bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of long‐term application of manure and nitrogen fertilizer on infiltration for a wheat–maize rotation system
Authors: Liu Shutang , Zhang Hanyu , Liu Qianjin , Zong Hui , Yu Xingxiu
Published: June 2018

Modelling soil infiltration capacity and identifying controlling factors under long‐term fertilizer application could help in developing better fertilization treatments to increase infiltration, thereby preventing land degradation. This study was performed at Laiyang long‐term fertilization experimental field in Shandong Province, China. Three application rates of manure (0, 30,000, and 60,000 kg ha−2) and nitrogen (0, 138, and 276 kg ha−2) were full designed in a nine‐treatment randomized block design with three replicates per treatment. The infiltration processes were detected using an automatic infiltration measurement system and represented by three indices, that is, initial infiltration rate for the first 3 min (Ii), the average infiltration rate for the whole 30‐min period (Ia), and the final infiltration rate for the last 3 min (If). Manure application could increaseIaandIfsignificantly (p < 0.01). Nitrogen application had no significant effect on infiltration. The linkage between potential influencing factors and infiltration capacity indices was analysed by partial least squares regression (PLSR), an efficient method that can deal with high colinear variables. The optimal PLSR model could explain 95% of the variability in potential influencing factors and 92% of the variability in soil infiltration capacity indices and could predict 82% of the variability in soil infiltration capacity. Three soil properties, that is, organic matter content, bulk density, and weight ratio of soil aggregate with diameter greater than 0.25 mm measured using wet sieving method, were identified as main influencing factors. The results would be informative to assess infiltration and then land degradation after a long‐term cultivation.
An assessment of the variation of soil properties with landscape attributes in the highlands of Cameroon
Authors: Takoutsing Bertin , Weber John C. , Rodríguez Martín Jose Antonio , Shepherd Keith , Aynekulu Ermias , Sila Andrew
Published: June 2018

Soil properties are useful for assessing the potential of landscapes to provide terrestrial ecosystem services, but they are affected by anthropogenic activities and environmental factors including landscape attributes. This study assessed how soil properties are influenced by landscape attributes and their interactions in the highlands of Cameroon using the Land Degradation Surveillance Framework as a data collection tool. Soil properties (soil organic carbon [SOC], clay content, exchangeable bases [ExBas], electric conductivity [EC], boron [B], manganese [Mn], phosphorus [P], pH) were quantified within classes of landscape attributes. Soil samples were collected on 160 (1,000 m2) plots randomly located in a sentinel site of 100 km2 and were analyzed using a combination of conventional laboratory methods and mid‐infrared spectroscopy. Soil properties were highly affected by soil depths, land use types, slope gradients, and topographic positions, but less by their interactions. Significant interactions existed between land use types and topographic positions for SOC, EC, ExBas, and pH, and between slope gradients and topographic positions for pH, whereas Mn was influenced by the interaction between land use types and slope gradients. Most soil properties were higher in low altitude plots and those with higher vegetation cover but decreased in the upslope direction. The pH and clay contents were less affected by slope gradient confirming the inherent nature of the properties. These results are useful for site‐specific implementation of ecological intensification in areas with complex topography such as the highlands of Cameroon, offering a reference for future ecological policies and landscape restoration.
Three‐dimensional mapping of soil salinity in the southern coastal area of Laizhou Bay, China
Authors: Liu Wenquan , Xu Xingyong , Lu Fang , Cao Jianrong , Li Ping , Fu Tengfei , Chen Guangquan , Su Qiao
Published: June 2018

Soil salinization is an important driver of land degradation and has been a major factor inhibiting agricultural production and development in the southern coastal area of Laizhou Bay. In this study, 3‐D and 2‐D geostatistics were respectively used to evaluate the spatial distribution of soil salinity and groundwater total dissolved solids (TDS) and depth. Results showed that soil electrical conductivity differed greatly within the same soil layer, and the difference in average electrical conductivity of different soil layers was relatively small. The mean value of TDS exceeded 3.0 g L−1 and the mean value of groundwater depth was 13.359 m. The geographic distribution showed that the soil salinity gradually decreased from the north to the south horizontally, and the soil salinity showed a bottom accumulation tendency vertically. Over 90% of the study area has TDS values exceeding 1.0 g L−1, and approximately one‐third of the area had a groundwater depth less than 3.0 m. TDS and groundwater depth had good correlations with soil salinity, with coefficients of determination of 0.544 and 0.572, respectively. Changes in vegetation corresponded to changes in soil salinity. Soil salinity gradually decreased perpendicular to coastal lines in tidal flats without vegetative coverage to inland agricultural areas of wheat and vegetables. Soil salinization in the study area is mainly slight and moderate. Reasonable regional management measures are conducive to improving land economic benefits. The results provide a theoretical basis and reference for the partition, improvement, management of saline soil, and support for land degradation control.
Frataxin‐Mediated PINK1–Parkin‐Dependent Mitophagy in Hepatic Steatosis: The Protective Effects of Quercetin
Authors: Liu Peiyi , Lin Hongkun , Xu Yanyan , Zhou Feng , Wang Jing , Liu Jingjing , Zhu Xinhong , Guo Xiaoping , Tang Yuhan , Yao Ping
Published: June 2018

Scope

Naturally occurring quercetin has been found to induce mitophagy and prevent nonalcoholic fatty liver disease (NAFLD). However, it still remains elusive whether frataxin upregulation by quercetin contributes to the beneficial effect through mitophagy or not.

Methods and results

Adult male C57BL/J mice were fed a high‐fat diet (HFD, 60% of energy from fat) with quercetin (100 mg kg−1 body weight) or not for 10 weeks. Quercetin alleviated HFD‐induced histopathological changes, disorders of lipid metabolism, and mitochondrial damage. Moreover, quercetin blocked mitophagy suppression by HFD based on the increased LC3II, PTEN‐induced putative kinase 1 (PINK1) and Beclin1 expressions, as well as decreased p62 levels. Quercetin also improved the Parkin translocation to mitochondria confirmed by immunofluorescence. Specifically, frataxin was lowered in the liver of HFD‐fed mice or HepG2 cell incubated with oleate/palmitate but restored by quercetin, and quercetin's regulation of frataxin may depend on p53. Furthermore, lentivirus‐mediated stable knockdown of frataxin in HepG2 inhibited PINK1–Parkin‐associated mitophagy and resulted in lipid accumulation. Frataxin was further decreased by free fatty acids in knockdown cells concomitantly with depressed PINK1–Parkin‐associated mitophagy, which was partially normalized by quercetin.

Conclusion

Quercetin alleviated hepatic steatosis by enhancing frataxin‐mediated PINK1/Parkin‐dependent mitophagy, highlighting a promising preventive strategy and mechanism for NAFLD by quercetin.
Essential Fatty Acids Linoleic Acid and α‐Linolenic Acid Sex‐Dependently Regulate Glucose Homeostasis in Obesity
Authors: Zhuang Pan , Shou Qiyang , Wang Wenqiao , He Lilin , Wang Jun , Chen Jingnan , Zhang Yu , Jiao Jingjing
Published: June 2018

Scope

To assess the associations of dietary linoleic acid (LA) and α‐linolenic acid (ALA) with type 2 diabetes (T2D) risk in a population‐based cohort and further explore the mechanism of action in a high‐fat‐diet (HFD) induced obese (DIO) mouse model.

Methods and results

The occurrence of T2D among 15 100 Chinese adults from China Health and Nutrition Survey (CHNS, 1997–2011) were followed up for a median of 14 years. The relations of ALA and LA intakes with T2D risk were modified by BMI, with significant associations restricted to obese/overweight subjects. Among them, relative risks (95% confidence intervals) comparing extreme quartiles of intakes were 0.55 (0.32–0.93) in men and 0.53 (0.34–0.85) in women for ALA, while 0.71 (0.41–1.16) in men and 0.56 (0.36–0.89) in women for LA. DIO mice were fed with LA‐ or ALA‐enriched HFD (0.2% wt wt−1) for 15 weeks and then significant sex‐dependent changes of gut microbiota were detected. Endotoxemia, systematic and adipose inflammation were relieved in ALA‐fed male and LA‐fed female mice.

Conclusions

Long‐term intake of LA (for women) and ALA may have a protective effect on T2D development for obese/overweight subjects through sex‐specific gut microbiota modulation and gut‐adipose axis.
An investigation into the INTRABEAM miniature x‐ray source dosimetry using ionization chamber and radiochromic film measurements
Authors: Watson Peter G. F. , Bekerat Hamed , Papaconstadopoulos Pavlos , Davis Stephen , Seuntjens Jan
Published: June 2018

Purpose

Intraoperative radiotherapy using The INTRABEAM System (Carl Zeiss Meditec AG, Jena, Germany), a miniature low‐energy x‐ray source, has proven to be an effective modality in the treatment of breast cancer. However, some uncertainties remain in its dosimetry. In this work, we investigated the INTRABEAM system dosimetry by performing ionization chamber and radiochromic film measurements of absorbed dose in a water phantom.

Methods

Ionization chamber measurements were performed with a PTW 34013 parallel‐plate soft x‐ray chamber at source to detector distances of 5 to 30 mm calculated using (a) the dose formula consistent with the TARGIT breast protocol (TARGIT), (b) the formula recommended by the manufacturer (Zeiss), and (c) the recently proposed formalism of Watson et al. (Physics in Medicine & Biology, 2018;63:015016) EBT3 Gafchromic film measurements were made at the same depths in water. To account for the energy dependence of EBT3 film, multiple dose response calibration curves were employed across a range of photon beam qualities relevant to the INTRABEAM spectrum in water.

Results

At all depths investigated, the TARGIT dose was significantly lower than that measured by the Zeiss and methods, as well as film. These dose differences ranged from 14% to as large as 80%. In general, the doses measured by film, and the Zeiss and methods were in good agreement to within measurement uncertainties (5–6%).

Conclusions

These results suggest that the TARGIT dose underestimates the physical dose to water from the INTRABEAM source. Understanding the correlation between the TARGIT and physical dose is important for any studies wishing to make dosimetric comparisons between the INTRABEAM and other radiation emitting devices.
Interstitial assessment of aggressive prostate cancer by physio‐chemical photoacoustics: An ex vivo study with intact human prostates
Authors: Huang Shengsong , Qin Yu , Chen Yingna , Pan Jing , Xu Chengdang , Wu Denglong , Chao Wan‐Yu , Wei John T. , Tomlins Scott A. , Wang Xueding , Fowlkes J. Brian , Carson Paul L. , Cheng Qian , Xu Guan
Published: June 2018

Purpose

Transrectal ultrasound (TRUS)‐guided biopsy is the standard procedure for evaluating the presence and aggressiveness of prostate cancer. TRUS biopsy involves tissue removal, and suffers from low core yield as well as high false negative rate. A less invasive and more accurate diagnostic procedure for prostate cancer is therefore highly desired. Combining the optical sensitivity and ultrasonic resolution to resolve the spatial distribution of the major molecular components in tissue, photoacoustic (PA) technology could be an alternative approach for the diagnosis of prostate cancer. The purpose of this study was to examine the feasibility of identifying aggressive prostate cancer using interstitial PA measurements.

Methods

Seventeen patients with prebiopsy magnetic resonance imaging (MRI), TRUS biopsies, and planned prostatectomies were enrolled in this study. The interstitial PA measurements were achieved using our recently developed needle PA probe, which was inserted into the ex vivo prostates in the fashion of a biopsy needle. A total of 70 interstitial PA measurements were acquired. The PA measurements were quantified by a previously established PA physio‐chemical analysis (PAPCA) method. The histology has confirmed the nonaggressive and aggressive cancerous conditions at the insertion locations. The diagnostic accuracy was also compared to that provided by the prebiopsy MRI.

Results

The quantitative study shows significant differences between the individual parameters of the nonaggressive and the aggressive cancerous regions (P < 0.005). Multivariate analysis of the quantitative features achieved a diagnostic accuracy of 78.6% for differentiating nonaggressive and aggressive prostate cancer tissues.

Conclusions

The proposed procedure has shown promises in the diagnosis of aggressive prostate cancer.
A phase field model for stress‐based evolution of load‐bearing structures
Authors: Muench I. , Gierden C. , Wagner W.
Published: June 2018

We present a continuum‐type optimality algorithm for the evolution of load‐bearing solid structures with linear elastic material. The objective of our model is to generate structures with help of a sensitivity function accounting for equivalent stress. Similar to Evolutionary Structural Optimization, a threshold of equivalent stress is evaluated. However, we do not consider a material rejection ratio. The evolution process is governed by an Allen‐Cahn equation in the context of phase field modeling. The steady state of phase transition is the final geometry of the structure. The model accounts for the desired filling level, geometry of the design space, static loadings, and boundary conditions. Our variational approach drops conservation of mass and couples density as well as stiffness of the continuum by a sophisticated function to the phase field variable. Continuous regions of voids and material evolve from the initial state of homogeneously distributed material. The complexity of evolving structures depends on two numerical parameters, which we discuss in several examples.
An optimization‐based phase‐field method for continuous‐discontinuous crack propagation
Authors: Geelen Rudy J. M. , Liu Yingjie , Dolbow John E. , Rodríguez-Ferran Antonio
Published: June 2018

A new continuous‐discontinuous strategy for the computational modeling of crack propagation within the context of phase‐field models of fracture is presented. The method is designed to introduce and update a sharp crack surface within an evolving damage band and to enhance the kinematics of the finite element approximation accordingly. The proposed approach relies on three key elements. First, we propose the use of a crack length functional to provide a trigger for initiating a continuous to discontinuous transition. Next, the crack path identification is addressed by introducing the concept of an auxiliary damage field that varies with an extension of the sharp crack surface. The sharp crack surface is extended through an optimization algorithm, in which the difference between the auxiliary field and the actual damage field stemming from the phase‐field framework is minimized. Finally, a strong discontinuity is inserted in the wake of the diffuse crack tip with the extended finite element method, completing the continuous to discontinuous transition. Several benchmark problems in two‐dimensional quasi‐static fracture mechanics are presented to demonstrate the accuracy and robustness of the method.
Interfering effect of maternal cell contamination on invasive prenatal molecular genetic testing
Authors: Koczok Katalin , Gombos Éva , Madar László , Török Olga , Balogh István
Published: June 2018

What is already known about this topic?

Analytical sensitivity of the studied molecular genetic methods such as Sanger DNA sequencing, multiplex ligation‐dependent probe amplification, and next‐generation sequencing has been studied previously in relation to somatic mosaicism testing.

What does this study add?

We determine significant maternal cell contamination levels for these molecular genetic techniques in a comprehensive way and also evaluate previously published data in the context of maternal cell contamination and prenatal molecular testing.
Coastally trapped disturbances caused by the tramontane wind on the northwestern Mediterranean: numerical study and sensitivity to short‐wave radiation
Authors: Gonzalez Sergi , Callado Alfons , Werner Ernest , Escribà Pau , Bech Joan
Published: June 2018

The Tramontane‐Cierzo wind system is a recurrent feature of the northwestern Mediterranean basin in front of the Catalan coast (northeast Spain). Associated with this feature, northeast wind surges occasionally affect the coast and become a weather hazard for low‐level aircraft operations, affecting for example the Barcelona international airport. This article first reports these surges characterizing them as Coastal‐Trapped Disturbances (CTDs). Climatological features are described, showing that CTDs occur frequently during the warm season and between the afternoon and the evening. We classified CTDs into two synoptic patterns related to the location of a mid‐level tropospheric geopotential trough and the Iberian Peninsula: pattern A, with the trough crossing eastwards along the north of Spain; and pattern B, with the trough over the Mediterranean, after crossing the Iberian Peninsula. To study the CTDs in detail, numerical simulations were conducted using the non‐hydrostatic and convection‐permitting numerical weather prediction model HARMONIE‐AROME. Two cases, one for each synoptic pattern, were studied showing that CTDs generate in the discontinuity between cool outflows and warmer air progressing southward as a density current, trapped by the mountain ranges parallel to the coastline. Cool outflows may have two different sources: in Pattern A the origin of the cold air is the tramontane itself, while in Pattern B convective outflows associated with storm downdraughts play this role. Both cases show similarities with CTDs studied on the California coast, showing an antitriptic and ageostrophic flow behind the CTD. An additional numerical sensitivity experiment was conducted by varying the short‐wave radiation to explore the effects of diabatic warming on CTDs. It is demonstrated that a large warming influences CTDs by enhancing the potential temperature gradient between the density current and the environment, modulating their intensity and speed.
Laboratory measurements of the sedimentation velocity of hexagonal planar ice crystals
Authors: Bürgesser Rodrigo E. , Castellano Nesvit E.
Published: June 2018

New experimental measurements of the falling velocity, size and orientation of individual hexagonal plate‐like ice crystals are reported. The measurements were conducted at three different temperatures: −13, −16 and −20 °C. The diameter of the ice crystals measured in the experiments were between 50 μm and 250 μm, a size range which is in agreement with the size found in natural clouds. In this range, ice crystals show a random orientation during free fall and a falling velocity which increases with size. Results show that the fall velocity is insensitive to the temperature at which the ice crystals grow for the temperatures used in this study. An empirical power‐law between the Best and Reynolds numbers is presented using the capacitance as characteristic length and an estimation of the ice crystal mass. Despite the dispersion of the experimental data, the Best–Reynolds relationship found seems to be similar to the relationship for falling spheres in Stokes flow using the capacitance as the hydrodynamic radius. The fall velocities of hexagonal and columnar ice crystals were compared. The columnar ice crystals show a velocity larger than that of hexagonal ice crystals with the same value of capacitance. However, both crystalline habits show a unique empirical Be–Re relationship.
Variability of urban surface temperatures and implications for aerodynamic energy exchange in unstable conditions
Authors: Crawford Ben , Grimmond Sue B. , Gabey Andrew , Marconcini Mattia , Ward Helen C. , Kent Christoph W.
Published: June 2018

Sensible heat flux (QH) is a critical driver of surface and boundary layer meteorological processes, especially in urban areas. Aerodynamic resistance methods (ARM) for modelling QH are promising because, in principle, all that is needed is surface temperature (T0), air temperature (TA) and an aerodynamic resistance term (rH). There are significant challenges in urban areas, however, due to uncertainties in satellite‐derived land surface temperatures (LST), logistical challenges in obtaining high‐resolution air temperatures, and a limited understanding of spatial and temporal variability of rH and associated variables (e.g. thermal roughness length). This work uses an extensive LST dataset covering 6 years (2011–2016) in central London and a long‐term in situ observation network to analyse the variability of LST and rH variables. Results show that LST is spatially correlated with building and vegetation land cover with coherent thermal structures at length scales less than 500–1,000 m. Additionally, satellite‐observed LST varies with average building height (up to 10% cooler in areas with tall buildings). The rH term and associated variables are observed to vary on daily and seasonal cycles, and findings are used to model QH using five variations of an ARM‐based approach on a 100 m pixel basis. Modelled QH is compared to observations from three scintillometer paths and an eddy covariance flux tower. We find generally good agreement between observations and models, although there is uncertainty in all methods (mean absolute error ranges from 58.1–129.3 W/m2) due to the challenges involved in determining high‐resolution meteorological and surface inputs, particularly LST and friction velocity (u*). Additional complexity in evaluating modelled QH arises from anthropogenic heat sources: long‐term tower‐based observations show that TA and the radiometer‐derived T0 are warmer during working weekdays than non‐working days (up to 0.7 °C) and that there is an observed lag (2–3 hr) between energy consumption and the observed warming and modelled QH.
Characteristics of monsoonal precipitating cloud systems over the Indian subcontinent derived from weather radar data
Authors: Sindhu Kapil Dev , Bhat G. S.
Published: June 2018

The convective area within a mesoscale convective system (MCS) contains intense convective cells or storms which themselves could be made of a single cumulonimbus cloud or several of them joined together. Interconnection between MCS evolution and storms has not been reported previously. We address this gap area by using the Doppler Weather Radar (DWR) data collected at four stations in India during the summer monsoon season of 2013. The four DWR locations selected have different climates ranging from coastal to semi‐arid. Storm is defined as a set of contiguous radar pixels in three‐dimensional space with a reflectivity threshold of 30 dBZ and the threshold criterion is satisfied in a volume of at least 50 km3. Monsoonal MCSs contain a few to more than 20 storms depending on geographic location and MCS life stage. The average area of storms ranges from 13 to 170 km2 while storm heights mostly lie between 6 and 10 km. The growth stage of an MCS is characterized by a rapid increase in the number of storms, while their number and average area decrease in the dissipation stage. Storms occupy 30–70% of the convective area within an MCS and contribute 90–97% of the convective precipitation at any given instant. Thus, a few to several cumulonimbus clouds grouped together in a contiguous manner matter most for convective precipitation, making storm scale an important scale in the hierarchy of scales in tropical deep convective cloud systems. This has implications for cumulus parametrization as well as planning satellite payloads for observing precipitation.
Revisiting entrainment relationships for shear‐free and sheared convective boundary layers through large‐eddy simulations
Authors: Liu Cheng , Fedorovich Evgeni , Huang Jianping
Published: June 2018

Entrainment is critical to the development of the atmospheric convective boundary layers (CBLs) and for the exchange of energy and substances between the boundary layer and free atmosphere. In this study, entrainment relationships are systematically evaluated from large‐eddy simulations (LESs) of shear‐free and sheared CBLs under a broad variety of atmospheric conditions. A total of 36 LES runs are conducted for varying free‐atmosphere stratifications, surface heat fluxes, and height‐constant geostrophic winds. It has been found that entrainment flux ratios have a common value of 0.2 regardless of the stratification of free atmosphere and the surface heat‐flux value when analysed within the zero‐order‐model (ZOM) framework for the shear‐free CBLs, whereas the actual (LES) entrainment ratios are not only stratification‐dependent, but also surface heat flux‐dependent. For the sheared CBLs, the entrainment‐flux ratios are substantially increased when the geostrophic winds are strong while they have a slight reduction under weak wind conditions. In the free‐encroachment regime, the dimensionless entrainment rates have been found to be approximately constant and surface heat‐flux independent, with the value in the range from 0.4 to 0.7 depending on the method used to evaluate the CBL depth.
Characterization of in vitro metabolites of three tetrahydroprotoberberine alkaloids in rat liver S9 by high‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry
Authors: Lin Li , Liu Xiu‐Bin , Zhou Qiao‐Yun , Liu Sha‐Sha , Zuo Meng‐Ting , Zeng Jian‐Guo , Liu Zhao‐Ying
Published: June 2018

Rationale

Tetrahydroberberine (THB), tetrahydrocoptisine (THCP) and tetrahydrocolumbamine (THCB) belong to the tetrahydroprotoberberine (THPB) alkaloids. Most of them have been extensively studied because of their pharmacological activities such as anti‐hypertension, anti‐arrhythmia, antimicrobial activity and antioxidant. However, limited information on the pharmacokinetics and metabolism of the three alkaloids has been reported. The purpose of this study was to investigate the in vitro metabolism of THB, THCP and THCB in rat liver S9 by using a rapid and accurate high‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry (HPLC/QqTOF‐MS) method.

Methods

The incubation mixture was processed with 15% trichloroacetic acid. Chromatographic separation of the three THPB alkaloids and their metabolites was achieved by HPLC/QqTOF‐MS and accurate mass measurements of metabolites were automatically performed through data‐dependent acquisition in only a 30‐min analysis. The detailed structural elucidations of these metabolites were performed by comparing the changes in their accurate molecular masses, elemental compositions and product ions with those of the parent drug.

Results

Five, five and four metabolites of THB, THCP and THCB were identified in rat liver S9, respectively. The results show that O‐demethylenation of the 9,10‐vicinal methoxyl group was the main metabolic pathway of THB and THCB and that demethylenation of the two methylenedioxy groups was the main metabolic pathway of THCP. In addition, minor oxidation and methylation reactions could occur for these alkaloids in rat liver S9.

Conclusions

This was the first investigation of the in vitro metabolism of THB, THCP and THCB in rat liver S9 by using a sensitive and accurate HPLC/QqTOF‐MS method. The tentatively proposed metabolic pathways of the three alkaloids will provide a basis for further studies of the in vivo metabolism of the three compounds in animals and humans.
Evaluation of lipid peroxidation by the analysis of volatile aldehydes in the headspace of synthetic membranes using selected ion flow tube mass spectrometry
Authors: Shestivska Violetta , Olšinová Marie , Sovová Kristýna , Kubišta Jiří , Smith David , Cebecauer Marek , Španěl Patrik
Published: June 2018

Rationale

Oxidative stress of cell membranes leads to a number of pathological processes associated with some diseases and is accompanied by the release of volatile aldehydes, which potentially can be used as biomarkers. Thus, the aim was to investigate peroxidation of defined synthetic membranes by direct quantitative analysis of volatile aldehydes.

Methods

The concentration spectra of volatile compounds present in the headspace of synthetic membranes under peroxidation stress and following mechanical stress due to sonication were obtained using solid‐phase microextraction (SPME) in combination with gas chromatography/mass spectrometry (SPME‐GC/MS) and selected ion flow tube mass spectrometry (SIFT‐MS). The focus was on the direct, real‐time quantification of volatile aldehydes. In addition, the total aldehydes in the aqueous membrane suspensions were quantified using the thiobarbituric acid reactive substances (TBARS) method.

Results

Propanal, butanal, pentanal, hexanal, heptanal and malondialdehyde were detected and quantified in the humid headspace of the media containing the synthetic membranes following peroxidation. The composition and concentration of these saturated aldehydes strongly depend on the representation of unsaturated fatty acids in the liposomes. Some protective effect of cholesterol was observed especially for membranes peroxidised by Fenton reagents and after application of a mechanical stress.

Conclusions

This study demonstrates that peroxidation of model synthetic membranes in vitro can be tracked in real time using direct quantification by SIFT‐MS of several specific aldehydes in the headspace of the membrane suspensions. Cholesterol plays an important role in retaining membrane structure and can indirectly protect membranes from lipid peroxidation.
Esterification and Characterization of Starch From Andean Tubers
Authors: Velásquez‐Barreto Frank F. , Bello‐Pérez Luis A. , Yee‐Madeira Hermani , Velezmoro Sánchez Carmen E.
Published: June 2018

Starch is isolated from the Andean tubers olluco (Ollucus tuberosus) and oca (Oxalis tuberosa) and modified with octenylsuccinic anhydride (OSA); subsequently, the morphological, molecular, and physicochemical characteristics are evaluated. The isolated starch of olluco and oca results in a powder with a purity of 93.2 and 92.8%, respectively; the amylose content of starch isolated from olluco and oca are 27.1 and 28.2%, respectively. The degree of substitution of OSA starch are 0.015 and 0.016 for olluco and oca, respectively. The peak viscosities of OSA starches ranges from 2.83 to 2.88 Pa · s and are higher than those of native starches. The gelatinization temperature and enthalpy of native starches are higher than those of OSA starches. A B‐type X‐ray diffraction pattern is observed for native and OSA starches, and the crystallinity of OSA starches is less than that of its native counterparts. Fourier transform infrared spectroscopy (FTIR) shows a decrease in the 995/1022 cm−1 ratio in OSA starches but not in native starches, which indicates an alteration of the double helical structure; FTIR shows two new peaks after modification with OSA (1724 and 1572 cm−1). Andean tubers can be used an alternative source for producing chemically modified starch with practical applications.
Presynaptic GCaMP expression decreases vesicle release probability at the calyx of Held
Authors: Singh Mahendra , Lujan Brendan , Renden Robert
Published: June 2018

Synaptic vesicle (SV) exocytosis is intimately dependent on free local Ca2+ near active zones. Genetically encoded calcium indicators (GECIs) have become an indispensable tool to monitor calcium dynamics during physiological responses, and they are widely used as a proxy to monitor activity in neuronal ensembles and at synaptic terminals. However, GECIs’ ability to bind Ca2+ at physiologically relevant concentration makes them strong candidates to affect calcium homeostasis and alter synaptic transmission by exogenously increasing Ca2+ buffering. In the present study, we show that genetically expressed GCaMP6m modulates SV release probability at the mouse calyx of Held synapse. GCaMP6m expression for approximately three weeks decreased initial SV release for both low‐frequency stimulation and high‐frequency stimulation trains, and slowed presynaptic short‐term depression. However, GCaMP6m does not affect quantal events during spontaneous activity at this synapse. This study emphasizes the careful use of GECIs as monitors of neuronal activity and inspects the role of these transgenic indicators which may alter calcium‐dependent physiological responses.
Test–retest variability of [11C]ABP688 estimates of metabotropic glutamate receptor subtype 5 availability in humans
Authors: Smart Kelly , Cox Sylvia M. L. , Nagano‐Saito Atsuko , Rosa‐Neto Pedro , Leyton Marco , Benkelfat Chawki
Published: June 2018

[11C]ABP688 is a positron emission tomography (PET) radioligand that binds selectively to metabotropic glutamate type 5 receptors (mGluR5). The use of this tracer has identified receptor binding changes in clinical populations, and has been informative in drug occupancy studies. However, previous studies have found significant increases in [11C]ABP688 binding in the later scan of same‐day comparisons, and estimates of test‐retest reliability under consistent scanning conditions are not available. The objective of this study was to assess the variability of [11C]ABP688 binding in healthy people in scans performed at the same time of day. Two [11C]ABP688 scans were acquired in eight healthy volunteers (6 women, 2 men) using a high‐resolution research tomograph (HRRT). Scans were acquired 3 weeks apart with start times between 10:00am and 1:30pm. Mean mGluR5 binding potential (BPND) values were calculated across cortical, striatal and limbic brain regions. Participants reported on subjective mood state after each scan and blood samples were drawn for cortisol analysis. No significant change in BPNDbetween scans was observed. Variability in BPNDvalues of 11–21% was observed across regions, with the greatest change in the hippocampus and amygdala. Reliability was low to moderate. BPNDwas not statistically related to scan start time, subjective anxiety, serum cortisol levels, or menstrual phase in women. Overall, [11C]ABP688 BPNDestimates show moderate variability in healthy people. Reliability is fair in cortical and striatal regions, and lower in limbic regions. Future research using this ligand should account for this in study design and analysis.
Toward identity‐oriented teacher education: Critical autoethnographic narrative
Authors: Yazan Bedrettin
Published: June 2018

Recent work on the theorization and exploration of language teacher identity contends that teacher education practices should focus on teacher identity as an explicit focus, yet little is known regarding how teacher identity can be integrated inTESOLteacher education. This article describes a teacher learning tool calledcritical autoethnographic narrativethat can be utilized to promote identity‐orientedTESOLteacher preparation. Theoretically, the design of this tool relies on the earlier work on critical language teacher education (Hawkins & Norton,), autoethnography as an account of identity development (Canagarajah,), narrative as a teacher learning tool (Johnson & Golombek,), and narrative as identity construction (Barkhuizen,). As a program‐wide endeavor, critical autoethnographic narrative requires teacher candidates’ ongoing engagement with their narrative account through coursework and internship by attempting to deconstruct the dominant discourses with teacher educators’ feedback. AcknowledgingTESOLteachers as knowledge generators, such endeavors also encourages teacher candidates to make contributions to scholarly publications with their narratives. The article closes with the description of possible challenges for teacher educators.
Five-particle phase-space integrals in QCD
Authors: Gituliar O. , Magerya V. , Pikelner A.
Published: June 2018

Abstract

We present analytical expressions for the 31 five-particle phase-space master integrals in massless QCD as an ϵ-series with coefficients being multiple zeta values of weight up to 12. In addition, we provide computer code for the Monte-Carlo integration in higher dimensions, based on the RAMBO algorithm, that has been used to numerically cross-check the obtained results in 4, 6, and 8 dimensions.
Searching for metastable particles with sub-millimeter displaced vertices at hadron colliders
Authors: Ito Hayato , Jinnouchi Osamu , Moroi Takeo , Nagata Natsumi , Otono Hidetoshi
Published: June 2018

Abstract

A variety of new-physics models predict metastable particles whose decay length is ≲ 1 mm. Conventional displaced-vertex searches are less sensitive to this sub-millimeter decay range, and thus such metastable particles have been looked for only in usual prompt decay searches. In this paper, we show that an additional event-selection cut based on the vertex reconstruction using charged tracks considerably improves the sensitivity of ordinary searches which rely only on kinematic selection criteria, for particles with a decay length of ≳ 100 μm. To that end, we consider a metastable gluino as an example, and study the impact of this new event-selection cut on gluino searches at the LHC by simulating both the signal and Standard Model background processes. Uncertainty of the displaced-vertex reconstruction due to the limited resolution of track reconstruction is taken into account. We also discuss possibilities for optimization of the kinematic selection criteria, which takes advantage of significant reduction of background through the requirement of displaced vertices. In addition, we demonstrate that using the method discussed in this paper it is possible to measure the lifetime of metastable particles with an

$$ \mathcal{O}(1) $$

O

1

accuracy at the high-luminosity LHC. Implications for a future 100 TeV collider are also studied, where produced particles tend to be more boosted and thus it is easier to detect the longevity of metastable particles.
Holographic complexity in Vaidya spacetimes. Part II
Authors: Chapman Shira , Marrochio Hugo , Myers Robert C.
Published: June 2018

Abstract

In this second part of the study initiated in [1], we investigate holographic complexity for eternal black hole backgrounds perturbed by shock waves, with both the complexity=action (CA) and complexity=volume (CV) proposals. In particular, we consider Vaidya geometries describing a thin shell of null fluid with arbitrary energy falling in from one of the boundaries of a two-sided AdS-Schwarzschild spacetime. We demonstrate how known properties of complexity, such as the switchback effect for light shocks, as well as analogous properties for heavy ones, are imprinted in the complexity of formation and in the full time evolution of complexity. Following our discussion in [1], we find that in order to obtain the expected properties of the complexity, the inclusion of a particular counterterm on the null boundaries of the Wheeler-DeWitt patch is required for the CA proposal.
The seven-gluon amplitude in multi-Regge kinematics beyond leading logarithmic accuracy
Authors: Del Duca Vittorio , Druc Stefan , Drummond James , Duhr Claude , Dulat Falko , Marzucca Robin , Papathanasiou Georgios , Verbeek Bram
Published: June 2018

Abstract

We present an all-loop dispersion integral, well-defined to arbitrary logarithmic accuracy, describing the multi-Regge limit of the 2 → 5 amplitude in planar$$ \mathcal{N}=4 $$N=4super Yang-Mills theory. It follows from factorization, dual conformal symmetry and consistency with soft limits, and specifically holds in the region where the energies of all produced particles have been analytically continued. After promoting the known symbol of the 2-loopN-particle MHV amplitude in this region to a function, we specialize toN= 7, and extract from it the next-to-leading order (NLO) correction to the BFKL central emission vertex, namely the building block of the dispersion integral that had not yet appeared in the well-studied six-gluon case. As an application of our results, we explicitly compute the seven-gluon amplitude at next-to-leading logarithmic accuracy through 5 loops for the MHV case, and through 3 and 4 loops for the two independent NMHV helicity configurations, respectively.
Self-interacting dark matter and muon (g − 2) in a gauged $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ model
Authors: Kamada Ayuki , Kaneta Kunio , Yanagi Keisuke , Yu Hai-Bo
Published: June 2018

Abstract

We construct a self-interacting dark matter model that could simultaneously explain the observed muon anomalous magnetic moment. It is based on a gauged

$$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$

U

1

L
μ

−

L
τ

extension of the standard model, where we introduce a vector-like pair of fermions as the dark matter candidate and a new Higgs boson to break the symmetry. The new gauge boson has a sizable contribution to muon (g − 2), while being consistent with other experimental constraints. The

$$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$

U

1

L
μ

−

L
τ

Higgs boson acts as a light force carrier, mediating dark matter self-interactions with a velocity-dependent cross section. It is large enough in galaxies to thermalize the inner halo and explain the diverse rotation curves and diminishes towards galaxy clusters. Since the light mediator dominantly decays to the

$$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$

U

1

L
μ

−

L
τ

gauge boson and neutrinos, the astrophysical and cosmological constraints are weak. We study the thermal evolution of the model in the early Universe and derive a lower bound on the gauge boson mass.
Decreasing entropy of dynamical black holes in critical gravity
Authors: Maeda Hideki , Švarc Robert , Podolský Jiří
Published: June 2018

Abstract

Critical gravity is a quadratic curvature gravity in four dimensions which is ghost-free around the AdS background. Constructing a Vaidya-type exact solution, we show that the area of a black hole defined by a future outer trapping horizon can shrink by injecting a charged null fluid with positive energy density, so that a black hole is no more a one-way membrane even under the null energy condition. In addition, the solution shows that the Wald-Kodama dynamical entropy of a black hole is negative and can decrease. These properties expose the pathological aspects of critical gravity at the non-perturbative level.
Liouville conformal field theories in higher dimensions
Authors: Levy Tom , Oz Yaron
Published: June 2018

Abstract

We consider a generalization of the two-dimensional Liouville conformal field theory to any number of even dimensions. The theories consist of a log-correlated scalar field with a background

$$ \mathcal{Q} $$

Q

-curvature charge and an exponential Liouville-type potential. The theories are non-unitary and conformally invariant. They localize semiclassically on solutions that describe manifolds with a constant negative

$$ \mathcal{Q} $$

Q

-curvature. We show that C

T
is independent of the

$$ \mathcal{Q} $$

Q

-curvature charge and is the same as that of a higher derivative scalar theory. We calculate the A-type Euler conformal anomaly of these theories. We study the correlation functions, derive an integral expression for them and calculate the three-point functions of light primary operators. The result is a higher-dimensional generalization of the two-dimensional DOZZ formula for the three-point function of such operators.
Bulk phase shift, CFT Regge limit and Einstein gravity
Authors: Kulaxizi Manuela , Parnachev Andrei , Zhiboedov Alexander
Published: June 2018

Abstract

The bulk phase shift, related to a CFT four-point function, describes two-to-two scattering at fixed impact parameter in the dual AdS spacetime. We describe its properties for a generic CFT and then focus on large N CFTs with classical bulk duals. We compute the bulk phase shift for vector operators using Regge theory. We use causality and unitarity to put bounds on the bulk phase shift. The resulting constraints bound three-point functions of two vector operators and the stress tensor in terms of the gap o the theory. Similar bounds should hold for any spinning operator in a CFT. Holographically this implies that in a classical gravitational theory any non-minimal coupling to the graviton, as well as any other particle with spin greater than or equal to two, is suppressed by the mass of higher spin particles.
Operator growth in the SYK model
Authors: Roberts Daniel A. , Stanford Douglas , Streicher Alexandre
Published: June 2018

Abstract

We discuss the probability distribution for the “size” of a time-evolving operator in the SYK model. Scrambling is related to the fact that as time passes, the distribution shifts towards larger operators. Initially, the rate is exponential and determined by the infinite-temperature chaos exponent. We evaluate the size distribution numerically for N = 30, and show how to compute it in the large-N theory using the dressed fermion propagator. We then evaluate the distribution explicitly at leading nontrivial order in the large-q expansion.
Probing beyond ETH at large c
Authors: Faulkner Thomas , Wang Huajia
Published: June 2018

Abstract

We study probe corrections to the Eigenstate Thermalization Hypothesis (ETH) in the context of 2D CFTs with large central charge and a sparse spectrum of low dimension operators. In particular, we focus on observables in the form of non-local composite operators

$$ {\mathcal{O}}_{\mathrm{obs}}(x)={\mathcal{O}}_L(x){\mathcal{O}}_L(0) $$

O

o
b
s

x

=

O
L

x

O
L

0

with h

L
≪ c. As a light probe,

$$ {\mathcal{O}}_{\mathrm{obs}}(x) $$

O

o
b
s

x

is constrained by ETH and satisfies

$$ {\left\langle {\mathcal{O}}_{\mathrm{obs}}(x)\right\rangle}_{h_H}\approx {\left\langle {\mathcal{O}}_{\mathrm{obs}}(x)\right\rangle}_{\mathrm{micro}} $$

O

o
b
s

x

h
H

≈

O

o
b
s

x

micro

for a high energy energy eigenstate |h

H
〉. In the CFTs of interests,

$$ {{\left\langle {\mathcal{O}}_{\mathrm{obs}}(x)\right\rangle}_h}_{{}_H} $$

O

o
b
s

x

h

H

is related to a Heavy-Heavy-Light-Light (HL) correlator, and can be approximated by the vacuum Virasoro block, which we focus on computing. A sharp consequence of ETH for

$$ {\mathcal{O}}_{\mathrm{obs}}(x) $$

O

o
b
s

x

is the so called “forbidden singularities”, arising from the emergent thermal periodicity in imaginary time. Using the monodromy method, we show that finite probe corrections of the form

$$ \mathcal{O}\left({h}_L/c\right) $$

O

h
L

/
c

drastically alter both sides of the ETH equality, replacing each thermal singularity with a pair of branch-cuts. Via the branch-cuts, the vacuum blocks are connected to infinitely many additional “saddles”. We discuss and verify how such violent modification in analytic structure leads to a natural guess for the blocks at finite c: a series of zeros that condense into branch cuts as c → ∞. We also discuss some interesting evidences connecting these to the Stoke’s phenomena, which are non-perturbative e
−c effects. As a related aspect of these probe modifications, we also compute the Renyi-entropy S

n
in high energy eigenstates on a circle. For subsystems much larger than the thermal length, we obtain a WKB solution to the monodromy problem, and deduce from this the entanglement spectrum.
Gauged and ungauged: a nonperturbative test
Authors: Berkowitz Evan , Hanada Masanori , Rinaldi Enrico , Vranas Pavlos
Published: June 2018

Abstract

We study the thermodynamics of the ‘ungauged’ D0-brane matrix model by Monte Carlo simulation. Our results appear to be consistent with the conjecture by Maldacena and Milekhin.