bluuebunny/crossref_metadata_2025 huggingface dataset:
Silent cities, silenced histories: subaltern experiences of everyday urban violence during COVID-19
Authors: Gupte Jaideep , Zahan Syeda Jenifa
Published: June 2021

The public health containment measures in response to COVID-19 have precipitated a significant epistemic and ontological shift in �bottom-up� and �action-oriented� approaches in development studies research. �Lockdown� necessitates physical and social distancing between research subject and researcher, raising legitimate concerns around the extent to which �distanced� action-research can be inclusive and address citizens� lack of agency. Top-down regimes to control urban spaces through lockdown in India have not stemmed the experience of violence in public spaces: some have dramatically intensified, while others have changed in unexpected ways. Drawing on our experiences of researching the silent histories of violence and memorialisation of past violence in urban India over the past three decades, we argue that the experience of subaltern groups during the pandemic is not an aberration from their sustained experiences of everyday violence predating the pandemic. Exceptionalising the experiences of violence during the pandemic silences past histories and disenfranchises long struggles for rights in the city. At the same time, we argue that research practices employed to interpret the experience of urban violence during lockdown in India need to engage the changing nature of infrastructural regimes, as they seek to control urban spaces, and as subaltern groups continue to mobilise and advocate, in new ways.
Role of arterial blood gas (ABG) as a valuable assessment tool of disease severity in SARS-CoV-2 patients
Authors: Amrita Jyot , Singh Arvinder
Published: June 2021

Background: COVID-19 is caused by a novel coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The foremost predominant complication of SARS-CoV-2 is arterial hypoxemia thereby disturbing lung compliance, requiring mechanical ventilation. The aim of the current research study is to analyze role of ABG as a valuable assessment tool of disease severity in SARS-CoV-2 patients. Methods: 170 arterial blood samples were collected from patients admitted in Intensive Care Unit (ICU) of Sri Guru Ram Das Charitable Hospital, Amritsar. They were analyzed for arterial blood gas using ABG analyzer. Parameters of ABG such as pH, pCO2, HCO3, O2 saturation, ionized calcium (iCa) and calculated ionized calcium (at pH 7.4) was calculated for all the samples. Results: Continuous variables were described as medians with interquartile ranges (IQRs) and categorical variables as percentages and frequencies. Spearman correlation test was done for calculation of correlation between pH and other ABG parameters. Analysis of arterial blood gas revealed significant negative correlation (p<0.05) between pH and pCO2 and significant positive correlation (p<0.05) between pH and HCO3 and between pH and delta ionized calcium. Low levels (98.2%) of ionized calcium were observed while monitoring the ABG findings though weak negative correlation (p<0.05) was observed between pH and iCa. Conclusions: Our study suggests that ABG analysis acts as a momentous indicator for critically ill patients admitted in Intensive Care Unit (ICU). Estimation of iCa in this critical care setting acts as a distinctive biochemical feature of SARS-CoV-2 disease, as an initial assessment tool, for hypocalcemia.
Hardware-enabled security:
Authors: Bartock Michael , Inbaraj Joseprabu , Knoll Tim , Righi Stefano , Savino Ryan , Scarfone Karen , Shetty Uttam , Souppaya Murugiah , Wheeler Jerry
Published: June 2021

In today's cloud data centers and edge computing, attack surfaces have significantly increased, hacking has become industrialized, and most security control implementations are not coherent or consistent. The foundation of any data center or edge computing security strategy should be securing the platform on which data and workloads will be executed and accessed. The physical platform represents the first layer for any layered security approach and provides the initial protections to help ensure that higher-layer security controls can be trusted. This report explains an approach based on hardware-enabled security techniques and technologies for safeguarding container deployments in multi-tenant cloud environments. It also describes a proof-of-concept implementation of the approach a prototype that is intended to be a blueprint or template for the general security community.
МИКРОБИОЛОШКА ИСПРАВНОСТ ВОДЕ У ПРИМАРНОЈ ПРОИЗВОДЊИ ХРАНЕ
Authors: ГОЛИЋ́ Бојан , КАЛАБА́ Весна , ИЛИЋ́ Тања
Published: June 2021

Здравствено безбједна вода представља основу здравог живљења и један је од приоритета у примарној здравственој заштити. Безбједност подразумијева микробиолошки, физичкохемијски и радиолошки исправну воду, довољне количине воде и њену континуирану испоруку. Због великог епидемиолошког значаја воде, чији је утицај непосредан и путем које се могу добити разне заразне болести, или унијети штетне и опасне хемијске материје, неопходно је, у циљу заштите здравља људи, контролисати здравствену исправност воде за пиће. Циљ истраживања је утврђивање микрoбиолошке исправности воде која се користи за потребе прехрамбене индустрије, као и за напајање животиња. У периоду 2015-2017. године, 26,20% узорака воде није задовољило регулативу (Пропис, 2010; Пропис, 2015). Највећи број незадовољавајућих узорака био је због повећаног броја микроорганизама на 22°C (63,40%) и 37°C (54,90%), a када су у питању патогени микроорганизми, због присуства цријевних ентерокока (58,80%). Најмањи ризик од присуства колиформа и E. coli јe у води из водовода, док је он унатно већи у бунарској и изворској води. Присуство цријевних ентерокока значајно у све три врсте воде за пиће, a присуство сулфидоредукујућих клостридија утврђено је само у изворској води.
First-order reversal curve diagram and its application in investigation of polarization switching behavior of HfO2-based ferroelectric thin films
Authors: Shi Zhi-Xin , Zhou Da-Yu , Li Shuai-Dong , Xu Jin , Uwe Schröder ,   Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China,   Dalian Neusoft University of Information, Dalian 116023, China,   NaMLab gGmbH, Dresden 01187, Germany
Published: June 2021

 From physical point of view, the “0, 1” read/write operation of ferroelectric memory is based on the polarization switching of ferroelectric memory. Therefore, the reliability of device relies directly on the stability of polarization switching behavior. The polarization behaviors of HfO2-based ferroelectric thin films subjected to bipolar cyclic electric field often exhibit wake-up, fatigue and split-up of transient switching current. These unstable switching properties seriously restrict the practical application of this new-type ferroelectric material in memory devices. It therefore becomes the critical task to explore the mechanism behind the complex evolution of polarization switching and find out possible approaches to optimizing the stability. However, it will be extremely difficult to accomplish the task by the traditional characterization methods. First-order reversal curve (FORC) diagram is regarded as “fingerprint identification” in the study of hysteresis systems, and has been used successfully to analyze the characteristic parameters of magnetic materials. The FORC diagram can intuitively determine the type, size and domain status of magnetic particles from distribution of both coercive field and interaction field. Moreover, it is also found that the FORC diagram is sensitive to measuring temperature.

 In this work, first, the Preisach model and implementation method of the FORC diagram are introduced. Then using Keithley 4200-SCS equipped with a remote pulse measurement unit, 60 FORCs are recorded for Si-doped HfO2 ferroelectric thin films experiencing different external field loading histories. By the mathematical treatment, switching density distributions determined by FORC measurements are obtained to explore the evolution of coercive field and bias field. The FORC diagram of pristine film contains three distribution regions with different bias fields, which merge into one distribution with an almost zero bias field after 104 wake-up cycles. Two oppositely biased regions can be observed after 2 × 109 sub-cycling treatments. Surprisingly, the bias fields nearly vanish again after 104 wake-up cycles. The main change of bias field instead of coercive field indicates that the migration of oxygen vacancies is likely to be the dominant mechanism behind the complex polarization switching behavior for HfO2-based ferroelectric thin films.
Discovery of Quantitative Electronic Structure‐OER Activity Relationship in Metal‐Organic Framework Electrocatalysts Using an Integrated Theoretical‐Experimental Approach
Authors: Zhou Jian , Han Zhongkang , Wang Xingkun , Gai Huiyu , Chen Zongkun , Guo Tong , Hou Xianbiao , Xu Liangliang , Hu Xiaojuan , Huang Minghua , Levchenko Sergey V. , Jiang Heqing
Published: June 2021

Developing cost‐effective and high‐performance catalysts for oxygen evolution reaction (OER) is essential to improve the efficiency of electrochemical conversion devices. Unfortunately, current studies greatly depend on empirical exploration and ignore the inherent relationship between electronic structure and catalytic activity, which impedes the rational design of high‐efficiency OER catalysts. Herein, a series of bimetallic Ni‐based metal‐organic frameworks (Ni‐M‐MOFs, M = Fe, Co, Cu, Mn, and Zn) with well‐defined morphology and active sites are selected as the ideal platform to explore the electronic‐structure/catalytic‐activity relationship. By integrating density‐functional theory calculations and experimental measurements, a volcano‐shaped relationship between electronic properties (d‐band center and eg filling) and OER activity is demonstrated, in which the NiFe‐MOF with the optimized energy level and electronic structure situated closer to the volcano summit. It delivers ultra‐low overpotentials of 215 and 297 mV for 10 and 500 mA cm−2, respectively. The identified electronic‐structure/catalytic activity relationship is found to be universal for other Ni‐based MOF catalysts (e.g., Ni‐M‐BDC‐NH2, Ni‐M‐BTC, Ni‐M‐NDC, Ni‐M‐DOBDC, and Ni‐M‐PYDC). This work widens the applicability of d band center and eg filling descriptors to activity prediction of MOF‐based electrocatalysts, providing an insightful perspective to design highly efficient OER catalysts.
High‐Efficiency (16.93%) Pseudo‐Planar Heterojunction Organic Solar Cells Enabled by Binary Additives Strategy
Authors: Wang Xinkang , Zhang Lifu , Hu Lei , Xie Zijun , Mao Houdong , Tan Licheng , Zhang Youdi , Chen Yiwang
Published: June 2021

Acquiring precision adjustable morphology of the blend films to improve the efficiency of charge separation and collection is a constant goal of organic solar cells (OSCs). Here, the above problem is improved by synergistically combining the sequential deposition (SD) method and the additive general strategy. By adding one additive 1,10‐decanediol (DDO) into PM6 and another 1‐chloronaphthalene (CN) into Y6, the molecule orientation of PM6 and the crystallite texture of the Y6 all become order. During the SD processing, a vertical phase separation OSCs device is formed where the donor enrichment at the anode and acceptor enrichment at the cathode. In comparison, the SD OSCs device with only CN additive still displays the bulk‐heterojunction morphology similar to PM6:Y6 blend film. The morphology with vertical phase distribution can not only inhibit charge recombination but also facilitate charge collection, finally enhancing the fill factor (FF) and photocurrent in binary additives SD‐type OSCs. As a result, the binary additives SD‐type OSCs with blend film PM6+DDO/Y6+CN exhibit a high FF of 77.45%, enabling a power conversion efficiency as high as 16.93%. This work reveals a simple but effective approach for boosting high‐efficiency OSCs with ideal morphologies and demonstrates that the additive is a promising processing alternative.
Microresonators in Lithium Niobate Thin Films
Authors: Xie Ran‐Ran , Li Gui‐Qin , Chen Feng , Long Gui‐Lu
Published: June 2021

Leveraging the outstanding nonlinear optical properties and the ultra‐high spatial confinement of light, microresonators based on lithium niobate (LN) thin films have emerged as intriguing elements in various frontiers such as integrated photonic circuits and quantum photonics. A number of applications have been realized based on LN thin‐film microresonators toward various on‐chip devices. In this paper, the recent advances of microresonators based on LN thin films are reviewed, including essential techniques used in fabrication/characterization and a detailed overview of applications, ranging from frequency conversion, electro‐optic modulation, frequency combs, microwave‐to‐optical transducers, quantum photonics, to lasing. A short summary and perspective is presented to indicate possible research topics related to LN thin‐film.
Reversible Photochemical Switching via Plasmonically Enhanced Upconversion Photoluminescence
Authors: Kim Byunghoon , Lee Kyu‐Tae , Cho Junhee , Darshanoju Narasimha Achary , Jung Kinam , Ahn In‐Hwan , Shin Jae‐Min , Oh Hyeongyeol , Ki Yeongcheol , Lee Hohjai , Kwon Seok Joon , Kim In Soo , Cai Wenshan , Ahn Kwang‐Hyun , Ko Doo‐Hyun
Published: June 2021

Photochromic molecule‐incorporated optical devices offer desirable properties for photocontrollable optical systems, including advanced optical data storage and super‐resolution imaging. However, these molecules require multiple illumination sources, such as UV and visible light, for reversible photochemical reactions, which restricts their potential for advanced application. This study reports an effective strategy for modulating photoisomerization via a single near‐infrared light source assisted by plasmonically enhanced photoswitchable upconversion photoluminescence (UCPL). The proposed quasi‐periodic metal nanostructures to facilitate the resonance modes in the broadband region enable the substitution of the detrimental high‐energy light source (i.e., UV light) with near‐infrared stimuli, which is associated with UCPL enhancement of over two orders with spectrum orthogonality. To validate this concept, the accelerated reversible‐photoisomerization kinetics is experimentally confirmed by three‐ and tenfold amplification of the PL intensities of the photochromic disulfonyldiarylethene derivatives. Further validation of the proposed strategy is performed using photodynamic imaging, which reveals accelerated photoisomerization, high photocyclization stability, and high spatial resolution.
Two‐Step Sequence Multicomponent Synthesis/Reductive Rearrangement of 2‐Acyl‐2,3‐dihydrofurans for Modular Assembly of Annulated 4H‐Pyrans
Authors: Demidov Maxim R. , Osipov Dmitry V. , Korol'kov Konstantin A. , Osyanin Vitaly A.
Published: June 2021

A variety of trans‐2‐acyl‐2,3‐dihydrofurans have been assembled from readily available structurally diverse precursors and then rearranged into a series of annulated 4H‐pyrans by the action of Sm/TMSCl or Zn/ZrCl4 redox systems. Present synthetic sequence is claimed as a modular approach to hetero‐ and carbon‐fused 4H‐pyrans. The rearrangement involves the SET reduction of carbonyl group to carbene followed by rare type of [1,2]‐aroxyl shift. Synthetic toolbar was enriched with the use of the Zn/ZrCl4 redox system.

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Review on Asymmetric Catalysis Employing 5H‐Oxazol‐4‐Ones as α‐Hydroxy Carboxylic Acid Surrogates
Authors: Jain Anshul , Rana Nirmal K.
Published: June 2021

Heterocycles play an essential role in medicinal as well as in organic synthetic chemistry. The synthesis of these valuable scaffolds is an emerging and challenging field of today‘s research in organic chemistry. In recent years, several heterocycles as new synthons have emerged as potential nucleophiles in asymmetric transformations. Among them, 5H‐oxazol‐4‐one is one of the strategic synthons for synthesizing enantioenriched α‐alkyl‐α‐hydroxycarboxylic acid derivatives, which are otherwise very challenging via direct installation of a hydroxy group at the α‐position of carbonyls. Over the years, considerable progress has been made to establish new and efficient methodologies under mild reaction conditions exploiting metal‐ and organo‐catalysis. This review presents a comprehensive summary of various catalytic development in asymmetric synthesis employing 5H‐oxazol‐4‐ones as α‐alkyl‐α‐hydroxycarboxylic acid surrogates.

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Recent advances in the rhodium‐catalyzed cyanation reactions
Authors: Soumya Puthukudichola Krishna , Vaishak Thottuvazhiyil Balakrishnan , Saranya Salim , Anilkumar Gopinathan
Published: June 2021

Cyanation reactions have found a dominant position in organic synthesis due to the propensity of the cyanide group for conversion to various other functionalities. This property has opened up wide application for cyanide group. In recent years, transition metal‐catalyzed reactions in general and rhodium‐catalyzed reactions in particular have attracted the attention of organic chemists, which lead up to a number of cyanation procedures and synthetic transformation of the cyanide group into highly functionalized products. This review provides an overview of the rhodium‐catalyzed cyanation reactions and subsequent transformations leading to the formation of various types of compounds such as amines, acids, indoles, isocyanides, nitriles, and oximes.
Preparation of chemically functionalized and self compatibilized short coir fiber ‐ high density polyethylene composites
Authors: Babu S. Archana , Narayanankutty Sunil K.
Published: June 2021

The interphase adhesion plays key role in the performance of composites. The commonly employed strategies include blending with an external compatibilizer or utilizing chemical grafting followed by purification and copolymerization. Here, we showcase a reformed and simple approach in the fabrication of chemically functionalized, self compatibilized composites [PE‐TCF5%‐MA2%] by insitu grafting of maleic anhydride in the polymer melt, followed by the reactive compatibilization of treated short coir fiber. Micro‐structural analysis of the composites revealed enhanced fiber/matrix adhesion. The improved mechanical, viscoelastic, and thermal properties of composites can be attributed to new interfacial bond formed, which was confirmed by Fourier transform infrared [FTIR] studies. PE‐TCF5%‐MA2% exhibited approximately 74% and 25% improvement in tensile strength compared to untreated (PE‐UCF) and treated (PE‐TCF) fiber composites respectively. Dynamic mechanical analysis of composites displayed similar trend with highest value of storage modulus recorded for PE‐TCF5%‐MA2%. Final decomposition temperature of all composites was shifted to higher side. Peak degradation temperature was increased with a marginal increase of residual char. Together with the goodness of agro‐based fiber and feasiblity of this low cost method suggests the potential of PE‐TCF‐MA toward bulk industrial prodution of composite panels.
Ultrahigh molecular weight polyethylene with improved crosslink density, oxidation stability, and microbial inhibition by chemical crosslinking and tea polyphenols for total joint replacements
Authors: Shah Nouman Ali , Ren Yue , Lan Ri‐Tong , Lv Jia‐Cheng , Gul Rizwan M. , Tan Peng‐Fei , Huang Shishu , Tan Lin , Xu Jia‐Zhuang , Li Zhong‐Ming
Published: June 2021

Highly crosslinked ultrahigh molecular weight polyethylene (UHMWPE) stabilized by vitamin E (VE) is widely applied in artificial joints as the bearings. Despite the approval, there is a discord that VE lowers the crosslinking efficiency, limiting its use at high concentration. In this work, we aim to obtain highly crosslinked and oxidation resistant UHMWPE through the conjunction of tea polyphenol and chemical crosslinking. We hypothesized that highly incorporated tea polyphenol with multiple reactive sites can ameliorate crosslinking efficiency of chemical crosslinked UHMWPE in comparison to VE. Epigallocatechin gallate (EGCG) as representative tea polyphenol was incorporated into UHMWPE at high concentration (2–8 wt%), followed by chemical crosslinking with 2 wt% organic peroxide. Unlike VE/UHMWPE blends as the control, chemical crosslinking achieved an increasing trend in crosslink density of EGCG/UHMWPE blends with increasing antioxidant concentration. High concentration of EGCG also enhanced the oxidation stability of UHMWPE. Intriguingly, EGCG endowed UHMWPE with an excellent antimicrobial property, which was inefficient in VE/UHMWPE. Cell viability was hardly affected by the high loaded antioxidant and peroxide. The chemically crosslinked UHMWPE blended with EGCG is proved to be a reasonable, cost effective and realistic alternative for use in artificial joints.
Synthesis of superhydrophobic nanocomposite coating films for self‐cleaning glass using nanoemulsion technique
Authors: Mohamed Reham H. , El‐Din M. R. Noor , N. O. Shaker
Published: June 2021

This work aims to fabricate new potent superhydrophobic‐hybrid coated nanocomposites used as a self‐cleaning coating on the glass surface. Three (styrene/vinyl acetate) copolymers with monomer molar ratios of 0.06:0.17, 0.12:0.11, and 0.17:0.06 denoted as Z1‐, Z2‐, and Z3‐copolymers were synthesized using the emulsion phase inversion concentration (EPIC) method. Two functionalized SiO2‐NPs using dodecyl triethoxysilane and hexadecyl trimethoxysilane as coupling agents denoted as E‐NPs and F‐NPs, respectively were fabricated by a sol–gel process to promote the hydrophobicity properties of the synthesized SiO2‐NPs. New hybrid composites denoted as Py and Ty(y = 1, 2, and 3) were fabricated by incorporating 1, 3, and 5 wt% of the functionalized SiO2‐NPs (E‐NPs or F‐NPs) into the Z3‐copolymers matrix, respectively. The chemical structures of the synthesized copolymers, unfunctionalized SiO2‐NPs, and the hybrid composites were elucidated by FTIR and 1HNMR spectroscopes. The surface wettability and topography of the glass‐surface coated by synthesized (styrene/vinyl acetate) copolymers and the silica hybrid composites were analyzed using water contact angle, scanning electron, and atomic force microscopes. The results showed that a highly superhydrophobic coated hybrid composite with a contact angle of 161.48° was achieved by Z3‐copolymer/F5‐NPs denoted as T3‐composite at F5‐NPs concentration of 5 wt%.
Simultaneous analysis of oxytetracycline hydrochloride, lidocaine, and bromhexine hydrochloride in the presence of many interfering excipients
Authors: Gamal Mohammed , Naguib Ibrahim A. , Abdelfatah Rehab M.
Published: June 2021

A gradient elution high‐performance liquid chromatographic method with a diode array detector is introduced for the first time for the simultaneous estimation of three drugs, namely, oxytetracycline hydrochloride (OXT), lidocaine (LDC), and bromhexine hydrochloride (BRH), in a veterinary formulation (OxyClear® solution) that contains many interfering additives. The method used a C‐8 column. The chromatographic eluting solution included acidified water (0.1% trifluoroacetic acid in water) and acetonitrile at a 1‐ml/min flow rate and 254 nm as a nominated detection wavelength. The chromatographic process was assessed in terms of linearity, precision, accuracy, LOD, and LOQ. OXT, LDC, and BRH were linear in the range of 1–60, 5–100, and 1–60 μg/ml, respectively. The three drugs were determined successfully without the interference of three excipients having UV absorbances. Furthermore, the purities of the peaks of the three drugs were confirmed by comparing the UV spectra of investigated peaks to the UV reference spectra in Clarke's Analysis of Drugs and Poisons. The greenness value of the method was 0.69 with a faint green‐colored pictogram using the AGREE tool. These merits recommend the application of the planned method in QC laboratories for purity testing and concentration assays for the pure drugs and commercial formulations.
Revisiting the decay of scientific email addresses
Authors: Rodriguez‐Esteban Raul , Vishnyakova Dina , Rinaldi Fabio
Published: June 2021

Email is the primary method of communication with authors of scientific publications. This study sought to measure the reliability, over time, of contact email addresses from biomedical publications, particularly depending on email type. Emails were written to randomly selected email addresses from publications in MEDLINE, and email bounce rates were modeled probabilistically. The use of personal email addresses was quantified and compared to the use of other types of email addresses. Eighteen percent of authors' contact email addresses in MEDLINE were estimated to be invalid. A steadily growing share of email addresses was personal: 32% of all new email addresses in MEDLINE in 2018 were of this kind. These email addresses were less likely to be invalid than email addresses from other types of providers. While the percentage of invalid email addresses was significant, it was lower than previously estimated. Personal email addresses are taking an increasingly more important role by supplying more reliable email addresses to scientists. To mitigate the problem of invalid email addresses, institutions should provide email forwarding, scientific directories should offer the possibility of contacting authors, or scientific authors should use more stable email addresses.
A ZIF‐8 Host for Dendrite‐Free Zinc Anodes and N,O Dual‐doped Carbon Cathodes for High‐Performance Zinc‐Ion Hybrid Capacitors
Authors: Lei Liling , Zheng Yiwei , Zhang Xichen , Su Yutian , Zhou Xi , Wu Shishan , Shen Jian
Published: June 2021

Zn is a promising anode for aqueous energy storage owing to it intrinsic superior properties such as large capacity, abundant reserves, low potential and safety. But, the growth of dendrites during charge and discharge leads to a decrease in reversibility. In addition, further development of zinc‐ion hybrid capacitors (ZICs) is seriously challenging because of the lack of an exceptional cathode. Herein, we use ZIF‐8 annealed at 500 °C (annealed ZIF‐8) as a host material for stable and dendrite‐free Zn anodes. Utilization of annealed ZIF‐8 results in dendrite‐free Zn deposition and stripping as a result of its porous construction, which contains trace Zn. Furthermore, we firstly proposed innovative N,O dual‐doped carbon which was designed by the derived ZIF‐8 (ZIF‐8 derived C) as cathode for high‐energy and power‐density ZICs. The new ZIC assembled by Zn@annealed ZIF‐8 anode and ZIF‐8 derived C cathode provides a capacity of 135.5 mAh g−1 and an energy density of 108.4 Wh kg−1 with a power density of 800 W kg−1 at 1.0 A g−1. In addition, it shows outstanding cycling stability of 91% capacity retention after 6000 cycles at 5.0 A g−1. Moreover, the solid‐state ZICs can drive LEDs and smart watches. This ZIC holds promise for the practical application of supercapacitors.
Chemo‐mechanistic multi‐scale model of a three‐dimensional tumor microenvironment to quantify the chemotherapy response of cancer
Authors: Nikmaneshi Mohammad R. , Firoozabadi Bahar , Mozafari Aliasghar
Published: June 2021

Exploring efficient chemotherapy would benefit from a deeper understanding of the tumor microenvironment (TME) and its role in tumor progression. As in vivo experimental methods are unable to isolate or control individual factors of the TME, and in vitro models often cannot include all the contributing factors, some questions are best addressed with mathematical models of systems biology. In this study, we establish a multi‐scale mathematical model of the TME to simulate three‐dimensional tumor growth and angiogenesis and then implement the model for an array of chemotherapy approaches to elucidate the effect of TME conditions and drug scheduling on controlling tumor progression. The hyperglycemic condition as the most common disorder for cancer patients is considered to evaluate its impact on cancer response to chemotherapy. We show that combining antiangiogenic and anticancer drugs improves the outcome of treatment and can decrease accumulation of the drug in normal tissue and enhance drug delivery to the tumor. Our results demonstrate that although both concurrent and neoadjuvant combination therapies can increase intratumoral drug exposure and therapeutic accuracy, neoadjuvant therapy surpasses this, especially against hyperglycemia. Our model provides mechanistic explanations for clinical observations of tumor progression and response to treatment and establishes a computational framework for exploring better treatment strategies.
Juveniles arrested for murder: A latent class analysis of male offenders
Authors: Fox Bryanna , Heide Kathleen , Khachatryan Norair , Michel Cedric , Cochran John
Published: June 2021

Researchers and practitioners have a need for valid and generalizable typologies of juvenile homicide offenders (JHOs) to better understand the heterogeneous nature of JHOs, and use this knowledge to inform prevention efforts. Prior studies of JHOs have typically utilized a clinical approach, which is rich in data but based on small nonrepresentative samples, or relied on larger aggregate datasets which are more reliable but have few measures available. This study aimed to address these limitations by examining the latent heterogeneity (i.e. unapparent differences) in JHOs, their victims, and incident characteristics among more than 40,000 male JHOs arrested in the United States between 1976 and 2016 using latent class analysis, to allow for the objective identification of latent taxonomies. Six distinct subtypes of male JHOs are found in the analysis, which contributes to the theoretical and substantive knowledge base regarding JHOs, and may be used to develop and implement more effective interventions and violence prevention programs for these young offenders.
Exploring evolution of augmented and virtual reality education space in 2020 through systematic literature review
Authors: Noah Naheem , Das Sanchari
Published: June 2021

Research is increasingly being conducted to identify the benefits provided by the latest developments in the AR/VR domain, which has seen an increase in interest as a result of the stay‐at‐home phenomena in 2020. Of particular interest is the application of AR/VR to education, a discipline that has seen a rapid shift to online modules in 2020. To better understand the advancements in AR/VR enabled education, we conducted a systematic literature review consisting of papers published in the year 2020 that focused on AR/VR in the education sector. We particularly focused on papers where studies have evaluated user perceptions in different countries, academic fields, and at varied educational levels. We found that while most papers conducted user studies and evaluated the technical applications of AR/VR, user perceptions, impact, and awareness were not explored in detail. Our findings highlight trends that can drive critically needed innovations through AR/VR especially to help a globalized digital evolution in the education sector.
Discovery of the Class I Antimicrobial Lasso Peptide Arcumycin
Authors: Stariha Lydia M. , McCafferty Dewey G.
Published: June 2021

Lasso peptides are a structurally diverse superfamily of conformationally constrained peptide natural products, of which a subset exhibits broad antimicrobial activity. Although advances in bioinformatics have increased our knowledge of strains harboring the biosynthetic machinery for lasso peptide production, relating peptide sequence to bioactivity remains a continuous challenge. To this end, genome mining investigation of Actinobacteria‐produced antimicrobial lasso peptides was performed to correlate predicted structure with antibiotic activity. Bioinformatic evaluation revealed eight putative novel class I lasso peptide sequences. Fermentation of one of these hits, Streptomyces NRRL F‐5639, resulted in the production of a novel class I lasso peptide, arcumycin. Arcumycin exhibited antibiotic activity against Gram‐positive bacteria including Bacillus subtilis (4 μg/mL), Staphylococcus aureus (8 μg/mL), and Micrococcus luteus (8 μg/mL). Arcumycin treatment of B. subtilis liaI‐β‐gal promoter fusion reporter strain resulted in upregulation of the liaRS system by the promoter liaI, indicating arcumycin interferes with lipid II biosynthesis. Cumulatively, the results illustrate the relationship between phylogenetically related lasso peptides and their bioactivity as validated through the isolation, structural determination, and evaluation of bioactivity of the novel class I antimicrobial lasso peptide arcumycin.
Comparing Separation vs. Fresh Start to Assess Reusability of Pd/C Catalyst in Liquid‐Phase Hydrogenation
Authors: Mironenko Roman M. , Saybulina Elina R. , Trenikhin Mikhail V. , Izmailov Rinat R. , Lotsman Kristina A. , Rodygin Konstantin S. , Ananikov Valentine P.
Published: June 2021

The reusability of metal catalysts is a key issue for the potential application of new catalysts in research and industrial practice. The most common procedure for testing catalyst reusability in liquid‐phase heterogeneous reactions is based on separating a catalyst from a reaction mixture followed by the next run. An alternative procedure called “fresh start” consists of the addition of a new portion of reagents to the reaction mixture without any isolation operation. In this work, we compare both procedures in a model Pd/C‐catalyzed hydrogenation with different heteroatoms, e. g., O‐, S‐, and N‐vinyl derivatives. It was shown that regardless of whether the catalyst is stable or potentially poisoned during the reaction, both procedures lead to comparable results. It appears that a much easier implementation of a fresh start procedure may be an option of choice. The possibilities of using both procedures to rationalize the experimental protocol for assessing Pd/C catalyst reusability in liquid‐phase hydrogenations are discussed.
Electrosynthetic Screening and Modern Optimization Strategies for Electrosynthesis of Highly Value‐added Products
Authors: Dörr Maurice , Hielscher Maximilian M. , Proppe Jonny , Waldvogel Siegfried R
Published: June 2021

Invited for this month's cover picture is the group of Siegfried R. Waldvogel at Johannes Gutenberg‐University in Mainz accompanied by Jonny Proppe at Georg‐August University in Göttingen. The cover picture shows three schemes illustrating the methods Principal Component Analysis, Machine Learning, and Design of Experiment as a representative of statistical methods to be used for optimization in electroorganic synthesis. The green power plug highlights the great potential of the combination of electrochemistry with these methods to propel the field to a highly sustainable future. All of the elements are backed with the contour plot of a mathematic model. Read the full text of the Minireview at 10.1002/celc.202100318.
Heterodinuclear Zn(II), Mg(II) or Co(III) with Na(I) Catalysts for Carbon Dioxide and Cyclohexene Oxide Ring Opening Copolymerizations
Authors: Lindeboom Wouter , Fraser Duncan A. X. , Durr Christopher B. , Williams Charlotte K.
Published: June 2021

A series heterodinuclear catalysts, operating without co‐catalyst, show good performances for the ring opening copolymerization (ROCOP) of cyclohexene oxide and carbon dioxide. The complexes feature a macrocyclic ligand designed to coordinate metals such as Zn(II), Mg(II) or Co(III), in a Schiff base ‘pocket’, and Na(I) in a modified crown‐ether binding ‘pocket’. The 11 new catalysts are used to explore the influences of the metal combinations and ligand backbones over catalytic activity and selectivity. The highest performance catalyst features the Co(III)Na(I) combination, [N,N′‐bis(3,3’‐triethylene glycol salicylidene)‐1,2‐ethylenediamino cobalt(III) di(acetate)]sodium (7), and it shows both excellent activity and selectivity at 1 bar carbon dioxide pressure (TOF=1590 h−1, >99 % polymer selectivity, 1 : 10: 4000, 100 °C), as well as high activity at higher carbon dioxide pressure (TOF=4343 h−1, 20 bar, 1 : 10 : 25000). Its rate law shows a first order dependence on both catalyst and cyclohexene oxide concentrations and a zeroth order for carbon dioxide pressure, over the range 10–40 bar. These new catalysts eliminate any need for ionic or Lewis base co‐catalyst and instead exploit the coordination of earth‐abundant and inexpensive Na(I) adjacent to a second metal to deliver efficient catalysis. They highlight the potential for well‐designed ancillary ligands and inexpensive Group 1 metals to deliver high performance heterodinuclear catalysts for carbon dioxide copolymerizations and, in future, these catalysts may also show promise in other alternating copolymerization and carbon dioxide utilizations.
Synthesis of Difluoroglycine Derivatives from Amines, Difluorocarbene, and CO2: Computational Design, Scope, and Applications
Authors: Hayashi Hiroki , Takano Hideaki , Katsuyama Hitomi , Harabuchi Yu , Maeda Satoshi , Mita Tsuyoshi
Published: June 2021

Invited for the cover of this issue are Satoshi Maeda, Tsuyoshi Mita, and co‐workers at ICReDD (Hokkaido University). The image depicts an Artificial Force Induced Reaction (AFIR) conducted on a supercomputer, which predicts a new chemical transformation and its application. Read the full text of the article at 10.1002/chem.202100812.
Operando Shell‐Isolated Nanoparticle‐Enhanced Raman Spectroscopy of the NO Reduction Reaction over Rhodium‐Based Catalysts
Authors: Ballotin Fabiane C. , Hartman Thomas , Koek Joris , Geitenbeek Robin G. , Weckhuysen Bert M.
Published: June 2021

Operando shell‐isolated nanoparticle‐enhanced Raman spectroscopy (SHINERS) with on‐line mass spectrometry (MS) has been used to investigate the surface species, such as NO, NOH, NO2, N2O, and reaction products of the NO reduction reaction with CO and H2 over supported Rh‐based catalysts in the form of catalyst extrudates. By correlating surface intermediates and reaction products, new insights in the reaction mechanism could be obtained. Upon applying different reaction conditions (i. e., H2 or CO), the selectivity of the catalytic reaction could be tuned towards the formation of N2. Furthermore, in the absence of Rh, no reaction products were detected. The importance of the operando SHINERS as a surface‐sensitive characterization technique in the field of heterogeneous catalysis provides routes towards a better understanding of catalytic performance.
Strategic Approach Towards Plastic Waste Valorization: Challenges and Promising Chemical Upcycling Possibilities
Authors: Roy Pallabi Sinha , Garnier Gil , Allais Florent , Saito Kei
Published: June 2021

Plastic waste, which is one of the major sources of pollution in the landfills and oceans, has raised global concern, primarily due to the huge production rate, high durability, and the lack of utilization of the available waste management techniques. Recycling methods are preferable to reduce the impact of plastic pollution to some extent. However, most of the recycling techniques are associated with different drawbacks, high cost and downgrading of product quality being among the notable ones. The sustainable option here is to upcycle the plastic waste to create high‐value materials to compensate for the cost of production. Several upcycling techniques are constantly being investigated and explored, which is currently the only economical option to resolve the plastic waste issue. This Review provides a comprehensive insight on the promising chemical routes available for upcycling of the most widely used plastic and mixed plastic wastes. The challenges inherent to these processes, the recent advances, and the significant role of the science and research community in resolving these issues are further emphasized.
Direct Transition‐Metal Free Benzene C−H Functionalization by Intramolecular Non‐Nitroarene Nucleophilic Aromatic Substitution of Hydrogen to Diverse AIEgens
Authors: Li Jinbiao , Zhang Shuaizhong , Lao Jiaxin , Zou Hongbin
Published: June 2021

Direct C(sp2)−H functionalization through nitroarene‐triggered nucleophilic aromatic substitution of hydrogen (SNArH) has attracted growing attention, owing to its high efficiency and low carbon footprint. In this study, non‐nitro‐group‐assisted SNArH has been developed for direct benzene functionalization in one pot under mild conditions. The electron‐withdrawing carbonyl group and the halide or trifluoromethyl group on the phenyl ring enable the σH adduct formation to fulfill the intramolecular C(sp2)−C(sp3) bond construction. Notably, the cyano group serves as both the electron‐withdrawing group to activate the C(sp3)−H bond and the leaving group to fulfill the β‐elimination. Three series of pyrrolo[1,2‐b]isoquinolinones, as well as unexpected rearrangement products 3‐(1H‐pyrrol‐2‐yl)‐1H‐inden‐1‐ones are regioselectively obtained through a simple and efficient base‐catalyzed one‐pot strategy. Mechanistic studies indicate that the σH adduct from carbanion addition to hydrogen serves as the sole intermediate for all of the aforementioned transformations. These molecules show intense luminescence and the subsequent one‐step structural modification results in the aggregation‐induced emission (AIE) derivatives with redshifted full‐color tunable fluorescence, large Stokes shifts, and good quantum yields. Further living cell imaging investigations suggest their potential application as specific bioprobes for lipid droplet localization and visualization.
Spatial and temporal changes in occupancy frequency distribution patterns of freshwater macrophytes in Finland
Authors: Suhonen Jukka
Published: June 2021

A useful method for characterizing biological numerous assemblages at regional scales is the species occupancy frequency distribution (SOFD). An SOFD shows the number or proportion of study sites each species occurred. Species that occur at only a few sites are termed satellite species, while species that occur at many sites are termed core species.

This study is the first to document and assess SOFD patterns in aquatic macrophytes. It characterizes SOFD patterns of freshwater macrophyte assemblages in Finland at two spatial and two temporal scales. For this, I analyzed three published datasets on freshwater macrophyte distributions: two from studies conducted at a local scale and the third from large national surveys. One local study and the national study also included data on temporal variation in species occupancy frequencies.

In the national study, the number of core and satellite species varied slightly between the older and the newer survey, respectively. Among the 113 waterbodies surveyed as part of the national study, the SOFD followed a unimodal satellite pattern. However, for the older dataset (from the 1930s), a bimodal symmetric pattern also fit the SOFD data well. At the local scale, I observed geographical variation in SOFD patterns. The dataset from southern Finland followed a unimodal satellite SOFD pattern; data from central Finland instead displayed a bimodal symmetric SOFD pattern, although they also fit equally well with a bimodal truncated pattern. Moreover, temporal patterns in central Finland seemed to demonstrate a shift from a bimodal symmetric to a bimodal asymmetric SOFD probably.

Geographical variation in the SOFD pattern may be due to variation in the regional species pool. The temporal changes in SOFD pattern may be due to lake eutrophication and anthropogenic disturbance around waterbodies, which may increase number of macrophyte species.
Wildcards in climate change biology
Authors: Srivastava Diane S. , Coristine Laura , Angert Amy L. , Bontrager Megan , Amundrud Sarah L. , Williams Jennifer L. , Yeung Alex C. Y. , de Zwaan Devin R. , Thompson Patrick L. , Aitken Sally N. , Sunday Jennifer M. , O'Connor Mary I. , Whitton Jeannette , Brown Norah E. M. , MacLeod Colin D. , Parfrey Laura Wegener , Bernhardt Joey R. , Carrillo Juli , Harley Christopher D. G. , Martone Patrick T. , Freeman Benjamin G. , Tseng Michelle , Donner Simon D.
Published: June 2021

Forecasting how climate change will impact biological systems represents a grand challenge for biologists. However, climate change biology lacks an effective framework for anticipating and resolving uncertainty. Here, we introduce the concept of climate change wildcards: biological or bioclimatic processes with a high degree of uncertainty and a large impact on our ability to address the biotic consequences of climate change. Wildcards may occur at multiple points in the progression of research—from understanding, to predicting, to forecasting biological responses. Our understanding of biological responses is limited by the components and processes we exclude to make research tractable. Our ability to predict biological responses often requires integration between biological levels of organization, across multiple stressors, and from specific cases to general systems. However, these types of integration can be dramatically affected by, respectively, differences between biological levels in their critical points, nonadditivity of the effects of different stressors, and historical and geographic contingency. Finally, our ability to forecast biological responses to climate change requires incorporating climatic projections in bioclimatic models. Such forecasts are vulnerable to the compounding of biological and climatic uncertainty, especially when biological responses occur in novel areas of bioclimatic parameter space. Both biological responses and climate change are dynamic processes; the potential of biological systems to be buffered against or rescued from the effects of climate change depends on the relative timing of biological and climatic effects—one of the least predictable aspects of both systems. In sum, our framework identifies stress points in the research process where we should anticipate and forestall wildcards. Focusing on universal currencies, like energy and elements, and universal structures, like functional traits and ecological networks, will improve our ability to generalize results. Most importantly, by modeling and communicating uncertainty, climate change biology can identify critical foci for future research.
Sea otter population collapse in southwest Alaska: assessing ecological covariates, consequences, and causal factors
Authors: Tinker Martin Tim , Bodkin James L. , Bowen Lizabeth , Ballachey Brenda , Bentall Gena , Burdin Alexander , Coletti Heather , Esslinger George , Hatfield Brian B. , Kenner Michael C. , Kloecker Kimberly , Konar Brenda , Miles A. Keith , Monson Daniel H. , Murray Michael J. , Weitzman Benjamin P. , Estes James A.
Published: June 2021

Sea otter (Enhydra lutris) populations in southwest Alaska declined substantially between about 1990 and the most recent set of surveys in 2015. Here we report changes in the distribution and abundance of sea otters, and covarying patterns in reproduction, mortality, body size and condition, diet and foraging behavior, food availability, health profiles, and exposure to environmental contaminants over this 25‐yr period. The population decline, which resulted in densities on the order of 5% of environmental carrying capacity, ranged from Attu Island in the west to about Castle Cape (on the south side of the Alaska Peninsula) in the east. Remaining sea otters moved closer to shore and into shallow, protected habitats. Reproductive rates appeared unchanged with the decline. Although the demographic cause of the decline was clearly elevated mortality, stranded carcasses were rare or absent. The net rate of energy gain by foraging sea otters, body length and condition, and prey biomass density, all increased after the decline and varied inversely with sea otter population density beyond the area of decline. Sea otters within the area of decline showed no increases in health anomalies, disease, contaminant exposure, or abnormal gene transcription patterns as compared to animals outside the area of decline. These collective findings are inconsistent with nutritional limitation, disease, or environmental contaminants, and consistent with predation (or possibly some other density‐independent factor) as the reason for the sea otter population decline. Our approach and analyses provide a broad conceptual template for thinking about and assessing the causes of wildlife population declines.