a record of air quality in the greater Beijing metropolitan area. We find that the PM2.5 observations correlate well with the other observations of particulate matter (PM) over the period 1 January–1 February 2013 using a tapered element oscillating microbalance and an aerosol mass spectrometer (AMS), and they exhibit a clear inverse correlation with visibility measured at BCIA. Using inverse visibility as a proxy of radiation extinction, we determine a dry mass extinction efficiency and a dependence of radiation extinction on relative humidity, which is consistent with other studies of polluted urban environments. We deduce a strong degree of homogeneity of particulate pollution across the Beijing metropolitan region and conclude that the U.S. Embassy measurements are a reliable sample of this particulate pollution during periods of photochemical smog. The U.S. Embassy observations of PM2.5 appear to remain consistent throughout the available record and can serve as a useful dataset for studying future trends in particulate matter as China implements ambitious measures to improve air quality in the region.
Oxidation‐Resistant and Elastic Mesoporous Carbon with Single‐Layer Graphene Walls
Authors: Nishihara Hirotomo , Simura Tomoya , Kobayashi Shunsuke , Nomura Keita , Berenguer Raúl , Ito Masashi , Uchimura Masanobu , Iden Hiroshi , Arihara Kazuki , Ohma Atsushi , Hayasaka Yuichiro , Kyotani Takashi
Published: July 2016

An oxidation‐resistant and elastic mesoporous carbon, graphene mesosponge (GMS), is prepared. GMS has a sponge‐like mesoporous framework (mean pore size is 5.8 nm) consisting mostly of single‐layer graphene walls, which realizes a high electric conductivity and a large surface area (1940 m2 g−1). Moreover, the graphene‐based framework includes only a very small amount of edge sites, thereby achieving much higher stability against oxidation than conventional porous carbons such as carbon blacks and activated carbons. Thus, GMS can simultaneously possess seemingly incompatible properties; the advantages of graphitized carbon materials (high conductivity and high oxidation resistance) and porous carbons (large surface area). These unique features allow GMS to exhibit a sufficient capacitance (125 F g−1), wide potential window (4 V), and good rate capability as an electrode material for electric double‐layer capacitors utilizing an organic electrolyte. Hence, GMS achieves a high energy density of 59.3 Wh kg−1 (material mass base), which is more than twice that of commercial materials. Moreover, the continuous graphene framework makes GMS mechanically tough and extremely elastic, and its mean pore size (5.8 nm) can be reversibly compressed down to 0.7 nm by simply applying mechanical force. The sponge‐like elastic property enables an advanced force‐induced adsorption control.
Impaired Chaperone Activity of Human Heat Shock Protein Hsp27 Site‐Specifically Modified with Argpyrimidine
Authors: Matveenko Maria , Cichero Elena , Fossa Paola , Becker Christian F. W.
Published: July 2016

Non‐enzymatic posttranslational modifications (nPTMs) affect at least ∼30 % of human proteins, but our understanding of their impact on protein structure and function is limited. Studies of nPTMs are difficult because many modifications are not included in common chemical libraries or protein expression systems and should be introduced site‐specifically. Herein, we probed the effect of the nPTM argpyrimidine on the structure and function of human protein Hsp27, which acquires argpyrimidine at residue 188 in vivo. We developed a synthetic approach to an argpyrimidine building block, which we then incorporated at position 188 of Hsp27 through protein semisynthesis. This modification did not affect the protein secondary structure, but perturbed the oligomeric assembly and impaired chaperone activity. Our work demonstrates that protein function can be altered by a single nPTM and opens up a new area of investigation only accessible by methods that allow site‐selective protein modification.
Evaluation of the emulsion copolymerization of vinyl pivalate and methacrylated methyl oleate
Authors: Jensen Alan Thyago , de Oliveira Ana Carolina Couto , Gonçalves Sílvia Belém , Gambetta Rossano , Machado Fabricio
Published: July 2016

In this study, we synthesized a new class of copolymeric lattices based on vinyl pivalate (VPi) and modified oleic acid (OA) through a batch emulsion polymerization process. The effects of the chemically modified OA [methacrylated methyl oleate (MAMO)] on the thermal stability, glass‐transition temperature (Tg), average molar masses [mass‐average molar mass (Mw) and number‐average molar mass (Mn)], and molar mass dispersity (Ð) of the copolymers were evaluated. The experimental results indicate that via the introduction of MAMO into the polymer chains resulted in significant reductions in Tg, Mw, Mn, and Ð; this demonstrated a decrease of Tg at approximately 40 °C when the MAMO molar fraction equaled 9% compared to the value observed for the pure poly(vinyl pivalate) (PVPi), which was equal to 80.5 °C. MAMO incorporation led to a significant decrease in the Mw value observed in the interval, with a differential from approximately 1.6 × 103 to 289.6 kg/mol, and Ð values between 2.17 to 1.55, which was when the MAMO molar fraction present in the VPi‐containing copolymers varied from zero (pure PVPi) to approximately 9 mol %. We also observed that the thermal stability of the copolymers decreased slightly when the MAMO concentration increased in the reaction medium. Despite this minor drawback, polymer lattices with a high colloidal stability were formed at a high rate of polymerization, and the elevated conversion was within the interval 90–100%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44129.
Epoxy composite reinforced with three‐dimensional polyimide fiber felt: Fabrication and tribological properties investigation
Authors: Wang Huaiyuan , Zhu Yixing , Yan Lei , Sun Liyuan , Zhu Yanji
Published: July 2016

Novel epoxy (EP) composite reinforced with three‐dimensional (3D) polyimide (PI) fiber felt (PI3D/EP) is first fabricated by vacuum assisted resin transfer molding. The tribological behaviors of pure EP and PI3D/EP composite under dry sliding and water lubricated condition are comparatively studied. Results indicate that both wear rates and friction coefficients of PI3D/EP composite are lower than those of pure EP. The wear resistance of PI3D/EP composite is 9.8 times higher than that of pure EP under dry sliding of 1.5 MPa and 0.76 m s−1 while a 27‐fold increase is achieved under water lubricated condition. The wear mechanisms of PI3D/EP composite are investigated based on tribological testing results and scanning electron microscopy observations. The PI fiber felt provides strong 3D structure supports to sustain most of the loads on the composite, improving the mechanical and tribological properties significantly. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44160.
Effect of human mesenchymal stem cell transplantation on cerebral ischemic volume‐controlled photothrombotic mouse model
Authors: Choi Yun‐Kyong , Urnukhsaikhan Enerelt , Yoon Hee‐Hoon , Seo Young‐Kwon , Park Jung‐Keug
Published: July 2016

Various animal models of stroke have been developed to simulate the human stroke with the development of the ischemic method facilitates preclinical stroke research. The photothrombotic ischemia model, based on the intravascular photochemical reaction, is widely used for in vivo studies. However, this study has limitations, which generated a relatively small‐sized infarction model on superficial cortex compared to that of the MCAO stroke model. In this study, the photothorombosis mouse model is adapted and the optimum conditions for generation of cell death and deficits with high reproducibility is determined. The extent of damage within the cortex was assessed by infarct volume and cellular/behavioral analyses. In this model, the neural cell death and inflammatory responses is detected; moreover, the degree of behavioral impairment is correlated with the brain infarct volume. Further, to enhance the understanding of neural repair, the effect of neural differentiation by transplantation of human bone marrow‐derived mesenchymal stem cells (BM‐MSCs) is analyzed. The authors demonstrated that transplantation of BM‐MSCs promoted the neural differentiation and behavioral performance in their photothrombosis model. Therefore, this research was meaningful to provide a stable animal model of stroke with low variability. Moreover, this model will facilitate development of novel MSC‐based therapeutics for stroke.
Characterizing neurocognitive impairment in young people with major depression: state, trait, or scar?
Authors: Allott Kelly , Fisher Caroline A. , Amminger Gunther Paul , Goodall Joanne , Hetrick Sarah
Published: July 2016

Background

Major depressive disorder (MDD) affects a quarter of adolescents and young adults and is associated with the greatest global burden of disease in this population. There is a growing literature, mostly in adults, showing that significant neurocognitive impairments are common in MDD. It remains unclear whether these impairments are pre‐existing trait markers of MDD, state‐related impairments that fluctuate with depressive symptoms, or ‘scar’ impairments that worsen with illness progression. The aim of this study is to provide a conceptual framework for understanding MDD and neurocognitive impairment in adolescence and young adulthood (ages 12–25 years).

Method

Examination of the evidence for neurocognitive deficits as trait, state, and scar features of MDD according to different study designs (family studies, premorbid studies, current depression, remitted depression, and longitudinal studies with repeated assessment) was conducted.

Results

The few premorbid and family studies conducted in youth provide equivocal evidence for neurocognitive impairments as trait markers of MDD. The presence of state‐based neurocognitive impairment remains unclear as evidence comes mostly from cross‐sectional studies. There are a limited, but growing number of longitudinal studies with repeated neurocognitive assessment in youth. Studies that examined neurocognition prior to the onset of MDD and with long‐term follow‐up provide tentative evidence for neurocognitive scarring.

Conclusion

Neurocognitive impairment is a feature of MDD in adolescents and young adults. To better understand the nature, timing, and pattern of impairment, longitudinal studies that examine neurocognition before and after the development of full‐threshold MDD, including following recurrence are needed. This knowledge will have important implications for mechanisms, prevention, and treatment of MDD in youth.
Helix‐Grafted Pleckstrin Homology Domains Suppress HIV‐1 Infection of CD4‐Positive Cells
Authors: Tennyson Rachel L. , Walker Susanne N. , Ikeda Terumasa , Harris Reuben S. , Kennan Alan J. , McNaughton Brian R.
Published: July 2016

The size, functional group diversity and three‐dimensional structure of proteins often allow these biomolecules to bind disease‐relevant structures that challenge or evade small‐molecule discovery. Additionally, folded proteins are often much more stable in biologically relevant environments compared to their peptide counterparts. We recently showed that helix‐grafted display—extensive resurfacing and elongation of an existing solvent‐exposed helix in a pleckstrin homology (PH) domain—led to a new protein that binds a surrogate of HIV‐1 gp41, a validated target for inhibition of HIV‐1 entry. Expanding on this work, we prepared a number of human‐derived helix‐grafted‐display PH domains of varied helix length and measured properties relevant to therapeutic and basic research applications. In particular, we showed that some of these new reagents expressed well as recombinant proteins in Escherichia coli, were relatively stable in human serum, bound a mimic of pre‐fusogenic HIV‐1 gp41 in vitro and in complex biological environments, and significantly lowered the incidence of HIV‐1 infection of CD4‐positive cells.
Reduction of Nitrophenyl Films in Aqueous Solutions: How Many Electrons?
Authors: Brooksby Paula A. , Shields James D. , Farquhar Anna K. , Downard Alison J.
Published: July 2016

The surface concentration of nitrophenyl (NP) films is commonly calculated from the charge associated with its redox reactions in aqueous solution. Reduction is usually carried out in acidic or basic solution and is assumed to proceed by either four electrons, or a mixed four and six electron process. Here, we reproducibly graft NP films of different thicknesses to glassy carbon electrodes from the corresponding diazonium ion and examine the reduction of the films in strongly acidic and basic solutions. We demonstrate that in most, if not all, cases, assumption of a four‐electron reduction of NP groups coupled with use of the redox reaction of the hydroxylamine product will lead to an underestimation of the surface concentration of NP groups. Use of acidic media with the assumption of a mixed four and six electron reduction of NP groups is shown to be an electrochemically and chemically sensible approach to estimating surface concentrations of NP groups.
Rational Design of Fluorescent Phthalazinone Derivatives for One‐ and Two‐Photon Imaging
Authors: Yang Lingfei , Zhu Yuanjun , Shui Mengyang , Zhou Tongliang , Cai Yuanbo , Wang Wei , Xu Fengrong , Niu Yan , Wang Chao , Zhang Jun‐Long , Xu Ping , Yuan Lan , Liang Lei
Published: July 2016

Phthalazinone derivatives were designed as optical probes for one‐ and two‐photon fluorescence microscopy imaging. The design strategy involves stepwise extension and modification of pyridazinone by 1) expansion of pyridazinone to phthalazinone, a larger conjugated system, as the electron acceptor, 2) coupling of electron‐donating aromatic groups such as N,N‐diethylaminophenyl, thienyl, naphthyl, and quinolyl to the phthalazinone, and 3) anchoring of an alkyl chain to the phthalazinone with various terminal substituents such as triphenylphosphonio, morpholino, triethylammonio, N‐methylimidazolio, pyrrolidino, and piperidino. Theoretical calculations were utilized to verify the initial design. The desired fluorescent probes were synthesized by two different routes in considerable yields. Twenty‐two phthalazinone derivatives were synthesized and their photophysical properties were measured. Selected compounds were applied in cell imaging, and valuable information was obtained. Furthermore, the designed compounds showed excellent performance in two‐photon microscopic imaging of mouse brain slices.
Quantitative Determination and Comparison of the Surface Binding of Phosphonic Acid, Carboxylic Acid, and Catechol Ligands on TiO2 Nanoparticles
Authors: Zeininger Lukas , Portilla Luis , Halik Marcus , Hirsch Andreas
Published: July 2016

The adsorption, desorption, co‐adsorption, and exchange behavior of phosphonic acid, carboxylic acid, and catechol derivatives on the surface of titanium oxide (anatase) nanoparticles are investigated. Thermogravimetric analysis provides a facile and fast‐track quantitative determination of the wet‐chemical monolayer adsorption constants and grafting densities of ten adsorbates, all under neutral pH conditions. This characterization protocol allows straightforward quantification of the relevant thermodynamic data of ligand adsorption and a comparison of ligand adsorption strengths. The reported procedure is proposed as a universal tool and it should be applicable to many other colloidal metal oxide materials. Moreover, the determined values for the adsorption constants and the monolayer grafting densities provide a toolbox for the assessment of the adsorbates’ behavior in desorption, exchange, and co‐adsorption equilibria. This versatile evaluation procedure will help to identify optimal monolayer–surface combinations and to evaluate critical parameters, such as monolayer robustness, ligand exchange rates, or targeted mixed assembly of functionalities.
B=N Units as Part of Extended π‐Conjugated Oligomers and Polymers
Authors: Helten Holger
Published: July 2016

The replacement of C=C units by their isoelectronic and isosteric B=N units (BN/CC isosterism) in π‐conjugated organic compounds, as a strategy to produce novel organic–inorganic hybrid materials, has recently been successfully transferred to π‐conjugated polymers. This Concept provides an overview of the recent advances in this quickly evolving field, with a focus on synthesis, photophysical and electrochemical properties of the new polymers and related oligomers, as well as possible future applications in organic electronics and optoelectronics.
Efficient Solar‐Driven Nitrogen Fixation over Carbon–Tungstic‐Acid Hybrids
Authors: Li Xiaoman , Wang Wenzhong , Jiang Dong , Sun Songmei , Zhang Ling , Sun Xiang
Published: July 2016

Ammonia synthesis under mild conditions is of supreme interest. Photocatalytic nitrogen fixation with water at room temperature and atmospheric pressure is an intriguing strategy. However, the efficiency of this method has been far from satisfied for industrialization, mainly due to the sluggish cleavage of the N≡N bond. Herein, we report a carbon–tungstic‐acid (WO3⋅H2O) hybrid for the co‐optimization of N2 activation as well as subsequent photoinduced protonation. Efficient ammonia evolution reached 205 μmol g−1 h−1 over this hybrid under simulated sunlight. Nitrogen temperature‐programmed desorption revealed the decisive role of carbon in N2 adsorption. Photoactive WO3⋅H2O guaranteed the supply of electrons and protons for subsequent protonation. The universality of carbon modification for enhancing the N2 reduction was further verified over various photocatalysts, shedding light on future materials design for ideal solar energy utilization.
Au‐Cu Alloy Formation on Cubic Cu2O Nanocrystals at Ambient Temperature and Their Catalytic Performance
Authors: Zhang Zhenhua , Cao Tian , Luo Liangfeng , Song Rui , Wang Huijuan , Huang Weixin
Published: July 2016

The synthesis of metal alloys usually requires harsh reaction conditions. We report herein that the chemical reactions of HAuCl4 and cubic Cu2O nanocrystal in an ethanol‐water mixture solution at ambient temperature can form supported Au‐Cu alloys. The parallel galvanic replacement reaction between HAuCl4 and Cu2O and disproportionation reaction of Cu2O simultaneously form Au and Cu atoms, respectively, on the Cu2O surface that cluster and grow into Au‐Cu alloys. The supported AuCu alloy particles exhibit excellent activity in catalyzing the liquid phase aerobic oxidation reaction of benzyl alcohol. These results demonstrate a novel approach to fabricate metal alloys with very mild conditions via oxide‐surface‐directed chemical synthesis.
Performance of linear and non‐linear precoders in G.fast ultra‐broadband DSL networks
Authors: Chuah Teong Chee , Ng Yin Hoe , Zainal Abidin Ahmadun Nijar , Asrokin Azhari , Hashim Nabihah
Published: July 2016

The new International Telecommunication Union Telecommunication G.fast standard for next‐generation ultra‐broadband digital subscriber line systems has stipulated mandatory use of vectoring for crosstalk mitigation. In this paper, we study the performance of downstream precoders in G.fast networks utilising the extended bandwidth up to 212 MHz. In particular, the issue of strong crosstalk encountered in practical copper cable bundles at high frequencies giving rise to channel matrices which are not row‐wise diagonally dominant (RWDD) as predicted theoretically, as well as the ramification of deploying precoders designed based on the RWDD assumption in practical G.fast channels are studied. To serve these purposes, an enhanced stochastic far‐end crosstalk (FEXT) model which provides distinct FEXT transfer functions with the dispersion range characterised experimentally whilst encompassing the dual‐slope FEXT encountered in non‐RWDD cables is used for evaluating the performance of precoders in diverse G.fast deployment scenarios. Furthermore, the performance sensitivity of precoders under realistic amount of channel estimation errors is investigated on a common framework, allowing a direct and fair comparison between linear and non‐linear precoders. Results show that the nonlinear optimal precoder outperforms linear precoders in all channel conditions; however, the former is found to be slightly more sensitive to channel estimation errors on shorter loops. Copyright © 2016 John Wiley & Sons, Ltd.