bluuebunny/crossref_metadata_2025 huggingface dataset:
In‐depth analysis of an RCD snubber applied to a DC‐DC boost converter
Authors: Vaz Alexandre Rodrigues , Tofoli Fernando Lessa
Published: December 2020

Resistor‐capacitor‐diode (RCD) snubbers are traditionally used in practice aiming to maintain the stresses on semiconductors within safe operating limits. However, a serious drawback is the power lost in the resistor, which may affect the converter efficiency significantly. In this context, this work proposes a detailed procedure for the accurate design of an RCD snubber based on two additional key parameters that are not considered in typical guidelines provided in didactic books, that is, the forward recovery time of the main diode and the inductor current ripple. The impact of the maximum additional voltage spike on the switch is first assessed considering that it influences both the power dissipated in the snubber resistor and the current stresses on all semiconductors. A systematic optimization of the design is presented later on, considering that proper tradeoffs can be made among the type of main diode used in the converter, the maximum voltage spike on the switch, and the inductor current ripple as demonstrated mathematically. A dc‐dc boost converter operating in continuous conduction mode (CCM) is thoroughly analyzed so that is possible to derive a consistent methodology comprising all power stage elements. This study intends to shed new light on an old research topic, as well to investigate the snubber impact on the converter operation and overall performance. The effectiveness of the proposed approach is demonstrated experimentally employing a laboratory prototype rated at 200 W. The results clearly show that is possible to optimize the design as desired, with good overall performance over a wide load range considering all aforementioned aspects.
Design of wide band compact bend triangular resonator artificial magnetic conductor and its application for antenna gain enhancement
Authors: Tamrakar Maruti , Kiran Kommuri Usha
Published: December 2020

In this paper, a compact bend triangular resonator (CBTR) structure is proposed as artificial magnetic conductor (AMC) to enhance antenna gain for wide frequency bandwidth. This paper presents the metamaterial properties of the CBTR structure like absorbance and reflection phase. The CBTR unit cell gives in‐phase reflection (0° ± 90°) for 55.2% bandwidth. The CBTR unit‐cell reflection phase analysis is presented for the different height of normal incident wave. The CBTR AMC performance is validated using a wideband dipole antenna. For −6‐dB impedance bandwidth, the standalone dipole antenna covers ultrawide frequency range 3.1–12 GHz and for −10‐dB impedance bandwidth, antenna has dual band frequency response 3.4–4.4 GHz and 8.3–11 GHz. The antenna shows good impedance matching and radiation characteristics for frequency range, where the unit‐cell reflection phase is 135° to 45° for frequency range 2.5–6.5 GHz (bandwidth of 88.8%). The broadside directivity of 7 dBi is achieved for the dipole antenna with CBTR AMC in the frequency range of 2.5–6.5 GHz and broadside gain of >5 dBi in the frequency range of 3.2–6.7 GHz (bandwidth of 70.7%). The antenna efficiency of 60% (minimum) is achieved for the frequency range of 3.68.0 GHz (75.8%). The proposed CBTR design is orthogonally symmetric and is useful for dual‐polarized wideband frequency applications like wireless local area network (WLAN) (2.4–2.5 and 5.15–5.85 GHz) and new radio (NR) 5G sub‐6‐GHz (3.3–5.0 GHz).
Isotopic and elemental compositions reveal density‐dependent nutrition pathways in a population of mixotrophic jellyfish
Authors: Djeghri Nicolas , Pondaven Philippe , Stockenreiter Maria , Behl Stephan , Huang Jessica Y. T. , Hansen Thomas , Patris Sharon , Ucharm Gerda , Stibor Herwig
Published: December 2020

Mixotrophic organisms are increasingly recognized as important components of ecosystems, but the factors controlling their nutrition pathways (in particular their autotrophy–heterotrophy balance) are little known. Both autotrophy and heterotrophy are expected to respond to density‐dependent mechanisms but not necessarily in the same direction and/or strength. We hypothesize that the autotrophy–heterotrophy balance of mixotrophic organisms might therefore be a function of population densities. To investigate this relationship, we sampled mixotrophic jellyfish holobionts (host, Mastigias papua etpisoni; symbiont, Cladocopium sp.) in a marine lake (Palau, Micronesia) on six occasions (from 2010 to 2018). Over this period, population densities varied ~100 fold. We characterized the nutrition of the holobionts using the δ13C and δ15N signatures as well as C:N ratios. δ13C values increased and δ15N values decreased with increasing population densities (respectively, R2 = 0.86 and 0.70, P < 0.05). Although less distinct, C:N ratios increased with increasing population densities (R2 = 0.59, 0.1 > P > 0.05). This indicates that the autotrophy–heterotrophy balance tends toward autotrophy when population densities increase. We propose that the availability of zooplanktonic prey is the main driver of this pattern. These results demonstrate that the autotrophy–heterotrophy balance of mixotrophic jellyfishes can be tightly regulated by density‐dependent mechanisms.
Combined use of the ketogenic diet and vagus nerve stimulation in pediatric drug‐resistant epilepsy
Authors: Abdelmoity Ayman T. , Le Pichon Jean‐Baptiste , Abdelmoity Sherouk A. , Sherman Ashley K. , Hall Ara S. , Abdelmoity Ahmed T.
Published: December 2020

Objective

Patients with drug‐resistant epilepsy (DRE) pose considerable management challenges for patients, their families, and providers. Both the vagus nerve stimulator (VNS) and the ketogenic diet (KD) have been shown to be safe and effective in treating DRE. Nevertheless, information is lacking regarding treatment with combination of both modalities. This study reports the efficacy and tolerability of combining VNS and KD in a pediatric cohort with intractable epilepsy.

Methods

This is a retrospective review of 33 patients (0‐17 years) with DRE treated with VNS and KD at a single pediatric level IV epilepsy center. We compared seizure reduction rates for each patient at baseline and at every clinic visit for 24 months after adding the second nonpharmacological therapy. The frequency of adverse events on the combined therapy was collected to assess safety and tolerability.

Results

There were a total of 170 visits for all patients while on the combined therapy. At 88% (95% CI: 83%‐93%) of the visits, patients reported some reduction in seizure frequency. The proportion of patients reporting a greater than 50% seizure reduction over all visits was 62% (95% CI: 55%‐69%). The proportion of a patient's visits with at least a greater than 50% reduction in seizure frequency had a median of 71% (IQR 33%‐100%). Continued improvement was seen over time of combined treatment; for every one‐unit time unit change (one month), there was a 6% increase in the odds of having a reduction in seizure frequency of >50% (OR = 1.06, 95% CI: 1.01‐1.11).

Significance

This study shows that combining the VNS and KD in patients with drug‐resistant epilepsy is well tolerated and reduces seizure frequency more than either one modality used alone and that the benefits in terms of seizure reduction continue to increase with the length of treatment.
A comprehensive review of experimental investigation procedures and thermal performance enhancement techniques of solar air heaters
Authors: Chamarthi Subbarao , Singh Satyender
Published: December 2020

This review composition aimed to comprehensively present the experimental investigation procedures and thermal performance augmentation techniques of solar air heaters. Various testing standards such as static and dynamic tests, and performance parameters, such as, thermal, thermo‐hydraulic, and exergy efficiencies, are incorporated to present the experimental investigation procedures. The present review work deals with testing conditions (indoor and outdoor), instrumentation, various parameters of interest with corresponding optimum values, their uncertainty levels together with SAH orientation, air flow type, thermal energy storage devices, duct modifications and heat transfer surfaces using fins, baffles, and ribs employed to enhance the thermal performance. The authors of this review work believed that the current composition constitutes a summary of details to quickly access the information for analyzing the various experimental investigation procedures and heat transfer augmentation techniques along with the optimum values of flow and geometric parameters. Moreover, economical and efficient solar air‐heating systems with low pressure drop and high heat exchange to air are presented and reviewed.
Having Fun (and Commercial Success) with Josiphos and Related Chiral Ferrocene Based Ligands.
Authors: Blaser Hans Ulrich , Pugin Benoît , Spindler Felix
Published: December 2020

The Josiphos ligand family is arguably one of the most versatile classes of chiral ligands with a wide range of applications, including one of the two largest known enantioselective catalytic hydrogenations. In this personal account, we take a look back at the beginning and describe the role Antonio Togni has played to reach this point and the significance of his contributions for the commercial success, especially concerning today's ligand business of Solvias. This seems a fitting point in time in light of Antonio’s statement on his ETH home page that he ‘is working as a professor at this institution since 1992 (a few more months to go), not looking for a job’ and that the three authors have already retired for some time (H. U. B.) or are about to retire soon (B. P., F. S.).
Communication between infant boys and their mothers with ADHD symptoms
Authors: Karagianni Eleni , Papaeliou Christina F. , Maniadaki Katerina , Kakouros Efthymios
Published: December 2020

Aim

This preliminary longitudinal study examined timing features and type of interaction between infant boys and their mothers with attention deficit hyperactivity disorder (ADHD) symptoms

Method

Ten infants and their mothers with ADHD symptoms and 10 control dyads were video recorded at home during free play interactions when infants were 2‐, 4‐, 6‐, and 9‐month old. Microanalysis of the video recordings was carried out to assess synchronization, turn‐taking, and type of interaction. Infants’ temperament was also assessed

Results

ADHD dyads showed shorter synchronization at 2 months and shorter duration of Joint Attention. Partial least squares regression analysis revealed that infant's ability for Joint Attention is predicted mainly by duration of maternal behavior as well as by earlier forms of communication, that is, protoconversations.

Conclusion

The data from our preliminary study suggest that mothers with ADHD symptoms may have difficulties maintaining their behavior for enough time possibly due to the core symptoms of the disorder, that is, inattention, hyperactivity, and impulsivity. This maternal deficit seems to affect temporal coordination with their infants and maybe the development of more complex forms of interaction. Clinical implications of these findings are also discussed.
Toxicological responses of BEAS‐2B cells to repeated exposures to benzene, toluene, m‐xylene, and mesitylene using air–liquid interface method
Authors: Méausoone Clémence , Landkocz Yann , Cazier Fabrice , Seigneur Marianne , Courcot Dominique , Billet Sylvain
Published: December 2020

In order to reduce exposure to toxic chemicals, the European REACH regulation (1907/2006) recommends substituting toxic molecules with compounds that are less harmful to human health and the environment. Toluene is one of the most frequently used solvents in industries despite its toxicity. The objective of this study is to better understand and compare the toxicity of toluene and its homologues in a bronchial cell model. Thus, human bronchial BEAS‐2B cells were exposed to steams of toluene, m‐xylene, mesitylene (1,3,5‐trimethylbenzene), and benzene (20 and 100 ppm). Exposure was carried out using an air–liquid interface (ALI) system (Vitrocell) during 1 h/day for 1, 3, or 5 days. Cytotoxicity, xenobiotic metabolism enzyme gene expression, and inflammatory response were evaluated following cell exposures. BEAS‐2B cell exposure to toluene and its homologues revealed the involvement of major (CYP2E1) and minor metabolic pathways (CYP1A1). A late induction of genes (EPHX1, DHDH, ALDH2, and ALDH3B1) was measured from Day 3 and can be linked to the formation of metabolites. An increase in the secretion level of inflammatory markers (TNF‐α, IL‐6, IL‐8, MCP‐1, and GM‐CSF) was also observed. In parallel, regulation between inflammatory mediators and the expression of transmembrane glycoprotein mucin MUC1 was also studied. This in vitro approach with ALI system points out the relevance of conducting repeated exposures to detect potential late effects. The difference recorded after cell exposure to toluene and its homologues highlights the importance of substitution principle.
Activation of Akt‐dependent Nrf2/ARE pathway by restoration of Brg‐1 remits high glucose‐induced oxidative stress and ECM accumulation in podocytes
Authors: Yan Hao , Xu Fei , Xu Jun , Song Ming‐Ai , Wang Kai , Wang Lulu
Published: December 2020

Brahma‐related gene 1 (Brg‐1) is perceived as a cytoprotective protein due to its role in alleviating oxidative stress and apoptosis. Our study aimed to explore the role and mechanism of Brg‐1 in high glucose (HG)‐stimulated podocytes. The HG exposure downregulated Brg‐1 and inactivated the protein kinase B (Akt) pathway in podocytes. Restoration of Brg‐1 inhibited HG‐induced viability reduction of podocytes. The HG‐induced increase of reactive oxygen species and malondialdehyde levels and decrease of superoxide dismutase activity in podocytes were reversed by the Brg‐1 overexpression. The Brg‐1 overexpression terminated the HG‐induced production of fibronectin, collagen IV, transforming growth factor‐β1, and connective tissue growth factor. In addition, the Brg‐1 overexpression activated Akt‐dependent nuclear factor E2‐related factor 2 (Nrf2)/antioxidant response element (ARE) signaling in HG‐stimulated podocytes. However, inhibition of the Akt pathway or Nrf2 silencing counteracted the protective effects of Brg‐1 in HG‐stimulated podocytes. In conclusion, the Brg‐1 overexpression suppressed HG‐induced oxidative stress and extracellular matrix accumulation by activation of Akt‐dependent Nrf2/ARE signaling in podocytes.
Fostering youth civic engagement through effective mentorship: Understanding the college student volunteer mentors who succeed
Authors: Maker Castro Elena , Cohen Alison K.
Published: December 2020

College student volunteers play a critical role in many school‐based educational programs and can foster valuable near‐peer relationships with adolescents, yet how to best select these volunteers has been understudied. We studied college student volunteer mentors for Generation Citizen, a non‐profit that provides school‐based action civics education programming, and their adolescent students. We identify three common characteristics possessed by the strongest college mentors. Participants were nine college volunteer mentors (67% female; 78% White); these mentors worked in pairs (and one trio) in four different classrooms. Using an action research approach, we conducted semistructured interviews, surveys, and classroom observations to generate quantitative and qualitative data. Effective mentors were: person‐oriented, emphasizing the mentor‐student connection; aligned with the organization's mission; and constantly honing their craft of mentorship. We recommend college volunteer programs select applicants for positions based on these key indicators to foster mission‐driven and motivating educational programming.
The effect and mechanism of neighbourhood choice on socioeconomic integration of migrants: Evidence from China
Authors: Zou Jing , Deng Xiaojun
Published: December 2020

On the basis of the 2013 China Migrants Dynamic Survey provided by the National Health and Family Planning Commission, we explored the impact of neighbourhood choice on the socioeconomic integration of migrants and the underlying mechanism. When problems with endogeneity were controlled, the findings showed that neighbourhood choice had a significant positive effect on the socioeconomic integration of migrants, that is, compared with migrants living in informal neighbourhoods (urban villages or outdated inner‐city housing), those living in formal neighbourhoods (commercial housing, affordable housing or work unit housing neighbourhoods) displayed higher socioeconomic integration. Further research found that neighbourhood choice did not directly affect the socioeconomic integration of migrants in China, partly because migrants living in formal neighbourhoods established localized social capital (contacting local residents and government personnel, seeking help from them and increasing expenditures on local invitations and gifts) to promote better integration into the city, and they had a stronger willingness to settle down, which encouraged them to work harder, actively integrated into the mainstream society.
mTORC2 negatively controls the maturation process of medullary thymic epithelial cells by inhibiting the LTβR/RANK‐NF‐κB axis
Authors: Liang Zhanfeng , Zhang Qian , Dong Xue , Zhang Zhaoqi , Wang Hongxia , Zhang Jiayu , Zhao Yong
Published: December 2020

The differentiation of mature medullary thymic epithelial cells (mTECs) is critical for the induction of central immune tolerance. Although the critical effect of mechanistic target of rapamycin complex 1 (mTORC1) in shaping mTEC differentiation has been studied, the regulatory role of mTORC2 in the differentiation and maturation of mTECs is poorly understood. We herein reported that TEC‐specific ablation of a rapamycin‐insensitive companion of mTOR (RICTOR), a key component of mTORC2, significantly decreased the thymus size and weight, the total cell number of TECs, and the cell number of mTECs with a smaller degree of reduced cortical thymic epithelial cells. Interestingly, RICTOR deficiency significantly accelerated the mTEC maturation process, as indicated by the increased ratios of mature mTECs (MHCIIhi, CD80+, and Aire+) to immature mTECs (MHCIIlo, CD80−, and Aire−) in Rictor‐deficient mice. The RNA‐sequencing assays showed that the upregulated nuclear factor‐κB (NF‐κB) signaling pathway in Rictor‐deficient mTECs was one of the obviously altered pathways compared with wild‐type mTECs. Our studies further showed that Rictor‐deficient mTECs exhibited upregulated expression of receptor activator of NF‐κB (RANK) and lymphotoxin β receptor (LTβR), as well as increased activity of canonical and noncanonical NF‐κB signaling pathways as determined by ImageStream and Simple Western. Finally, our results showed that inhibition of NF‐κB signaling pathways could partially reverse the accelerated maturation of mTECs in Rictor conditional KO mice. Thus, mTORC2 negatively controls the kinetics of the mTEC maturation process by inhibiting the LTβR/RANK‐NF‐κB signal axis.
Microbial controls on net production of nitrous oxide in a denitrifying woodchip bioreactor
Authors: Nordström Albin , Hellman Maria , Hallin Sara , Herbert Roger B.
Published: December 2020

Denitrifying woodchip bioreactors are potential low‐cost technologies for the removal of nitrate (NO3−) in water through denitrification. However, if environmental conditions do not support microbial communities performing complete denitrification, other N transformation processes will occur, resulting in the export of nitrite (NO2−), nitrous oxide (N2O), or ammonium (NH4+). To identify the factors controlling the relative accumulation of NO2−, N2O, and/or NH4+in denitrifying woodchip bioreactors, porewater samples were collected over two operational years from a denitrifying woodchip bioreactor designed for removing NO3−from mine water. Woodchip samples were collected at the end of the operational period. Changes in the abundances of functional genes involved in denitrification, N2O reduction, and dissimilatory NO3−reduction to NH4+were correlated with porewater chemistry and temperature. Temporal changes in the abundance of the denitrification genenirSwere significantly correlated with increases in porewater N2O concentrations and indicated the preferential selection of incomplete denitrifying pathways ending with N2O. Temperature and the total organic carbon/NO3−ratio were strongly correlated with NH4+concentrations and inversely correlated with the ratio between denitrification genes and the genes indicative of ammonification (Σnir/nrfA), suggesting an environmental control on NO3−transformations. Overall, our results for a denitrifying woodchip bioreactor operated at hydraulic residence times of 1.0–2.6 d demonstrate the temporal development in the microbial community and indicate an increased potential for N2O emissions with time from the denitrifying woodchip bioreactor.
Microglial derived extracellular vesicles activate autophagy and mediate multi‐target signaling to maintain cellular homeostasis
Authors: Van den Broek Bram , Pintelon Isabel , Hamad Ibrahim , Kessels Sofie , Haidar Mansour , Hellings Niels , Hendriks Jerome J.A. , Kleinewietfeld Markus , Brône Bert , Timmerman Vincent , Timmermans Jean‐Pierre , Somers Veerle , Michiels Luc , Irobi Joy
Published: December 2020

Microglia, the immunocompetent cells of the central nervous system (CNS), play an important role in maintaining cellular homeostasis in the CNS. These cells secrete immunomodulatory factors including nanovesicles and participate in the removal of cellular debris by phagocytosis or autophagy. Accumulating evidence indicates that specifically the cellular exchange of small extracellular vesicles (EVs), participates in physiology and disease through intercellular communication. However, the contribution of microglial‐derived extracellular vesicles (M‐EVs) to the maintenance of microglia homeostasis and how M‐EVs could influence the phenotype and gene function of other microglia subtypes is unclear. In addition, knowledge of canonical signalling pathways of inflammation and immunity gene expression patterns in human microglia exposed to M‐EVs is limited. Here, we analysed the effects of M‐EVs produced in vitro by either tumour necrosis factor alpha (TNFα) activated or non‐activated microglia BV2 cells. We showed that M‐EVs are internalized by both mouse and human C20 microglia cells and that the uptake of M‐EVs in microglia induced autophagic vesicles at various stages of degradation including autophagosomes and autolysosomes. Consistently, stimulation of microglia with M‐EVs increased the protein expression of the autophagy marker, microtubule‐associated proteins 1A/1B light chain 3B isoform II (LC3B‐II), and promoted autophagic flux in live cells. To elucidate the biological activities occurring at the transcriptional level in C20 microglia stimulated with M‐EVs, the gene expression profiles, potential upstream regulators, and enrichment pathways were characterized using targeted RNA sequencing. Inflammation and immunity transcriptome gene panel sequencing of both activated and normal microglia stimulated with M‐EVs showed involvement of several canonical pathways and reduced expression of key genes involved in neuroinflammation, inflammasome and apoptosis signalling pathways compared to control cells. In this study, we provide the perspective that a beneficial activity of in vitro cell culture produced EVs could be the modulation of autophagy during cellular stress. Therefore, we use a monoculture system to study microglia‐microglia crosstalk which is important in the prevention and propagation of inflammation in the brain. We demonstrate that in vitro produced microglial EVs are able to influence multiple biological pathways and promote activation of autophagy in order to maintain microglia survival and homeostasis.
The proteomic landscape of small urinary extracellular vesicles during kidney transplantation
Authors: Braun Fabian , Rinschen Markus , Buchner Denise , Bohl Katrin , Plagmann Ingo , Bachurski Daniel , Richard Späth Martin , Antczak Philipp , Göbel Heike , Klein Corinna , Lackmann Jan‐Wilm , Kretz Oliver , Puelles Victor G. , Wahba Roger , Hallek Michael , Schermer Bernhard , Benzing Thomas , Huber Tobias B. , Beyer Andreas , Stippel Dirk , Kurschat Christine E. , Müller Roman‐Ulrich
Published: December 2020

Kidney transplantation is the preferred renal replacement therapy available. Yet, long‐term transplant survival is unsatisfactory, partially due to insufficient possibilities of longitudinal monitoring and understanding of the biological processes after transplantation. Small urinary extracellular vesicles (suEVs) – as a non‐invasive source of information – were collected from 22 living donors and recipients. Unbiased proteomic analysis revealed temporal patterns of suEV protein signature and cellular processes involved in both early response and longer‐term graft adaptation. Complement activation was among the most dynamically regulated components. This unique atlas of the suEV proteome is provided through an online repository allowing dynamic interrogation by the user. Additionally, a correlative analysis identified putative prognostic markers of future allograft function. One of these markers – phosphoenol pyruvate carboxykinase (PCK2) – could be confirmed using targeted MS in an independent validation cohort of 22 additional patients. This study sheds light on the impact of kidney transplantation on urinary extracellular vesicle content and allows the first deduction of early molecular processes in transplant biology. Beyond that our data highlight the potential of suEVs as a source of biomarkers in this setting.
Methamphetamine use alters human plasma extracellular vesicles and their microRNA cargo: An exploratory study
Authors: Sandau Ursula S. , Duggan Erika , Shi Xiao , Smith Sierra J. , Huckans Marilyn , Schutzer William E. , Loftis Jennifer M. , Janowsky Aaron , Nolan John P. , Saugstad Julie A.
Published: December 2020

Methamphetamine (MA) is the largest drug threat across the globe, with health effects including neurotoxicity and cardiovascular disease. Recent studies have begun to link microRNAs (miRNAs) to the processes related to MA use and addiction. Our studies are the first to analyse plasma EVs and their miRNA cargo in humans actively using MA (MA‐ACT) and control participants (CTL). In this cohort we also assessed the effects of tobacco use on plasma EVs. We used vesicle flow cytometry to show that the MA‐ACT group had an increased abundance of EV tetraspanin markers (CD9, CD63, CD81), but not pro‐coagulant, platelet‐, and red blood cell‐derived EVs. We also found that of the 169 plasma EV miRNAs, eight were of interest in MA‐ACT based on multiple statistical criteria. In smokers, we identified 15 miRNAs of interest, two that overlapped with the eight MA‐ACT miRNAs. Three of the MA‐ACT miRNAs significantly correlated with clinical features of MA use and target prediction with these miRNAs identified pathways implicated in MA use, including cardiovascular disease and neuroinflammation. Together our findings indicate that MA use regulates EVs and their miRNA cargo, and support that further studies are warranted to investigate their mechanistic role in addiction, recovery, and recidivism.
Epitranscriptomic m6A regulation following spinal cord injury
Authors: Xing Lingyan , Cai Yunyun , Yang Tuo , Yu Weiwei , Gao Mengdie , Chai Rui , Ding Sujun , Wei Jinhuan , Pan Jingying , Chen Gang
Published: December 2020

RNA methylation is involved in multiple physiological and pathological processes. However, the role of RNA methylation in spinal cord regeneration has not been reported. In this study, we find an altered m6A (N6‐methyladenosine) RNA methylation profiling following zebrafish spinal cord injury (SCI), in line with an altered transcription level of the m6A methylase Mettl3. Interestingly, many of the differential m6A‐tagged genes associated with neural regeneration are hypomethylated, but their transcription levels are upregulated in SCI. Moreover, we find that METTL3 may be important for spinal cord regeneration. We also show a conserved feature of METTL3 changes in mouse SCI model, in which the expression of METTL3 is increased in both astrocytes and neural stem cells. Together, our results indicate that m6A RNA methylation is dynamic and conserved following SCI and may contribute to spinal cord regeneration.
Endocannabinoids regulate cerebellar GABAergic transmission in a synapse type‐dependent manner
Authors: Hirono Moritoshi , Yanagawa Yuchio
Published: December 2020

Endocannabinoids (eCBs) act as ubiquitous modulators of synaptic transmission via the activation of cannabinoid receptors (CBRs). Cerebellar Purkinje cells (PCs) make strong inhibitory synaptic contacts not only with neurons in the deep cerebellar nuclei (DCN) but also with Lugaro cells and globular cells, whose cell bodies are located underneath the PC layer. However, little is known about the modulatory actions of eCBs on GABA release from PC axon terminals. Here, we examined the effects of eCBs on the GABAergic transmission at PC‐globular cell synapses and PC‐large DCN neuron synapses electrophysiologically using mouse cerebellar slices. We showed that the types 1 and 2 CBR agonist WIN55212 did not affect either spontaneous or miniature inhibitory postsynaptic currents (IPSCs) in globular cells under control conditions and in a state of enhanced synaptic activity. By contrast, another Gi/o protein‐coupled receptor agonist, baclofen, significantly reduced the miniature IPSC frequency in globular cells. WIN55212 had no effects on IPSCs in large DCN neurons. A type 2 CBR agonist, HU308, also had no effects on IPSCs in either globular cells or large DCN neurons. Moreover, the PCs' target neurons did not elicit depolarization‐induced suppression of inhibition. These results suggest the lack of a functional role of CBRs at PCs' axon terminals. This is in sharp contrast to the fact that PCs receive abundant excitatory and inhibitory inputs that are under eCB‐mediated presynaptic inhibitory modulation. The actions of eCBs are selective to distinct synapses and possibly contribute to information processes and rigorous signal transmission in the cerebellum.
Phosphodiesterase‐5 inhibition improves bone regeneration at the early stages of ischemic osteonecrosis of the femoral head in rats
Authors: de Campos Pessoa André L. , de Oliveira Araújo Victor H. V. , Rosa Nascimento Ana L. , Elias Nelson , de Carvalho Jorge J.
Published: December 2020

Posttraumatic osteonecrosis of the femoral head (ONFH) affects patients at different ages and may lead to functional limitation and joint replacement, with total hip arthroplasty, which is a costly procedure. Proposed methods to optimize ischemic tissue regeneration have been reported. Phosphodiesterase‐5 inhibitors act by inhibiting the degradation of guanosine 3′,5′‐cyclic monophosphate in the nitric oxide pathway, increasing its bioavailability and promoting vascular endothelial growth factor (VEGF)‐mediated neovascular recruitment and the induction of tissue regeneration in the traumatized bone. Thirty male Sprague–Dawley rats (6 months old) were subjected to an experimental model of traumatic ONFH divided into two groups, according to the administration of 5 mg/kg sildenafil or water (control group). Rats were then killed at 7, 14, and 21 days. Histological (Goldner's trichrome), histochemical (periodic acid–Schiff [PAS]), and immunohistochemical (VEGF and osteopontin [OPN]) techniques were used to quantify bone and vascular responses. Higher levels of VEGF (p < 0.01) and OPN (p < 0.01) immunostaining in the epiphysis, the greater formation of osteoid tissue (p < 0.01 on Day 7; p < 0.05 on Day 14), and higher levels of PAS staining (p < 0.01 on Day 7) were observed in the sildenafil‐treated group. The present study demonstrated that sildenafil optimized bone tissue regeneration by increasing VEGF signaling and OPN expression, with increased bone formation (osteoid and carbohydrate macromolecule deposition) in the early stages following traumatic ischemic insult. Thus, sildenafil treatment may improve the prognosis of patients with osteonecrosis.
Sagittaria trifolia tuber: bioconstituents, processing, products, and health benefits
Authors: Zhang Yang , Yang Guihong , Wang Xinyu , Ni Gaoyang , Cui Zhumei , Yan Zhaowei
Published: December 2020

Sagittaria trifolia is an aquatic plant that is distributed worldwide. The edible tuber part of S. trifolia is a very common and popular vegetable in China. The aim of the present review is to discuss the discovery of nutraceuticals from S. trifolia tuber by reviewing its major constituents, food processing, food products, and health‐promoting benefits. Sagittaria trifolia tuber comprises a series of nutritional and bioactive constituents, including dietary fibers, amino acids, minerals, starches, non‐starch polysaccharides, diterpenoids, colchicine, phenols, and organic acids. Food processing affects its flavor, biocomponents, and bioactivity. Numerous S. trifolia tuber‐based food products and nutraceuticals have been developed, but new categories of products and the anticipated functions still need to be explored. The non‐starch polysaccharides could be the central ingredients that contribute to the plant's antioxidant, hepatoprotective, hypoglycemic, lipid‐regulating, and immunostimulatory properties. Of these, antioxidant and hepatoprotective effects have been thoroughly investigated. Procedures for the extraction and purification of polysaccharides influence their health‐promoting actions. Overall, S. trifolia tuber is an underutilized aquatic vegetable species that is an emerging subject for nutraceutical research. © 2020 Society of Chemical Industry
Effects of ryegrass canopy and roots on the distribution characteristics of eroded sediment particles during heavy rainfall events on steep loess‐cinnamon slopes in Zhangjiakou, China
Authors: Liu Xiaona , Yu Xinxiao , Fan Dengxing , Jia Guodong
Published: December 2020

To evaluate the effects of ryegrass (Lolium perenne) canopy and roots on eroded sediment particle distribution characteristics, simulated rainfall tests were implemented on grass caopy, roots, and bare slopes. The grass coverage density were 0, 20, 40, and 60%. The results showed that ryegrass canopies mainly contributed to runoff reduction and ryegrass roots primarily contributed to erosion reduction. With increasing rainfall duration, smaller particles (clay and fine silt particles) increased and larger particles (coarse silt and sand particles) decreased in the eroded sediment on the grass slope while the opposite trend was observed for the roots and bare slopes. Moreover, the clay and sand particles were eroded as aggregates and most silt particles were transported in the form of primary particles. Compared to the original soil, larger particles in the eroded sediment mainly occurred on the grass slopes because smaller particles were intercepted by the grass canopies, while smaller particles primarily occurred in the eroded sediment of the root slopes because grass roots inhibited soil erosion. These results illustrate that grass cover can prevent the loss of small particles in the topsoil and avoid soil coarsening, which provides guidance for the comprehensive control of soil erosion.
Photoluminescent Behaviors of Thermally Activated Delayed Fluorescence Polymeric Emitters in Nanofibers
Authors: Li Chensen , Liu Yuchao , Zhao Zhennan , Liu Junteng , Ren Zhongjie , Yan Shouke
Published: December 2020

Anisotropic 1D nanostructures with high surface‐area‐to‐volume ratio display the enhanced optoelectronic properties of light‐emitting compounds compared to bulk or 2D systems. To study the effect of nanometer‐constrained space on photoluminescent behavior of thermally activated delayed fluorescence (TADF) polymeric emitters, electrospinning technique is used to produce nanofibers of TADF emitters. Herein, two TADF polymer (P1 and P3) nanofibers with 90% polyacrylonitrile (PAN) are fabricated and their photophysical properties are studied and compared with their spin‐coated film counterparts. The distinguishing polarized photoluminescencent properties of P1/PAN or P3/PAN electrospun nanofibers are obtained due to high orientation degree and superior molecular arrangement. Moreover, the better TADF properties in nanofibers can be observed comparing with their spin‐coated films, including longer‐lived excited states, higher photoluminescence quantum efficiency, lower internal conversion decay rate, and higher reverse intersystem crossing rate constant.
Pantoea ananatis carotenoid production confers toxoflavin tolerance and is regulated by Hfq‐controlled quorum sensing
Authors: Choi Okhee , Kang Byeongsam , Lee Yongsang , Lee Yeyeong , Kim Jinwoo
Published: December 2020

Carotenoids are widely used in functional foods, cosmetics, and health supplements, and their importance and scope of use are continuously expanding. Here, we characterized carotenoid biosynthetic genes of the plant‐pathogenic bacterium Pantoea ananatis, which carries a carotenoid biosynthetic gene cluster (including crtE, X, Y, I, B, and Z) on a plasmid. Reverse transcription–polymerase chain reaction (RT‐PCR) analysis revealed that the crtEXYIB gene cluster is transcribed as a single transcript and crtZ is independently transcribed in the opposite direction. Using splicing by overlap extension with polymerase chain reaction (SOE by PCR) based on asymmetric amplification, we reassembled crtE–B, crtE–B–I, and crtE–B–I–Y. High‐performance liquid chromatography confirmed that Escherichia coli expressing the reassembled crtE–B, crtE–B–I, and crtE–B–I–Y operons produced phytoene, lycopene, and β‐carotene, respectively. We found that the carotenoids conferred tolerance to UV radiation and toxoflavin. Pantoea ananatis shares rice environments with the toxoflavin producer Burkholderia glumae and is considered to be the first reported example of producing and using carotenoids to withstand toxoflavin. We confirmed that carotenoid production by P. ananatis depends on RpoS, which is positively regulated by Hfq/ArcZ and negatively regulated by ClpP, similar to an important regulatory network of E. coli (HfqArcZ →RpoS Ͱ ClpXP). We also demonstrated that Hfq‐controlled quorum signaling de‐represses EanR to activate RpoS, thereby initiating carotenoid production. Survival genes such as those responsible for the production of carotenoids of the plant‐pathogenic P. ananatis must be expressed promptly to overcome stressful environments and compete with other microorganisms. This mechanism is likely maintained by a brake with excellent performance, such as EanR.
Some aspects of the Markovian SIRS epidemic on networks and its mean‐field approximation
Authors: Ottaviano Stefania , Bonaccorsi Stefano
Published: December 2020

We study the spread of an SIRS‐type epidemic with vaccination on network. Starting from an exact Markov description of the model, we investigate the mean epidemic lifetime by providing a sufficient condition for fast extinction that depends on the model parameters and the topology of the network. Then, we pass to consider a first‐order mean‐field approximation of the exact model and its stability properties, by relying on the graph‐theoretical notion of equitable partition. In the case of graphs possessing this kind of partition, we prove that the endemic equilibrium can be computed by using a lower‐dimensional dynamical system. Finally, in the special case of regular graphs, we investigate the domain of attraction of the endemic equilibrium.
Fast automatic segmentation of thalamic nuclei from MP2RAGE acquisition at 7 Tesla
Authors: Datta Ritobrato , Bacchus Micky K. , Kumar Dushyant , Elliott Mark A. , Rao Aditya , Dolui Sudipto , Reddy Ravinder , Banwell Brenda L. , Saranathan Manojkumar
Published: December 2020

Purpose

Thalamic nuclei are largely invisible in conventional MRI due to poor contrast. Thalamus Optimized Multi‐Atlas Segmentation (THOMAS) provides automatic segmentation of 12 thalamic nuclei using white‐matter‐nulled (WMn) Magnetization Prepared Rapid Gradient Echo (MPRAGE) sequence at 7T, but increases overall scan duration. Routinely acquired, bias‐corrected Magnetization Prepared 2 Rapid Gradient Echo (MP2RAGE) sequence yields superior tissue contrast and quantitative T1 maps. Application of THOMAS to MP2RAGE has been investigated in this study.

Methods

Eight healthy volunteers and five pediatric‐onset multiple sclerosis patients were recruited at Children's Hospital of Philadelphia and scanned at Siemens 7T with WMn‐MPRAGE and multi‐echo‐MP2RAGE (ME‐MP2RAGE) sequences. White‐matter‐nulled contrast was synthesized (MP2‐SYN) from T1maps from ME‐MP2RAGE sequence. Thalamic nuclei were segmented using THOMAS joint label fusion algorithm from WMn‐MPRAGE and MP2‐SYN datasets. THOMAS pipeline was modified to use majority voting to segment bias corrected T1‐weighted uniform (MP2‐UNI) images. Thalamic nuclei from MP2‐SYN and MP2‐UNI images were evaluated against corresponding nuclei obtained from WMn‐MPRAGE images using dice coefficients, volume similarity indices (VSIs) and distance between centroids.

Results

For MP2‐SYN, dice > 0.85 and VSI > 0.95 was achieved for five larger nuclei and dice > 0.6 and VSI > 0.7 was achieved for seven smaller nuclei. The dice and VSI were slightly higher, whereas the distance between centroids were smaller for MP2‐SYN compared to MP2‐UNI, indicating improved performance using the MP2‐SYN image.

Conclusions

THOMAS algorithm can successfully segment thalamic nuclei in MP2RAGE images with essentially equivalent quality as WMn‐MPRAGE, widening its applicability in studies focused on thalamic involvement in aging and disease.
Results on existence and controllability results for fractional evolution inclusions of order 1 < r < 2 with Clarke's subdifferential type
Authors: Mohan Raja M. , Vijayakumar V. , Udhayakumar R. , Nisar Kottakkaran Sooppy
Published: December 2020

In our paper, we primarily concentrate on the existence and controllability results for fractional evolution inclusions of order 1 < r < 2 with Clarke's subdifferential type. By applying the facts related to the measure of noncompactness, fractional calculus, and fixed‐point technique, the principal results are proved. Initially, we are concentrating the existence and continue to prove the controllability of the fractional evolution system. In the end, we present an example to demonstrate the theory.
Acidity enhancement of α‐carbon of beta diketones via hydroxyl substituents: A density functional theory study
Authors: Rahimi Mona , Fattahi Alireza
Published: December 2020

Density functional theory method and B3LYP/6‐311++G(d,p) level of theory were used to determine the acidity of α‐carbon in the hydroxyl derivatives of beta diketones in the gas phase. An investigation of acidity strength in the gas phase indicates that α‐carbon of hydroxyl derivatives of beta diketones become stronger acids than the α‐carbon of beta diketone itself as their conjugate bases gain more stability via both enolate and hydrogen bond formation. Natural bond orbital and quantum theory of atoms in molecules analyses also confirm the role of hydrogen bond interactions on increasing the acidity of α‐carbon of hydroxyl derivatives of beta diketones.
High‐resolution minirhizotrons advance our understanding of root‐fungal dynamics in an experimentally warmed peatland
Authors: Defrenne Camille E. , Childs Joanne , Fernandez Christopher W. , Taggart Michael , Nettles W. Robert , Allen Michael F. , Hanson Paul J. , Iversen Colleen M.
Published: December 2020

Societal Impact Statement

Mycorrhizal fungi enable plants to thrive in the cold, waterlogged, organic soils of boreal peatlands and, with saprotrophic fungi, largely contribute to the sequestration of atmospheric carbon in peat. Hence, fungi support the contribution of peatlands to global climate regulation, on which society depends. Here we used high‐resolution minirhizotrons for an unprecedented glimpse of the belowground world of a forested bog and highlighted linkages between environmental change and the abundance, dynamics, and morphology of vascular plant fine roots and fungal mycelium. These changes may have implications for peat carbon accumulation on the boreal landscape.

Summary

Minirhizotron technology has rarely been deployed in peatlands which has limited our understanding of root‐fungal dynamics in one of planet's most carbon‐dense ecosystems.

We used novel, high‐resolution minirhizotrons in a forested bog to explore temporal variation in the abundance and growth of plant fine roots and fungal mycelium with changes in peat temperature and moisture. We utilized the framework of the Spruce and Peatland Responses Under Changing Environments experiment and focused on two minirhizotron tubes installed at the coldest (+0, elevated CO2) and warmest (+9°C, elevated CO2) ends of the experimental temperature gradient, respectively.

We found that in warmer and drier peat, ericaceous shrub roots and ectomycorrhizal fungal rhizomorphs were more abundant, and the growth of rhizomorphs and sporocarps was greater. In turn, fine roots of trees, ectomycorrhizas, and dark‐colored fungal hyphae were more abundant in colder, wetter peat. Ultimately, the belowground active season for both plant roots and fungi was extended by 62 days at the warmest compared to the coldest end of the gradient, with implications for belowground carbon, water, and nutrient fluxes.

High‐resolution minirhizotrons in peatlands provided an unprecedented view of ericaceous shrub and tree fine roots and their mycorrhizal fungal partners in situ. Therefore, this technology advanced our understanding of linkages between environmental change and the abundance, morphology, and dynamics of vascular plant fine roots and fungal mycelium.
Development of new active nanocomposite packaging films containing polyhedral oligomeric silsesquioxane for walnut (Juglans regiaL.) kernel packaging
Authors: Kavuncuoglu Hatice , Yalcin Hasan , Dogan Mehmet
Published: December 2020

Active nanocomposite films made from low‐density polyethylene (LDPE) and polyhedral oligomeric silsesquioxane (POSS) were prepared as of food packaging material for walnut kernels (Juglans regia L.) oil protection against lipid oxidation. N‐Phenylaminopropyl‐POSS (NP‐POSS), octaammonium‐POSS (QA‐POSS) and methacryl‐POSS (M‐POSS) were utilized as convenient additives. Intact and crushed walnut kernels were stored in conditions set to accelerate oxidation (24 h of light, 38°C, and 33% RH). On the 14th day, peroxide value (PV) was determined as 14.13 meq O2/kg in intact walnut kernel oil (WKO), whereas the PV of walnuts was measured as 5.94 meq O2/kg and 7.95 meq O2/kg wrapped with 5 wt% NP‐POSS and 3 wt% QA‐POSS containing the film, respectively. At the end of the storage, K232 values were measured as 4.42 and 6.12 packaged with control films, whereas K232 values ranged 2.72 and 3.14 in samples packaged with 5 wt% NP‐POSS. Similarly, K232 value of WKO wrapped with QA‐POSS containing films was detected as 2.89 and 3.20 in intact and crushed walnut samples, respectively. The p‐anisidine value of WKO wrapped with pure LDPE reached 4.86 and 7.33 for WKO obtained from the intact and crushed walnut kernel, and the lowest p‐anisidine values observed intact (2.07) and crushed (3.84) samples of packaged with 5 wt% NP‐POSS, respectively. The results have shown that novel nanocomposite food packaging films, including NP‐POSS and QA‐POSS, for vacuum‐packed walnut kernels are sufficient to protect against oxidation.