bluuebunny/crossref_metadata_2025 huggingface dataset:
Gastrin, via activation of PPARα, protects the kidney against hypertensive injury
Authors: Gu Daqian , Fang Dandong , Zhang Mingming , Guo Jingwen , Ren Hongmei , Li Xinyue , Zhang Ziyue , Yang Donghai , Zou Xue , Liu Yukai , Wang Wei Eric , Wu Gengze , Jose Pedro A. , Han Yu , Zeng Chunyu
Published: January 2021

Hypertensive nephropathy (HN) is a common cause of end-stage renal disease with renal fibrosis; chronic kidney disease is associated with elevated serum gastrin. However, the relationship between gastrin and renal fibrosis in HN is still unknown. We, now, report that mice with angiotensin II (Ang II)-induced HN had increased renal cholecystokinin receptor B (CCKBR) expression. Knockout of CCKBR in mice aggravated, while long-term subcutaneous infusion of gastrin ameliorated the renal injury and interstitial fibrosis in HN and unilateral ureteral obstruction (UUO). The protective effects of gastrin on renal fibrosis can be independent of its regulation of blood pressure, because in UUO, gastrin decreased renal fibrosis without affecting blood pressure. Gastrin treatment decreased Ang II-induced renal tubule cell apoptosis, reversed Ang II-mediated inhibition of macrophage efferocytosis, and reduced renal inflammation. A screening of the regulatory factors of efferocytosis showed involvement of peroxisome proliferator-activated receptor α (PPAR-α). Knockdown of PPAR-α by shRNA blocked the anti-fibrotic effect of gastrin in vitro in mouse renal proximal tubule cells and macrophages. Immunofluorescence microscopy, Western blotting, luciferase reporter, and Cut&tag-qPCR analyses showed that CCKBR may be a transcription factor of PPAR-α, because gastrin treatment induced CCKBR translocation from cytosol to nucleus, binding to the PPAR-α promoter region, and increasing PPAR-α gene transcription. In conclusion, gastrin protects against HN by normalizing blood pressure, decreasing renal tubule cell apoptosis, and increasing macrophage efferocytosis. Gastrin-mediated CCKBR nuclear translocation may make it act as a transcription factor of PPAR-α, which is a novel signaling pathway. Gastrin may be a new potential drug for HN therapy.
Iterative registration for multi‐modality retinal fundus photographs using directional vessel skeleton
Authors: Kong Wenwen , Zang Pengxiao , Niu Sijie , Li Dengwang
Published: January 2021

This paper proposes an automated registration method for multi‐modality retinal fundus photographs based on the directional vessel skeleton. The main purpose is to register two retinal fundus photographs with different modalities of the same scanning region, which can provide multi‐modality information for clinicians to diagnose retinal diseases or to make a treatment decision. The directional vessel skeleton of each fundus image is first detected by bias field correction and Gabor filter. The final registered fundus photographs are then obtained by the iterative affine registration between the detected directional vessel skeletons of two photographs. In this work, four kinds of fundus photographs in the macular regions of the patient with diseases, consisting of 20 optical coherence tomography fundus images, 20 colour fundus photographs, 20 fluorescein fundus angiography images and 20 indocyanine green angiography images, are utilised to quantitatively evaluate the proposed method. The root‐mean‐square errors show an advantageous performance in both registration success rate and accuracy.
A stochastic approach for automated brain MRI segmentation
Authors: Chatterjee Pubali , Sharma Kaushik Das , Chakrabarti Amlan
Published: January 2021

This paper presents an approach to segment lesions from brain magnetic resonance images in a fully automatic manner. The proposed idea leverages the strength of classical random walker algorithm and graph cut optimization technique in a single framework. We demonstrate that formulating a “prior” from a stochastic model can ameliorate the need of manually selected seed selection process in the random walker framework, thus making the algorithm fully automatic in a generic manner. By analytically solving a linear system of equations in the random walk process, initial labelling ∈ [0, 1] of each pixel in the image are computed to obtain the likelihood probability. These probabilities are then used to compute the likelihood for the data fidelity term in the energy function to compute the final segmentation, which is minimized by min cut max flow algorithm. Experimental results show the superiority of the proposed method over the state‐of‐the‐art techniques on publicly available datasets.
SAR image despeckling using deep CNN
Authors: Passah Alicia , Amitab Khwairakpam , Kandar Debdatta
Published: January 2021

Synthetic aperture radar (SAR) images are contaminated with noise called speckle that is multiplicative in nature. The presence of speckles in SAR images makes it impossible to understand and interpret for extensive range of applications. However, certain characteristics of SAR and the ability to function irrespective of weather conditions, are making such images worth processing in order to be able to extract relevant information. A despeckling model is proposed that uses deeper convolutional neural networks, which was never used before, as far as authors are concerned, for diminishing speckle in noisy SAR images. Multiple skip connections from the ResNet model are also employed in authors' proposed architecture. In order to maintain uniformity, a formula to be followed while applying skip connections is also derived. A hybrid loss function is developed to train the network more consistently to achieve the desired output. Experiments on simulated SAR images using the NWPU‐RESISC benchmark are conducted and tested on real TerraSAR‐X images and compared with the state‐of‐the‐art techniques. Results show that the proposed method achieved considerable improvements compared to state‐of‐the‐art methods with PSNRs 27.02, 24.60, and 22.01 for looks 10, 4, and 1, respectively.
SYNGuard: Dynamic threshold‐based SYN flood attack detection and mitigation in software‐defined networks
Authors: Rahouti Mohamed , Xiong Kaiqi , Ghani Nasir , Shaikh Farooq
Published: January 2021

SYN flood attacks (half‐open attacks) have been proven a serious threat to software‐defined networking (SDN)‐enabled infrastructures. A variety of intrusion detection and prevention systems (IDPS) have been introduced for identifying and preventing such security threats, but they often result in significant performance overhead and response time. Therefore, those existing approaches are inflexible for large‐scale networks and real‐time applications. For this reason, a novel and adaptive threshold‐based kernel‐level intrusion detection and prevention system by leveraging SDN capabilities are proposed. The proposed systems to detect and mitigate the aforementioned threats within an SDN over widely used traditional IDPS technologies, Snort and Zeek, are comparatively examined. The approach is evaluated using a mixture of fundamental adverse attacks and SDN‐specific threats on a real‐world testbed. The experimental results demonstrate the efficacy of the mechanism to detect and mitigate SYN flood attacks within an SDN environment.
Investigation of the influence of the carbon dioxide (CO2) injection rate on the activity of the water pressure system during gas condensate fields development
Authors: Matkivskyi Serhii , Kondrat Oleksandr , Burachok Oleksandr
Published: January 2021

The development of gas condensate fields under the conditions of elastic water drive is characterized by uneven movement of the gas-water. Factors of hydrocarbon recovery from producing reservoirs which are characterized by the active water pressure drive on the average make up 50-60%. To increase the efficiency of fields development, which are characterized by an elastic water drive, a study of the effect of different volumes of carbon dioxide injection at the gas-water contact on the activity of the water pressure system and the process of flooding producing wells was carried out. Using a three-dimensional model, the injection of carbon dioxide into wells located at the boundary of gas-water contact with flow rates from 20 to 500 thousand m3/day was investigated. Analyzing the simulation data, it was found that increasing the volume of carbon dioxide injection provides an increase in accumulated gas production and a significant reduction in water production. The main effect of the introduction of this technology is achieved by increasing the rate of carbon dioxide injection to 300 thousand m3/day. The set injection rates allowed us to increase gas production by 67% and reduce water production by 83.9% compared to the corresponding indicators without injection of carbon dioxide. Taking into account above- mentioned, the final decision on the introduction of carbon dioxide injection technology and optimal technological parameters of producing and injection wells operation should be made on the basis of a comprehensive technical and economic analysis using modern methods of the hydrodynamic modeling of reservoir systems.
Research into phase transformations in reservoir systems models in the presence of thermodynamic hydrate formation inhibitors of high concentration
Authors: Pedchenko Nazar , Zezekalo Ivan , Pedchenko Larysa , Pedchenko Mykhailo
Published: January 2021

Gas hydrates have been and still remain a difficult problem in the oil and gas industry, solution of which requires considerable efforts and resources. In this work, the mechanism of phase transformations at negative temperatures in the formation of the solid phase is preliminarily studied using the reservoir system models consisting of a gas mixture and a solution of gas hydrate formation inhibitor of thermodynamic action with high concentration in distilled water. A system of three-dimensional lighting and image magnification is used to visually detect phase boundaries by creating optical effects. Thus, in the system “inhibitor solution – gas hydrate – gas” in the process of gas hydrate recrystallization in the conditions close to equilibrium, microzones of supercooled water may occur, which in the absence of gas molecules access is crystallized into ice. The result of such solid phase structure formation is its increased stability in nonequilibrium conditions for a relatively long period of time.
Development of the rational bottomhole assemblies of the directed well drilling
Authors: Ihnatov Andrii , Koroviaka Yevhenii , Rastsvietaiev Valerii , Tokar Larysa
Published: January 2021

The problem of development of gas hydrate deposits is complicated by a range of problems connected with the adaptation of traditional methods and procedures to develop the mentioned type of raw materials. Construction methods of the directed well deserve high attention since they are the most efficient solution to provide a stable process of gas fraction production. Experts of the Dnipro University of Technology are at the top among the studies engaged in implementation and operation of gas hydrate deposits. Among other things, the experts have designed rational bottomhole assemblies of the directed drilling for the conditions of gas hydrate deposits. Such devices have a number of functional features. The paper describes following particularities being the most significant ones: a material to produce destructive balls and their physical properties; operating modes of a drilling process; directionality of bottomhole circulation processes as for the operational parameters of flushing fluids; and spatial location of well direction. Both calculations and bench tests favoured the process intended to identify functional features of the devices and proved convincingly the truthfulness of the initial theoretical foundations to drill the directed wells with the help of the modernized hydromechanical boring tool combined with a feeding device. The paper purpose is to analyze and substantiate structural solutions within the certain units of techniques for complex use as well as determine the rational operating schedules of the latter in the context of specific geological conditions where the directed wells are under construction.
Dossier « L’économie circulaire : modes de gouvernance et développement territorial » – Quelle durabilité pour le développement territorial ? Réflexions sur les composantes spatiales de l’économie circulaire
Authors: Dermine-Brullot Sabrina , Torre André
Published: January 2021

L’objectif de cet article est de fournir des éléments de réflexion sur la place de l’espace et la dimension territoriale dans les processus d’économie circulaire ainsi que d’interroger leur contribution au développement durable des territoires. Nous commençons par examiner les racines territoriales des grandes stratégies d’économie circulaire définies par les pouvoirs publics français en faisant une place particulière à l’écologie industrielle et territoriale, qui manifeste un intérêt plus fort pour les dimensions spatiales des processus circulaires. Dans une seconde partie, nous interrogeons la capacité réelle de l’économie circulaire à contribuer au développement durable de la société dans son ensemble et à sa mise en action au niveau local : après avoir proposé une définition du développement territorial durable, nous procédons à un examen des différentes stratégies en cours fondées sur les principes ainsi définis.
Anatomy of Pelvic leak points in the context of varicose veins
Authors: Delfrate Roberto
Published: January 2021

Pelvic venous networks (competent themselves or not) can be the origin of reflux in the superficial leg veins. They are frequently involved in recurrences after classical venous treatment options, as they are not treated in that context. Studies based on various assessments (clinical, ultrasound, venography) conclude that around 10 % of women with varicose vein have their origin in pelvic leaks points, this incidence is 4 times higher in multiparous than in nulliparous. Claude Franceschi first analyzed and described the reflux pathways for this pelvic leak points. The most frequently involved escape points or “Pelvic Leak Points” are the perineal points (PP), draining through the labial region to the leg and the inguinal points through the inguinal ring (IP). Others are the Clitoridian point (CP), gluteal points (GP) and obturatorian point (OP). Their investigation has to be performed in standing position and using Valsalva – but the most important part of the investigation is the anatomic knowledge about the different pathways.
Cardiotoxicity and cardiac monitoring following the use of radiotheranostics agents including 177Lu-PSMA for prostate cancer and 177Lu-DOTATATE for neuroendocrine tumors
Authors: Jafari Esmail , Amini Abdul Latif , Ahmadzadehfar Hojjat , Bagheri Dara , Assadi Majid
Published: January 2021

Background The aim of this study was to determine the probable cardiotoxicity following radionuclide therapy (RNT), specifically peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE and radioligand therapy (RLT) with 177Lu-PSMA by evaluation of serum troponin I and cardiac profile change during a follow-up time.

Materials and Methods Patients with prostate cancer and neuroendocrine tumours (NETs) referred for PRRT and RLT, respectively, were enrolled in this study. The cardiac profiles of the patients were evaluated by a cardiologist and a cardiac history was obtained from all patients. Also, troponin I was measured before and 48 hours after treatment.

Results In this retrospective study for assessment of RLT associated cardiotoxicity, 24 patients were evaluated with a median age of 64 years (27–99 years) including 13 NET patients and 11 prostate cancer patients. Patients were followed up for 4 to 31 months which no cardiovascular problem was observed. In evaluation of troponin I, 39 RNT cycles were evaluated. In all patients, the value of troponin I was in normal range. In all patients, the median values of serum troponin I before and after treatment were 0.2 ± 0.02 (range: 0.00–0.42) and 0.28 ± 0.02 (range: 0.00–0.46) ng/ml, respectively (p > 0.05). In the prostate cancer patients, the median values of serum troponin I before and after treatment were 0.26 ± 0.04 (0.04–0.42) and 0.30 ± 0.04 (0.00–0.41) ng/ml, respectively (p > 0.05). In the NET patients, the median values of serum troponin I before and after treatment were 0.18 ± 0.03 (0.00–0.42) and 0.17 ± 0.03 (0.00–0.46) ng/ml, respectively (p > 0.05).

Conclusion PRRT with 177Lu-DOTATATE and RLT with 177Lu-PSMA as emerging therapeutic modalities have no significant cardiotoxicity. However, further well-designed studies are recommended.
Internal Neurolysis (Nerve Combing) for Trigeminal Neuralgia without Neurovascular Compression
Authors: Gonzales-Portillo Marco , Huamán Luis Adrián
Published: January 2021

Objective The aim of the present study was to describe and evaluate the initial and the long-term clinical outcome of internal neurolysis (IN) for trigeminal neuralgia (TN) without neurovascular compression (NVC).

Methods A total of 170 patients diagnosed with TN were treated by posterior fossa exploration, during the period between April 2012 and October 2019. The patients were divided into two groups: Group A (50 patients) was treated by IN and Group B (120 patients) received microvascular decompression (MVD). Surgical outcomes and postoperative complications were compared between the two groups. Pain intensity was assessed by the Barrow Neurological Institute (BNI) pain intensity score and BNI facial numbness score. Pain recurrence was statistically evaluated with Kaplan-Meier analysis.

Results Pain was completely relieved in 44 patients (88%) who underwent IN (group A); 3 (6%) experienced occasional pain but did not require medication (BNI 2). In group B, 113 (94%) experienced immediate pain relief after MVD. The median duration of follow-ups was 4 years (6 months to 7.5 years). In Group A, there was a meantime recurrence of 27 months in 3 patients (6%). The recurrence in Group B was of 5.8% during the follow-up period. There were no statistically significant differences in the surgical outcomes between the two groups. All patients with IN experienced some degree of numbness, 88% of the cases resolved in 6 months, on average.

Conclusion Internal neurolysis is an effective, safe and durable treatment option for trigeminal neuralgia when NVC is absent.
Pleomorphic Xanthoastrocytoma with Oligodendroglioma-Like Areas with Negative 1p19q Co-Deletion
Authors: Goel Deepa , Sharma Shobhna , Gupta Aditya
Published: January 2021

The most common mixed glioma encountered in routine surgical practice is oligoastrocytoma (OA); however, its is currently considered a vanishing entity. The 2016 classification of the World Health Organization (WHO) discourages the diagnosis of tumors as mixed glioma. The recommendations are that diffuse gliomas, including those with mixed or ambiguous histological features, should be subjected to molecular testing. Dual-genotype OAs are not yet a distinct entity or variant in the classification. We report a case of mixed glioma: a pleomorphic xanthoastrocytoma (PXA) mixed with an oligodendroglioma. The immunohistochemistry (IHC) pattern of isocitrate dehydrogenase 1 (IDH1) negativity with retained nuclear expression of the alpha-thalassemia x-linked intellectual disability syndrome (ATRX) protein, and 1p19q co-deletion negativity in both the components enabled its identification as a mixed glioma rather than a collision tumor. To the best of our knowledge, the case herein presented is the fourth case of PXA with oligodendroglioma. Out of the other three reported cases, only one was of a collision tumor with a dual genotype, and the other two showed similar molecular signatures in both components. The present article discusses the histological, immunohistochemical and molecular features of the aforementioned case.
Can Routine Blood Biochemistry Parameters be Predictive Prognostic Marker(s) in Operated Patients with Meningioma WHO Grade 1?
Authors: Yuksel Ulas , Ozdemir Alemiddin , Kisa Ucler , Ogden Mustafa , Bakar Bulent
Published: January 2021

Background Today, there is a need for new and independent additional advanced markers that can predict the prognosis of meningioma patients, postoperatively. The present study aimed to find out postoperative short-term prognostic markers in patients with meningioma using their demographic data and routine blood biochemistry findings evaluated preoperatively.

Methods The Glasgow Coma Scale (GCS), and Glasgow Outcome Scale (GOS) scores of the patients were recorded. Additionally, preoperatively obtained serum glucose, C-reactive protein (CRP), sodium, potassium, creatinine, blood urea nitrogen, aspartate aminotransferase (AST), alanine aminotransferase, and hemoglobin level values, platelet, leukocyte, neutrophil, lymphocyte, eosinophil, basophil, and monocyte count results, erythrocyte sedimentation rate (ESR), neutrophil-lymphocyte ratio, platelet-lymphocyte ratio (PLR) and lymphocyte-monocyte ratio (LMR) values were evaluated.

Results In the present study, 23 operated patients with meningioma World Health Organization (WHO) grade 1 (17 females, 6 males) were included. Correlation test results revealed that the GCS score, platelet count, and serum potassium level values could directly predict the short-term prognosis of these patients. Additionally, these test results suggested that the lymphocyte, monocyte, and eosinophil count values, PLR, LMR, ESR, serum glucose, CRP, and AST level values could be indirect markers in predicting the short-term prognosis. However, likelihood ratio test results revealed that only monocyte count value, LMR value, and serum CRP level value could be the markers for prediction of the short-term prognosis.

Conclusion At the end of the present study, it was concluded that the monocyte count value, LMR value, and serum CRP level value could be the best markers in predicting the short-term prognosis of the operated meningioma patients.
Recent Advances on Supramolecular Gels: From Stimuli-Responsive Gels to Co-Assembled and Self-Sorted Systems
Authors: Chu Chih-Wei , Schalley Christoph A.
Published: January 2021

Gels prepared from low-molecular-weight gelators (LMWGs) represent versatile soft materials. Self-assembly of LMWGs forms nanofibers and above critical gelation concentrations, the entanglement of which leads to self-supporting gels. Owing to the dynamic properties of the self-assembly process, stimuli-responsive LMWGs have prospered in the last decade. In addition, incorporating multiple LMWGs into one system brings the opportunity to achieve sophisticated designs and functions. This review covers recent advances in the field of supramolecular gels, from stimuli-responsive gelators to multicomponent systems that are self-sorting and/or co-assembling.
Modulation of Crystallinity and Optical Properties in Composite Materials Combining Iron Oxide Nanoparticles and Dye-Containing Covalent Organic Frameworks
Authors: Sánchez-Naya Roberto , Stepanenko Vladimir , Mandel Karl , Beuerle Florian
Published: January 2021

Two series of organic–inorganic composite materials were synthesized through solvothermal imine condensation between diketopyrrolopyrrole dialdehyde DPP-1 and 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP) in the presence of varying amounts of either amino- or carboxy-functionalized superparamagnetic iron oxide nanoparticles (FeO). Whereas high FeO loading induced cross-linking of the inorganic nanoparticles by amorphous imine polymers, a lower FeO content resulted in the formation of crystalline covalent organic framework domains. All hybrid materials were analyzed by magnetization measurements, powder X-ray diffraction, electron microscopy, IR, and UV/Vis absorption spectroscopy. Crystallinity, chromophore stacking, and visible absorption features are directly correlated to the mass fraction of the components, thus allowing for a fine-tuning of materials properties.
The COVID-19 effect on the Paris agreement
Authors: Reilly John M. , Chen Y.-H. Henry , Jacoby Henry D.
Published: January 2021

The pandemic and efforts to control it are causing sharp reductions in global economic activity and associated fossil energy use, with unknown influence on longer-term efforts to limit greenhouse gas emissions under the Paris Climate Agreement. To explore this effect, estimates of economic recession and recovery in near-term months are extended to cover a return to full employment in future years, to be compared with an estimate of growth had COVID-19 not occurred. On the assumption that the Paris emissions pledges for 2020 will be met in any case, projection of global emissions with and without the pandemic show that, through its growth impact alone, it will yield only a small effect on emissions in 2030 and beyond. Other COVID legacies may include residual influences in patterns of consumption and travel, and the direction of recovery funds to low carbon investments. Most important, however, will be the effect of the economic shocks on the willingness of nations to meet (or augment) their existing Paris emissions pledges. The main effect of the pandemic on the threat of climate change, therefore, will be not its growth impact but its influence on national commitments to action.
The COVID-19 pandemic underscores the need for an equity-focused global health agenda
Authors: Jensen N. , Kelly A. H. , Avendano M.
Published: January 2021

Over the past few months, COVID-19 has ravaged health systems and economies in countries across the world. While many would argue that a pandemic of respiratory disease was predictable, the systematic failures of the response came as a surprise. From the shortage of hospital beds and medical equipment to the gross insufficiencies in national surveillance systems, supply chains and laboratory capacity, COVID-19 has laid bare the health care limitations that ‘global north’ and ‘global south’ share. A stark set of differences, however, run across the parallels in our collective predicament: indeed, what has become ever-more apparent is the radically uneven distribution of the health, social and economic risks associated with the pandemic—and the public health measures implemented in response—both within and between societies. As concerns grow over a prolonged period of COVID-19 waves, further insights are needed into who bears the largest share of COVID-19 burden and why. The pursuit of health equity is widely held to be global health’s raison d’être; and yet, the deep inequities laid bare by the current pandemic underscore that the field must do more and we must do better. This article identifies five key domains for equity research and action going forward. These ‘equity frontiers’ are not meant to be exhaustive. Rather our emphasis here is on drawing lessons from the COVID-19 pandemic as a prompt for a revived—if not rethought—equity agenda for an evolving global health field.
Heat stress effects in primiparous and multiparous lactating crossbred cows under a warm environment and their responses to a cooling treatment
Authors: Castro-Montoya J. , Corea E. E.
Published: January 2021

Context
In temperate climates, multiparous cows are more susceptible to heat stress (HS) than are primiparous cows. However, these differences in susceptibility may vary in warm environments, where the overall production level is lower, cow size is smaller, and adaptation to HS increases.

Aim
The different effects of HS and its alleviation on primiparous and multiparous cows was tested in crossbred cows (3/4 Holstein × 1/4 Brahman) in a warm environment.

Method
Twelve cows during the rainy season (August–September 2014) and 12 cows during the dry season (March–April 2015; six primiparous, six multiparous) were monitored for rectal temperature and respiration rate, indicators of HS, and milk yield (MY) in a dairy farm in El Salvador. Ambient temperature and relative humidity were recorded hourly to estimate temperature–humidity index throughout the day. During the rainy season, all cows were housed in a pen without cooling treatment. During the dry season, fans and sprinklers were installed in the pen and provided cooling to the herd in two 15-day periods, alternated with two periods without cooling (Control).

Key results
Primiparous cows were more susceptible to HS. Cooling alleviated HS, resulting in an increased feed intake and MY, with a greater impact on primiparous cows. During the cooling treatment, HS parameters increased overnight after the last cooling cycle of the day. This indicated that, despite the cooling treatment, cows still suffered from HS outside the hottest hours of the day. Furthermore, despite a higher temperature–humidity index during the rainy season, rectal temperature and MY remained similar in both the dry and the rainy season for cows without cooling, indicating that animals effectively lower their body temperature by increasing their respiration rate.

Conclusions
The cooling only partially helped alleviate HS in both multiparous and primiparous cows, with the effects being greater on the latter. However, the increments in MY were proportional to the increases in feed intake, indicating that the efficiency of feed utilisation was likely to be not improved.

Implications
More attention should be given to the susceptibility of primiparous cows to HS, as well as to the adjustment of cooling protocols towards alleviating HS in early morning and late afternoon hours.
DNA Binding and DNA Cleavage Activities of Newly Synthesized Co
Authors: Das Ananya , Mishra Dipu Kumar , Gurung Pritika , Dakua Vikas Kumar , Sinha Biswajit
Published: January 2021

Two water soluble complexes with CoII and CuII ions were synthesized using a novel β-cyclodextrin based azo-functionalized Schiff base as a ligand. The Schiff base and its metal complexes were characterized by different physico-chemical and spectroscopic methods. From the analyses of the experimental data, distorted octahedral geometry has been assigned for both the metal complexes. The binding interactions between the metal complexes and DNA were investigated by means of a thermal denaturation study and viscosity measurements as well as by electronic absorption and fluorescence spectroscopy. The DNA cleavage efficacy of the metal complexes was also studied by agarose gel electrophoresis using pBR DNA. These studies revealed that both the metal complexes followed an intercalative mode of binding to calf thymus (CT)-DNA and also effectively cleaved the supercoiled pBR DNA. The CoII complex, however, more efficiently cleaved CT-DNA than the CuII complex as much as the experimental results are concerned.
Accessing Bodies that Matter
Authors: Krasuska Karolina , Janion Ludmiła , Usiekniewicz Marta
Published: January 2021

In this self-reflexive paper, co-written by scholars currently collaborating on the Polish translation of Judith
Butler’s Bodies that Matter, we discuss the political and activist stakes of translating a canonical queer theory
text over 25 years after its original publication, in the context of anti-lgbtq+ public discourse in today’s Poland. We argue that
the collective character of our translation process turns it into an activist workshop that negotiates social norms and works on
the invention and application of their alternatives. This activist practice results in a programmatically accessible translation,
written in gender-inclusive and queer-sensitive language that follows the poststructuralist philosophical underpinnings of the
1993 source text and its gendered language. Discussing examples of Butler’s use of grammatical gender and her politicized style in
our translation, the article contributes to understanding the queer activist practice of translation and, specifically,
underwritten questions of translating queer theory in a contemporary Polish (linguistic) context.
Spin waves in unsaturated single- and double-layered ferromagnetic nanorings
Authors: Hussain B , Haghshenasfard Z , Cottam M G
Published: January 2021

A theoretical analysis is described for the spin waves in single- and double-layered nanorings using a microscopic, or Hamiltonian-based, formalism. The calculations, which yield the frequencies and spatially-dependent intensities of the quantized spin waves, are applied to the vortex and onion (bi-domain) states in a single nanoring, as well as to the field-induced switching. In the case of asymmetric double-layered nanorings (with a nonmagnetic spacer) there are coupled spin waves controlled by varying the spacer thickness to change the strength of the inter-ring dipolar interactions. The different possible magnetic states, depending on the applied magnetic field, may involve vortex states (with the same or opposite chirality) in both layers, a vortex state in one layer and onion state in the other, or onion states in both layers. Numerical applications are made to permalloy nanorings with realistic dimensions and magnetic parameter values.
A rechargeable all-solid-state sodium peroxide (Na2O2) battery with low overpotential
Authors: Jiang Chenggong , Mao Baohua , Diao Fangyuan , Li Qingtian , Wen Zhaoyin , Si Pengchao , Zhang Hui , Liu Zhi
Published: January 2021

Na–O2 batteries have been attracting attention owing to their intrinsically high theoretical energy density. Several Na–O2 systems can produce various discharge products with different electrochemical performances. For example, sodium superoxide (NaO2) batteries have a low overpotential, and sodium peroxide (Na2O2) batteries have a high capacity. Studies of Na2O2 batteries are relatively scarce, owing to the difficulty of forming pure Na2O2 discharge products. A pure Na2O2 battery system is highly desirable for fully exploring the formation and decomposition of Na2O2 in Na–O2 batteries and evaluating their potential. This model of a Na2O2 battery should also be compatible with in situ characterization. To this end, we constructed a simple rechargeable all-solid-state Na2O2 battery. Using a nanoporous gold film as the cathode and Na–β″-Al2O3 as a solid electrolyte, we assembled a Na–O2 battery that can produce and decompose Na2O2. The all-solid-state Na–O2 battery is a simple model for conducting in situ ambient-pressure x-ray photoelectron spectroscopy (APXPS) investigations. The battery can be cycled at a low overpotential (≈450 mV). Qualitative and quantitative analyses of the APXPS and Raman results demonstrated that Na2O2 was the main discharge product and its transformation occurred during the charge and discharge periods. The operando investigation of this type of all-solid-state Na2O2 battery can help in the comprehensive exploration of the potential of Na–O2 batteries.
Laser scattering by submicron droplets formed during the electrical explosion of thin metal wires
Authors: Romanova V M , Ivanenkov G V , Parkevich E V , Tilikin I N , Medvedev M A , Shelkovenko T A , Pikuz S A , Selyukov A S
Published: January 2021

This paper presents the results of studying dispersed media formation during the electrical explosion of thin metal wires in vacuum by using low-current generators (∼1–10 kA). Particular attention is paid to the analysis of the composition and structure of the corresponding explosion products as well as to the problem of their visualization using simultaneous laser interferometry and shadow imaging at two wavelengths (1.064 µm and 0.532 µm). Our findings indicate the important role in the visualization of the explosion products that belongs to multiple scattering by submicron droplets of dense condensed matter, which are mixed with metal vapor. The hypothesis on the existence of submicron droplets in the products of exploding metal wires correlates with the results obtained by soft x-ray radiography combined with a laser probing technique. Taking into account the multiple scattering by submicron droplets, it is possible to significantly clarify the parameters of the explosion products visualized via laser probing techniques as well as to gain a deeper insight into the physics behind the electrical wire explosion.
Temperature dependent 89Y NMR study on multiferroic YCrO3
Authors: Mall Ashish Kumar , Pramanik A K
Published: January 2021

In this manuscript, we report the 89Y NMR measurement as a function of temperature on single phase and pure polycrystalline YCrO3 sample to study the magnetism and relaxation times on a microscopic level across the magnetic transition (T
N ≃ 141 K) from paramagnetic to antiferromagnetic state. The NMR peak width broadens abruptly upon crossing T
N due to the onset of internal magnetic fields, while peakshift slight decreases. A slight increase and subsequent anomalous decrease in the NMR peak intensity is observed on approaching T
N from 300 K. There is also a significant increase in peak width. The temperature dependence of the 89Y NMR spin–lattice relaxation rates 1/T
1 indicates a phase transition at T
N which is of magnetic origin due to Cr3+ ions, with an anomalously rise of fluctuations below T
N. Above T
N, this spin–lattice relaxation rate can be fitted to a power-law scaling behavior 1/T
1 ∼ T

β
with an exponent factor β ≈ 0.8, indicates low energy spin fluctuations. Moreover, Knight shift and 1/TT
1 scales linear with the bulk susceptibility which suggests the antiferromagnetic spin fluctuation in the YCrO3 system.
Assessment of empirical interatomic potential to predict thermal conductivity in ThO2 and UO2
Authors: Jin Miaomiao , Khafizov Marat , Jiang Chao , Zhou Shuxiang , Marianetti Chris A , Bryan Matthew S , Manley Michael E , Hurley David H
Published: January 2021

Computing vibrational properties of crystals in the presence of complex defects often necessitates the use of (semi-)empirical potentials, which are typically not well characterized for perfect crystals. Here we explore the efficacy of a commonly used embedded-atomempirical interatomic potential for the U
x
Th1−x
O2 system, to compute phonon dispersion, lifetime, and branch specific thermal conductivity. Our approach for ThO2 involves using lattice dynamics and the linearized Boltzmann transport equation to calculate phonon transport properties based on second and third order force constants derived from the empirical potential and from first-principles calculations. For UO2, to circumvent the accuracy issues associated with first-principles treatments of strong electronic correlations, we compare results derived from the empirical interatomic potential to previous experimental results. It is found that the empirical potential can reasonably capture the dispersion of acoustic branches, but exhibits significant discrepancies for the optical branches, leading to overestimation of phonon lifetime and thermal conductivity. The branch specific conductivity also differs significantly with either first-principles based results (ThO2) or experimental measurements (UO2). These findings suggest that the empirical potential needs to be further optimized for robust prediction of thermal conductivity both in perfect crystals and in the presence of complex defects.
Coexistence of polar distortion and conduction in doped 2D group-IV ferroelectrics: SiGe, SiSn, and GeSn
Authors: Yao Cheng-Jun , Huang Hong-Fei , Yao Yang , Wu Yin-Zhong , Hao Xiang
Published: January 2021

Since the concept of ferroelectric metal predicted in the 1960s has been experimentally realized in the bulk Weyl semimetal WTe2 [Sharma et al 2019 Sci. Adv.
5, eaax5080], it is significant to find the ultrathin polar metal or ferroelectric metal due to the demand of miniature of electronic nanodevices. Here, 2D buckled monolayers composed of group-IV elements such as SiGe, SiSn, and GeSn are selected as prototype. Then, the stability of 2D ferroelectricity in the above monolayers are confirmed based on the results of first-principles calculations. Most interesting, a robustly metallic polar state has been found in the above 2D ferrolectrics under both the electron doping and hole doping, and the polar distortion becomes even more remarkable when the electrons are doped as compared with the undoped system. Thus, the coexistence of polar state and conduction is theoretically verified in the doped group-IV monolayers. We hope the 2D ferroelectric materials can be used as a starting point to look for the polar metals with atomic thickness, and further broaden their applications in 2D electronics or spintronics in the future.
Segregation of hydrogen and vacancies at the Σ5(210)[001] symmetric tilt grain boundary in Ni and influence on cohesion
Authors: Shen X J , Connétable D , Andrieu E , Tanguy D
Published: January 2021

The segregation of hydrogen and vacancies at the Σ5(210)[001] symmetric tilt grain boundary (GB) was studied by atomic scale simulations in Ni. First, the hydrogen segregation energies and hydrogen–hydrogen pair interaction energies were calculated on every interstitial site of the GB. The vacancy–hydrogen clusters’ formation energies were also determined on the most favorable site. All these calculations were done using the density functional theory. Second, based on these elementary energies, a free energy functional was built to determine the concentration of segregated hydrogen and of vacancy-hydrogen clusters, as a function of the bulk hydrogen concentration and the temperature. It was found that two configurations exits in typical conditions where embrittlement is observed experimentally: H segregation only, with up to 3 hydrogen atom per structural unit or 50% occupancy by VH5 clusters (1 cluster every two structural unit). The cohesive stress and ideal work of fracture were evaluated by fracturing the GB with different degrees of hydrogen and vacancy segregation. H segregation alone (no vacancy) decreased the work of fracture by 25%. A significantly larger decrease of cohesion was obtained when considering vacancy-hydrogen clusters. A maximum drop of the cohesive stress, of a magnitude of 40%, was obtained when every structural unit was hosting a VH4 cluster. Finally, these data were transformed into cohesive stress models. They were used to evaluate the degree of localization of the shear displacement at the crack tip. The conclusion is that, even if cohesion is very significantly decreased, shear localization is still effective, meaning that dislocation emission should occur at the expense of crack propagation. The comparison with other grain boundaries in the literature shows that the GB studied is almost an ideal sink and therefore is very favorable for the formation of equilibrium VH
n
. It represents more an upper bound of the effect. Therefore, extra ingredients should be considered to explain the embrittlement observed experimentally.
Data-mining of dislocation microstructures: concepts for coarse-graining of internal energies
Authors: Song Hengxu , Gunkelmann Nina , Po Giacomo , Sandfeld Stefan
Published: January 2021

Continuum models of dislocation plasticity require constitutive closure assumptions, e.g., by relating details of the dislocation microstructure to energy densities. Currently, there is no systematic way for deriving or extracting such information from reference simulations, such as discrete dislocation dynamics (DDD) or molecular dynamics. Here, a novel data-mining approach is proposed through which energy density data from systems of discrete dislocations can be extracted. Our approach relies on a systematic and controlled coarse-graining process and thereby is consistent with the length scale of interest. For data-mining, a range of different dislocation microstructures that were generated from 2D and 3D DDD simulations, are used. The analyses of the data sets result in energy density formulations as a function of various dislocation density fields. The proposed approach solves the long-standing problem of voxel-size dependent energy calculation during coarse graining of dislocation microstructures. Thus, it is crucial for any continuum dislocation dynamics simulation.
Diblock copolymers directing construction of hierarchically porous metal-organic frameworks for enhanced-performance supercapacitors
Authors: You Yuxiu , Li Fanggang , Ai Yan , Wei Facai , Cui Jing , Fu Jianwei , Zheng Maojun , Liu Shaohua
Published: January 2021

A rationally designed strategy is developed to synthesize hierarchically porous Fe-based metal-organic frameworks (P-Fe-MOF) via solution-based self-assembly of diblock copolymers. The well-chosen amphiphilic diblock copolymers (BCP) of polystyrene-block-poly(acrylic acid) (PS-b-PAA) exhibits outstanding tolerance capability of rigorous conditions (e.g. strong acidity or basicity, high temperature and pressure), steering the peripheral crystallization of Fe-based MOF by anchoring ferric ions with outer PAA block. Importantly, the introduction of BCP endows MOF materials with additional mesopores (∼40 nm) penetrating whole crystals, along with their inherent micropores and introduced macropores. The unique hierarchically porous architecture contributes to fast charge transport and electrolyte ion diffusion, and thus promotes their redox reaction kinetics processes. Accordingly, the resultant P-Fe-MOF material as a new electrode material for supercapacitors delivers the unprecedented highest specific capacitance up to 78.3 mAh g−1 at a current density of 1 A g−1, which is 9.8 times than that of Fe-based MOF/carbon nanotubes composite electrode reported previously. This study may inspire new design of porous metal coordination polymers and advanced electrode materials for energy storage and conversion field.
Dielectric optical nanoantennas
Authors: Hasan Md Rabiul , Hellesø Olav Gaute
Published: January 2021

Nanophotonics allows the manipulation of light on the subwavelength scale. Optical nanoantennas are nanoscale elements that enable increased resolution in bioimaging, novel photon sources, solar cells with higher absorption, and the detection of fluorescence from a single molecule. While plasmonic nanoantennas have been extensively explored in the literature, dielectric nanoantennas have several advantages over their plasmonic counterparts, including low dissipative losses and near-field enhancement of both electric and magnetic fields. Nanoantennas increase the optical density of states, which increase the rate of spontaneous emission due to the Purcell effect. The increase is quantified by the Purcell factor, which depends on the mode volume and the quality factor. It is one of the main performance parameters for nanoantennas. One particularly interesting feature of dielectric nanoantennas is the possibility of integrating them into optical resonators with a high quality-factor, further improving the performance of the nanoantennas and giving very high Purcell factors. This review introduces the properties and parameters of dielectric optical nanoantennas, and gives a classification of the nanoantennas based on the number and shape of the nanoantenna elements. An overview of recent progress in the field is provided, and a simulation is included as an example. The simulated nanoantenna, a dimer consisting of two silicon nanospheres separated by a gap, is shown to have a very small mode volume, but a low quality-factor. Some recent works on photonic crystal resonators are reviewed, including one that includes a nanoantenna in the bowtie unit-cell. This results in an enormous increase in the calculated Purcell factor, from 200 for the example dimer, to 8 × 106 for the photonic crystal resonator. Some applications of dielectric nanoantennas are described. With current progress in the field, it is expected that the number of applications will grow and that nanoantennas will be incorporated into new commercial products. A list of relevant materials with high refractive indexes and low losses is presented and discussed. Finally, prospects and major challenges for dielectric nanoantennas are addressed.