bluuebunny/crossref_metadata_2025 huggingface dataset:
Fecal short chain fatty acids in children living on farms and a link between valeric acid and protection from eczema
Authors: Gio-Batta Monica , Sjöberg Fei , Jonsson Karin , Barman Malin , Lundell Anna-Carin , Adlerberth Ingegerd , Hesselmar Bill , Sandberg Ann-Sofie , Wold Agnes E.
Published: December 2020

Children growing up on farms have low rates of allergy, but the mechanism for this protective effect has not been fully elucidated. Short chain fatty acids (SCFAs) produced by the gut microbiota may play a role in protection from allergy. We measured fecal SCFA levels in samples collected from 28 farming and 37 control children over the first 3 years of life using gas chromatography. Data on diet and other host factors were recorded and allergy was diagnosed at 8 years of age. Among all children, median propionic and butyric acid concentration increased over the first 3 years, and longer SCFAs typically appeared by 1 year of age. Farm children had higher levels of iso-butyric, iso-valeric and valeric acid at 3 years of age than rural controls. In addition, children with elder siblings had higher levels of valeric acid at 3 years of age, and dietary factors also affected SCFA pattern. High levels of valeric acid at 3 years of age were associated with low rate of eczema at 8 years of age. The fecal SCFA pattern in farm children suggests a more rapid maturation of the gut microbiota. Valeric acid or associated microbes may have protective potential against eczema.
A method for studying pico to microsecond time-resolved core-level spectroscopy used to investigate electron dynamics in quantum dots
Authors: Sloboda Tamara , Svanström Sebastian , Johansson Fredrik O. L. , Andruszkiewicz Aneta , Zhang Xiaoliang , Giangrisostomi Erika , Ovsyannikov Ruslan , Föhlisch Alexander , Svensson Svante , Mårtensson Nils , Johansson Erik M. J. , Lindblad Andreas , Rensmo Håkan , Cappel Ute B.
Published: December 2020

Time-resolved photoelectron spectroscopy can give insights into carrier dynamics and offers the possibility of element and site-specific information through the measurements of core levels. In this paper, we demonstrate that this method can access electrons dynamics in PbS quantum dots over a wide time window spanning from pico- to microseconds in a single experiment carried out at the synchrotron facility BESSY II. The method is sensitive to small changes in core level positions. Fast measurements at low pump fluences are enabled by the use of a pump laser at a lower repetition frequency than the repetition frequency of the X-ray pulses used to probe the core level electrons: Through the use of a time-resolved spectrometer, time-dependent analysis of data from all synchrotron pulses is possible. Furthermore, by picosecond control of the pump laser arrival at the sample relative to the X-ray pulses, a time-resolution limited only by the length of the X-ray pulses is achieved. Using this method, we studied the charge dynamics in thin film samples of PbS quantum dots on n-type MgZnO substrates through time-resolved measurements of the Pb 5d core level. We found a time-resolved core level shift, which we could assign to electron injection and charge accumulation at the MgZnO/PbS quantum dots interface. This assignment was confirmed through the measurement of PbS films with different thicknesses. Our results therefore give insight into the magnitude of the photovoltage generated specifically at the MgZnO/PbS interface and into the timescale of charge transport and electron injection, as well as into the timescale of charge recombination at this interface. It is a unique feature of our method that the timescale of both these processes can be accessed in a single experiment and investigated for a specific interface.
A model to rate strategies for managing disease due to COVID-19 infection
Authors: Wang Shiyan , Ramkrishna Doraiswami
Published: December 2020

Considering looming fatality and economic recession, effective policy making based on ongoing COVID-19 pandemic is an urgent and standing issue. Numerous issues for controlling infection have arisen from public discussion led by medical professionals. Yet understanding of these factors has been necessarily qualitative and control measures to correct unfavorable trends specific to an infection area have been lacking. The logical implement for control is a large scale stochastic model with countless parameters lacking robustness and requiring enormous data. This paper presents a remedy for this vexing problem by proposing an alternative approach. Machine learning has come to play a widely circulated role in the study of complex data in recent times. We demonstrate that when machine learning is employed together with the mechanistic framework of a mathematical model, there can be a considerably enhanced understanding of complex systems. A mathematical model describing the viral infection dynamics reveals two transmissibility parameters influenced by the management strategies in the area for the control of the current pandemic. Both parameters readily yield the peak infection rate and means for flattening the curve, which is correlated to different management strategies by employing machine learning, enabling comparison of different strategies and suggesting timely alterations. Treatment of population data with the model shows that restricted non-essential business closure, school closing and strictures on mass gathering influence the spread of infection. While a rational strategy for initiation of an economic reboot would call for a wider perspective of the local economics, the model can speculate on its timing based on the status of the infection as reflected by its potential for an unacceptably renewed viral onslaught.
Differences of the tumour cell glycocalyx affect binding of capsaicin-loaded chitosan nanocapsules
Authors: von Palubitzki Lydia , Wang Yuanyuan , Hoffmann Stefan , Vidal-y-Sy Sabine , Zobiak Bernd , Failla Antonio V. , Schmage Petra , John Axel , Osorio-Madrazo Anayancy , Bauer Alexander T. , Schneider Stefan W. , Goycoolea Francisco M. , Gorzelanny Christian
Published: December 2020

The glycocalyx regulates the interaction of mammalian cells with extracellular molecules, such as cytokines. However, it is unknown to which extend the glycocalyx of distinct cancer cells control the binding and uptake of nanoparticles. In the present study, exome sequencing data of cancer patients and analysis of distinct melanoma and bladder cancer cell lines suggested differences in cancer cell-exposed glycocalyx components such as heparan sulphate. Our data indicate that glycocalyx differences affected the binding of cationic chitosan nanocapsules (Chi-NCs). The pronounced glycocalyx of bladder cancer cells enhanced the internalisation of nanoencapsulated capsaicin. Consequently, capsaicin induced apoptosis in the cancer cells, but not in the less glycosylated benign urothelial cells. Moreover, we measured counterion condensation on highly negatively charged heparan sulphate chains. Counterion condensation triggered a cooperative binding of Chi-NCs, characterised by a weak binding rate at low Chi-NC doses and a strongly increased binding rate at high Chi-NC concentrations. Our results indicate that the glycocalyx of tumour cells controls the binding and biological activity of nanoparticles. This has to be considered for the design of tumour cell directed nanocarriers to improve the delivery of cytotoxic drugs. Differential nanoparticle binding may also be useful to discriminate tumour cells from healthy cells.
Reliance on model-based and model-free control in obesity
Authors: Janssen Lieneke K. , Mahner Florian P. , Schlagenhauf Florian , Deserno Lorenz , Horstmann Annette
Published: December 2020

Consuming more energy than is expended may reflect a failure of control over eating behaviour in obesity. Behavioural control arises from a balance between two dissociable strategies of reinforcement learning: model-free and model-based. We hypothesized that weight status relates to an imbalance in reliance on model-based and model-free control, and that it may do so in a linear or quadratic manner. To test this, 90 healthy participants in a wide BMI range [normal-weight (n = 31), overweight (n = 29), obese (n = 30)] performed a sequential decision-making task. The primary analysis indicated that obese participants relied less on model-based control than overweight and normal-weight participants, with no difference between overweight and normal-weight participants. In line, secondary continuous analyses revealed a negative linear, but not quadratic, relationship between BMI and model-based control. Computational modelling of choice behaviour suggested that a mixture of both strategies was shifted towards less model-based control in obese participants. Our findings suggest that obesity may indeed be related to an imbalance in behavioural control as expressed in a phenotype of less model-based control potentially resulting from enhanced reliance on model-free computations.
Maternal separation in rats induces neurobiological and behavioral changes on the maternal side
Authors: Bölükbas Ibrahim , Mundorf Annakarina , Freund Nadja
Published: December 2020

The time after parturition is a sensitive period for mothers where they are prone to develop psychopathological symptoms. Studies investigating dams after separation from their pups (maternal separation, MS) showed that MS induces alterations similar to postpartum depression. This study aims to give further details on affected behavior and neurobiology of dams after MS. MS in rats from postnatal day 2–20 over four hours daily was performed. Upon reunion, maternal behavior, and ultrasonic vocalization (USV) of dams were measured. On the day of weaning, dams were tested for anxiety-like behavior in the elevated-plus-maze and marble burying test. Then Morc1 mRNA in the medial prefrontal cortex and Nr3c1 encoding the glucocorticoid receptor mRNA in the hippocampus were measured using real-time PCR to examine possible neurobiological correlates in psychopathology and social behavior. GABA and glutamate serum levels were analyzed by high-performance liquid chromatography as peripheral markers for stress-induced psychopathology. MS in dams increased maternal care towards pups even though both groups show high levels of maternal behavior even in late lactation. Furthermore, the emission of 50-kHz and 22-kHz USVs increased significantly. No differences in anxiety-like behavior were detected. MS further reduced Morc1 but not Nr3c1 expression. Serum GABA but not glutamate levels were significantly increased in separated dams. This study reinforces the benefit of investigating dams after MS for studying postpartum stress. Subclinical markers mainly connected to depression, namely Morc1 and GABA, proved to be useful allowing for earlier detection of symptoms of critical postpartum stress.
Defining eligible patients for allele-selective chemotherapies targeting NAT2 in colorectal cancer
Authors: Rendo Veronica , Kundu Snehangshu , Rameika Natallia , Ljungström Viktor , Svensson Richard , Palin Kimmo , Aaltonen Lauri , Stoimenov Ivaylo , Sjöblom Tobias
Published: December 2020

Therapies targeting somatic bystander genetic events represent a new avenue for cancer treatment. We recently identified a subset of colorectal cancer (CRC) patients who are heterozygous for a wild-type and a low activity allele (NAT2*6) but lack the wild-type allele in their tumors due to loss of heterozygosity (LOH) at 8p22. These tumors were sensitive to treatment with a cytotoxic substrate of NAT2 (6-(4-aminophenyl)-N-(3,4,5-trimethoxyphenyl)pyrazin-2-amine, APA), and pointed to NAT2 loss being a therapeutically exploitable vulnerability of CRC tumors. To better estimate the total number of treatable CRC patients, we here determined whether tumor cells retaining also other NAT2 low activity variants after LOH respond to APA treatment. The prevalent low activity alleles NAT2*5 and NAT2*14, but not NAT2*7, were found to be low metabolizers with high sensitivity to APA. By analysis of two different CRC patient cohorts, we detected heterozygosity for NAT2 alleles targetable by APA, along with allelic imbalances pointing to LOH, in ~ 24% of tumors. Finally, to haplotype the NAT2 locus in tumor and patient-matched normal samples in a clinical setting, we develop and demonstrate a long-read sequencing based assay. In total, > 79.000 CRC patients per year fulfil genetic criteria for high sensitivity to a NAT2 LOH therapy and their eligibility can be assessed by clinical sequencing.
Reduced insulin clearance is linked to subclinical atherosclerosis in individuals at risk for type 2 diabetes mellitus
Authors: Randrianarisoa Elko , Lehn-Stefan Angela , Hieronimus Anja , Wagner Robert , Maucher Jakob , Rittig Kilian , Balletshofer Bernd , Birkenfeld Andreas L. , Peter Andreas , Stefan Norbert , Häring Hans-Ulrich , Fritsche Andreas , Heni Martin
Published: December 2020

Hyperglycemia and insulin resistance contribute to vascular damage and are regulated by different pathophysiological processes. The aim of the study was to systematically investigate the relative contributions of multiple fasting state- and oral glucose tolerance test (oGTT)-derived glycemic traits to carotid intima-media thickness (cIMT), a surrogate parameter of subclinical atherosclerosis, in individuals with increased risk for type 2 diabetes mellitus (T2D). 667 volunteers (417 women and 250 men, mean age 44.1 years), who were free of cardiovascular disease (CVD), were included in this cross-sectional study. Glucose tolerance, insulin sensitivity, insulin secretion and insulin clearance were assessed by frequently sampled 75 g oGTT. CIMT was measured by high-resolution ultrasound. Insulin clearance was associated with cIMT in univariate analysis (ßst = − 0.17, p < 0.0001) and in a stepwise regression analysis on 15 variables possibly affecting cIMT, age (r2 = 0.3923, p < 0.0001), insulin clearance (r2 = 0.4564, p < 0.0001), systolic blood pressure (r2 = 0.4733, p < 0.0001), body mass index (BMI) (r2 = 0.4804, p = 0.002), gender (r2 = 0.4831, p = 0.013), and fasting insulin clearance (r2 = 0.4857, p = 0.030) turned out to be significant determinants of cIMT. In a cross-validated model resulting from this analysis, insulin clearance was found to be an independent determinant of cIMT (ßst = − 0.16, p < 0.0001) even after adjusting for traditional CVD risk factors. Reduced insulin clearance may be an early marker of damage on the vasculature, independent of classical CVD risk factors. Reduced insulin clearance should be considered with regard to vascular insulin resistance.
Electrocatalytic CO2 reduction on earth abundant 2D Mo2C and Ti3C2 MXenes
Authors: Attanayake Nuwan H. , Banjade Huta R. , Thenuwara Akila C. , Anasori Babak , Yan Qimin , Strongin Daniel R.
Published: December 2020

The electrocatalytic reduction of CO2 to CO on the Mo2C and Ti3C2 MXenes. DFT calculations show that surface oxygen vacancies are reaction active sites.
The construction of a novel luminescent lanthanide framework for the selective sensing of Cu2+ and 4-nitrophenol in water
Authors: Lin Zeng-Gang , Song Fu-Qiang , Wang Hui , Song Xue-Qin , Yu Xin-Xin , Liu Wei-sheng
Published: December 2020

Two water stable Ln-MOFs that take the (4,4,4)-connected nets with unprecedented topology symbol of {42·6·83}2{42·62·82}{42·84} were developed for sensing Cu2+ and 4-NP in aqueous media with high selectivity and sensitivity.
Optical phase‐sensitive amplification of higher‐order QAM signal with single Mach–Zehnder amplitude modulator
Authors: Shimizu S. , Kobayashi T. , Kazama T. , Umeki T. , Enbutsu K. , Kasahara R. , Miyamoto Y.
Published: December 2020

An optical phase‐sensitive amplifier (PSA) has the potential of low‐noise optical amplification. A frequency non‐degenerate PSA (ND‐PSA) can amplify arbitrary modulation formats including higher‐order QAM. The ND‐PSA requires a co‐propagating phase conjugated light (idler light) that has been conventionally created with an optical phase conjugator at the transmitter side. We propose a transmitter configuration using simultaneous signal generation of both a signal and its idler by double‐sideband modulation for transmission systems with ND‐PSAs. The proposed scheme provides a simple configuration with a single Mach–Zehnder amplitude modulator without optically creating the idler light. We performed experiments using 16QAM, 32QAM, and probabilistically shaped 256QAM signals. As a result, a phase‐sensitive amplification with each modulation format was successfully demonstrated using the proposed transmitter configuration.
H.266/VVC fast intra prediction using Sobel edge features
Authors: Yang Shih‐Hsuan , Hsiao Sheng‐Jung
Published: December 2020

Versatile video coding is the next‐generation video coding standard. Compared with the previous high efficiency video coding standard, versatile video coding reduces 30% or more bitrate but requires significantly higher encoding complexity. This Letter proposes a fast intra prediction algorithm for partition type selection and mode decision of versatile video coding. The Sobel operator is employed to extract the gradient intensity and edge direction of coding blocks. Early skip conditions for partition types are developed based on the dominant edge indicated by block gradients. The intra prediction modes are further restricted to the directions close to the edge orientation of a coding block. Experimental results indicate that the proposed method in the Intra‐only configuration saves 34.66% of the encoding time with a slight (0.61%) increase in Bjøntegaard delta bit rate, which achieves the best tradeoff between acceleration and quality among all the investigated methods.
Designing matching waveform pair with sparse frequency and low autocorrelation sidelobes
Authors: Chen Xiaoying , Chen Baixiao , Wu Chuanzhang
Published: December 2020

Sparse frequency waveform is widely used to suppress the narrowband interferences. The performance that can be achieved with a single waveform is limited. The authors study the approach to design a pair of matching waveforms with low autocorrelation sidelobes and arbitrary frequency stopbands. Two algorithms based on the minimum mean square error (MMSE) between the actual waveform characteristics and the desired waveform characteristics are proposed to deal with this problem. The constrained optimization problem is solved by an alternating iteration method. Numerical experiments show that the proposed algorithms can provide better performance than the existing methods.
Nearest feature line classifier based on collaborative representation with nearest neighbour search algorithm
Authors: Zhuang Zhongjie , Pan Jeng‐Shyang , Chu Shu‐Chuan , Luo Hao
Published: December 2020

Nearest feature line is an effective classification algorithm. However, if a test sample cannot be linear represented by the training samples, the algorithm may not work very well. Moreover, another problem is that it will have a large computation complexity. Therefore, the authors propose a novel algorithm. To begin with, the test sample is linear represented by all the training samples, and the errors between the test sample and every training sample are calculated. The authors only keep the training samples with small errors. In this way, on the one hand, training samples are not suitable for the test sample will be ignored, on the other hand, running time can be reduced. To further reduce the computing time of the algorithm, nearest neighbour search technique is applied to the algorithm. Experiments on numerical and image database show the algorithm cannot only improve the classification accuracy, but also reduce runtime.
A self‐biased and all‐in‐one voltage and current reference
Authors: Wang Yuanfei , Luo Ping , Yang Bingzhong , Tang Tianyuan , Zhang Bo
Published: December 2020

This Letter presents a high‐performance self‐biased and all‐in‐one voltage and current reference without BJT and V–I converter exploiting the zero‐temperature‐coefficient point of the N‐type MOSFET. With the help of the low‐temperature‐coefficient resistors and the self‐biased two‐stage OTA structure, the all‐in‐one reference can achieve the average temperature coefficients of 6.6 and 34 ppm/°C of voltage and current reference from −40 to 125 °C, respectively. Meanwhile, the line sensitivities are 0.08%/V and 0.23%/V of voltage and current reference. And the power supply rejection ratio of the voltage reference is −93 dB@100 Hz with the power consumption of 12.6 μW@tt corner and VDD = 2.5 V. The reference circuit is realized in a standard 180 nm CMOS process with the area of 0.0621 mm × mm.
Short‐term load demand forecasting through rich features based on recurrent neural networks
Authors: Zhao Dongbo , Ge Qian , Tian Yuting , Cui Jia , Xie Boqi , Hong Tianqi
Published: December 2020

With the emerging penetration of renewables and dynamic loads, the understanding of grid edge loading conditions becomes increasingly substantial. Load modelling researches commonly consist of explicitly expressed load models and non‐explicitly expressed techniques, of which artificial intelligence approaches turn out to be the major path. This paper reveals the artificial intelligence‐based load modelling technique to enhance the knowledge of current and future load information considering geographical and weather dependencies. This paper presents a recurrent neural network based sequence to sequence (Seq2Seq) model to forecast the short‐term power loads. Also, a feature attention mechanism, which is along channel and time directions, is developed to improve the efficiency of feature learning. The experiments over three publicly available datasets demonstrate the accuracy and effectiveness of the proposed model.
The stability control for isolated wind‐diesel power system based on the cross coupling effect model
Authors: Mi Yang , Lang Zhongjie , Chen Xin , Fu Yang , Jin Chi , Shi Shuai , Zhao Yao , Jiang Enyu
Published: December 2020

In the isolated wind‐diesel hybrid power system, the system voltage and frequency may be affected simultaneously by the fluctuated wind turbine output power and variable load, which can make the system crash in extreme cases without control strategy. Therefore, in order to reduce the voltage and frequency deviation caused by system power fluctuation, both the battery and super twisting algorithm sliding mode state observer (STATCOM) are equipped to adjust the active power and reactive power for load power demand in the isolated small‐scale power system. Then, the system mathematical model is established which considers the cross‐coupling effect exist in the small‐scale power system. In order to improve the control effect of battery and STATCOM, the unified control strategy is designed for battery and STATCOM by using the super twisting sliding mode state observer and the adaptive sliding mode controller according to the constructed cross‐coupling effect model. Furthermore, the parameters of controller are further optimized by using the fuzzy method. Finally, the simulation experiments are performed by the real‐time digital simulator to validate the effectiveness of the proposed control strategy under different operation points.
Analytical approximation for macroscopic fundamental diagram of urban corridor with mixed human and connected and autonomous traffic
Authors: Hu Guojing , Lu Weike , Whalin Robert W. , Wang Feng , Kwembe Tor A.
Published: December 2020

Advances in connected and autonomous vehicles have the promise to reshape the future of the transportation system. How and when the benefits associated with automation and connectivity technology will start to impact the performance of an urban corridor is an issue of interest for traffic operators. This paper proposes an analytical capacity model for urban corridors with mixed traffic based on the concept of macroscopic fundamental diagram. The model incorporates the full spectrum of connected and autonomous vehicle penetration rates as well as the reaction times of different vehicle following patterns. The connected and autonomous vehicle platoon intensity, formulated as an exponential function of the connected and autonomous vehicle penetration rate, is also considered in the proposed analytical capacity model. Numerical experiments are conducted to verify that different reaction time settings yield disparate results. Some reaction time settings were found to cause the corridor capacity to increase monotonically with the connected and autonomous vehicle penetration rate while others led to decreases in corridor capacity with connected and autonomous vehicle penetration rates. Finally, the validity of the proposed methodology is verified via simulation tests in VISSIM 2020.
Synthesis of multi‐band filters based on multi‐prototype transformation
Authors: Chen Xianhong
Published: December 2020

In this article, a new synthesis method for generalized multi‐band filters has been proposed. Different from the traditional frequency transformation method, which transforms a low‐pass prototype into a multi‐band filter, multiple low‐pass prototypes have been transformed into a multi‐band filter. This study introduces the idea of transforming more than two lowpass prototypes into a filter, called multi‐prototype transformation. It divides the multi‐band filter to be synthesized into different segments each of which corresponds to a low‐pass prototype. After frequency transformation, these segments are combined together to get the final transfer function. The multi‐band filter synthesized by this method can have different orders, bandwidths or return losses in different passbands. Prescribed transmission zeros can also be realized. The return loss adjustment, segment boundary estimation and equal‐ripple realization of this method are further explained in theory. To verify this method, an asymmetric quad‐band filter is synthesized as an example and a symmetric triple‐band filter is synthesized, designed, fabricated and measured. The obtained results show good agreement with the simulation.
Compact parallel‐plate waveguide half‐Luneburg geodesic lens in the Ka‐band
Authors: Fonseca Nelson J.G. , Liao Qingbi , Quevedo‐Teruel Oscar
Published: December 2020

A parallel‐plate waveguide half‐Luneburg geodesic lens is designed and experimentally validated in the Ka‐band. The geodesic lens profile is modulated using spline functions to reduce its height, while the symmetry halving the lens enables reduction of its in‐plane dimensions. This design provides high gain, equivalent to that of a full‐Luneburg lens, over a reduced angular range of ±20° to ±30° in azimuth. The specific design reported here has a maximum realized gain of 23.3 dBi in measurement, compared with 23.8 dBi for a full‐Luneburg lens twice the size of this design. Very wideband operation is demonstrated both in simulations and measurements. This design is of interest for applications having limited space like millimetre‐wave systems on board cubesats and small satellites.
Novel single‐armed modular multilevel converter for reducing total converter capacitance
Authors: Pourgharibshahi Hamed , Jafarishiadeh Seyyedmahdi , Mahmoudi Hamid , Zargarzadeh Hassan , Ahmadi Reza
Published: December 2020

During normal operation of a conventional Modular Multilevel Converter (MMC), half of its capacitors remain bypassed at any time instant, increasing the total required capacitance for converter operation, and in turn leading to a larger size and volume MMC for a target capacitor voltage ripple limit. This paper presents a novel MMC topology that utilizes all converter capacitors at all times during the operation. Therefore, the total required capacitance for generating a voltage waveform with the same number of levels and the same target capacitor voltage ripple limit is greatly reduced compared to conventional MMCs. The new topology inherits all the desirable features of conventional MMCs such as modularity, reliability, and scalability, and is compatible with many of the previously proposed control techniques for conventional MMCs. The process of synthesizing the proposed MMC topology and a new voltage balancing scheme as well as the dynamic model and capacitor sizing procedure for the proposed MMC are reported in the paper. Furthermore, experimental results are presented to evaluate the performance of the proposed converter.
A family of high voltage gain quasi‐Δ‐source impedance networks
Authors: Rezazadeh Hamed , Monfared Mohammad , Nikbahar Ali , Sharifi Saeed
Published: December 2020

This paper proposes a class of impedance networks, called quasi‐Δ‐source, as an improvement to the successful Δ‐source one. Compared to their origin, the three proposed networks offer higher voltage gains with a better magnetic circuit utilization and a smooth continuous input current. A lower magnetizing and total inductance required for the Δ‐shaped coupled inductors of the proposed networks allows smaller and cheaper magnetic cores utilization. Also, a lower total power loss of the magnetically coupled elements is another interesting advantage of the proposed networks. Moreover, the total required capacitance of the proposed networks is the same and even slightly lower than that of the conventional Δ‐source one. All these improve the performance of the proposed class of networks with the smaller size of components compared to their conventional competitor. The principles of operation are developed and the theoretical analysis is performed. Also, by using the circuit averaging technique, the small‐signal models of the Δ‐source and the proposed networks are derived as well as their control‐to‐output transfer function is achieved. Finally, the experiments on a 300 W rated power prototype of the proposed networks successfully confirm the theoretical achievements.
Observing the changing surface structures of the active K giant
σ Geminorum with SONG
Authors: Korhonen H. , Roettenbacher R. M. , Gu S. , Grundahl F. , Andersen M. F. , Henry G. W. , Jessen-Hansen J. , Antoci V. , Pallé P. L.
Published: December 2020

Aims. We aim to study the spot evolution and differential rotation in the magnetically active cool K-type giant star σ Gem from broadband photometry and continuous spectroscopic observations that span 150 nights.

Methods. We use high-resolution, high signal-to-noise ratio spectra obtained with the Hertzsprung SONG telescope to reconstruct surface (photospheric) temperature maps with Doppler imaging techniques. The 303 observations span 150 nights and allow for a detailed analysis of the spot evolution and surface differential rotation. The Doppler imaging results are compared to simultaneous broadband photometry from the Tennessee State University T3 0.4 m Automated Photometric Telescope. The activity from the stellar chromosphere, which is higher in the stellar atmosphere, is also studied using SONG observations of Balmer Hα line profiles and correlated with the photospheric activity.

Results. The temperature maps obtained during eight consecutive stellar rotations show mainly high-latitude or polar spots, with the main spot concentrations above latitude 45°. The spots concentrate around phase 0.25 near the beginning of our observations and around phase 0.75 towards the end. The photometric observations confirm a small jump in spot phases that occurred in February 2016. The cross-correlation of the temperature maps reveals rather strong solar-like differential rotation, giving a relative surface differential rotation coefficient of α = 0.10 ± 0.02. There is a weak correlation between the locations of starspots and enhanced emission in the chromosphere at some epochs.
Vacuum ultraviolet photoabsorption spectroscopy of space-related ices: formation and destruction of solid carbonic acid upon 1 keV electron irradiation
Authors: Ioppolo S. , Kaňuchová Z. , James R. L. , Dawes A. , Ryabov A. , Dezalay J. , Jones N. C. , Hoffmann S. V. , Mason N. J. , Strazzulla G.
Published: December 2020

Context. Carbonic acid (H2CO3) is a weak acid relevant to astrobiology which, to date, remains undetected in space. Experimental work has shown that the β-polymorph of H2CO3 forms under space relevant conditions through energetic (UV photon, electron, and cosmic ray) processing of CO2- and H2O-rich ices. Although its α-polymorph ice has been recently reassigned to the monomethyl ester of carbonic acid, a different form of H2CO3 ice may exist and is synthesized without irradiation through surface reactions involving CO molecules and OH radicals, that is to say γ-H2CO3.

Aims. We aim to provide a systematic set of vacuum ultraviolet (VUV) photoabsorption spectroscopic data of pure carbonic acid that formed and was destroyed under conditions relevant to space in support of its future identification on the surface of icy objects in the Solar System by the upcoming Jupiter ICy moons Explorer mission and on interstellar dust by the James Webb Space Telescope spacecraft.

Methods. We present VUV photoabsorption spectra of pure and mixed CO2 and H2O ices exposed to 1 keV electrons at 20 and 80 K to simulate different interstellar and Solar System environments. Ices were then annealed to obtain a layer of pure H2CO3 which was further exposed to 1 keV electrons at 20 and 80 K to monitor its destruction pathway. Fourier-transform infrared (FT-IR) spectroscopy was used as a secondary probe providing complementary information on the physicochemical changes within an ice.

Results. Our laboratory work shows that the formation of solid H2CO3, CO, and O3 upon the energetic processing of CO2:H2O ice mixtures is temperature-dependent in the range between 20 and 80 K. The amorphous to crystalline phase transition of H2CO3 ice is investigated for the first time in the VUV spectral range by annealing the ice at 200 and 225 K. We have detected two photoabsorption bands at 139 and 200 nm, and we assigned them to β-H2CO3 and γ-H2CO3, respectively. We present VUV spectra of the electron irradiation of annealed H2CO3 ice at different temperatures leading to its decomposition into CO2, H2O, and CO ice. Laboratory results are compared to Cassini UltraViolet Imaging Spectrograph observations of the 70−90 K ice surface of Saturn’s satellites Enceladus, Dione, and Rhea.
Ligand-Driven Advances in Iridium-Catalyzed sp3 C–H Borylation: 2,2′-Dipyridylarylmethane
Authors: Schley Nathan D. , Jones Margaret R.
Published: December 2020

The field of catalytic C–H borylation has grown considerably since its founding, providing a means for the preparation of synthetically versatile organoborane products. Although sp2 C–H borylation methods have found widespread and practical use in organic synthesis, the analogous sp3 C–H borylation reaction remains challenging and has seen limited application. Existing catalysts are often hindered by incomplete consumption of the diboron reagent, poor functional-group tolerance, harsh reaction conditions, and the need for excess or neat substrate. These challenges acutely affect the C–H borylation chemistry of unactivated hydrocarbon substrates, which has lagged in comparison to methods for the C–H borylation of activated compounds. Herein, we discuss recent advances in the sp3 C–H borylation of undirected substrates in the context of two particular challenges: (1) utilization of the diboron reagent and (2) the need for excess or neat substrate. Our recent work on the application of dipyridylarylmethane ligands in sp3 C–H borylation has allowed us to make contributions in this space and has presented an additional ligand scaffold to supplement traditional phenanthroline ligands.
Indispensability of Clinical Bioinformatics for Effective Implementation of Genomic Medicine in Pathology Laboratories
Authors: Chamala Srikar , Majety Siddardha , Mishra Shesh Nath , Newsom Kimberly J. , Gothi Shaileshbhai Revabhai , Walton Nephi A. , Dolin Robert H. , Starostik Petr
Published: December 2020

Patient care is rapidly evolving toward the inclusion of precision genomic medicine when genomic tests are used by clinicians to determine disease predisposition, prognosis, diagnosis, and improve therapeutic decision-making. However, unlike other clinical pathology laboratory tests, the development, deployment, and delivery of genomic tests and results are an intricate process. Genomic technologies are diverse, fast changing, and generate massive data. Implementation of these technologies in a Clinical Laboratory Improvement Amendments-certified and College of American Pathologists-accredited pathology laboratory often require custom clinical grade computational data analysis and management workflows. Additionally, accurate classification and reporting of clinically actionable genetic mutation requires well-curated disease/application-specific knowledgebases and expertise. Moreover, lack of “out of the box” technical features in electronic health record systems necessitates custom solutions for communicating genetic information to clinicians and patients. Genomic data generated as part of clinical care easily adds great value for translational research. In this article, we discuss current and future innovative clinical bioinformatics solutions and workflows developed at our institution for effective implementation of precision genomic medicine across molecular pathology, patient care, and translational genomic research.
Pharmacologic Thromboprophylaxis and Thrombosis in Hospitalized Patients with COVID-19: A Pooled Analysis
Authors: Patell Rushad , Chiasakul Thita , Bauer Ethan , Zwicker Jeffrey I.
Published: December 2020

Background Coronavirus disease 2019 (COVID-19) increases thrombosis in hospitalized patients prompting adoption of different thromboprophylaxis strategies. Safety and efficacy of escalated-dose pharmacologic thromboprophylaxis are not established.

Objectives To determine the pooled incidence of thrombosis/bleeding in hospitalized patients with COVID-19 for standard-dose, intermediate-dose, therapeutic anticoagulation, and no pharmacologic thromboprophylaxis.

Methods MEDLINE, EMBASE, and Cochrane CENTRAL were searched up to August 29, 2020 for studies reporting pharmacologic thromboprophylaxis and thrombosis or bleeding. Pooled event rates were calculated using a random-effects model.

Results Thirty-five observational studies were included. The pooled incidence rates of total venous thromboembolism (N = 4,685) were: no prophylaxis 41.9% (95% confidence interval [CI]: 28.1–57.2, I 2 = 76%), standard-dose prophylaxis 19.8% (95% CI: 13.2–28.6, I 2 = 95%), intermediate-dose prophylaxis 11.9% (95% CI: 4.3–28.6, I 2 = 91%), and therapeutic-dose anticoagulants 10.5% (95% CI: 4.2–23.8, I 2 = 82%, p = 0.003). The pooled incidence rates of arterial thrombosis (N = 1,464) were: no prophylaxis 11.3% (95% CI: 5.2–23.0, I 2 = 0%), standard-dose prophylaxis 2.5% (95% CI: 1.4–4.3, I 2 = 45%), intermediate-dose prophylaxis 2.1% (95% CI: 0.5–7.7, I 2 = 45%), and therapeutic-dose anticoagulants 1.3% (95% CI: 0.2–8.8, I 2 = 0, p = 0.009). The pooled bleeding event rates (N = 6,393) were nonsignificantly higher in therapeutic-dose anticoagulants compared with standard-dose prophylaxis, (6.3 vs. 1.7%, p = 0.083).

Conclusion Thrombosis rates were lower in hospitalized COVID-19 patients who received pharmacologic thromboprophylaxis. Thrombosis and bleeding rates for patients receiving intermediate-dose thromboprophylaxis or therapeutic anticoagulation were similar to those who received standard-dose pharmacologic thromboprophylaxis.
The Association between Blood-Based Global DNA Methylation and Venous Thromboembolism
Authors: Wang Xiao , Memon Ashfaque A. , Palmér Karolina , Svensson Peter J. , Sundquist Jan , Sundquist Kristina
Published: December 2020

Alterations in DNA methylation patterns have been associated with many diseases. However, the role of DNA methylation in venous thromboembolism (VTE) is not well established. The aim of this study was to investigate a possible association between global DNA methylation and VTE. The study participants consisted of 168 individuals including 74 patients with primary VTE from the Malmö Thrombophilia Study (MATS) and 94 healthy controls. Among 74 primary VTE patients, 37 suffered VTE recurrence during the follow-up period; 37 nonrecurrent VTE patients were included for comparison. Blood-based global DNA methylation was assessed by an enzyme-linked immunosorbent assay. Global DNA methylation was significantly higher in primary VTE patients compared with the healthy controls (median: 0.17 vs. 0.08%; p < 0.001). After stratification of data from primary VTE patients according to sex, the association between higher global DNA methylation and shorter recurrence-free survival time was of borderline statistical significance in males (β = –0.2; p = 0.052) but not in females (β = 0.02; p = 0.90). Our results show that global DNA methylation is associated with primary VTE and that higher levels of global DNA methylation may be associated with early VTE recurrence in males but not in females. Further investigation on the role of DNA methylation as a diagnostic or preventive biomarker in VTE is warranted.
Cross-subunit interactions that stabilize open states mediate gating in NMDA receptors
Authors: Iacobucci Gary J. , Wen Han , Helou Matthew , Liu Beiying , Zheng Wenjun , Popescu Gabriela K.
Published: December 2020

Significance

NMDA receptors are glutamatergic channels whose activation controls the strength of excitatory synapses in the central nervous system. Agonist binding initiates a complex activation reaction that consists of a stepwise sequence of reversible isomerizations. In addition to previously identified steps in this series, which include agonist-induced closure of the ligand-binding lobes and the subsequent mechanical pulling by the ligand-binding domain on the gate-forming transmembrane helix, we identify a cross-subunit interaction that stabilizes open receptors and slows the rate of the current decay. Naturally occurring NMDA receptor variants lacking this interaction are pathogenic.
Viewing images of foods evokes taste quality-specific activity in gustatory insular cortex
Authors: Avery Jason A. , Liu Alexander G. , Ingeholm John E. , Gotts Stephen J. , Martin Alex
Published: December 2020

Significance

Does a picture of an apple taste sweet? Previous studies have shown that viewing food pictures activates brain regions involved in taste perception. However, it is unclear if this response is actually specific to the taste of depicted foods. Using ultrahigh-resolution functional magnetic resonance imaging and multivoxel pattern analysis, we decoded specific tastes delivered during scanning, as well as the dominant tastes associated with food pictures within primary taste cortex. Thus, merely viewing pictures of food evokes an automatic retrieval of information about the taste of those foods. These results show how higher-order information from one sensory modality (i.e., vision) can be represented in brain regions thought to represent only low-level information from a different modality (i.e., taste).
Discrimination and anxiety: Using multiple polygenic scores to control for genetic liability
Authors: Cuevas Adolfo G. , Mann Frank D. , Williams David R. , Krueger Robert F.
Published: December 2020

Significance

Genetic factors can concurrently influence perceptions of threatening and stressful events, like discriminatory experiences, and increase liability for anxiety and negative affect. The question has remained unsettled as to whether genetic susceptibility to anxiety and negative affect confounds the relationship between discrimination exposure and these phenotypes. In a national probability sample of noninstitutionalized, English-speaking respondents (
n
= 1,146), we found that discrimination was positively associated with anxiety and negative affect, operationalized by a common latent factor, even after accounting for genetic confounds. These findings suggest that discrimination is a risk factor for anxiety and related disorders rather than a result of common genetic liability alone. Reducing exposure to discrimination has the potential to improve mental health at the population level.
Minimal gene set from
Sinorhizobium
(
Ensifer
)
meliloti
pSymA required for efficient symbiosis with
Medicago
Authors: Geddes Barney A. , Kearsley Jason V. S. , Huang Jiarui , Zamani Maryam , Muhammed Zahed , Sather Leah , Panchal Aakanx K. , diCenzo George C. , Finan Turlough M.
Published: December 2020

Significance

Modern agriculture is dependent on the yearly application of large quantities of nitrogen fertilizer acquired via the chemical fixation of N
2
in the Haber–Bosch process. More sustainable agricultural systems take advantage of biological nitrogen fixation, particularly the symbiosis between nitrogen-fixing bacteria called rhizobia and leguminous plants. A long-term goal of symbiotic nitrogen-fixation (SNF) research is to optimize its use in agriculture by improving rhizobia or by engineering symbiotic relationships into nonlegumes. Using the model rhizobium
Sinorhizobium
(
Ensifer
)
meliloti
, we establish that only 58 genes from the 1.35-Mb pSymA megaplasmid are required for effective SNF. This minimal SNF gene set, and genetic platform, have important implications for engineering approaches to optimize rhizobia inoculants and transfer symbiotic abilities to novel backgrounds.
Human species D adenovirus hexon capsid protein mediates cell entry through a direct interaction with CD46
Authors: Persson B. David , John Lijo , Rafie Karim , Strebl Michael , Frängsmyr Lars , Ballmann Monika Z. , Mindler Katja , Havenga Menzo , Lemckert Angelique , Stehle Thilo , Carlson Lars-Anders , Arnberg Niklas
Published: December 2020

Significance

The adenovirus capsid protein is built by three main capsomers: hexon, fiber, and penton base. Entry is mediated by fiber proteins anchoring the virus to host cell receptors and is followed by penton base proteins engaging coreceptors, resulting in entry. Here, we demonstrate that human adenovirus species D types, which constitute two-thirds of all human adenoviruses, enter host cells through a direct interaction between the hexon protein and CD46. This study provides insights into the entry mechanisms used by human adenoviruses. As these viruses are also used as vaccine vectors for prevention of other infectious diseases, the results provided will also be useful for further development of human adenovirus species D types as vaccine vectors.
STING agonist promotes CAR T cell trafficking and persistence in breast cancer
Authors: Xu Nuo , Palmer Douglas C. , Robeson Alexander C. , Shou Peishun , Bommiasamy Hemamalini , Laurie Sonia J. , Willis Caryn , Dotti Gianpietro , Vincent Benjamin G. , Restifo Nicholas P. , Serody Jonathan S.
Published: December 2020

CAR T therapy targeting solid tumors is restrained by limited infiltration and persistence of those cells in the tumor microenvironment (TME). Here, we developed approaches to enhance the activity of CAR T cells using an orthotopic model of locally advanced breast cancer. CAR T cells generated from Th/Tc17 cells given with the STING agonists DMXAA or cGAMP greatly enhanced tumor control, which was associated with enhanced CAR T cell persistence in the TME. Using single-cell RNA sequencing, we demonstrate that DMXAA promoted CAR T cell trafficking and persistence, supported by the generation of a chemokine milieu that promoted CAR T cell recruitment and modulation of the immunosuppressive TME through alterations in the balance of immune-stimulatory and suppressive myeloid cells. However, sustained tumor regression was accomplished only with the addition of anti–PD-1 and anti–GR-1 mAb to Th/Tc17 CAR T cell therapy given with STING agonists. This study provides new approaches to enhance adoptive T cell therapy in solid tumors.