bluuebunny/crossref_metadata_2025 huggingface dataset:
Instability and turbulent relaxation in a stochastic magnetic field
Authors: Cao Mingyun , Diamond P H
Published: January 2022

An analysis of instability dynamics in a stochastic magnetic field is presented for the tractable case of the resistive interchange. Externally prescribed static magnetic perturbations convert the eigenmode problem to a stochastic differential equation, which is solved by the method of averaging. The dynamics are rendered multi-scale, due to the size disparity between the test mode and magnetic perturbations. Maintaining quasi-neutrality at all orders requires that small-scale convective cell turbulence be driven by disparate scale interaction. The cells in turn produce turbulent mixing of vorticity and pressure, which is calculated by fluctuation-dissipation type analyses, and are relevant to pump-out phenomena. The development of correlation between the ambient magnetic perturbations and the cells is demonstrated, showing that turbulence will ‘lock on’ to ambient stochasticity. Magnetic perturbations are shown to produce a magnetic braking effect on vorticity generation at large scale. Detailed testable predictions are presented. The relations of these findings to the results of available simulations and recent experiments are discussed.
Coalescence and counterflow of droplets on needle electrode with negative corona discharge
Authors: Wang Zutao , Li Chuan , Xiao Menghan , Wang Pengyu , Zhang Ming , Shi Peng , Li Jiawei , Li Dingchen , He Fuyou , Yang Wendi , Yang Yong , Yu Kexun , Pan Yuan
Published: January 2022

The coalescence of droplets on the discharge electrode surface in high humidity environments has rarely been studied, which may affect discharge characteristics. Meanwhile, directional transport of droplets is of great significance for many applications ranging from fluidic processing to thermal management. Here, corona discharge in a needle-plate electrode is adopted to explore the coalescence rule of droplets attached on the discharge electrode surface in a high-humidity environment, and to realize the counterflow of droplets. The experimental results show that the number of coalesced droplets on the needle electrode surface reaches the maximum under −7.5 kV at relative humidity ∼94% and ambient temperature ∼20 °C. When the applied voltage increases from −6 kV to −11 kV, the droplet moves up 2.76 mm in 5 s. The size of the attached droplet depends on the balance of coalescence and evaporation. The coalescence is mainly attributed to the dielectrophoretic force caused by the high electric field gradient. The evaporation is related to the ionic wind generated by the corona discharge. With regard to the counterflow phenomenon of the droplet, we speculate that the high concentration gradient of positive ions near the needle electrode provides a driving force for the negatively charged droplets. Meanwhile, the electrons and negative ions below the needle tip offer a repulsive force to the droplet. The shape and moving direction of the droplet attached to the needle surface can be manipulated by changing the voltage applied to the needle electrode, which shows the potential application value in realizing the self-cleaning of electrodes, liquid lenses and so on.
Hybrid simulation of instabilities in capacitively coupled RF CF4/Ar plasmas
Authors: Dong Wan , Zhang Yi-Fan , Dai Zhong-Ling , Schulze Julian , Song Yuan-Hong , Wang You-Nian
Published: January 2022

Radio frequency capacitively coupled plasmas (RF CCPs) sustained in fluorocarbon gases or their mixtures with argon are widely used in plasma-enhanced etching. In this work, we conduct studies on instabilities in a capacitive CF4/Ar (1:9) plasma driven at 13.56 MHz at a pressure of 150 mTorr, by using a one-dimensional fluid/Monte-Carlo (MC) hybrid model. Fluctuations are observed in densities and fluxes of charged particles, electric field, as well as electron impact reaction rates, especially in the bulk. As the gap distance between the electrodes increases from 2.8 cm to 3.8 cm, the fluctuation amplitudes become smaller gradually and the instability period gets longer, as the driving power density ranges from 250 to 300 W m−2. The instabilities are on a time scale of 16–20 RF periods, much shorter than those millisecond periodic instabilities observed experimentally owing to attachment/detachment in electronegative plasmas. At smaller electrode gap, a positive feedback to the instability generation is induced by the enhanced bulk electric field in the highly electronegative mode, by which the electron temperature keeps strongly oscillating. Electrons at high energy are mostly consumed by ionization rather than attachment process, making the electron density increase and overshoot to a much higher value. And then, the discharge becomes weakly electronegative and the bulk electric field becomes weak gradually, resulting in the continuous decrease of the electron density as the electron temperature keeps at a much lower mean value. Until the electron density attains its minimum value again, the instability cycle is formed. The ionization of Ar metastables and dissociative attachment of CF4 are noticed to play minor roles compared with the Ar ionization and excitation at this stage in this mixture discharge. The variations of electron outflow from and negative ion inflow to the discharge center need to be taken into account in the electron density fluctuations, apart from the corresponding electron impact reaction rates. We also notice more than 20% change of the Ar+ ion flux to the powered electrode and about 16% difference in the etching rate due to the instabilities in the case of 2.8 cm gap distance, which is worthy of more attention for improvement of etching technology.
Axial and radial development of the hot electron distribution in a helicon plasma source, measured by a retarding field energy analyzer (RFEA)
Authors: Buschmann Lisa , Fredriksen Åshild
Published: January 2022

The information about the electron population of a helicon source plasma that expands along a magnetic nozzle is important for understanding the plasma acceleration across the potential drop that forms in the nozzle. The electrons need an energy higher than the potential drop to escape from the source. At these energies the signal of a Langmuir probe is less accurate. An inverted RFEA measures the high-energy tail of the electrons. To reach the probe, they must have energies above the plasma potential V
P, which can vary over the region of the measurement. By constructing a full distribution by applying the electron temperature T
e obtained from the electron IV-curve and the V
P obtained from the ion collecting RFEA or an emissive probe, a density measure of the hot electron distribution independent of V
P can be obtained. The variation of the high-energy tail of the EEDF in both radial and axial directions, in the two different cases of (1) a purely expanding magnetic field nozzle, and (2) a more constricted one by applying current in a third, downstream coil was investigated. The electron densities and temperatures from the source are then compared to two analytic models of the downstream development of the electron density. The first model considers the development for a pure Boltzmann distribution while the second model takes an additional magnetic field expansion into account. A good match between the measured densities and the second model was found for both configurations. The RFEA probe also allows for directional measurement of the electron current to the probe. This property is used to compare the densities from the downstream and upstream directions, showing a much lower contribution of downstream electrons into the source for a purely expanding magnetic field in comparison to the confined magnetic field configuration.
Dynamic stop pooling for flexible and sustainable ride sharing
Authors: Lotze Charlotte , Marszal Philip , Schröder Malte , Timme Marc
Published: January 2022

Ride sharing—the bundling of simultaneous trips of several people in one vehicle—may help to reduce the carbon footprint of human mobility. However, the complex collective dynamics pose a challenge when predicting the efficiency and sustainability of ride sharing systems. Standard door-to-door ride sharing services trade reduced route length for increased user travel times and come with the burden of many stops and detours to pick up individual users. Requiring some users to walk to nearby shared stops reduces detours, but could become inefficient if spatio-temporal demand patterns do not well fit the stop locations. Here, we present a simple model of dynamic stop pooling with flexible stop positions. We analyze the performance of ride sharing services with and without stop pooling by numerically and analytically evaluating the steady state dynamics of the vehicles and requests of the ride sharing service. Dynamic stop pooling does a priori not save route length, but occupancy. Intriguingly, it also reduces the travel time, although users walk parts of their trip. Together, these insights explain how dynamic stop pooling may break the trade-off between route lengths and travel time in door-to-door ride sharing, thus enabling higher sustainability and service quality.
Spiral waves within a bistability parameter region of an excitable medium
Authors: Zykov V S , Bodenschatz E
Published: January 2022

Spiral waves are a well-known and intensively studied dynamic phenomenon in excitable media of various types. Most studies have considered an excitable medium with a single stable resting state. However, spiral waves can be maintained in an excitable medium with bistability. Our calculations, performed using the widely used Barkley model, clearly show that spiral waves in the bistability region exhibit unique properties. For example, a spiral wave can either rotate around a core that is in an unexcited state, or the tip of the spiral wave describes a circular trajectory located inside an excited region. The boundaries of the parameter regions with positive and ‘negative’ cores have been defined numerically and analytically evaluated. It is also shown that the creation of a positive or ‘negative’ core may depend on the initial conditions, which leads to hysteresis of spiral waves. In addition, the influence of gradient flow on the dynamics of the spiral wave, which is related to the tension of the scroll wave filaments in a three-dimensional medium, is studied.
Hubble-induced phase transitions on the lattice with applications to Ricci reheating
Authors: Bettoni Dario , Lopez-Eiguren Asier , Rubio Javier
Published: January 2022

Using 3+1 classical lattice simulations, we follow the symmetry breaking pattern and subsequent non-linear evolution of a spectator field non-minimally coupled to gravity when the post-inflationary dynamics is given in terms of a stiff equation-of-state parameter. We find that the gradient energy density immediately after the transition represents a non-negligible fraction of the total energy budget, steadily growing to equal the kinetic counterpart. This behaviour is reflected on the evolution of the associated equation-of-state parameter, which approaches a universal value 1/3, independently of the shape of non-linear interactions. Combined with kination, this observation allows for the generic onset of radiation domination for arbitrary self-interacting potentials, significantly extending previous results in the literature. The produced spectrum at that time is, however, non-thermal, precluding the naive extraction of thermodynamical quantities like temperature. Potential identifications of the spectator field with the Standard Model Higgs are also discussed.
Probing neutrino decay scenarios by using the Earth matter effects on supernova neutrinos
Authors: Delgado Edwin A. , Nunokawa Hiroshi , Quiroga Alexander A.
Published: January 2022

The observation of Earth matter effects in the spectrum of neutrinos coming from a next galactic core-collapse supernova (CCSN) could, in principle, reveal if neutrino mass ordering is normal or inverted. One of the possible ways to identify the mass ordering is through the observation of the modulations that appear in the spectrum when neutrinos travel through the Earth before they arrive at the detector. These features in the neutrino spectrum depend on two factors, the average neutrino energies, and the difference between the primary neutrino fluxes of electron and other flavors produced inside the supernova. However, recent studies indicate that the Earth matter effect for CCSN neutrinos is expected to be rather small and difficult to be observed by currently operating or planned neutrino detectors mainly because of the similarity of average energies and fluxes between electron and other flavors of neutrinos, unless the distance to CCSN is significantly smaller than the typically expected one, ∼ 10 kpc. Here, we are looking towards the possibility if the non-standard neutrino properties such as decay of neutrinos can enhance the Earth matter effect. In this work we show that invisible neutrino decay can potentially enhance significantly the Earth matter effect for both νe and ν̅e channels at the same time for both mass orderings, even if the neutrino spectra between electron and other flavors of neutrinos are very similar, which is a different feature not expected for CCSN neutrinos with standard oscillation without the decay effect.
Method of Separating Cosmic-Ray Positrons from Electrons in the DAMPE Experiment
Authors: Dai Hao-Ting , Zang Jing-Jing , Wang Ying , Luo Chuan-Ning , Zhang Yun-Long , Zhang Zhi-Yong , Wei Yi-Feng , Wu Li-Bo , Liu Cheng-Ming , Zhao Cong , Wang Xiao-Lian , Xu Zi-Zong , Huang Guang-Shun
Published: January 2022

A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer (DAMPE) experiment. As there is no onboard magnet on the satellite, the different features imposed by the geomagnetic field on these two species were exploited for the particle identification. Application of this method to the simulation of on-orbit electrons/positrons/protons and the real flight data proves that separately measuring the CR positrons/electrons with DAMPE is feasible, though limited by the field of view for the present observation data. Further analysis on the positron flux with this method can be expected in the future.
Temperature Analysis of Flaring (AR 11283) and Non-flaring (AR 12194) Coronal Loops
Authors: Fathalian Narges , Somayeh Hosseini Rad Seyedeh , Alipour Nasibeh , Safari Hossein
Published: January 2022

Here, we study the temperature structure of flaring and non-flaring coronal loops, using extracted loops from images taken in six extreme ultraviolet channels recorded by Atmospheric Imaging Assembly/Solar Dynamics Observatory. We use data for loops of an X2.1-class-flaring active region (AR 11283) during 22:10 UT until 23:00 UT, on 2011 September 6; and a non-flaring active region (AR 12194) during 08:00:00 UT until 09:00:00 UT on 2014 October 26. By using the spatially synthesized Gaussian differential emission measure (DEM) forward-fitting method, we calculate the peak temperatures for each strip of the loops. We apply the Lomb–Scargle method to compute the oscillation periods for the temperature series of each strip. The periods of the temperature oscillations for the flaring loops ranged from 7 to 28.4 minutes. These temperature oscillations show very close behavior to the slow-mode oscillation. We observe that the temperature oscillations in the flaring loops started at least around 10 minutes before the transverse oscillations and continue for a long time duration even after the transverse oscillations ended. The temperature amplitudes increased during the flaring time (20 minutes) in the flaring loops. The periods of the temperatures obtained for the non-flaring loops ranged from 8.5 to 30 minutes, but their significances are less (below 0.5) in comparison with the flaring ones (near to one). Hence the detected temperature periods for the non-flaring loops’ strips are less probable in comparison with the flaring ones, and maybe they are just fluctuations. Based on our confined observations, it seems that the flaring loops’ periods show more diversity and their temperatures have wider ranges of variation than the non-flaring ones. More accurate commentary in this respect requires more extensive statistical research and broader observations.
Intrinsic somatosensory feedback supports motor control and learning to operate artificial body parts
Authors: Amoruso E , Dowdall L , Kollamkulam M T , Ukaegbu O , Kieliba P , Ng T , Dempsey-Jones H , Clode D , Makin T R
Published: January 2022

Objective. Considerable resources are being invested to enhance the control and usability of artificial limbs through the delivery of unnatural forms of somatosensory feedback. Here, we investigated whether intrinsic somatosensory information from the body part(s) remotely controlling an artificial limb can be leveraged by the motor system to support control and skill learning. Approach. We used local anaesthetic to attenuate somatosensory inputs to the big toes while participants learned to operate through pressure sensors a toe-controlled and hand-worn robotic extra finger. Motor learning outcomes were compared against a control group who received sham anaesthetic and quantified in three different task scenarios: while operating in isolation from, in synchronous coordination, and collaboration with, the biological fingers. Main results. Both groups were able to learn to operate the robotic extra finger, presumably due to abundance of visual feedback and other relevant sensory cues. Importantly, the availability of displaced somatosensory cues from the distal bodily controllers facilitated the acquisition of isolated robotic finger movements, the retention and transfer of synchronous hand-robot coordination skills, and performance under cognitive load. Motor performance was not impaired by toes anaesthesia when tasks involved close collaboration with the biological fingers, indicating that the motor system can close the sensory feedback gap by dynamically integrating task-intrinsic somatosensory signals from multiple, and even distal, body-parts. Significance. Together, our findings demonstrate that there are multiple natural avenues to provide intrinsic surrogate somatosensory information to support motor control of an artificial body part, beyond artificial stimulation.
Electrochemical microelectrode degradation monitoring: in situ investigation of platinum corrosion at neutral pH
Authors: Doering Moritz , Kieninger Jochen , Urban Gerald A , Weltin Andreas
Published: January 2022

Objective. The stability of platinum and other noble metal electrodes is critical for neural implants, electrochemical sensors, and energy sources. Beyond the acidic or alkaline environment found in most electrochemical studies, the investigation of electrode corrosion in neutral pH and chloride containing electrolytes is essential, particularly regarding the long-term stability of neural interfaces, such as brain stimulation electrodes or cochlear implants. In addition, the increased use of microfabricated devices demands the investigation of thin-film electrode stability in combination with electrode performance. Approach. We developed a procedure of electrochemical methods for continuous tracking of electrode degradation in situ over the complete life cycle of platinum thin-film microelectrodes in a unique combination with simultaneous chemical sensing. We used chronoamperometry and cyclic voltammetry to measure electrode surface and analyte redox processes, together with accelerated electrochemical degradation. Main results. We compared degradation between thin-film microelectrodes and bulk electrodes, neutral to acidic pH, different pulsing schemes, and the presence of the redox active species oxygen and hydrogen peroxide. Results were confirmed by electrochemical impedance spectroscopy, as well as mechanical profilometry and microscopy to determine material changes on a nanometer scale. We found that electrode degradation is mainly driven by repeated formation and removal of the platinum surface oxide, also within the electrochemical stability window of water. There was no considerable difference between thin-film micro- and macroscopic bulk electrodes or in the presence of reactive species, whereas acidic pH or extending the potential window led to increased degradation. Significance. Our results provide valuable fundamental information on platinum microelectrode degradation under conditions found in biomedical applications. For the first time, we employed a unified method to report quantitative data on electrode degradation up to a defined endpoint. Our method is a widely applicable framework for comparative long-term studies of electrode micro-/nanomaterial, sensor and neural interface stability.
Core-edge 2D fluid modeling of full tokamak discharge with varying magnetic equilibrium: from WEST start-up to ramp-down
Authors: Scotto d’Abusco M. , Giorgiani G. , Artaud J.F. , Bufferand H. , Ciraolo G. , Ghendrih P. , Serre E. , Tamain P.
Published: January 2022

In the present work we investigate for the first time the 2D fluid transport of the plasma in WEST during an entire discharge from the start-up to the ramp-down (shot #54487). The evolution of density profile, electron and ion temperatures together with the experimental magnetic equilibrium, total current and gas-puff rate is investigated. Comparisons with the interferometry diagnostic show a remarkable overall qualitative agreement during the discharge that can be quantitative at some locations in the plasma core. If at the onset of the X-points during the ramp-up the electron heat flux is dominant at the target, present results show that the ion heat flux becomes dominant during the stationary phase of the discharge. Using a simple model for erosion, present results assess the tungsten sputtering due to deuterium ions during the start-up and ramp-up phases of the discharge and confirm the need to consider full discharge simulation to accurately treat the W source of contamination. This work also demonstrates the interest of developing magnetic equilibrium free solver including efficient time integration to step toward predictive capabilities in the future for fusion operation.
Multi-contrast CT imaging using a high energy resolution CdTe detector and a CZT photon-counting detector
Authors: Clements N. , Richtsmeier D. , Hart A. , Bazalova-Carter M.
Published: January 2022

Computed tomography (CT) imaging with high energy resolution
detectors shows great promise in material decomposition and
multi-contrast imaging. Multi-contrast imaging was studied by
imaging a phantom with iodine (I), gadolinium (Gd), and gold (Au)
solutions, and mixtures of the three using a cadmium telluride
(CdTe) spectrometer with an energy resolution of 1% as well as with
a cadmium zinc telluride (CZT) detector with an energy resolution of
13%. The phantom was imaged at 120 kVp and 1.1 mA with 7 mm of
aluminum filtration. For the CdTe data collection, the phantom was
imaged using a 0.2 mm diameter x-ray beam with 96 ten-second data
acquisitions across the phantom at 45 rotation angles. For the CZT
detector, we had 720 projections using a cone beam, and the six
detector energy thresholds were set to 23, 33, 50, 64, 81, and
120 keV so that three thresholds corresponded to the K-edges of the
contrast agents. Contrast agent isolation methods were then
examined. K-edge subtraction and novel spectrometric algebraic image
reconstruction (SAIR) were used for the CdTe data. K-edge
subtraction alone was used for the CZT data. Linearity plots
produced similar R
2 values and slopes for all three
reconstruction methods. Comparing CdTe methods, SAIR offered less
noise than CdTe K-edge subtraction and better geometric accuracy at
low contrast concentrations. CdTe contrast agent images of I, Gd,
and Au offered less noise and greater contrast than the CZT images,
highlighting the benefits of high energy resolution CdTe detectors
for possible use in pre-clinical or clinical CT imaging.
Emptiness formation in polytropic quantum liquids
Authors: Yeh Hsiu-Chung , Gangardt Dimitri M , Kamenev Alex
Published: January 2022

We study large deviations in interacting quantum liquids with the polytropic equation of state P(ρ) ∼ ρ

γ
, where ρ is density and P is pressure. By solving hydrodynamic equations in imaginary time we evaluate the instanton action and calculate the emptiness formation probability (EFP), the probability that no particle resides in a macroscopic interval of a given size. Analytic solutions are found for a certain infinite sequence of rational polytropic indexes γ and the result can be analytically continued to any value of γ ⩾ 1. Our findings agree with (and significantly expand on) previously known analytical and numerical results for EFP in quantum liquids. We also discuss interesting universal spacetime features of the instanton solution.
Potential of nanoparticles and nanopolymers in treatment of age-associated diseases
Authors: Saadatpour Fatemeh , Mohammadipanah Fatemeh , Zohourian Nazanin , Hodjat Mahshid
Published: January 2022

Aging is an inevitable process caused by the accumulation of degenerative destructions, which ultimately leads to organism death. As the aging process occurs at the molecular, cellular, and tissue levels, understanding the whole details of age-related disorders is the prerequisite for the development of anti-aging therapy. More than 300 compounds of different sources have been reported with an anti-aging activity that controls age-related diseases through regulating single or multiple signalling pathways. Recent innovations in nanotechniques could lead to the development of nanomaterials having effects on age-associated malfunctions or acting as nanocarrier systems and distributers of anti-aging drugs. In this review, we summarised the molecular mechanisms of longevity and the prospect of developing anti-aging nanomaterials targeting aging pathways.
Photo de-mixing in mixed halide perovskites: the roles of ions and electrons
Authors: Wang Ya-Ru , Yeong Kim Gee , Kotomin Eugene , Moia Davide , Maier Joachim
Published: January 2022

Mixed halide perovskites have attracted great interest for applications in solar cells, light emitting diodes and other optoelectronic devices due to their tunability of optical properties. However, these mixtures tend to undergo de-mixing into separate phases when exposed to light (photo de-mixing), which compromises their operational reliability in devices. Several models have been proposed to elucidate the origin of the photo de-mixing process, including the contribution of strain, electronic carrier stabilization due to composition dependent electronic energies, and light induced ionic defect formation. In this perspective we discuss these hypotheses and focus on the importance of investigating defect chemical and ion transport aspects in these systems. We discuss possible optoionic effects that can contribute to the driving force of de-mixing and should therefore be considered in the overall energy balance of the process. These effects include the selective self-trapping of photo-generated holes as well as scenarios involving multiple defects. This perspective provides new insights into the origin of photo de-mixing from a defect chemistry point of view, raising open questions and opportunities related to the phase behavior of mixed halide perovskites.
Tumor Size, Not Small Vessel Invasion, Predicts Survival in Patients With Hepatocellular Carcinoma
Authors: Zhang Dongwei , Love Tanzy , Hao Yansheng , Liu Bella Lingjia , Thung Swan , Fiel Maria Isabel , Whitney-Miller Christa L , Liao Xiaoyan
Published: January 2022

Objectives

The 8th edition American Joint Committee on Cancer (AJCC) staging system for hepatocellular carcinoma (HCC) has been criticized for failing to stratify patients. We aimed to reassess and modify the tumor staging criteria for HCC.

Methods

Three independent study cohorts were collected and analyzed.

Results

The initial cohort consists of 103 patients with HCC. By Kaplan-Meier survival analysis, the 8th edition failed to distinguish between T1b and T2. Only tumor size and large vessel invasion, but not small vessel invasion or other histopathologic parameters, predicted HCC survival. We modified the T staging criteria by eliminating small vessel invasion while emphasizing tumor size in the middle categories (T2 and T3), which achieved more even distribution of cases and significantly improved risk stratifications (P < .001). This modification was then validated in a cohort of 250 consecutive patients from Mount Sinai Hospital and an online Surveillance, Epidemiology, and End Results data set comprising 9,685 patients, which showed similar results. Small vessel invasion was not an independent prognostic factor in either validation cohort.

Conclusions

Our study showed that tumor size, but not small vessel invasion, predicts survival in patients with HCC. We suggest incorporating our modified T staging criteria in future AJCC revisions.
Rh(D) Alloimmunization Risk After Rh(D)-Incompatible Solid Organ Transplantations in Rh(D)-Negative Recipients
Authors: Ahn Ari , Yang John Jeongseok , Youk Hee Jeong , Cho Duck , Oh Heung-Bum , Ko Dae-Hyun , Hwang Sang-Hyun
Published: January 2022

Objectives

Rh(D)-incompatible (Rh-i) solid organ transplantations are not considered for organ matching, but no consensus guidelines exist regarding the need for anti-D immunoglobulin (RhIG) prophylaxis.

Methods

We reviewed 35 Rh(D)-negative patients who had received Rh-i solid organ transplantation. We divided the patients into a RhIG-administered group and a nonadministered group. All patients also underwent an antibody screening test to assess Rh alloimmunization. Graft function was monitored with serum creatinine or bilirubin and kidney or liver biopsy whenever a rejection was suspected. Overall survival was also assessed.

Results

The median (range) age of transplant recipients was 48.5 (4-69) years, and 73.5% of patients were male. Median (range) follow-up time after transplantation was 60 (2-246) months. In the RhIG nonadministered group (n = 16), anti-D was not detected in any of the patients. More rejection episodes occurred in the RhIG-administered group among those undergoing kidney transplant (P = .0278).

Conclusions

The low rate of Rh(D) alloimmunization is associated with the immunosuppressive state of the patients. RhIG prophylaxis seems to have no clinical benefit in Rh-i solid organ transplantation.
Effects of Renin–Angiotensin System Inhibitors on Mortality and Disease Severity of COVID-19 Patients: A Meta-analysis of Randomized Controlled Trials
Authors: Yin Juntao , Wang Chaoyang , Song Xiaoyong , Li Xiumin , Miao Mingsan
Published: January 2022

BACKGROUND

There is controversy over the effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) on the prognosis in patients with coronavirus disease 2019 (COVID-19), therefore, we aim to further explore the effect of renin–angiotensin–aldosterone system inhibitors on COVID-19-associated disease severity and mortality.

METHODS

We systematically searched PubMed, Embase, Cochrane Library databases, medRxiv, and bioRxiv from inception to 6 September 2021. The primary outcome was all-cause mortality. Secondary outcome was severe disease which was defined as admission to the intensive care unit, the use of noninvasive or invasive mechanical ventilation, or death.

RESULTS

A total of 7 randomized controlled trials involving 1,321 COVID-19 patients were included. Fixed-effects meta-analysis demonstrated that the use of ACEI/ARB was not associated with higher risk of mortality (risk ratio [RR] = 0.84, 95% confidence interval [CI] 0.57–1.22, P = 0.10, I2 = 43%) and disease severity (RR = 0.86, 95% CI 0.71–1.05, P = 0.11, I2 = 47%). However, the subgroup analysis showed that compared with no ACEI/ARB use, the use of ARB was associated with a significant reduction of mortality (RR = 0.23, CI 0.09–0.60, P = 0.55, I2 = 0%) and disease severity (RR = 0.38, CI 0.19–0.77, P = 0.007).

CONCLUSIONS

In conclusion, based on the available data, ACEI/ARB is not associated with the risk of mortality and disease severity in COVID-19 patients. And ACEI/ARB medications, especially ARB, should not be discontinued for patients with COVID-19.
Medicinal plants show remarkable antiproliferative potential in human cancer cell lines
Authors: Nawaz Aisha , Arif Amina , Jamal Adil , Shahid Muhammad Naveed , Nomani Ibtesam , Bahwerth Fayez Saeed
Published: January 2022

Molecules isolated and identified from plant origin are used to manufacture most chemotherapeutic drugs for cancer treatment. We assumed that these plant extracts contain prolific bioactive compounds with potent antiproliferative activities and could be effective against different human cancer cells. Ethanolic extracts were prepared from Chelidonium majus, Myrica cerifera, Fumaria indica, Nigella sativa, and Silybum marianum, and the antiproliferative assay was performed in HepG2 and HeLa human cancer cell lines. All plants extract exhibited antiproliferative potential against studied cancer cell lines in the dose and time-dependent manner. Chelidonium majus and Silybum marianum have shown promising results against HepG2 and HeLa cells, respectively, followed by Myrica cerifera, Fumaria indica, and Nigella sativa. Results indicated that utilization of whole plant extract as anticancer compounds could be of great value in generating novel chemotherapeutic drugs.
Anc2vec: embedding gene ontology terms by preserving ancestors relationships
Authors: Edera Alejandro A , Milone Diego H , Stegmayer Georgina
Published: January 2022

The gene ontology (GO) provides a hierarchical structure with a controlled vocabulary composed of terms describing functions and localization of gene products. Recent works propose vector representations, also known as embeddings, of GO terms that capture meaningful information about them. Significant performance improvements have been observed when these representations are used on diverse downstream tasks, such as the measurement of semantic similarity between GO terms and functional similarity between proteins. Despite the success shown by these approaches, existing embeddings of GO terms still fail to capture crucial structural features of the GO. Here, we present anc2vec, a novel protocol based on neural networks for constructing vector representations of GO terms by preserving three important ontological features: its ontological uniqueness, ancestors hierarchy and sub-ontology membership. The advantages of using anc2vec are demonstrated by systematic experiments on diverse tasks: visualization, sub-ontology prediction, inference of structurally related terms, retrieval of terms from aggregated embeddings, and prediction of protein–protein interactions. In these tasks, experimental results show that the performance of anc2vec representations is better than those of recent approaches. This demonstrates that higher performances on diverse tasks can be achieved by embeddings when the structure of the GO is better represented. Full source code and data are available at https://github.com/sinc-lab/anc2vec.
Kiss1 expression in the hypothalamic arcuate nucleus is lower in dairy cows of reduced fertility
Authors: Clarke Iain J , Reed Charlotte B , Burke Chris R , Li Qun , Meier Susanne
Published: January 2022

We tested the hypothesis that divergent genetic merit for fertility of dairy cows is due to aberrant reproductive neuroendocrine function. The kisspeptin status of non-pregnant cows of either positive (POS) or negative (NEG) breeding values (BVs) for fertility was studied in three groups (n = 8), based on their previous post-partum period: POS cows, which had spontaneous ovarian cycles (POS-CYC) and NEG cows, which either cycled (NEG-CYC) or did not cycle (NEG-NONCYC). Ovarian cycles were synchronized, blood samples were taken to define endocrine status, and the animals were slaughtered in an artificial follicular phase. The brains and the pituitary glands were collected for quantitative polymerase chain reaction (qPCR) and in situ hybridization of hypothalamic GNRH1, Kiss1, TAC3, and PDYN and pituitary expression of LHB and FSHB. Gonadotropin releasing hormone (GnRH) and kisspeptin levels were quantified in snap frozen median eminence (ME). GNRH1 expression and GnRH levels in the ME were similar across groups. Kiss1 expression in the preoptic area of the hypothalamus was also similar across groups, but Kiss1 in the arcuate nucleus was almost 2-fold higher in POS-CYC cows than in NEG groups. TAC3 expression was higher in POS-CYC cows. The number of pituitary gonadotropes and the level of expression of LHB and FSHB were similar across groups. We conclude that the lower levels of Kiss1 and TAC3 in NEG cows with low fertility status and may lead to deficient GnRH and gonadotropin secretion.
Age-associated changes in cumulus cells and follicular fluid: the local oocyte microenvironment as a determinant of gamete quality
Authors: Babayev Elnur , Duncan Francesca E
Published: January 2022

The ovary is the first organ to age in humans with functional decline evident already in women in their early 30s. Reproductive aging is characterized by a decrease in oocyte quantity and quality, which is associated with an increase in infertility, spontaneous abortions, and birth defects. Reproductive aging also has implications for overall health due to decreased endocrinological output. Understanding the mechanisms underlying reproductive aging has significant societal implications as women globally are delaying childbearing and medical interventions have greatly increased the interval between menopause and total lifespan. Age-related changes inherent to the female gamete are well-characterized and include defects in chromosome and mitochondria structure, function, and regulation. More recently, it has been appreciated that the extra-follicular ovarian environment may have important direct or indirect impacts on the developing gamete, and age-dependent changes include increased fibrosis, inflammation, stiffness, and oxidative damage. The cumulus cells and follicular fluid that directly surround the oocyte during its final growth phase within the antral follicle represent additional critical local microenvironments. Here we systematically review the literature and evaluate the studies that investigated the age-related changes in cumulus cells and follicular fluid. Our findings demonstrate unique genetic, epigenetic, transcriptomic, and proteomic changes with associated metabolomic alterations, redox status imbalance, and increased apoptosis in the local oocyte microenvironment. We propose a model of how these changes interact, which may explain the rapid decline in gamete quality with age. We also review the limitations of published studies and highlight future research frontiers.
Extracellular vesicle research in reproductive science: Paving the way for clinical achievements
Authors: Aleksejeva Elina , Zarovni Natasa , Dissanayake Keerthie , Godakumara Kasun , Vigano Paola , Fazeli Alireza , Jaakma Ülle , Salumets Andres
Published: January 2022

Mammalian conception involves a multitude of reciprocal interactions via a molecular dialogue between mother and conceptus. Extracellular vesicles (EVs) are secreted membrane-encapsulated particles that mediate cell-to-cell communication in various contexts. EVs, which are present in seminal, follicular, oviductal, and endometrial fluids, as well as in embryo secretions, carry molecular constituents that impact gamete maturation, fertilization, early embryo development, and embryo–maternal communication. The distribution, concentration, and molecular cargo of EVs are regulated by steroid hormones and the health status of the tissue of origin, and thus are influenced by menstrual phase, stage of conception, and the presence of infertility-associated diseases. EVs have been recognized as a novel source of biomarkers and potential reproductive medicine therapeutics, particularly for assisted reproductive technology (ART). There are still many technological and scientific hindrances to be overcome before EVs can be used in clinical diagnostic and therapeutic ART applications. Issues to be resolved include the lack of standardized measurement protocols and an absence of absolute EV quantification technologies. Additionally, clinically suitable and robust EV isolation methods have yet to be developed. In this review, we provide an overview of EV-mediated interactions during the early stages of reproduction from gamete maturation to embryo implantation and then outline the technological progress that must be made for EV applications to be translated to clinical settings.
Curcumin-incorporated 3D bioprinting gelatin methacryloyl hydrogel reduces reactive oxygen species-induced adipose-derived stem cell apoptosis and improves implanting survival in diabetic wounds
Authors: Xia Sizhan , Weng Tingting , Jin Ronghua , Yang Min , Yu Meirong , Zhang Wei , Wang Xingang , Han Chunmao
Published: January 2022

Background

Gelatin methacryloyl (GelMA) hydrogels loaded with stem cells have proved to be an effective clinical treatment for wound healing. Advanced glycation end product (AGE), interacting with its particular receptor (AGER), gives rise to reactive oxygen species (ROS) and apoptosis. Curcumin (Cur) has excellent antioxidant activity and regulates intracellular ROS production and apoptosis. In this study, we developed a Cur-incorporated 3D-printed GelMA to insert into adipose-derived stem cells (ADSCs) and applied it to diabetic wounds.

Methods

GelMA hydrogels with Cur were fabricated and their in vitro effects on ADSCs were investigated. We used structural characterization, western blot, ROS and apoptosis assay to evaluate the antioxidant and anti-apoptotic activity, and assessed the wound healing effects to investigate the mechanism underlying regulation of apoptosis by Cur via the AGE/AGER/nuclear factor-κB (NF-κB) p65 pathway.

Results

A 10% GelMA scaffold exhibited appropriate mechanical properties and biocompatibility for ADSCs. The circular mesh structure demonstrated printability of 10% GelMA and Cur-GelMA bioinks. The incorporation of Cur into the 10% GelMA hydrogel showed an inhibitory effect on AGEs/AGER/NF-κB p65-induced ROS generation and ADSC apoptosis. Furthermore, Cur-GelMA scaffold promoted cell survival and expedited in vivo diabetic wound healing.

Conclusions

The incorporation of Cur improved the antioxidant activity of 3D-printed GelMA hydrogel and mitigated AGE/AGER/p65 axis-induced ROS and apoptosis in ADSCs. The effects of scaffolds on wound healing suggested that Cur/GelMA-ADSC hydrogel could be an effective biological material for accelerating wound healing.
Cystathionine-β-synthase (CBS)/H2S system promotes lymph node metastasis of esophageal squamous cell carcinoma (ESCC) by activating SIRT1
Authors: Liu Ya , Pan Limin , Li Yuxi , Deng Yuying , Han Xue , Fu Han , Wang Tianxiao
Published: January 2022

Lymph node metastasis is a key factor of death and prognosis in patients with esophageal squamous cell carcinoma (ESCC). Previous studies have demonstrated that Cystathionine-β-synthase (CBS)/H2S system plays important roles in progression of various cancer. However, the function and mechanism of CBS/H2S system in lymph node metastasis of ESCC remains unclear. Here, we found that CBS was highly expressed in human ESCC tissues and closely associated with lymph node metastasis in ESCC patients. Functional studies demonstrated that CBS could significantly promote lymph node metastasis of ESCC tumor cells. In vitro, CBS knockdown inhibited tumor cell proliferation, migration and invasion, whereas CBS overexpression produced the opposite results. In vivo, downregulation of CBS distinctly inhibited ESCC tumor growth and lymphatic metastasis, as evidenced by the decreased size and weight of tumor and popliteal lymph node. Meanwhile, we also found high expression of CBS-induced ESCC angiogenesis and lymphangiogenesis in vitro and in vivo by upregulating VEGF, VEGF-C, and VEGF-D. Mechanistically, CBS up-regulated the expression of SIRT1 and thus interrupted the Notch1/Hes1 axis, which plays a crucial role in lymph node metastasis of ESCC. Moreover, it was demonstrated that H2S derived from CBS-activated SIRT1 via increasing the NAD+/NADH ratio and promoting the phosphorylation of SIRT1. In addition, H2S derived from CBS also enhanced SIRT1 protein stability. Taken together, these data show that the high expression of CBS/H2S system promotes ESCC lymph node metastasis via activating SIRT1 signaling pathway and CBS could serve as a potential therapeutic target for clinical intervention in ESCC.
Whole Genome Sequencing Assessing Impact of Diabetes Mellitus on Tuberculosis Mutations and Type of Recurrence in India
Authors: Mave Vidya , Chen Liang , Ranganathan Uma Devi , Kadam Dileep , Vishwanathan Vijay , Lokhande Rahul , S Siva Kumar , Kagal Anju , Pradhan Neeta N , Shivakumar Shri Vijay Bala Yogendra , Paradkar Mandar S , Deshmukh Sona , Tornheim Jeffrey A , Kornfeld Hardy , Farhat Maha , Gupta Amita , Padmapriyadarsini Chandrasekaran , Gupte Nikhil , Golub Jonathan E , Mathema Barun , Kreiswirth Barry N
Published: January 2022

Background

Evidence describing the impact of diabetes mellitus (DM) on the recurrence and mutation rate of Mycobacterium tuberculosis (Mtb) is limited.

Methods

This study was nested in 3 cohort studies of tuberculosis (TB) patients with and without DM in India. Paired Mtb isolates recovered at baseline and treatment failure/recurrence underwent whole genome sequencing. We compared acquisition of single-nucleotide polymorphisms (SNPs), TB drug resistance mutations, and type of recurrence (endogenous reactivation [<8 SNPs] or exogenous reinfection [≥8 SNPs]) by DM status.

Results

Of 1633 enrolled in the 3 parent cohorts, 236 (14.5%) had microbiologically confirmed TB treatment failure/recurrence; 76 Mtb isolate pairs were available for sequencing (22 in TB-DM and 54 in TB-only). The SNP acquisition rate was overall was 0.43 (95% confidence interval [CI], .25–.64) per 1 person-year (PY); 0.77 (95% CI, .40–1.35) per 1 PY, and 0.44 (95% CI, .19–.86) per 1 PY at treatment failure and recurrence, respectively. Significant difference in SNP rates by DM status was seen at recurrence (0.21 [95% CI, .04–.61]) per 1 PY for TB-only vs 1.28 (95% CI, .41–2.98) per 1 PY for TB-DM; P = .02). No significant difference in SNP rates by DM status was observed at treatment failure. Acquired TB drug resistance was seen in 4 of 18 (22%) in TB-DM vs 4 of 45 (9%) in TB-only (P = .21). Thirteen (17%) participants had exogenous reinfection; the reinfection rate at recurrence was 25% (3/12) for TB-DM vs 17% (4/24) in TB-only (P = .66).

Conclusions

Considerable intrahost Mtb mutation rates were present at recurrence among patients with DM in India. One-fourth of patients with DM had exogenous reinfection at recurrence.