bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly efficient nitrogen fixation enabled by an atmospheric pressure rotating gliding arc
Authors: Chen Hang , Wu Angjian , Mathieu Stéphanie , Gao Peihan , Li Xiaodong , Xu Bo Z. , Yan Jianhua , Tu Xin
Published: April 2021

A rotating gliding arc is proposed as a promising alternative to enable direct nitrogen fixation from ubiquitous air under mild conditions. The effect of different process parameters on NO
x
generation and energy consumption has been investigated through a combination of experiments and artificial neural network (ANN) modeling. The optical emission spectroscopic diagnostics together with electrical diagnostics and high‐speed photography has been used to understand the variation of the discharge characteristics. The lowest energy consumption of NO
x
production (4.2 MJ/mol) is achieved at a gas flow rate of 12 L/min and an O2 concentration of 20 vol%. The simulation results from the ANN model show a good agreement with the experimental data and the model enables us to evaluate the relative importance of the process parameters to the reaction performance.
CsPbBr3 Perovskite–Coated Paper Substrate for the Cost‐Effective Detection of Fluoride, Chloride, and Iodide Ions in Water
Authors: Sandeep K. , Hamida K. T.
Published: April 2021

Developing a simple and cost‐effective substrate for the detection of the halide ions present in water is extremely important due to their adverse effects at higher concentrations. A good substrate should behave differently in the presence of different halide ions. Herein, a CsPbBr3‐coated paper substrate is used for the detection of fluoride, chloride, and iodide ions. As a result of the fast anion exchange reactions, in the presence of each halide ion, the CsPbBr3‐coated paper shows different emission behaviors. The presence of chloride and iodide ions results in blueshifted and redshifted absorption and emission, respectively. In the presence of fluoride ions, anion exchange followed by decomposition of the perovskite nanocrystal is observed. The anion exchange reactions of CsPbBr3 perovskites are faster than the moisture‐induced decomposition, which enables the detection of micromolar concentrations of fluoride, chloride, and iodide ions in water.
Sarsasapogenin ameliorates diabetes‐associated memory impairment and neuroinflammation through down‐regulation of PAR‐1 receptor
Authors: Kong Li , Liu Yue , Zhang Yu‐Meng , Li Yu , Gou Ling‐Shan , Ma Teng‐Fei , Liu Yao‐Wu
Published: April 2021

Sarsasapogenin (Sar), a natural steroidal compound, shows neuroprotection, cognition‐enhancement, antiinflammation, antithrombosis effects, and so on. However, whether Sar has ameliorative effects on diabetes‐associated cognitive impairment remains unknown. In this study, we found that Sar ameliorated diabetes‐associated memory impairment in streptozotocin‐induced diabetic rats, evidenced by increased numbers of crossing platform and percentage of time spent in the target quadrant in Morris water maze tests, and suppressed the nucleotide‐binding domain and leucine‐rich repeat containing protein 1 (NLRP1) inflammasome in hippocampus and cerebral cortex. Furthermore, Sar inhibited advanced glycation end‐products and its receptor (AGEs/RAGE) axis and suppressed up‐regulation of thrombin receptor protease‐activated receptor 1 (PAR‐1) in cerebral cortex. On the other hand, Sar mitigated high glucose‐induced neuronal damages, NLRP1 inflammasome activation, and PAR‐1 up‐regulation in high glucose‐cultured SH‐SY5Y cells, but did not affect thrombin activity. Moreover, the effects of Sar were similar to those of a selective PAR‐1 antagonist vorapaxar. Further studies indicated that activation of the NLRP1 inflammasome and NF‐κB mediated the effect of PAR‐1 up‐regulation in high glucose condition by using PAR‐1 knockdown assay. In summary, this study demonstrated that Sar prevented memory impairment caused by diabetes, which was achieved through suppressing neuroinflammation from activated NLRP1 inflammasome and NF‐κB regulated by cerebral PAR‐1.

Highlights

Sarsasapogenin ameliorated memory impairment caused by diabetes in rats.

Sarsasapogenin mitigated neuronal damages and neuroinflammation by down‐regulating cerebral PAR‐1.

The NLRP1 inflammasome and NF‐κB signaling mediated the pro‐inflammatory effects of PAR‐1.

Sarsasapogenin was a pleiotropic neuroprotective agent and memory enhancer in diabetic rodents.
Spatial and temporal trends of Minnesota River phytoplankton and zooplankton
Authors: Sindt Anthony R. , Wolf Michael C.
Published: April 2021

Plankton communities have important roles in aquatic ecosystems, but studies of plankton in lotic systems are infrequent. We collected over 100 water, phytoplankton, and zooplankton samples during 2016–2018 to explore spatiotemporal trends in Minnesota River plankton communities and evaluate relationships with physico‐chemical factors. Phytoplankton and zooplankton community structure exhibited temporal patterns but only the zooplankton community differed spatially. Cyanobacteria (M ± SE; 11.27 ± 1.43 mm3/L) and diatoms (8.12 ± 1.08 mm3/L) dominated phytoplankton biovolume with seasonal peaks in Cyanobacteria occurring during July–September and peaks in diatoms occurring during May, August, and September. All phytoplankton taxa except Cryptophyta exhibited a negative relationship with relative discharge. Crustacean zooplankton biomass was greatest at two upstream sites (146.7 ± 32.6 μg/L) where cladocerans and copepods were likely exported from upstream of dams where water residence time is greater. Within the lower free‐flowing reach rotifers dominated the zooplankton community (207.9 ± 40.9 individuals/L and 6.5 ± 1.0 μg/L). Thus, spatial differences in zooplankton community structure were primarily attributed to the influence of dams. Seasonal patterns in zooplankton community structure included peaks in Chydoridae, cyclopoid, immature copepod, and rotifer biomass during May and Bosminidae biomass during October. Excluding the influence of dams on zooplankton, the cumulative effects of month and relative discharge were the most important for explaining variability in plankton community structure. Baseline understanding of plankton community dynamics provides the ability to quantify responses to future perturbations such as climate change and establishment of invasive planktivores.
Dynamics of large wood added to Midwestern USA streams
Authors: Bosio Samuel F. , Shirey Patrick D. , Entrekin Sally A. , Hoellein Timothy J. , Moerke Ashley H. , Rosi Emma J. , Tank Jennifer L. , Lamberti Gary A.
Published: April 2021

Large wood (LW) additions are commonly used to restore degraded streams, particularly in regenerating forests that have low LW recruitment due to past logging. While the short‐term effects of LW input on stream structure and function are well studied, the long‐term dynamics of added wood are less documented. We assessed the long‐term movement and condition of LW added to three small (mean discharge, 28–47 L s−1) midwestern USA streams. In 2004, 25 aspen logs (2.5 m L × 0.5 m D) were added to 100‐m treatment reaches of three replicate streams in northern Michigan, USA, that contained low prior LW abundance. We monitored log movement and evaluated factors contributing to that movement over 14 years. Across all three streams, 41 of the 75 added logs moved downstream, with a mean travel distance of 4.0 m (SD, 7.0 m; n = 75). However, all logs still remained within their original reaches. Most log movements occurred within the first 3 years following placement and were associated with high flow events. Individual log mobility was related to position in the channel; logs that were at least 70% submerged, and near horizontal in inclination, accounted for 83% of the single movements ≥0.5 m. In addition, after 14 years 32% of logs became part of aggregations and 86% displayed substantial decay. Our study suggests that restoration efforts that add LW to small, groundwater‐dominated streams can pose minimal risk to downstream reaches or human structures and may provide sustained ecological benefits to the ecosystem.
Rich −NH2 Mesoporous g‐C3N4 Nanosheets Efficient for Cycloaddition of CO2 to Epoxides without Solvent and Co‐Catalyst
Authors: Wang Hefang , Liu Guanghui , Hao Xiaojun , Li Manhua , Yang Lijia , Sun Peidong , Zhang Huixin
Published: April 2021

Graphitic carbon nitride (g‐C3N4) with N‐containing groups is an attractive catalyst for various CO2‐activating reactions. Herein, a rich −NH2 mesoporous g‐C3N4 nanosheets catalyst was successfully prepared by thermal exfoliation from bulk g‐C3N4 with porous structure using urea and melamine as precursors. With urea as precursor and bubble template, the nanosheets after thermal exfoliation showed large surface area (236.4 m2 g−1), rich mesopores and −NH2 groups, which are base sites of cycloaddition of CO2 to epoxides. The obtained catalyst showed high catalytic performance for CO2 cycloaddition without solvent and co‐catalyst. Propylene oxide (PO) and CO2 cycloaddition to propylene carbonate (PC) was used as probe reaction to evaluate the catalytic performance. Under the optimal reaction conditions (130 °C, 2.5 MPa, 20 h), the conversion of PO was 97.8 % and selectivity to PC was 98.1 %. In addition, the obtained catalyst showed good suitability for various substrates in CO2 cycloaddition and stability.
A Novel Fluorescent 1,10‐Phenanthroline‐2,9‐dicarboxaldehyde‐ 2,5‐diaminoterephthalicacid‐Schiff Base Polymer for Cu2+ Detection
Authors: Wang Shiqi , Cai Keying , Song Yonghai , Zhu Yongmei
Published: April 2021

A novel fluorescent Schiff base polymer (PTDA‐DATA‐SBP) is synthesized by amine aldehyde condensation reaction between 1,10‐phenanthroline‐2,9‐dicarboxaldehyde (PTDA) and 2,5‐diaminoterephthalicacid (DATA) as a selective fluorescent probe for Cu2+ detection. The as‐prepared PTDA‐DATA‐SBP displayed irregular nanospheres with a diameter of about 5 μm. Under the excitation of 338 nm, the PTDA‐DATA‐SBP had a characteristic emission peak at 565 nm. The PTDA groups in PTDA‐DATA‐SBP could coordinate with Cu2+ under help of carboxyl groups of DATA. Owing to the photoinduced electron transfer mechanism, the fluorescence of PTDA‐DATA‐SBP was weakened after the addition of Cu2+ in the presence of common ions. Hence, the PTDA‐DATA‐SBP was exploited as a fluorescent nanosensor for sensing Cu2+. The PTDA‐DATA‐SBP showed high selectivity and fast response towards Cu2+ even in presence of other relevant metal ions. The PTDA‐DATA‐SBP fluorescent sensor has a good linear range of 3.45 nM–8.00 μM, and the limit of detection was as low as 1.15 nM. The proposed PTDA‐DATA‐SBP sensor could also detect Cu2+ in actual samples. The work not only provided a good fluorescent probe for Cu2+ detection but also provided a feasible strategy to construct highly selective fluorescent probes.
Bimetal CoNi Active Sites on Mesoporous Carbon Nanosheets to Kinetically Boost Lithium−Sulfur Batteries
Authors: Luo Rui , Zhang Zhengchunyu , Zhang Jing , Xi Baojuan , Tian Fang , Chen Weihua , Feng Jinkui , Xiong Shenglin
Published: April 2021

In order to solve the problem that soluble polysulfide intermediates diffuse between cathode and anode during charging and discharging, which leads to rapid attenuation of battery cycle life, the separator modification materials come into people's sight. Herein, a mesoporous carbon‐supported cobalt‐nickel bimetal composite (CoNi@MPC) is synthesized and directly coated on the original separator to serve as a secondary collector for lithium−sulfur batteries. CoNi@MPC exhibits multiple Co‐Ni active sites, able to catalyze the reactions of soluble polysulfides, specifically accelerating the generation and decomposition of insoluble Li2S in lithiation and delithiation process testified by the electrochemical results and density functional theory calculation. Relying on the bifunctionality of CoNi@MPC composite, the shuttle effect of lithium polysulfides can be effectively alleviated. Moreover, porous carbon as the conductive scaffold favors the improvement of electronic conductivity. Benefiting from the above advantages, the cell with CoNi@MPC separator indicates significantly enhanced electrochemical performances with excellent cycling life over 500 cycles and superior rate capabilities.
An In Silico Glioblastoma Microenvironment Model Dissects the Immunological Mechanisms of Resistance to PD‐1 Checkpoint Blockade Immunotherapy
Authors: Zhang Zhuoyu , Liu Lunan , Ma Chao , Cui Xin , Lam Raymond H. W. , Chen Weiqiang
Published: April 2021

The PD‐1 immune checkpoint‐based therapy has emerged as a promising therapy strategy for treating the malignant brain tumor glioblastoma (GBM). However, patient response varies in clinical trials, mainly due to the tumor heterogeneity and immunological resistance in the tumor microenvironment. To further understand how mechanistically the niche interplay and competition drive anti‐PD‐1 resistance, an in silico model is established to quantitatively describe the biological rationale of critical GBM‐immune interactions, such as tumor growth and apoptosis, T cell activation and cytotoxicity, and tumor‐associated macrophage (TAM) mediated immunosuppression. Such an in silico experimentation and predictive model, based on the in vitro microfluidic chip‐measured end‐point data and patient‐specific immunological characteristics, allows for a comprehensive and dynamic analysis of multiple TAM‐associated immunosuppression mechanisms against the anti‐PD‐1 immunotherapy. The computational model demonstrates that the TAM‐associated immunosuppression varies in severity across different GBM subtypes, which results in distinct tumor responses. The prediction results indicate that a combination therapy by co‐targeting of PD‐1 checkpoint and TAM‐associated CSF‐1R signaling can enhance the immune responses of GBM patients, especially those patients with mesenchymal GBM who are irresponsive to the single anti‐PD‐1 therapy. The development of a patient‐specific in silico–in vitro GBM model will help navigate and personalize immunotherapies for GBM patients.
Polarizable High‐Index Nanoparticles Used for Light‐Induced Crystal‐Silicon Passivation and Dielectric Antenna for High‐Efficiency Solar Cell
Authors: Zhang Guohua , Wang Yusheng , Liang Dong , Hong Zhiwei , Li Yajuan , Li Ya , Zhong Qixuan , Song Tao , Wang Tao , Yang Xinbo , Lu Linfeng , Cui Wei , Wang Jilei , Yang Liyou , Li Dongdong , Sun Baoquan
Published: April 2021

Heterojunction crystal‐silicon (c‐Si) solar cells generate current from harvesting light via sweeping excited carriers away under built‐in asymmetry through amorphous silicon layers. However, loss of energy beyond the bandgap is known to hinder their efficiency. Herein, a strategy is provided to convert short‐wavelength energy into a polarization electrical field and the light dielectric antenna effect, where enhanced surface passivation and carrier collection occur simultaneously. By depositing an ultrathin polarizable nanoparticle layer on a transparent conducting oxide (TCO), a light‐induced electrical field is built up by light‐harvesting accumulation, which benefits for c‐Si surface passivation. An enchanting open‐circuit voltage (Voc) of 736.6 mV for the light‐induced field‐effect solar cell is achieved. In addition, the high‐index dielectric nanoparticles generate more photons to be absorbed in the long‐wavelength in c‐Si solar cells, which results in enhanced short‐circuit current (Jsc). As a result, benefiting from the light‐induced building‐up extra field and dielectric antenna effect, the device yields a power conversion efficiency of 22.41%, with the maximal improvement of Voc (≈4 mV), Jsc (≈0.4 mA cm−2), and fill factor (≈1%), respectively. This work provides a strategy to enhance solar cell efficiency by continuously harvesting beyond‐bandgap light to offer an additional asymmetrical field and the light antenna effect.
Review on the Oxidation Behaviors and Kinetics of Magnetite in Particle Scale
Authors: Zheng Heng , Schenk Johannes , Spreitzer Daniel , Wolfinger Thomas , Daghagheleh Oday
Published: April 2021

One possible route for ironmaking process is using a hydrogen‐gas‐based fluidized bed to produce direct reduced iron (DRI), which allows to use the natural magnetite directly in particle scale. The magnetite particles are oxidized during the preheating stage before being charged into the reduction unit. The exothermic effect, the crystal transformation, and the structural evolution during the oxidation of magnetite are introduced. The oxidation of magnetite is summarized in both thermodynamics and kinetics aspects. Furthermore, the influence of the oxidation of magnetite on its subsequent reduction behavior is examined.
Cardioprotective effects of transplanted adipose‐derived stem cells under Ang II stress with Danggui administration augments cardiac function through upregulation of insulin‐like growth factor 1 receptor in late‐stage hypertension rats
Authors: Barik Parthasarathi , Shibu Marthandam Asokan , Hsieh Dennis Jine‐Yuan , Day Cecilia Hsuan , Chen Ray‐Jade , Kuo Wei‐Wen , Chang Yung‐Ming , Padma V. Vijaya , Ho Tsung‐Jung , Huang Chih‐Yang
Published: April 2021

In aging hypertensive conditions, deterioration of insulin‐like growth factor 1 receptor (IGF1R) cause a pathological impact on hypertensive hearts with an increased Ang II level. Recovering these adverse conditions through transplanted adipose‐derived stem cells is a challenging approach. Moreover, Danggui, a Traditional Chinese medicine (TCM), is used for the treatment of cardioprotective effects. In this study, to evaluate whether the combined effect of MSCs and TCM can recover the cardiac function in late‐stage hypertension rats. We observed that lower dose of Danggui crude extract treatment showed an increased level of cell viability with maintained stemness properties and growth rate in rat adipose‐derived stem cells (rADSCs). Further, we cocultured the H9c2 cells with rADSCs and the results revealed that Danggui‐treated MSCs enhanced the IGF1R expression and attenuated the hypertrophy in H9c2 cells against Ang II challenge by immunoblot and rhodamine‐phalloidin staining. In addition, Danggui crude extract was also quantified and characterized by HPLC and LC–MS analysis. Furthermore, the in vivo study was performed by considering 11 months old rats (n = 7). Importantly, the oral administration of Danggui crude extract with stem cells intravenous injection in SHR‐D‐ADSCs group showed a combination effect to augment the cardiac function through enhancement of ejection fraction, fractional shortening, contractility function in the late‐stage hypertension conditions. We have also observed a decreased apoptosis rate in the heart tissue of SHR‐D‐ADSCs group. Taken together, these results indicate that the combinatorial effects of Danggui crude extract and stem cell therapy enhanced cardiac function in late‐stage SHR rats.
Nigella sativa oil protects against emamectin benzoate‐Induced neurotoxicity in rats
Authors: Madkour Doaa A. , Ahmed Mohamed M. , Orabi Sahar H. , Sayed Samy M. , Korany Reda M. S. , Khalifa Hanem K.
Published: April 2021

This study evaluated the ameliorative impact of Nigella sativa oil (NSO) on emamectin benzoate (EMB) neurotoxicity. Thirty‐five male rats were randomly allocated into 5 groups (n = 7). G1 (control): received distilled water; G2: received NSO (3 ml. Kg−1 B.W.) for 6 weeks; G3: received EMB (9 mg kg−1 B.W.) for 6 weeks; G4: was co‐treated with NSO and EMB for 6 weeks; G5: was treated with EMB for 4 weeks then, received NSO for 2 weeks. All treatments were given orally every other day. EMB increased serum urea, creatinine levels; brain dopamine, serotonin, malondialdehyde levels; brain expression levels of caspase 3 and TNF‐α. While, it decreased serum total protein, albumin, brain GABA, AChE, GSH‐Px, CAT, and SOD levels. Histopathological findings revealed hemorrhage, congestion, severe degeneration, and edema of the brain tissues. NSO reversed the EMB‐induced biochemical and histopathological alterations. This NSO effect is mostly due to its antioxidant, antiinflammatory, and antiapoptotic activities. These findings suggest NSO as a potential protective and therapeutic agent for EMB‐induced neurotoxicity.
Synthesis, Crystal Structure and Characterization of Two Cobalt (II) Complexes Based on Pyridine Carboxylic Acid Ligands
Authors: Wei Runzhi , Liu Zheng , Wei Wenchang , Liang Chuxin , Han Guo‐Cheng , Zhan Ling
Published: April 2021

Two undocumented cobalt (II) complexes [Co(5‐Br‐2,3‐pydc)(H2O)3 ⋅ H2O]n (namely Co‐MOF 1) and [Co(6‐Me‐2,3‐pydc)(H2O)3]n (namely Co‐MOF 2), were successfully synthesized by solvothermal method. The X‐ray single crystal diffraction, infrared spectrometer (IR), UV‐Vis spectrum and X‐ray diffraction were used to characterize and analyze the structure of the two MOFs. The single crystal structure analysis showed that Co‐MOF 1 reconnected by Co−N bond and Co−O bond to form a one‐dimensional chains. The Co‐MOF 2 was connected by Co−O and Co−N bonds to form a one‐dimensional chain.The results indicated that complexes Co‐MOF 1 and Co‐MOF 2 have a certain thermal stability and fluorescence properties.
1,4,7‐Triazacyclononane (tacn) with N,N′‐bridging methylene‐bis(phosphinic acid) group and its complexes
Authors: Pazderová Lucia , Kubíček Vojtěch , Kotek Jan , Hermann Petr
Published: April 2021

A bicyclic ligand, 1,4,7‐triazacyclononane 1,4‐bridged with methylene‐bis(phosphinate) and bearing benzyl substituent on the remaining amino group, was synthesized from N‐benzyl‐tacn and CH2(PO2H2)2 by two sequential Mannich‐type reactions in a high yield. Basicity of the macrocycle is high (pK1=12.25). Complexes with CuII and NiII ions show dimeric structures in the solid state. The structures exhibit distorted octahedral environment with two ring amino groups from one molecule and two oxygen atoms of chelating bis(phosphinate) anion from the other molecule in the equatorial plane, and with the apical positions occupied by the remaining macrocycle amino group and by one of the phosphinate oxygen atoms. The metal ions in the dimers are additionally bridged by one phosphinate group. Stability of the CuII complex is more than ten orders of magnitude lower than that of the [Cu(nota)]− complex due to a different number and different nature of the pendant arms, and inappropriate arrangement of donor atoms in the ligand bicyclic structure. Rigidity of the short P−C−P chain of the geminal methylene‐bis(phosphinate) does not allow simultaneous coordination of both phosphinate groups and the ring amines to the same metal ion. The low solubility of NiII and ZnII complexes disabled determination of their stability constants.
Healthcare of Undocumented Migrants
Authors: Jauhiainen Jussi S. , Tedeschi Miriam
Published: April 2021

Finnish authorities provide undocumented migrants with at least emergency healthcare services, but very few (if any) undocumented migrants use these or other public healthcare services. There are challenges to accessing healthcare, including language, culture or communication, inadequate information, difficult opening times, lack of specialised services, fear of using such services, and lack of networks relating to social and healthcare services. The provision of wider healthcare services and prevention of illnesses is actually less expensive for countries than providing undocumented migrants with only emergency healthcare.

This chapter discusses the undocumented migrants’ access to healthcare and their use of healthcare services. The Constitution of Finland guarantees emergency healthcare services for everyone staying in Finland, including undocumented migrants; however, the actual provision of healthcare (emergency or otherwise) for undocumented migrants varies greatly among local municipalities. Furthermore, few migrants use these available services. The majority turn to unofficial services, with some risk for themselves and the local community. The chapter highlights issues regarding the mental and physical health of undocumented migrants, who often suffer from trauma, which is not properly treated. It also discusses the effect of the COVID-19 pandemic on undocumented migrants in Finland.
Improvement of Human and Environmental Health Through Waste Management in Antigua and Barbuda
Authors: Spencer Ruth Viola
Published: April 2021

Antigua and Barbuda is currently experiencing an expansion in integrated waste management driven by local community groups. These events are catalytic and transformational, fit well into SEPLS methodologies, and contribute to many of the biodiversity targets and Sustainable Development Goals (SDGs). With waste being a direct driver of and major challenge for biodiversity, climate change and land degradation, many positive multi-dimensional impacts are being seen, realised and manifested that contribute positively to reducing land-based sources of pollution through community stewardship. Such local actions positively impact the sustainable management of natural resources and the protection of habitats. Likewise, they support land degradation neutrality, protection and safeguarding of the ecosystems that provide our soil, air and water resources, sustain livelihoods, and facilitate transfer of knowledge to children and youth.

This attempt to pilot a circular economy approach is providing vocational and life skills training, as well as income generation for the local community, including new forms of capacity building and development, while reducing soil, water and air pollution. Public-private partnerships built through this project are motivating other groups to follow a similar path to biodiversity transformation. Changes in attitudes and behaviours, and the building of knowledge and capacities in the next generation, is taking place through school and community outreach programmes.

The project has led to community empowerment in understanding that everyone has a role to play in sustainable development and that through collective actions, changes to improve public health can be made.
On topological recursion for Wilson loops in $$ \mathcal{N} $$ = 4 SYM at strong coupling
Authors: Beccaria M. , Hasan A.
Published: April 2021

Abstract

We consider U(N) $$ \mathcal{N} $$
N
= 4 super Yang-Mills theory and discuss how to extract the strong coupling limit of non-planar corrections to observables involving the $$ \frac{1}{2} $$

1
2

-BPS Wilson loop. Our approach is based on a suitable saddle point treatment of the Eynard-Orantin topological recursion in the Gaussian matrix model. Working directly at strong coupling we avoid the usual procedure of first computing observables at finite planar coupling λ, order by order in 1/N, and then taking the λ ≫ 1 limit. In the proposed approach, matrix model multi-point resolvents take a simplified form and some structures of the genus expansion, hardly visible at low order, may be identified and rigorously proved. As a sample application, we consider the expectation value of multiple coincident circular supersymmetric Wilson loops as well as their correlator with single trace chiral operators. For these quantities we provide novel results about the structure of their genus expansion at large tension, generalising recent results in arXiv:2011.02885.
q-deformation of corner vertex operator algebras by Miura transformation
Authors: Harada Koichi , Matsuo Yutaka , Noshita Go , Watanabe Akimi
Published: April 2021

Abstract

Recently, Gaiotto and Rapcak proposed a generalization of WN algebra by considering the symmetry at the corner of the brane intersection (corner vertex operator algebra). The algebra, denoted as YL,M,N, is characterized by three non-negative integers L, M, N. It has a manifest triality automorphism which interchanges L, M, N, and can be obtained as a reduction of W1+∞ algebra with a “pit” in the plane partition representation. Later, Prochazka and Rapcak proposed a representation of YL,M,N in terms of L + M + N free bosons by a generalization of Miura transformation, where they use the fractional power differential operators.

In this paper, we derive a q-deformation of the Miura transformation. It gives a free field representation for q-deformed YL,M,N, which is obtained as a reduction of the quantum toroidal algebra. We find that the q-deformed version has a “simpler” structure than the original one because of the Miki duality in the quantum toroidal algebra. For instance, one can find a direct correspondence between the operators obtained by the Miura transformation and those of the quantum toroidal algebra. Furthermore, we can show that the both algebras share the same screening operators.
Clock-dependent spacetime
Authors: Lee Sung-Sik
Published: April 2021

Abstract

Einstein’s theory of general relativity is based on the premise that the physical laws take the same form in all coordinate systems. However, it still presumes a preferred decomposition of the total kinematic Hilbert space into local kinematic Hilbert spaces. In this paper, we consider a theory of quantum gravity that does not come with a preferred partitioning of the kinematic Hilbert space. It is pointed out that, in such a theory, dimension, signature, topology and geometry of spacetime depend on how a collection of local clocks is chosen within the kinematic Hilbert space.
On the challenges of searching for GeV-scale long-lived particles at the LHC
Authors: Bernreuther Elias , Mejia Juliana Carrasco , Kahlhoefer Felix , Krämer Michael , Tunney Patrick
Published: April 2021

Abstract

Many models of dark matter predict long-lived particles (LLPs) that can give rise to striking signatures at the LHC. Existing searches for displaced vertices are however tailored towards heavy LLPs. In this work we show that this bias severely affects their sensitivity to LLPs with masses at the GeV scale. To illustrate this point we consider two dark sector models with light LLPs that decay hadronically: a strongly-interacting dark sector with long-lived exotic mesons, and a Higgsed dark sector with a long-lived dark Higgs boson. We study the sensitivity of an existing ATLAS search for displaced vertices and missing energy in these two models and find that current track and vertex cuts result in very low efficiency for light LLPs. To close this gap in the current search programme we suggest two possible modifications of the vertex reconstruction and the analysis cuts. We calculate projected exclusion limits for these modifications and show that they greatly enhance the sensitivity to LLPs with low mass or short decay lengths.
Non-equilibrium effective field theory and second sound
Authors: Landry Michael J.
Published: April 2021

Abstract

We investigate the phenomenon of second sound in various states of matter from the perspective of non-equilibrium effective field theory (EFT). In particular, for each state of matter considered, we find that at least two (though sometimes multiple) qualitatively different EFTs exist at finite temperature such that there is always at least one EFT with a propagating second-sound wave and at least one with no such second-sound wave. To aid in the construction of these EFTs, we use the method of cosets developed for non-equilibrium systems. It turns out that the difference between the EFTs with and without second-sound modes can be understood as arising from different choices of a new kind of inverse Higgs constraint. Finally, we demonstrate that it is possible to bypass the need for new inverse Higgs constraints by formulating EFTs on a new kind of manifold that is like the usual fluid worldvolume, but with reduced gauge symmetries.
Entropy linear response theory with non-Markovian bath
Authors: Chen Yu
Published: April 2021

Abstract

We developed a perturbative calculation for entropy dynamics, which considers a sudden coupling between a system and a bath. The theory we developed can work in a general environment without Markovian approximation. A perturbative formula is given for bosonic environments and fermionic environments, respectively. We find the Rényi entropy response is only related to the spectral functions of the system and the environment, together with a statistical kernel distribution function. We find at2growth/decay in the short time limit and a lineartgrowth/decay in a longer time scale for the second Rényi entropy response. A non-monotonic behavior of Rényi entropy for fermionic systems is found to be quite general when the environmental temperature is the lower one. A Fourier’s law in heat transport is obtained when two systems’ temperatures are close to each other. A consistency check is made for Sachdev-Ye-Kitaev model coupling to free fermions, a Page curve alike dynamics is found in a process dual to black hole evaporation. An oscillation of Rényi entropy is found for an environment with a gapped spectrum.
Two point functions in defect CFTs
Authors: Herzog Christopher P. , Shrestha Abhay
Published: April 2021

Abstract

This paper is designed to be a practical tool for constructing and investigating two-point correlation functions in defect conformal field theory, directly in physical space, between any two bulk primaries or between a bulk primary and a defect primary, with arbitrary spin. Although geometrically elegant and ultimately a more powerful approach, the embedding space formalism gets rather cumbersome when dealing with mixed symmetry tensors, especially in the projection to physical space. The results in this paper provide an alternative method for studying two-point correlation functions for a generic d-dimensional conformal field theory with a flat p-dimensional defect and d − p = q co-dimensions. We tabulate some examples of correlation functions involving a conserved current, an energy momentum tensor and a Maxwell field strength, while analysing the constraints arising from conservation and the equations of motion. A method for obtaining bulk-to-defect correlators is also explained. Some explicit examples are considered: free scalar theory on ℝp× (ℝq/ℤ2) and a free four dimensional Maxwell theory on a wedge.
Diabetes-related lower extremity complications in a multi-ethnic Asian population: a 10 year observational study in Singapore
Authors: Riandini Tessa , Pang Deanette , Toh Matthias P. H. S. , Tan Chuen Seng , Liu Daveon Y. K. , Choong Andrew M. T. L. , Chandrasekar Sadhana , Tai E Shyong , Tan Kelvin B. , Venkataraman Kavita
Published: April 2021

Aims/hypothesis

Diabetes progression and complication risk are different in Asian people compared with those of European ancestry. In this study, we sought to understand the epidemiology of diabetes-related lower extremity complications (DRLECs: symptomatic peripheral arterial disease, ulceration, infection, gangrene) and amputations in a multi-ethnic Asian population.

Methods

This was a retrospective observational study using data obtained from one of three integrated public healthcare clusters in Singapore. The population consisted of individuals with incident type 2 diabetes who were of Chinese, Malay, Indian or Other ethnicity. We examined incidence, time to event and risk factors of DRLECs and amputation.

Results

Between 2007 and 2017, of the 156,593 individuals with incident type 2 diabetes, 20,744 developed a DRLEC, of whom 1208 underwent amputation. Age- and sex-standardised incidence of first DRLEC and first amputation was 28.29/1000 person-years of diabetes and 8.18/1000 person-years of DRLEC, respectively. Incidence of both was highest in individuals of Malay ethnicity (DRLEC, 36.09/1000 person-years of diabetes; amputation, 12.96/1000 person-years of DRLEC). Median time from diabetes diagnosis in the public healthcare system to first DRLEC was 30.5 months for those without subsequent amputation and 10.9 months for those with subsequent amputation. Median time from DRLEC to first amputation was 2.3 months. Older age (p < 0.001), male sex (p < 0.001), Malay ethnicity (p < 0.001), Indian ethnicity (p = 0.014), chronic comorbidities (nephropathy [p < 0.001], heart disease [p < 0.001], stroke [p < 0.001], retinopathy [p < 0.001], neuropathy [p < 0.001]), poorer or missing HbA1c(p < 0.001), lower (p < 0.001) or missing (p = 0.002) eGFR, greater or missing BMI (p < 0.001), missing LDL-cholesterol (p < 0.001) at diagnosis, and ever-smoking (p < 0.001) were associated with higher hazard of DRLEC. Retinopathy (p < 0.001), peripheral vascular disease (p < 0.001), poorer HbA1c(p < 0.001), higher (p = 0.009) or missing (p < 0.001) LDL-cholesterol and missing BMI (p = 0.008) were associated with higher hazard of amputation in those with DRLEC. Indian ethnicity (p = 0.007) was associated with significantly lower hazard of amputation.

Conclusions/interpretation

This study has revealed important ethnic differences in risk of diabetes-related lower limb complications, with Malays most likely to progress to DRLEC. Greater research efforts are needed to understand the aetiopathological and sociocultural processes that contribute to the higher risk of lower extremity complications among these ethnic groups.

Graphical abstract
WEDM single crater asymmetry
Authors: Esteves Paulo M. B. , Wiessner Moritz , Costa João V. M. R. , Sikora Maria , Wegener Konrad
Published: April 2021

In wire electrical discharge machining (WEDM), the erosion is made through a series of overlapped craters. The shape of these craters has a relevant impact on the characteristics of the machined surface, from surface roughness to heat effects during the spark. Current models on EDM process do not represent specific WEDM characteristics, such as radial asymmetry of the crater or geometrical effects on the crater shape. In order to characterize the crater’s dimensions in WEDM, single discharge experiments are performed on polished steel for pulses with different energy levels. A 3D optical microscope is used to map the single craters’ topographies (experimental work). To capture the craters’ dimensions, an ellipsoidal equation is applied with a Levenberg–Marquardt algorithm. The ellipsoidal equation is capable of identifying the dimensions along the wire length, perpendicular to the wire and the depth of the crater. The ratio between the dimension along the wire and the dimension perpendicular to the wire is used to define a crater’s aspect ratio and characterizes its elongation. The aspect ratio of the single craters is found to be dependent on the pulse energy. Low-energy pulses create rounder craters, while high-energy pulses form elongated craters that are longer along the wire length. Such behavior suggests that the crater formation is constricted by the wire geometry, having a preferential direction of growth, along the wire length.
Short-baseline interferometry local-tie experiments at the Onsala Space Observatory
Authors: Varenius Eskil , Haas Rüdiger , Nilsson Tobias
Published: April 2021

We present results from observation, correlation and analysis of interferometric measurements between the three geodetic very long baseline interferometry (VLBI) stations at the Onsala Space Observatory. In total, 25 sessions were observed in 2019 and 2020, most of them 24 h long, all using X band only. These involved the legacy VLBI station ONSALA60 and the Onsala twin telescopes, ONSA13NE and ONSA13SW, two broadband stations for the next-generation geodetic VLBI global observing system (VGOS). We used two analysis packages: $$\nu $$
ν
Solve to pre-process the data and solve ambiguities, and ASCOT to solve for station positions, including modelling gravitational deformation of the radio telescopes and other significant effects. We obtained weighted root mean square post-fit residuals for each session on the order of 10–15 ps using group-delays and 2–5 ps using phase-delays. The best performance was achieved on the (rather short) baseline between the VGOS stations. As the main result of this work, we determined the coordinates of the Onsala twin telescopes in VTRF2020b with sub-millimetre precision. This new set of coordinates should be used from now on for scheduling, correlation, as a priori for data analyses, and for comparison with classical local-tie techniques. Finally, we find that positions estimated from phase-delays are offset $$\sim +3$$

∼
+
3

 mm in the up-component with respect to group-delays. Additional modelling of (elevation dependent) effects may contribute to the future understanding of this offset.
Exhaustion in tumor-infiltrating Mucosal-Associated Invariant T (MAIT) cells from colon cancer patients
Authors: Rodin William , Sundström Patrik , Ahlmanner Filip , Szeponik Louis , Zajt Kamil Kajetan , Wettergren Yvonne , Bexe Lindskog Elinor , Quiding Järbrink Marianne
Published: April 2021

Mucosal-associated invariant T (MAIT) cells are unconventional T cells recognizing microbial metabolites, presented by the invariant MR1 protein. Upon activation, MAIT cells rapidly secrete cytokines and exert cytotoxic functions, and may thus be highly relevant also in tumor immunity. MAIT cells accumulate in colon tumors, but in contrast to other cytotoxic T cell subsets, their presence in tumors has been associated with worse patient outcome. Here we investigated if exhaustion may contribute to reduced anti-tumor immunity by MAIT cells. Freshly isolated lymphocytes from colon tumors, unaffected tissue and blood from the same patients were analyzed by flow cytometry to detect MAIT cells with effector functions that are relevant for tumor immunity, and their expression of inhibitory receptors and other exhaustion markers. Our studies show that MAIT cells with a PD-1highTim-3+CD39+ terminally exhausted phenotype and an increased proliferation accumulate in colon tumors. The exhausted MAIT cells have reduced polyfunctionality with regard to production of important anti-tumor effector molecules, and blocking antibodies to PD-1 partly improved activation of tumor-infiltrating MAIT cells in vitro. We conclude that the tumor microenvironment leads to exhaustion not only of conventional T cells, but also MAIT cells, and that checkpoint blockade therapy may be useful also to reinvigorate tumor-infiltrating MAIT cells.
Effect of n-3 PUFA on extracellular matrix protein turnover in patients with psoriatic arthritis: a randomized, double-blind, placebo-controlled trial
Authors: Holm Nielsen Signe , Sardar Samra , Siebuhr Anne Sofie , Schlemmer Annette , Schmidt Erik Berg , Bay-Jensen Anne-Christine , Karsdal Morten A. , Christensen Jeppe Hagstrup , Kristensen Salome
Published: April 2021

Psoriatic arthritis (PsA) is a chronic inflammatory disease characterized by involvement of skin, axial and peripheral skeleton. An altered balance between extracellular matrix (ECM) formation and breakdown is a key event in PsA, and changes in ECM protein metabolites may provide insight to tissue changes. Dietary fish oils (n-3 PUFA) might affect the inflammation driven tissue turnover. The aim was to evaluate ECM metabolites in patients with PsA compared to healthy individuals and investigate the effects of n-3 PUFA. The 24-week randomized, double-blind, placebo-controlled trial of PUFA included 142 patients with PsA. Fifty-seven healthy individuals were included for comparison. This study is a sub-study investigating biomarkers of tissue remodelling as secondary outcomes. Serum samples at baseline and 24 weeks and healthy individuals were obtained, while a panel of ECM metabolites reflecting bone and soft tissue turnover were measured by ELISAs: PRO-C1, PRO-C3, PRO-C4, C1M, C3M, C4M, CTX-I and Osteocalcin (OC). C1M, PRO-C3, PRO-C4 and C4M was found to be elevated in PsA patients compared to the healthy individuals (from 56 to 792%, all p < 0.0001), where no differences were found for OC, CTX-I, PRO-C1 and C3M. PRO-C3 was increased by 7% in patients receiving n-3 PUFA after 24 weeks compared to baseline levels (p = 0.002). None of the other biomarkers was changed with n-3 PUFA treatment. This indicates that tissue turnover is increased in PsA patients compared to healthy individuals, while n-3 PUFA treatment for 24 weeks did not have an effect on tissue turnover. Trial registration NCT01818804. Registered 27 March 2013–Completed 18 February 2016. https://clinicaltrials.gov/ct2/show/NCT01818804?term=NCT01818804&rank=1
Measuring standing hindfoot alignment: reliability of different approaches in conventional x-ray and cone-beam CT
Authors: Brandenburg Leonard Simon , Siegel Markus , Neubauer Jakob , Merz Johanna , Bode Gerrit , Kühle Jan
Published: April 2021

Introduction

Currently there is no consensus how hindfoot alignment (HA) should be assessed in CBCT scans. The aim of this study is to investigate how the reliability is affected by the anatomical structures chosen for the measurement.

Materials and methods

Datasets consisting of a Saltzman View (SV) and a CBCT of the same foot were acquired prospectively and independently assessed by five raters regarding HA. In SVs the HA was estimated as follows: transversal shift between tibial shaft axis and heel contact point (1); angle between tibial shaft axis and a tangent at the medial (2) or lateral (3) calcaneal wall. In CBCT the HA was estimated as follows: transversal shift between the centre of the talus and the heel contact point (4); angle between a perpendicular line and a tangent at the medial (5) or lateral (6) calcaneal wall; angle between the distal tibial surface and a tangent at the medial calcaneal wall (7). Intraclass correlation coefficients (ICC) were calculated to assess inter-rater reliability. A linear regression was performed to compare the different measurement regarding their correlation.

Results

32 patients were included in the study. The ICCs for the measurements 1–7 were as follows: (1) 0.924 [95% CI 0.876–0.959] (2) 0.533 [95% CI 0.377–0.692], (3) 0.553 [95% CI 0.399–0.708], (4) 0.930 [95% CI 0.866–0.962], (5) 0.00 [95% CI − 0.111 to 0.096], (6) 0.00 [95% CI − 0.103 to 0.111], (7) 0.152 [95% CI 0.027–0.330]. A linear regression between measurement 1 and 4 showed a correlation of 0.272 (p = 0.036).

Conclusions

It could be shown that reliability of measuring HA depends on the investigated anatomical structure. Placing a tangent along the calcaneus (2, 3, 5, 6, 7) was shown to be unreliable, whereas determining the weight-bearing heel point (1, 4) appeared to be a reliable approach. The correlation of the measurement workflows is significant (p = 0.036), but too weak (0.272) to be used clinically.
Learning of across- and within-task contingencies modulates partial-repetition costs in dual-tasking
Authors: Pelzer Lasse , Naefgen Christoph , Gaschler Robert , Haider Hilde
Published: April 2021

Dual-task costs might result from confusions on the task-set level as both tasks are not represented as distinct task-sets, but rather being integrated into a single task-set. This suggests that events in the two tasks are stored and retrieved together as an integrated memory episode. In a series of three experiments, we tested for such integrated task processing and whether it can be modulated by regularities between the stimuli of the two tasks (across-task contingencies) or by sequential regularities within one of the tasks (within-task contingencies). Building on the experimental approach of feature binding in action control, we tested whether the participants in a dual-tasking experiment will show partial-repetition costs: they should be slower when only the stimulus in one of the two tasks is repeated from Trial n − 1 to Trial n than when the stimuli in both tasks repeat. In all three experiments, the participants processed a visual-manual and an auditory-vocal tone-discrimination task which were always presented concurrently. In Experiment 1, we show that retrieval of Trial n − 1 episodes is stable across practice if the stimulus material is drawn randomly. Across-task contingencies (Experiment 2) and sequential regularities within a task (Experiment 3) can compete with n − 1-based retrieval leading to a reduction of partial-repetition costs with practice. Overall the results suggest that participants do not separate the processing of the two tasks, yet, within-task contingencies might reduce integrated task processing.