bluuebunny/crossref_metadata_2025 huggingface dataset:
Light-induced depigmentation in planarians models the pathophysiology of acute porphyrias
Authors: Stubenhaus Bradford M , Dustin John P , Neverett Emily R , Beaudry Megan S , Nadeau Leanna E , Burk-McCoy Ethan , He Xinwen , Pearson Bret J , Pellettieri Jason
Published: May 2016

Porphyrias are disorders of heme metabolism frequently characterized by extreme photosensitivity. This symptom results from accumulation of porphyrins, tetrapyrrole intermediates in heme biosynthesis that generate reactive oxygen species when exposed to light, in the skin of affected individuals. Here we report that in addition to producing an ommochrome body pigment, the planarian flatworm Schmidtea mediterranea generates porphyrins in its subepithelial pigment cells under physiological conditions, and that this leads to pigment cell loss when animals are exposed to intense visible light. Remarkably, porphyrin biosynthesis and light-induced depigmentation are enhanced by starvation, recapitulating a common feature of some porphyrias – decreased nutrient intake precipitates an acute manifestation of the disease. Our results establish planarians as an experimentally tractable animal model for research into the pathophysiology of acute porphyrias, and potentially for the identification of novel pharmacological interventions capable of alleviating porphyrin-mediated photosensitivity or decoupling dieting and fasting from disease pathogenesis.
Tumor suppression in basal keratinocytes via dual non-cell-autonomous functions of a Na,K-ATPase beta subunit
Authors: Hatzold Julia , Beleggia Filippo , Herzig Hannah , Altmüller Janine , Nürnberg Peter , Bloch Wilhelm , Wollnik Bernd , Hammerschmidt Matthias
Published: May 2016

The molecular pathways underlying tumor suppression are incompletely understood. Here, we identify cooperative non-cell-autonomous functions of a single gene that together provide a novel mechanism of tumor suppression in basal keratinocytes of zebrafish embryos. A loss-of-function mutation in atp1b1a, encoding the beta subunit of a Na,K-ATPase pump, causes edema and epidermal malignancy. Strikingly, basal cell carcinogenesis only occurs when Atp1b1a function is compromised in both the overlying periderm (resulting in compromised epithelial polarity and adhesiveness) and in kidney and heart (resulting in hypotonic stress). Blockade of the ensuing PI3K-AKT-mTORC1-NFκB-MMP9 pathway activation in basal cells, as well as systemic isotonicity, prevents malignant transformation. Our results identify hypotonic stress as a (previously unrecognized) contributor to tumor development and establish a novel paradigm of tumor suppression.
Two new moss records in the family Grimmiaceae from Turkey, Southwest Asia.
Authors: Karakas Mustafa , Ezer Tülay
Published: May 2016

Grimmia incurva Schwägr. and Schistidium umbrosum (J.E.Zetterst.) H.H. Blom (Grimmiaceae) are reported

for the first time from Turkey, Southwest Asia. Turkish plants are described and illustrated from material

collected from Göllüdağ Volcano in the Central Anatolia (Niğde) which has a semi-arid, continental climate

with a severe frost period in winter.
Initial breakdown and fast leaders in lightning discharges producing long‐lasting disturbances of the lower ionosphere
Authors: Kotovsky D. A. , Moore R. C. , Zhu Y. , Tran M. D. , Rakov V. A. , Pilkey J. T. , Caicedo J. A. , Hare B. , Jordan D. M. , Uman M. A.
Published: May 2016

The recent discovery of long recovery, early VLF scattering events (LOREs) indicates that the electric field changes from lightning discharges are capable of producing long‐lasting disturbances (up to tens of minutes) in the upper mesosphere and lower ionosphere. Comparison of lightning mapping array, broadband (up to 10 MHz) electric field, and VLF (∼300 Hz to 42 kHz) magnetic field measurements shows that the field changes produced by initial breakdown (IB) processes and the following leaders in natural, cloud‐to‐ground lightning discharges are detectable in VLF magnetic field measurements at long distances. IB radiation has been detected in VLF for lightning discharges occurring up to 2630 km away from the VLF observing station. Radio atmospherics associated with 52 LOREs, 51 regular recovery events, and 3098 flashes detected by National Lightning Detection Network and/or GLD360 were examined for IB radiation occurring up to 15 ms before the return stroke. Our analysis reveals that in contrast to regular recovery early VLF events, LOREs are strongly associated with lightning discharges which exhibit an intense IB process and a fast first leader (typical duration <4 ms). These experimental results demonstrate that initial breakdown and leader processes are indicators of discharge properties highly relevant to the total energy transfer between lightning discharges and the middle/upper atmosphere.
Influence of temperature, pressure, and oxygen fugacity on the electrical conductivity of dry eclogite, and geophysical implications
Authors: Dai Lidong , Hu Haiying , Li Heping , Wu Lei , Hui Keshi , Jiang Jianjun , Sun Wenqing
Published: May 2016

The electrical conductivity of eclogite was measured at temperatures of 873–1173 K and pressures of 1.0–3.0 GPa within a frequency range of 0.1–106 Hz using a YJ‐3000t multianvil press and Solartron‐1260 impedance/gain‐phase analyzer. Three solid‐state oxygen buffers (Cu + CuO, Ni + NiO, and Mo + MoO2) were employed to control the oxygen fugacity. Experimental results indicate that the electrical conductivity of the samples tended to increase with increasing temperature, conforming to an Arrhenius relation. Under the control of a Cu + CuO oxygen buffer, the electrical conductivity of the eclogite decreased with a rise in pressure, and its corresponding activation volume and activation energy at atmospheric pressure were calculated as −2.51 ± 0.29 cm3/mole and 0.86 ± 0.12 eV, respectively. At 2.0 GPa, the electrical conductivity of the eclogite increased with increasing oxygen fugacity, and the preexponential factor increased while the activation enthalpy decreased. The observed positive exponential factor for the dependence of electrical conductivity on oxygen fugacity, as well as the negative activation volume, confirm that the hopping of small polarons is the dominant conduction mechanism in eclogite at high temperatures and pressures. Our results suggest that the electrical conductivity of dry eclogite under various redox conditions cannot explain the high anomalies in conductivity under stable midlower continental crust and under the Dabie‐Sulu ultrahigh‐pressure metamorphic belt of eastern China.
High temporal resolution observations of auroral electron density using superthermal electron enhancement of Langmuir waves
Authors: Vierinen Juha , Bhatt Asti , Hirsch Michael A. , Strømme Anja , Semeter Joshua L. , Zhang Shun‐Rong , Erickson Philip J.
Published: May 2016

We report high temporal resolution auroral electron precipitation observations using the Sondrestrom incoherent scatter radar. The observations make use of the superthermal electron enhancement of Langmuir waves, which is shown to give accurate observations of the electron density during auroral ionization at a subsecond temporal resolution. This is important when matching to the time scales of auroral precipitation‐related phenomena, such as energy input into the atmosphere and magnetospheric electron acceleration mechanisms. We describe the measurement technique and show an example observation of auroral precipitation. The results show transients in electron density in the order of a few seconds, which are fully resolved by the plasma line measurements. An electron precipitation model is used to estimate precipitation energy and flux density. The energetic electron flux during the example event has variations even at short time scales. The results show that electron density profiles derived from plasma lines can be a powerful new observational capability.
Milne‐Eddington inversion for unresolved magnetic structures in the quiet Sun photosphere
Authors: Bommier Véronique
Published: May 2016

This paper is first devoted to present our method for modeling unresolved magnetic structures in the Milne‐Eddington inversion of spectropolarimetric data. The related definitions and other approaches and different used inversion algorithms are recalled for comparison. In a second part, we apply our method to quiet Sun data outside active regions. We obtain the quiet Sun photospheric magnetic field as composed of unresolved opening and connected magnetic flux tubes, which form a loop carpet of field lines. We then analyze the spatial correlation, which we also observed for the magnetic field vector, in terms of flux tube diameter, distance, and field strength. We find that different observations with the Zurich imaging polarimeter and THEMIS polarimeter mounted on the THEMIS telescope give very close results, and we add results also very close derived from HINODE/Solar Optical Telescope/spectropolarimeter observations analyzed with the same method. We obtain a mean flux tube diameter of 30 km, a mean flux tube distance of 230 km, and a mean flux tube magnetic field of 1.3 kG.
Compressional ULF wave modulation of energetic particles in the inner magnetosphere
Authors: Liu H. , Zong Q.‐G. , Zhou X.‐Z. , Fu S. Y. , Rankin R. , Wang L.‐H. , Yuan C. J. , Wang Y. F. , Baker D. N. , Blake J. B. , Kletzing C. A.
Published: May 2016

We present Van Allen Probes observations of modulations in the flux of very energetic electrons up to a few MeV and protons between 1200 and 1400 UT on 19 February 2014. During this event the spacecraft were in the dayside magnetosphere at L⋆≈5.5. The modulations extended across a wide range of particle energies, from 79.80 keV to 2.85 MeV for electrons and from 82.85 keV to 636.18 keV for protons. The fluxes of π/2 pitch angle particles were observed to attain maximum values simultaneously with the ULF compressional magnetic field component reaching a minimum. We use peak‐to‐valley ratios to quantify the strength of the modulation effect, finding that the modulation is larger at higher energies than at lower energies. It is shown that the compressional wave modulation of the particle distribution is due to the mirror effect, which can trap relativistic electrons efficiently for energies up to 2.85 MeV and trap protons up to ≈600 keV. Larger peak‐to‐valley ratios at higher energies also attributed to the mirror effect. Finally, we suggest that protons with energies higher than 636.18 keV cannot be trapped by the compressional ULF wave efficiently due to the finite Larmor radius effect.
On subsurface cooling associated with the Biobio River Canyon (Chile)
Authors: Sobarzo Marcus , Saldías Gonzalo S. , Tapia Fabian J. , Bravo Luis , Moffat Carlos , Largier John L.
Published: May 2016

Submarine canyons cutting across the continental shelf can modulate the cross‐shelf circulation being effective pathways to bring water from the deep ocean onto the shelf. Here, we use 69 days of moored array observations of temperature and ocean currents collected during the spring of 2013 and winter‐spring 2014, as well as shipboard hydrographic surveys and sea‐level observations to characterize cold, oxygen poor, and nutrient‐rich upwelling events along the Biobio Submarine Canyon (BbC). The BbC is located within the Gulf of Arauco at 36° 50'S in the Central Chilean Coast. The majority of subtidal temperature at 150 m depth is explained by subtidal variability in alongshore currents on the canyon with a lag of less than a day (r2 = 0.65). Using the vertical displacement of the 10° and 10.5°C isotherms, we identified nine upwelling events, lasting between 20 h to 4.5 days, that resulted in vertical isothermal displacements ranging from 29 to 137 m. The upwelled water likely originated below 200 m. Majority of the cooling events were related with strong northward (opposite Kelvin wave propagation) flow and low pressure at the coast. Most of these low pressure events occur during relatively weak local wind forcing conditions, and were instead related with Coastal Trapped Waves (CTWs) propagating southwards from lower latitudes. These cold, high‐nutrient, low‐oxygen waters may be further upwelled and advected into the Gulf of Arauco by wind forcing. Thus, canyon upwelling may be a key driver of biological productivity and oxygen conditions in this Gulf.
Magnetic anomalies concentrated near and within Mercury's impact basins: Early mapping and interpretation
Authors: Hood L. L.
Published: May 2016

Ninety‐five low‐altitude passes of MErcury Surface, Space ENvironment, GEochemistry, and Ranging magnetometer data from February, March, and April of 2015 have been applied to produce an approximate map of the crustal magnetic field at a constant altitude of 40 km covering latitudes of 35°–75°N and longitudes of 90°–270°E. Anomalies are concentrated near and within the Caloris impact basin. A smaller concentration occurs over and around Sobkou Planitia and an associated older large impact basin. The strongest anomalies are found within Caloris and are distributed in a semicircular arc that is roughly concentric with the basin rim. They imply the existence of a core dynamo at the time when Caloris formed (∼3.9 Gyr ago). Anomalies over high‐reflectance volcanic plains are relatively weak while anomalies over low‐reflectance material that has been reworked by impact processes are relatively strong. The latter characteristics are qualitatively consistent with the ejecta deposit model for anomaly sources.
A semi‐adaptive control approach to closed‐loop medication infusion
Authors: Jin Xin , Kim Chang‐Sei , Dumont Guy A. , Ansermino J. Mark , Hahn Jin‐Oh
Published: May 2016

This paper presents a semi‐adaptive control approach to closed‐loop medication infusion problems. The rationale underlying this approach is to design a controller that can adapt model parameters with a large impact on the model's fidelity while fixing the remaining parameters at nominal values. In this paper, a control‐oriented model for this purpose is derived via system identification and sensitivity analysis of a low‐order model capturing the direct dose‐response relationship Using the model thus derived, a model‐reference adaptive controller and a composite adaptive controller are designed and compared with each other. In‐silico simulation results using remifentanil's effect on respiratory rate as an example indicate that both controllers can regulate the output at commanded set points. Copyright © 2016 John Wiley & Sons, Ltd.
Utilization of the Antiferromagnetic IrMn Electrode in Spin Thermoelectric Devices and Their Beneficial Hybrid for Thermopiles
Authors: Kim Dong‐Jun , Lee Kyeong‐Dong , Surabhi Srivathsava , Yoon Soon‐Gil , Jeong Jong‐Ryul , Park Byong‐Guk
Published: May 2016

The thermoelectric effect in various magnetic systems, in which electric voltage is generated by a spin current, has attracted much interest owing to its potential applications in energy harvesting, but its power generation capability has to be improved further for actual applications. In this study, the first instance of the formation of a spin thermopile via a simplified and straightforward method which utilizes two distinct characteristics of antiferromagnetic IrMn is reported: the inverse spin Hall effect and the exchange bias. The former allows the IrMn efficiently to convert the thermally induced spin current into a measurable voltage, and the latter can be used to control the spin direction of adjacent ferromagnetic materials. It is observed that a thermoelectric signal is successfully amplified in spin thermopiles with exchange‐biased IrMn/CoFeB structures, where an alternating magnetic alignment is formed using the IrMn thickness dependence of the exchange bias. The scalable signal on a number of thermopiles allowing a large‐area application paves the way toward the development of practical spin thermoelectric devices. A detailed model analysis is also provided for a quantitative understanding of the thermoelectric voltages, which consist of the spin Seebeck and anomalous Nernst contributions.
Overall Water Splitting Catalyzed Efficiently by an Ultrathin Nanosheet‐Built, Hollow Ni3S2‐Based Electrocatalyst
Authors: Wu Yuanyuan , Li Guo‐Dong , Liu Yipu , Yang Lan , Lian Xinran , Asefa Tewodros , Zou Xiaoxin
Published: May 2016

Making highly efficient catalysts for an overall ​water splitting reaction is vitally important to bring solar/electrical‐to‐hydrogen energy conversion processes into reality. Herein, the synthesis of ultrathin nanosheet‐based, hollow MoOx/Ni3S2 composite microsphere catalysts on nickel foam, using ammonium molybdate as a precursor and the triblock copolymer pluronic P123 as a structure‐directing agent is reported. It is also shown that the resulting materials can serve as bifunctional, non‐noble metal electrocatalysts with high activity and stability for the hydrogen evolution reaction (HER) as well as the oxygen evolution reaction (OER). Thanks to their unique structural features, the materials give an impressive water‐splitting current density of 10 mA cm−2 at ≈1.45 V with remarkable durability for >100 h when used as catalysts both at the cathode and the anode sides of an alkaline electrolyzer. This performance for an overall water splitting reaction is better than even those obtained with an electrolyzer consisting of noble metal‐based Pt/C and IrOx/C catalytic couple—the benchmark catalysts for HER and OER, respectively.
Characterization of a Polymer‐Based, Fully Organic Prosthesis for Implantation into the Subretinal Space of the Rat
Authors: Antognazza Maria Rosa , Di Paolo Mattia , Ghezzi Diego , Mete Maurizio , Di Marco Stefano , Maya‐Vetencourt José Fernando , Maccarone Rita , Desii Andrea , Di Fonzo Fabio , Bramini Mattia , Russo Angela , Laudato Lucia , Donelli Ilaria , Cilli Michele , Freddi Giuliano , Pertile Grazia , Lanzani Guglielmo , Bisti Silvia , Benfenati Fabio
Published: May 2016

Replacement strategies arise as promising approaches in case of inherited retinal dystrophies leading to blindness. A fully organic retinal prosthesis made of conjugated polymers layered onto a silk fibroin substrate is engineered. First, the biophysical and surface properties are characterized; then, the long‐term biocompatibility is assessed after implantation of the organic device in the subretinal space of 3‐months‐old rats for a period of five months. The results indicate a good stability of the subretinal implants over time, with preservation of the physical properties of the polymeric layer and a tight contact with the outer retina. Immunoinflammatory markers detect only a modest tissue reaction to the surgical insult and the foreign body that peaks shortly after surgery and progressively decreases with time to normal levels at five months after implantation. Importantly, the integrity of the polymeric layer in direct contact with the retinal tissue is preserved after five months of implantation. The recovery of the foreign‐body tissue reaction is also associated with a normal b‐wave in the electroretinographic response. The results demonstrate that the device implanted in nondystrophic eyes is well tolerated, highly biocompatible, and suitable as retinal prosthesis in case of photoreceptor degeneration.
Self‐Assembly of DNA Functionalized Gold Nanoparticles at the Liquid‐Vapor Interface
Authors: Zhang Honghu , Wang Wenjie , Hagen Noah , Kuzmenko Ivan , Akinc Mufit , Travesset Alex , Mallapragada Surya , Vaknin David
Published: May 2016

Surface sensitive synchrotron X‐ray scattering and spectroscopy are used to monitor and characterize the spontaneous formation of 2D Gibbs monolayers of thiolated single‐stranded DNA‐functionalized gold nanoparticles (ssDNA‐AuNPs) at the vapor–solution interface by manipulating salt concentrations. Grazing incidence small‐angle X‐ray scattering and X‐ray reflectivity show that the noncomplementary ssDNA‐AuNPs dispersed in aqueous solution spontaneously accumulate at the vapor–liquid interface in the form of a single layer by increasing MgCl2 or CaCl2 concentrations. Furthermore, the monoparticle layer undergoes a transformation from short‐ to long‐range (hexagonal) order above a threshold salt‐concentration. Using various salts at similar ionic strength to those of MgCl2 or CaCl2 such as, NaCl or LaCl3, it is found that surface adsorbed NPs lack any order. X‐ray fluorescence near total reflection of the same samples provides direct evidence of interfacial gold and more importantly a significant surface enrichment of the cations. Quantitative analysis reveals that divalent cations screen the charge of ssDNA, and that the hydrophobic hexyl‐thiol group, commonly used to functionalize the ssDNA (for capping the AuNPs), is likely the driving force for the accumulation of the NPs at the interface.
Logic Control of Interface‐Induced Charge‐Trapping Effect for Ultrasensitive Gas Detection with All‐Mirror‐Image Symmetry
Authors: Jia Chuancheng , Wang Qing , Xin Na , Zhou Jian , Gong Yao , Li Lidong , Sun Qiang , Guo Xuefeng
Published: May 2016

Controlling the type and concentration of charge carriers is at the heart of modern electronics because of its importance to realize functional devices for potential applications in broad areas ranging from integrated circuits and energy conversion to catalysis and chemical/biological detection. Toward this objective, here a straightforward design of a high‐performance stimuli‐responsive hybrid optoelectronic device with high‐level mirror‐image symmetry is presented. The device consists of suspended pristine graphene that is in direct contact with photoactive TiO2 quantum dots. Through a combination of photoexcitation and gate regulation, two types of photoinduced free electrons trapped at the TiO2/graphene interface with different behaviors are identified, allowing logical control of both the carrier type and charge trapping/detrapping process. Such control leads to the TiO2‐decorated graphene displaying high chemical environment sensitivity. Upon exposure of the photoexcited hybrid device to different gases, such as O2 as an electron acceptor and NH3 or H2 as an electron donor, all‐mirror‐image sensing with controllable fast response rate and ultralow detection limit in a single optoelectronic device is established. This approach offers novel interface engineering insights to develop high‐performance multifunctional environmental/chemical sensors and other optoelectronic devices.
Upconversion Nanocrystal‐Doped Glass: A New Paradigm for Photonic Materials
Authors: Zhao Jiangbo , Zheng Xianlin , Schartner Erik P. , Ionescu Paul , Zhang Run , Nguyen Tich‐Lam , Jin Dayong , Ebendorff‐Heidepriem Heike
Published: May 2016

The integration of novel luminescent nanomaterials into glassy matrix can lead to new hybrid materials and photonic devices with promising material performance and device functions. Lanthanide‐containing upconversion nanocrystals have become unique candidates for sensing, bioimaging, photon energy management, volumetric displays, and other photonic applications. Here, a versatile direct‐doping approach is developed to integrate bright upconversion nanocrystals in tellurite glass with tailored nanoscale properties. Following our two‐temperature glass‐melting technique, the doping temperature window of 550–625 °C and a 5 min dwell time at 577 °C are determined as the key to success, which balances the survival and dispersion of upconversion nanocrystals in glass. It is identified that the fine spectra of upconversion emissions can be used to diagnose the survival and dissolution fraction of doped nanocrystals in the glass. Moreover, 3D dispersion of nanocrystals in the glass is visualized by upconversion scanning confocal microscopy. It is further demonstrated that a low‐loss fiber, drawn from the highly transparent nanocrystals‐doped glass retains the distinct optical properties of upconversion nanocrystals. These results suggest a robust strategy for fabrication of high‐quality upconversion nanocrystal‐doped glasses. The new class of hybrid glasses allows for fiber‐based devices to be developed for photonic applications or as a useful tool for tailoring light–nanoparticles interactions study.
Quantification of Multiple Molecular Fingerprints by Dual‐Resonant Perfect Absorber
Authors: Cetin Arif E. , Korkmaz Semih , Durmaz Habibe , Aslan Ekin , Kaya Sabri , Paiella Roberto , Turkmen Mustafa
Published: May 2016

A dual‐resonant perfect absorber (PA) based on multiple dipolar nanoantenna configuration is introduced. The PA platform exhibits near‐unity (95%–98%) absorbance in dual‐resonances. A fine‐tuning mechanism of dual‐resonances is determined via geometrical device parameters of the constituting dipolar elements of the compact PA system. It is also shown that the dual plasmonic resonances are associated with easily accessible and large local electromagnetic fields. Possessing large absorbance with strong nearfields, the PA system is highly advantageous for surface enhanced infrared absorption (SEIRA) spectroscopy applications. The simultaneous detection of absorption signals corresponding to C=O and C–H bands of a polymethyl methacrylate (PMMA) film, which are separated by as large as ≈1255 cm−1, is experimentally shown. Furthermore, the interaction between plasmonic modes of the PA platform and the molecular vibrational modes of the PMMA film is investigated by tuning the optical resonances within the C=O spectral window. The coupling strength between plasmonic and vibrational modes is determined by Hamilton analysis, which leads to mode splitting and anticrossing behavior within the PA absorption spectra. The PA platform, by enabling simultaneous identification of different molecular fingerprints, can provide more reliable sensing information compared to classical SEIRA systems based only on a single vibrational mode.
Cobalt molybdenum oxide catalysts for selective oxidation of cyclohexane
Authors: Unnarkat Ashish P. , Sridhar Tam , Wang Huanting , Mahajani Sanjay , Suresh Akkihebbal K.
Published: May 2016

Oxidation of cyclohexane has been carried out using molecular oxygen over cobalt molybdenum oxide (CoMoO4) catalysts in solvent free conditions. The catalysts were prepared using citrate method with three different molar ratios of Co:Mo, 1:1, 1:2, and 2:1 along with individual oxides for comparative studies. While all the catalysts showed significant activity and selectivity, CoMoO4 with 1:1 ratio showed the best performance compared to the others with a conversion of 7.38%, with selectivity to cyclohexanol and cyclohexanone (KA oil) of 94.3%, in 1 h. The performance of the catalyst, has been studied as a function of oxygen pressure, reaction temperature, and catalyst loading. It was observed that the catalyst deactivates during the course of the reaction. The reasons for deactivation and methods for restoring the activity have been studied. A kinetic model is presented that captures the complex kinetics and matches well with the experimental data. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4384–4402, 2016
Alteration of lymphocyte phenotype and function in sickle cell anemia: Implications for vaccine responses
Authors: Balandya Emmanuel , Reynolds Teri , Obaro Stephen , Makani Julie
Published: May 2016

Individuals with sickle cell anemia (SCA) have increased susceptibility to infections, secondary to impairment of immune function. Besides the described dysfunction in innate immunity, including impaired opsonization and phagocytosis of bacteria, evidence of dysfunction of T and B lymphocytes in SCA has also been reported. This includes reduction in the proportion of circulating CD4+ and CD8+ T cells, reduction of CD4+ helper: CD8+ suppressor T cell ratio, aberrant activation and dysfunction of regulatory T cells (Treg), skewing of CD4+ T cells towards Th2 response and loss of IgM‐secreting CD27 + IgMhighIgDlow memory B cells. These changes occur on the background of immune activation characterized by predominance of memory CD4+ T cell phenotypes, increased Th17 signaling and elevated levels of C‐reactive protein and pro‐inflammatory cytokines IL‐6 and TNF‐α, which may affect the immunogenicity and protective efficacy of vaccines available to prevent infections in SCA. Thus, in order to optimize the use of vaccines in SCA, a thorough understanding of T and B lymphocyte functions and vaccine reactivity among individuals with SCA is needed. Studies should be encouraged of different SCA populations, including sub‐Saharan Africa where the burden of SCA is highest. This article summarizes our current understanding of lymphocyte biology in SCA, and highlights areas that warrant future research. Am. J. Hematol. 91:938–946, 2016. © 2016 Wiley Periodicals, Inc.
Spatial variation of dental caries in late holocene samples of Southern South America: A geostatistical study
Authors: Menéndez Lumila Paula
Published: May 2016

Objective

The spatial variation of dental caries in late Holocene southern South American populations will be analyzed using geostatistical methods. The existence of a continuous geographical pattern of dental caries variation will be tested.

Methods

The author recorded dental caries in 400 individuals, collated this information with published caries data from 666 additional individuals, and calculated a Caries Index. The caries spatial distribution was evaluated by means of 2D maps and scatterplots. Geostatistical analyses were performed by calculating Moran's I, correlograms and a Procrustes analysis.

Results

There is a relatively strong latitudinal continuous gradient of dental caries variation, especially in the extremes of the distribution. Moreover, the association between dental caries and geography was relatively high (m12 = 0.6). Although northern and southern samples had the highest and lowest frequencies of dental caries, respectively, the central ones had the largest variation and had lower rates of caries than expected.

Conclusion

The large variation in frequencies of dental caries in populations located in the center of the distribution could be explained by their subsistence strategies, characterized either by the consumption of wild cariogenic plants or cultigens (obtained locally or by exchange), a reliance on fishing, or the incorporation of plants rich in starch rather than carbohydrates. It is suggested that dental caries must be considered a multifactorial disease which results from the interaction of cultural practices and environmental factors. This can change how we understand subsistence strategies as well as how we interpret dental caries rates. Am. J. Hum. Biol., 2016. © 2016 Wiley Periodicals, Inc. Am. J. Hum. Biol. 28:825–836, 2016. © 2016Wiley Periodicals, Inc.
Divergent Synthesis of 3,3‐Disubstituted Oxindoles Initiated by Palladium‐Catalyzed Intramolecular Arylation of Unsaturated Amides
Authors: Wei Fang , Wei Lei , Zhou Ling , Tung Chen‐Ho , Ma Yudao , Xu Zhenghu
Published: May 2016

3,3‐Disubstituted oxindole derivatives are privileged five‐membered heterocycles widely presented in a variety of natural products and pharmaceuticals with significant biological activities. In this paper, diverse boron‐substituted oxindoles have been successfully synthesized by Pd‐catalyzed intramolecular arylation and borylation cascade of unsaturated amides. More importantly, simply switching the reaction solvents led to other reductive Heck products with the same catalyst and reactants. Control experiments showed that the reductive Heck products were transformed from 3,3‐disubstituted oxindole boronic esters in the presence of base.
Solvent‐Mediated Control of the Electrochemical Discharge Products of Non‐Aqueous Sodium–Oxygen Electrochemistry
Authors: Aldous Iain M. , Hardwick Laurence J.
Published: May 2016

The reduction of dioxygen in the presence of sodium cations can be tuned to give either sodium superoxide or sodium peroxide discharge products at the electrode surface. Control of the mechanistic direction of these processes may enhance the ability to tailor the energy density of sodium–oxygen batteries (NaO2: 1071 Wh kg−1 and Na2O2: 1505 Wh kg−1). Through spectroelectrochemical analysis of a range of non‐aqueous solvents, we describe the dependence of these processes on the electrolyte solvent and subsequent interactions formed between Na+ and O2−. The solvents ability to form and remove [Na+‐O2−]ads based on Gutmann donor number influences the final discharge product and mechanism of the cell. Utilizing surface‐enhanced Raman spectroscopy and electrochemical techniques, we demonstrate an analysis of the response of Na‐O2 cell chemistry with sulfoxide, amide, ether, and nitrile electrolyte solvents.
Hofmeister‐Effekte unter der Lupe: Die direkte Anion‐Amid‐Bindung ist schwächer als die Kation‐Amid‐Bindung
Authors: Balos Vasileios , Kim Heejae , Bonn Mischa , Hunger Johannes
Published: May 2016

Trotz vermehrter Hinweise auf direkte Wechselwirkungen als Ursache für die Destabilisierung von Proteinen durch Ionen blieb die Frage nach der Stärke der Bindung von Anionen zu Proteinen im Vergleich zu jener von Kationen offen. Die Rotation eines Modellamids wurde nun als Maß für die Wechselwirkung verschiedener Anionen mit der Amidgruppe verwendet. Die Untersuchungen zeigen, dass Protein‐stabilisierende Salze wie KCl und KNO3 die Rotationsmobilität des Amids nicht beeinflussen. Umgekehrt reduzieren denaturierende Salze wie KSCN und KI die Rotationsfreiheitsgrade der Amidgruppe merklich. Diese Beobachtungen liefern den Nachweis für eine Proteindenaturierung durch direkte Ion‐Protein‐Kontakte. Der Vergleich dieser Daten mit denjenigen für die entsprechenden Kation‐Amid‐Wechselwirkungen zeigt, dass – entgegen der weit verbreiteten Meinung – die Anion‐Amid‐ schwächer als die Kation‐Amid‐Bindung ist.
Organokatalytische Synthese von enantiomerenreinen 2H‐ und 3H‐Pyrrolen: Inhibitoren des Hedgehog‐Signalwegs
Authors: Kötzner Lisa , Leutzsch Markus , Sievers Sonja , Patil Sumersing , Waldmann Herbert , Zheng Yiying , Thiel Walter , List Benjamin
Published: May 2016

Es wird über die organokatalytische divergente Synthese von enantiomerenreinen 2H‐ und 3H‐Pyrrolen, unter Verwendung einer Fischer‐Indolisierung und einer [1,5]‐Alkyl‐Verschiebung, berichtet. Katalysiert durch die chirale Phosphorsäure STRIP konnten die entsprechenden Produkte in guten bis exzellenten Ausbeuten sowie Enantioselektivitäten erhalten werden. Bemerkenswerterweise zeigten biologische Untersuchungen, dass eines der neuartigen 2H‐Pyrrole ein potenter aber nicht toxischer Inhibitor des Hedgehog‐Signalwegs ist und an das Smoothened‐Protein bindet.
Observation of Spontaneous C=C Bond Breaking in the Reaction between Atomic Boron and Ethylene in Solid Neon
Authors: Jian Jiwen , Lin Hailu , Luo Mingbiao , Chen Mohua , Zhou Mingfei
Published: May 2016

A ground‐state boron atom inserts into the C=C bond of ethylene to spontaneously form the allene‐like compound H2CBCH2 on annealing in solid neon. This compound can further isomerize to the propyne‐like HCBCH3 isomer under UV light excitation. The observation of this unique spontaneous C=C bond insertion reaction is consistent with theoretical predictions that the reaction is thermodynamically exothermic and kinetically facile. This work demonstrates that the stronger C=C bond, rather than the less inert C−H bond, can be broken to form organoboron species from the reaction of a boron atom with ethylene even at cryogenic temperatures.
Selective Catalytic Synthesis Using the Combination of Carbon Dioxide and Hydrogen: Catalytic Chess at the Interface of Energy and Chemistry
Authors: Klankermayer Jürgen , Wesselbaum Sebastian , Beydoun Kassem , Leitner Walter
Published: May 2016

The present Review highlights the challenges and opportunities when using the combination CO2/H2 as a C1 synthon in catalytic reactions and processes. The transformations are classified according to the reduction level and the bond‐forming processes, covering the value chain from high volume basic chemicals to complex molecules, including biologically active substances. Whereas some of these concepts can facilitate the transition of the energy system by harvesting renewable energy into chemical products, others provide options to reduce the environmental impact of chemical production already in today's petrochemical‐based industry. Interdisciplinary fundamental research from chemists and chemical engineers can make important contributions to sustainable development at the interface of the energetic and chemical value chain. The present Review invites the reader to enjoy this exciting area of “catalytic chess” and maybe even to start playing some games in her or his laboratory.
The Organocatalytic Approach to Enantiopure 2H‐ and 3H‐Pyrroles: Inhibitors of the Hedgehog Signaling Pathway
Authors: Kötzner Lisa , Leutzsch Markus , Sievers Sonja , Patil Sumersing , Waldmann Herbert , Zheng Yiying , Thiel Walter , List Benjamin
Published: May 2016

A divergent approach to enantioenriched 2H‐ and 3H‐pyrroles catalyzed by a spirocyclic phosphoric acid is reported that makes use of a Fischer‐type indolization and a [1,5]‐alkyl shift. Catalyzed by the chiral phosphoric acid STRIP, good to excellent yields and enantioselectivities could be obtained. Remarkably, biological evaluation reveals one of these novel 2H‐pyrroles to be a potent but nontoxic inhibitor of the Hedgehog signaling pathway by binding to the Smoothened protein.
Study on the preparation, characterization, and release behavior of carbosulfan/polyurethane microcapsules
Authors: Xu Yong , Wang Liying , Tong Yujia , Xiang Sheng , Guo Xinyu , Li Jing , Gao Haixiang , Wu Xuemin
Published: May 2016

Polyurethane, a controlled release material, has been widely applied in many fields due to its high thermal and mechanical stability, corrosion resistance, and low cost. In this article, we prepared carbosulfan/polyurethane microcapsules by an interfacial polymerization method using modified isocyanate as the precursor and triethanolamine as a curing agent. The microcapsules were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis, and their release kinetics, chemical stability, and the safety of wheat seeds coating were also detected. The microcapsules had an excellent encapsulation efficiency and loading ability for carbosulfan ∼96.23% and 50%, respectively. Furthermore, the microcapsules improved the chemical stability of the carbosulfan and exhibited an excellent sustained release property (above 30 days), which controlled the carbosulfan and carbofuran at an appropriate level for reducing the adverse effects on the environment and agricultural products. The coated wheat seeds germination rate test showed that compared with the emulsifiable concentrate, the microcapsules almost had no effect on the germination rate, plant height, and root length. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43844.
Development of an encapsulated phase change material via emulsion and coaxial electrospinning
Authors: Chalco‐Sandoval Wilson , Fabra María José , López‐Rubio Amparo , Lagaron Jose M.
Published: May 2016

This article reports on the encapsulation of a phase change material (PCM) into a hydrophilic polymer, poly(vinyl alcohol) (PVOH), by means of electrospinning. Different strategies were carried out to improve the thermal buffering capacity and the stability of the developed structures when they were exposed to different relative humidity (RH) conditions. On the one hand, the thermal energy storage capacity of PVOH/PCM structures obtained through emulsion electrospinning was optimized by using different amounts of polyoxyethylene sorbitan monolaureate (Tween 20). Surfactant addition successfully increased the heat storage capacity of the developed structures, reaching an optimum performance at a concentration of 0.32% in weight with respect to the total emulsion weight. However, the hydrophilic nature of the developed structures made them extremely difficult to handle due to swelling with increasing RH. To avoid this issue an additional shell layer of poly(caprolactone) (PCL), was applied by coaxial electrospinning. In this case, the PVOH/PCM ratio (core) was optimized to reach the highest heat storage capacity per gram of sample and, then, a PCL solution was used as a shell material to hydrophobize the structures. The optimized coaxial electrospun structures were able to encapsulate about 82% of PCM. The use of both emulsion and coaxial electrospinning strategies are introduced here for the first time as advanced strategies to overcome application issues such as unintended migration and performance drop in the previously developed monophase materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43903.
Enhanced Thermoelectric Properties of Polyaniline Nanofilms Induced by Self‐Assembled Supramolecules
Authors: Wang Liming , Yao Qin , Xiao Juanxiu , Zeng Kaiyang , Shi Wei , Qu Sanyin , Chen Lidong
Published: May 2016

Polyaniline (PANI) is one of the most promising candidates for flexible organic thermoelectric (TE) applications owing to its relatively low cost and high stability. Herein, the self‐assembled supramolecule (SAS) (3,6‐dioctyldecyloxy‐1,4‐benzenedicarboxylic acid) was used as an additive and was introduced into PANI films as a template. Raman spectroscopy, X‐ray diffraction, and conductive atomic force microscopy analyses demonstrated that the highly ordered chain structure of PANI was achieved by chemical interactions between PANI and the SAS. Moreover, the ordered regions in the PANI‐SAS film increased with a decrease in the film thickness. Consequently, the TE properties of PANI‐SAS films were not only much higher than those of PANI films, but they also increased with a decrease in film thickness. The maximum TE power factor of the PANI‐SAS film reached 31 μW m−1 K−2, which is approximately six times higher than the power factor of a PANI film with a similar thickness. This work offers a promising way to prepare PANI thin films with enhanced TE properties.
Silver(I)‐Catalyzed Three‐Component Reaction of Propargylic Alcohols, Carbon Dioxide and Monohydric Alcohols: Thermodynamically Feasible Access to β‐Oxopropyl Carbonates
Authors: Zhou Zhi‐Hua , Song Qing‐Wen , Xie Jia‐Ning , Ma Ran , He Liang‐Nian
Published: May 2016

A silver(I)‐catalyzed three‐component reaction of propargylic alcohols, CO2, and monohydric alcohols was successfully developed for the synthesis of β‐oxopropyl carbonates. As such, a series of β‐oxopropyl carbonates were exclusively produced in excellent yields (up to 98 %), even under atmospheric pressure of CO2. The silver catalyst works efficiently for both the carboxylative cyclization of propargylic alcohols with CO2 and subsequent transesterification of α‐alkylidene cyclic carbonates with monohydric alcohols; thus this tandem process performs smoothly under mild conditions. This work provides a versatile and thermodynamically favorable approach to dissymmetric dialkyl carbonates.
Frequency Interval Cross Gramians for Linear and Bilinear Systems
Authors: Jazlan Ahmad , Sreeram Victor , Shaker Hamid Reza , Togneri Roberto , Minh Ha Binh
Published: May 2016

In many control engineering problems, it is desired to analyze the systems at particular frequency intervals of interest. This paper focuses on the development of frequency interval cross gramians for both linear and bilinear systems. New generalized Sylvester equations for calculating the frequency interval cross gramians are derived in order to be used to obtain information regarding controllability and observability within a single matrix. The advantage of the proposed method is that it is computationally more efficient compared to existing gramian‐based techniques since only half of the number of equations need to be solved in order to obtain information regarding the controllability and observability of a system compared to existing techniques. Numerical examples are provided to demonstrate the computational efficiency of the proposed method which uses frequency interval cross gramians relative to existing methods.
Redundant Input Safety Tracking for Omnidirectional Rehabilitative Training Walker with Control Constraints
Authors: Sun Ping , Wang Shuoyu
Published: May 2016

This study proposes a nonlinear safety tracking method based on redundant degrees of freedom with control constraints to protect against actuator faults that may occur in robotic rehabilitative walkers. A redundant input model with uniform actuator faults is constructed by separating the corresponding columns of the control matrix, and an adaptive robust control method is presented to deal with the separated term that is considered in relation to the extrinsic bounded interference that occurs on robotic walker systems. Based on the backstepping technique, an adjustable control law can be designed to maintain stability in terms of solving linear matrix inequality. The trajectory tracking error performance and the velocity tracking error performance are derived simultaneously. As an application, simulation results confirm the effectiveness of the proposed method and verify that the walker can provide safe sequential motions even when one wheel actuator fails.
The side‐chain hydroxy groups of a cyclic α,α‐disubstituted α‐amino acid promote oligopeptide 310‐helix packing in the crystalline state
Authors: Demizu Yosuke , Doi Mitsunobu , Yamashita Hiroko , Misawa Takashi , Oba Makoto , Kurihara Masaaki , Suemune Hiroshi , Tanaka Masakazu
Published: May 2016

A single chiral cyclic α,α‐disubstituted amino acid with side‐chain methoxymethyl (MOM) protecting groups, (3S,4S)−1‐amino‐(3,4‐dimethoxymethoxy)cyclopentanecarboxylic acid [(S, S)‐Ac5cdOMOM], or side‐chain hydroxy groups, (3S,4S)−1‐amino‐(3,4‐dihydroxy)cyclopentanecarboxylic acid [(S, S)‐Ac5cdOH], was attached to the N‐terminal or C‐terminal position of α‐aminoisobutyric acid (Aib) tetrapeptide segments; i.e., we designed and synthesized four pentapeptides, Cbz‐[(S, S)‐Ac5cdOMOM]‐(Aib)4‐OEt (1), Cbz‐[(S, S)‐Ac5cdOH]‐(Aib)4‐OEt (2), Cbz‐(Aib)4‐[(S, S)‐Ac5cdOMOM]‐OMe (3), and Cbz‐(Aib)4‐[(S, S)‐Ac5cdOH]‐OMe (4). We then analyzed the peptides’ structures in the crystalline state. The four peptides all folded into 310‐helical structures; 1 formed a left‐handed (M) 310‐helix, 2 formed a mixture of right‐handed (P) and (M) 310‐helices, 3 formed a mixture of (P) and (M) 310‐helices, and 4 formed a (P) 310‐helix, respectively. In packing mode, the molecules of peptides 1 and 3, which both possessed an Ac5cdOMOM residue, were connected by intermolecular hydrogen bonds along the peptide backbone (NH···O type). On the other hand, the packing of peptides 2 and 4, which both contained an Ac5cdOH residue, was based on intermolecular hydrogen bonds derived from both the peptide backbone and the side‐chain hydroxy groups of the amino acid Ac5cdOH (OH···O type). © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 757–768, 2016.
A Selective Na+ Aptamer Dissected by Sensitized Tb3+ Luminescence
Authors: Zhou Wenhu , Ding Jinsong , Liu Juewen
Published: May 2016

A previous study of two RNA‐cleaving DNAzymes, NaA43 and Ce13d, revealed the possibility of a common Na+ aptamer motif. Because Na+ binding to DNA is a fundamental biochemical problem, the interaction between Ce13d and Na+ was studied in detail by using sensitized Tb3+ luminescence spectroscopy. Na+ displaces Tb3+ from the DNAzyme, and thus quenches the emission from Tb3+. The overall requirement for Na+ binding includes the hairpin and the highly conserved 16‐nucleotide loop in the enzyme strand, along with a few unpaired nucleotides in the substrate. Mutation studies indicate good correlation between Na+ binding and cleavage activity, thus suggesting a critical role of Na+ binding for the enzyme activity. Ce13d displayed a Kd of ∼20 mm with Na+ (other monovalent cations: 40–60 mm). The Kd values for other metal ions are mainly due to non‐specific competition. With a single nucleotide mutation, the specific Na+ binding was lost. Another mutant improved Kd to 8 mm with Na+. This study has demonstrated a Na+ aptamer with important biological implications and analytical applications. It has also defined the structural requirements for Na+ binding and produced an improved mutant.