bluuebunny/crossref_metadata_2025 huggingface dataset:
Uterine Fibroids “Spectrum of Presentation and Its Impact on Women’s Health
Authors: Koohara Yasmeen , Bala Madhu , Mehmood Misbah , Bushra . , Asif Bushra , Tasneem Bushra , Mirza Alina
Published: May 2022

Objective: Uterine fibroids are the most frequently observed benign tumor that develops in female reproductive system, most commonly found in women of 50 years of age. Menorrhagia is the most common clinical manifestation of uterine fibroids. Therefore, the aim of this study was to determine the clinical presentation, early detection with the best treatment modalities in women with uterine fibroids.

Methodology: This was a prospective hospital based observational study conducted at a tertiary care hospital in Mirpurkhas after taking ethical approval from institution review board. The duration of the study was about 9 months from July 2019 to March 2020. A total of 100 women in their reproductive age (20-50 years) who ever experienced menstrual abnormalities, complained of abdomino-pelvic mass, pain, urinary and bowl symptoms, anemia and infertility were included in the study. Categorical variables such as parity, age, anemic status, associated symptoms, diagnostic method, and treatment modalities were analyzed as frequencies and percentages.

Results: The study results showed that out of 100 patients, 19 (19.0%) patients were between 20-30 years of age, 23 (23.0%) between 31-40 years and 58 (58.0%) falls between 41-45 years of age, 67(67.0%) women had >3 children. Symptoms associated with uterine fibroids included 74(74.0%) were anemic. Dysmenorrhea was seen in 50(50.0%) patients, menorrhagia in 50(50.0%) patients. Palpable fibroid mass was felt in 35(35.0%) patients while 78(78.0%) cases reported fibroid masses on ultrasonography. Treatment of uterine fibroid included total abdominal hysterectomy was performed in 65 (65.0%) patients, myomectomy was carried out in 21 (21.0%).

Conclusion: This study concluded that multiparous patients were reported to have uterine fibroids more frequently as compared to nulliparous particularly in the age of 41-50 years old. The most common clinical manifestation was menorrhagia with anemia, persistent pain and pressure symptoms that have a negative impact on women’s social, sexual, and work life.
Investigating the Topside Choking and Riser Base Gas lifting Methods of Attenuating Severe Slug Formation in Deepwater Production Risers
Authors: Damola Shiyanbade , Nmegbu C. J. G. , Nwosi-Anele A. S.
Published: May 2022

Severe slugging involves large magnitude fluctuations in pressure and flow rate in a riser due to low gas flow rates and low Gas-liquid ratio (GLR). This work evaluates two mitigation concepts: topside choking and riser base gas lift to determine which technique is more desirable.

A base case model was created to understand the nature of slugging with an input mass flowrate of 15kg/s, separator operating at 22.5Bar and 370C. After 8hours of simulation, the presence of a severe slug was observed at the production riser. Two models were created from the base case to mitigate the severe slugging. An introduction of topside choke to eliminate or reduce the riser slugging, likewise deployment of Riser base gas lift (RBGL) to achieve the same purpose.

The result indicated that with the introduction of the topside choke and reducing the opening percentages of the choke from 80% to 5% stepwise, the slugging amplitudes were greatly reduced from 3.3bar to 0.3bar. Though this led to back pressure and a reduction in production. A 50% choke opening was suggested as the optimal choke opening for the simulated case. Results from the introduction of dehydrated gas with a mass flow rate of 1.2kg/s at the riser base indicated slug elimination from the riser and flowline. The results of this simulation were observed at the end of the riser (inlet to the separator) after about 8hours 20mins

This report identifies that of the two simulated techniques (topside choking and RBGL), RBGL is more efficient in addressing slug issues without impacting field production.
The degree of unsaturation of fatty acids in phosphatidylserine alters the rate of insulin aggregation and the structure and toxicity of amyloid aggregates
Authors: Matveyenka Mikhail , Rizevsky Stanislav , Kurouski Dmitry
Published: May 2022

Phosphatidylserine (PS) in the plasma membrane plays an important role in cell signaling and apoptosis. Cell degeneration is also linked to numerous amyloid diseases, pathologies that are associated with aggregation of misfolded proteins. In this work, we examine the effect of both saturated PS (DMPS) and unsaturated PS (DOPS and POPS) on the aggregation properties of insulin, as well as the structure and toxicity of insulin aggregates formed in the presence of these phospholipids. We found that the degree of unsaturation of fatty acids in PS alters the rate of insulin aggregation. We also found that toxicity of insulin–DMPS aggregates is significantly lower than the toxicity of DOPS– and POPS–insulin fibrils, whereas all these lipid‐containing aggregates exert lower cell toxicity than insulin fibrils grown in a lipid‐free environment.
Quantification of the Effect of Increased Pre‐Deformation on Microstructure and Mechanical Properties of 2A55 Al–Li Alloy
Authors: Zeng Guang-Jun , Ning Hong , Deng San-Xi , Li Jin-Feng , Yao Yong , Guo You-Jie , Lu Ding-Ding , Li Yu-Zhuo , Liu Zhi-Hao , Ma Peng-Cheng , Zhang Rui-Feng
Published: May 2022

Herein, the effects of pre‐deformation to higher levels on mechanical properties, strengthening contribution, and microstructures of 2A55 Al–Li alloy are investigated. It is shown in the results that the tensile strength of 2A55 Al–Li alloy approaches 660 MPa with an elongation of 9.28% after 15% pre‐deformation. The strengthening contribution from precipitates and strain is calculated based on detailed microstructure information. The strengthening model reveals that the joint strengthening contribution of T1 and θ′ precipitates decreased with increasing the pre‐deformation. In contrast to the decreased strengthening contribution of precipitates in severely pre‐deformed samples, the part from pre‐deformation dramatically increases thus leading to the enhanced yield strength. It is revealed that the recovery of dislocation structure introduced by pre‐deformation is suppressed during artificial aging. Additionally, herein, the trade‐off between the strengthening contribution and elongation is presented, which can be optimized by selecting proper pre‐deformation processing.
Effect of PGMEA Addition on Zinc‐Tin‐Oxide Thin‐Film Transistor Fabricated by Inkjet‐Printing Process
Authors: Lee Yong Gu , Choi Woon-Seop
Published: May 2022

Zinc‐tin‐oxide (ZTO) thin‐film transistors (TFTs) are made using a low‐viscosity inkjet‐printing process, and their electrical properties are dramatically improved by adding a propylene monomethyl ether acetate (PGMEA) to a solution‐processed ZTO formulation. The addition of 15 wt% PGMEA to the inkjet formulation results in a mobility of 12.29 cm2 V−1 s−1, on–off current ratio of 4.72 × 108, threshold voltage of 3.04 V, and subthreshold slope of 0.3 V dec−1. The TFTs also has stable hysteresis characteristics and improved positive bias stability. These improvements are attributed to the better jetting properties, denser thin film with surface smoothness, and the formation of more metal–oxide networks.
Enhancement of Magnetic Properties and Magnetocaloric Effects for Mn0.975Fe0.975P0.5Si0.5 Alloys by Optimizing Quenching Temperature
Authors: Zheng Zhigang , Wang Hongyu , Li Chengfeng , Chen Xinglin , Zeng Dechang , Yuan Shengfu
Published: May 2022

The effect of quenching temperature on phase structure and magnetocaloric properties of the Mn0.975Fe0.975P0.5Si0.5 alloys are systematically studied by X‐ray diffraction, scanning electron microscope, differential scanning calorimetry, and vibrating sample magnetometer. The Mn0.975Fe0.975P0.5Si0.5 alloys quenched at 1323, 1073, 873, and 673 K are all crystallized in the hexagonal Fe2P‐type phase and the phase fraction of the Fe2P phase increases with the decreases of quenching temperature. As the quenching temperature decreases from 1323 to 673 K, the crystal lattice of alloys expands and the atoms' occupation is more ordered, while the saturation magnetic moment increases from 3.71 to 4.10 μB f.u.−1 The values of thermal hysteresis increase linearly from 30 to 41 K when the quenching temperature is down to 673 K. This enhancement of the first‐order magnetic transition (FOMT) yields the maximum value of magnetic entropy change at 5 T increasing by 36%. To obtain excellent comprehensive properties for (Mn,Fe)2(P,Si) alloys, the methods of doping B element in the Mn0.975Fe0.975P0.5Si0.5 alloy are employed to tune the magnetocaloric properties. The results provide insights and systematic understanding into the effect of quenching temperature on the magnetocaloric properties of (Mn,Fe)2(P,Si)‐based alloys.
Unleashing Insulating Polymer as Charge Transport Cascade Mediator
Authors: Li Shen , Mo Qiao‐Ling , Zhu Shi‐Cheng , Wei Zhi‐Quan , Tang Bo , Liu Bi‐Jian , Liang Hao , Xiao Yang , Wu Gao , Ge Xing‐Zu , Xiao Fang‐Xing
Published: May 2022

Crafting spatially controllable charge transfer channels at the nanoscale level remains an enduring challenge in solar‐to‐chemical conversion technology. Despite the advancements, it still suffers from sluggish interfacial charge transport kinetics and scarcity of strategies to finely modulate charge transport pathways. Herein, this article demonstrates the unexpected charge modulation property of non‐conjugated insulating polymer assisted by a universal layer‐by‐layer self‐assembly tactic. Oppositely charged poly(dimethyl diallyl ammonium chloride) (PDDA) and Ti3C2 MXene quantum dots (MQDs) are periodically attached to the wide bandgap metal oxides (WMOs) to design multilayered heterostructured photoanodes. The intermediate PDDA layer acts as an efficacious charge relay medium to access directional electron flow from WMOs to Ti3C2 MQDs, while Ti3C2 MQDs serve as the electron extractor. Charge transfer cascade is thus stimulated on account of the simultaneous electron‐trapping capabilities of interim PDDA layer and Ti3C2 MQDs, which synergistically favors the conspicuously boosted charge separation over WMOs, affording the WMOs/(PDDA/MQDs)n photoanodes with considerably enhanced photoelectrochemical (PEC) water oxidation performances. Moreover, PEC performances of such photoanodes can be tuned by interface configuration via assembly number and sequence. This work will provide an insightful perspective to craft a directional charge transfer pathway through insulating polymer for solar energy conversion.
Tailoring Ultrafast and High‐Capacity Sodium Storage via Binding‐Energy‐Driven Atomic Scissors
Authors: Peng Baixin , Lv Zhuoran , Xu Shumao , Pan Jun , Zhao Wei , Dong Chenlong , Huang Fuqiang
Published: May 2022

Controllably tailoring alloying anode materials to achieve fast charging and enhanced structural stability is crucial for sodium‐ion batteries with high rate and high capacity performance, yet remains a significant challenge owing to the huge volume change and sluggish sodiation kinetics. Here, a chemical tailoring tool is proposed and developed by atomically dispersing high‐capacity Ge metal into the rigid and conductive sulfide framework for controllable reconstruction of GeS bonds to synergistically realize high capacity and high rate performance for sodium storage. The integrated GeTiS3 material with stable Ti–S framework and weak GeS bonding delivers high specific capacities of 678 mA h g−1 at 0.3 C over 100 cycles and 209 mA h g−1 at 32 C over 10 000 cycles, outperforming most of the reported alloying type anode materials for sodium storage. Interestingly, in situ Raman, X‐ray diffraction (XRD), and ex situ transmission electron microscopy (TEM) characterizations reveal the formation of well‐dispersed NaxGe confined in the rigid Ti–S matrix with suppressed volume change after discharge. The synergistically coupled alloying‐conversion and surface‐dominated redox reactions with enhanced capacitive contribution and high reaction reversibility by a binding‐energy‐driven atomic scissors method would break new ground on designing a high‐rate and high‐capacity sodium‐ion batteries.
Slip‐Line‐Guided Growth of Graphene
Authors: Li Yanglizhi , Liu Haiyang , Chang Zhenghua , Li Haoxiang , Wang Shenxing , Lin Li , Peng Hailin , Wei Yujie , Sun Luzhao , Liu Zhongfan
Published: May 2022

Manipulating the crystal orientation of emerging 2D materials via chemical vapor deposition (CVD) is a key premise for obtaining single‐crystalline films and designing specific grain‐boundary (GB) structures. Herein, the controllable crystal orientation of graphene during the CVD process is demonstrated on a single‐crystal metal surface with preexisting atomic‐scale stair steps resulting from dislocation slip lines. The slip‐line‐guided growth principle is established to explain and predict the crystal orientation distribution of graphene on a variety of metal facets, especially for the multidirectional growth cases on Cu(hk0) and Cu(hkl) substrates. Not only large‐area single‐crystal graphene, but also bicrystal graphene with controllable GB misorientations, are successfully synthesized by rationally employing tailored metal substrate facets. As a demonstration, bicrystal graphenes with misorientations of ≈21° and ≈11° are constructed on Cu(410) and Cu(430) foils, respectively. This guideline builds a bridge linking the crystal orientation of graphene and the substrate facet, thereby opening a new avenue for constructing bicrystals with the desired GB structures or manipulating 2D superlattice twist angles in a bottom‐up manner.
A Light‐Hole Germanium Quantum Well on Silicon
Authors: Assali Simone , Attiaoui Anis , Vecchio Patrick Del , Mukherjee Samik , Nicolas Jérôme , Moutanabbir Oussama
Published: May 2022

The quiet quantum environment of holes in solid‐state devices is at the core of increasingly reliable architectures for quantum processors and memories. However, due to the lack of scalable materials to properly tailor the valence band character and its energy offsets, the precise engineering of light‐hole (LH) states remains a serious obstacle toward coherent optical photon–spin interfaces needed for a direct mapping of the quantum information encoded in photon flying qubits to stationary spin processors. Herein, to alleviate this long‐standing limitation, an all‐group‐IV low‐dimensional system is demonstrated, consisting of a highly tensile strained germanium quantum well grown on silicon allowing new degrees of freedom to control and manipulate the hole states. Wafer‐level, high bi‐isotropic in‐plane tensile strain (<1%) is achieved using strain‐engineered, metastable germanium–tin alloyed buffer layers yielding quantum wells with LH ground state, high g‐factor anisotropy, and a tunable splitting of the hole sub‐bands. The epitaxial heterostructures display sharp interfaces with sub‐nanometer broadening and show room‐temperature excitonic transitions that are modulated and extended to the mid‐wave infrared by controlling strain and thickness. This ability to engineer quantum structures with LH selective confinement and controllable optical response enables manufacturable silicon‐compatible platforms relevant to integrated quantum communication and sensing technologies.
Design of Ultracompact High‐Speed‐Integrated Lithium–Niobate Periodic Dielectric Waveguide Modulator
Authors: Qi Yifan , Zhang Zheng , Jia Wenhe , Chen Sai , Yang Yuanmu , Li Yang
Published: May 2022

Modern communications and microwave photonics require compact electro‐optic modulators with ultrahigh bandwidth and low power consumption. These requirements can be satisfied by integrated lithium–niobate electro‐optic modulators with high bandwidth and low power consumption. However, most integrated lithium–niobate modulators cannot achieve a good balance between an ultracompact size and a high modulation bandwidth. These challenges are overcome by designing an integrated lithium–niobate periodic dielectric waveguide modulator, featuring a compact modulation length of 87.4 μm, a theoretical modulation bandwidth over 600 GHz, a voltage‐length product of 0.0874 V cm, and a high sideband suppression ratio up to 36.1 dB. These performances are achieved by taking advantage of a capacitor configuration consisting of a nonresonant periodic dielectric waveguides sandwiched between two indium tin oxide (ITO) electrodes. This design provides an ultrabroadband and compact solution to next‐generation communications and microwave photonics.
Nonideality‐Aware Training for Accurate and Robust Low‐Power Memristive Neural Networks
Authors: Joksas Dovydas , Wang Erwei , Barmpatsalos Nikolaos , Ng Wing H. , Kenyon Anthony J. , Constantinides George A. , Mehonic Adnan
Published: May 2022

Recent years have seen a rapid rise of artificial neural networks being employed in a number of cognitive tasks. The ever‐increasing computing requirements of these structures have contributed to a desire for novel technologies and paradigms, including memristor‐based hardware accelerators. Solutions based on memristive crossbars and analog data processing promise to improve the overall energy efficiency. However, memristor nonidealities can lead to the degradation of neural network accuracy, while the attempts to mitigate these negative effects often introduce design trade‐offs, such as those between power and reliability. In this work, authors design nonideality‐aware training of memristor‐based neural networks capable of dealing with the most common device nonidealities. The feasibility of using high‐resistance devices that exhibit high I‐V nonlinearity is demonstrated—by analyzing experimental data and employing nonideality‐aware training, it is estimated that the energy efficiency of memristive vector‐matrix multipliers is improved by almost three orders of magnitude (0.715 TOPs−1W−1 to 381 TOPs−1W−1) while maintaining similar accuracy. It is shown that associating the parameters of neural networks with individual memristors allows to bias these devices toward less conductive states through regularization of the corresponding optimization problem, while modifying the validation procedure leads to more reliable estimates of performance. The authors demonstrate the universality and robustness of this approach when dealing with a wide range of nonidealities.
Prospecting Cellular Gold Nanoparticle Biomineralization as a Viable Alternative to Prefabricated Gold Nanoparticles
Authors: Schwartz‐Duval Aaron S. , Sokolov Konstantin V.
Published: May 2022

Gold nanoparticles (GNPs) have shown considerable potential in a vast number of biomedical applications. However, currently there are no clinically approved injectable GNP formulations. Conversely, gold salts have been used in the clinic for nearly a century. Further, there is evidence of GNP formation in patients treated with gold salts (i.e., chrysiasis). Recent reports evaluating this phenomenon in human cells and in murine models indicate that the use of gold ions for in situ formation of theranostic GNPs could greatly improve the delivery within dense biological tissues, increase efficiency of intracellular gold uptake, and specificity of GNP formation within cancer cells. These attributes in combination with safe clinical application of gold salts make this process a viable strategy for clinical translation. Here, the first summary of the current knowledge related to GNP biomineralization in mammalian cells is provided along with critical assessment of potential biomedical applications of this newly emergent field.
Microcrystalline Hybridization Enhanced Coal‐Based Carbon Anode for Advanced Sodium‐Ion Batteries
Authors: Chen He , Sun Ning , Zhu Qizhen , Soomro Razium Ali , Xu Bin
Published: May 2022

Sodium‐ion batteries (SIBs) are regarded as a kind of promising candidate for large‐scale energy storage technology. The development of advanced carbon anodes with high Na‐storage capacity and initial Coulombic efficiency (ICE) from low cost, resources abundant precursors is critical for SIBs. Here, a carbon microcrystalline hybridization route to synthesize hard carbons with extensive pseudo‐graphitic regions from lignite coal with the assistance of sucrose is proposed. Employing the cross‐linked interaction between sucrose and lignite coal to generate carbon‐based hybrid microcrystalline states, the obtained hard carbons possess pseudo‐graphitic dominant phases with large interlayer spaces that facilitate Na ion's storage and transportation, as well as fewer surface defects that guarantee high ICE. The LCS‐73 with an optimum cross‐link demonstrates the highest Na‐storage capacity of 356 mAh g−1 and an ICE of 82.9%. The corresponding full‐cell delivers a high energy density of 240 Wh kg−1 (based on the mass of anode and cathode materials) and excellent rate capability of 106 mAh g−1 at 10 C in addition to outstanding cycle performance with 80% retention over 500 cycles at 2 C. The proposed work offers an efficient route to develop high‐performance, low‐cost carbon‐based anode materials with potential application for advanced SIBs.
Separator‐Wetted, Acid‐ and Water‐Scavenged Electrolyte with Optimized Li‐Ion Solvation to Form Dual Efficient Electrode Electrolyte Interphases via Hexa‐Functional Additive
Authors: Li Xin , Liu Jiandong , He Jian , Qi Shihan , Wu Mingguang , Wang Huaping , Jiang Gaoxue , Huang Junda , Wu Daxiong , Li Fang , Ma Jianmin
Published: May 2022

The performance of lithium metal batteries (LMBs) is determined by many factors from the bulk electrolyte to the electrode‐electrolyte interphases, which are crucially affected by electrolyte additives. Herein, the authors develop the heptafluorobutyrylimidazole (HFBMZ) as a hexa‐functional additive to inhibit the dendrite growth on the surface of lithium (Li) anode, and then improve the cycling performance and rate capabilities of Li||LiNi0.6Co0.2Mn0.2O2 (NCM622). The HFBMZ can remove the trace H2O and HF from the electrolyte, reducing the by‐products on the surface of solid electrolyte interphase (SEI) and inhibiting the dissolution of metal ions from NCM622. Also, the HFBMZ can enhance the wettability of the separator to promote uniform Li deposition. HFBMZ can make Li+ easy to be desolvated, resulting in the increase of Li+ flux on Li anode surface. Moreover, the HFBMZ can optimize the composition and structure of SEI. Therefore, the Li||Li symmetrical cells with 1 wt% HFBMZ‐contained electrolyte can achieve stable cycling for more than 1200 h at 0.5 mA cm–2. In addition, the capacity retention rate of the Li||NCM622 can reach 92% after 150 cycles at 100 mA g–1.
Consumer willingness to pay for environmentally sustainable meat and a plant‐based meat substitute
Authors: Katare Bhagyashree , Yim Hyejin , Byrne Anne , Wang H. Holly , Wetzstein Michael
Published: May 2022

We investigate consumers' willingness to pay premiums for environmentally sustainably produced meat and plant‐based meat substitutes. We conducted a randomized control study coupled with an incentive‐compatible experimental auction. Treatment consisted of information nudges concerning the environmental and health externalities of meat production and consumption. Results show that demand for sustainably produced beef and a plant‐based meat substitute is inelastic. We elicited participants' time preferences to analyze whether consumer behavior varies with their time preference. Present‐biased treated female participants were willing to pay a significantly lower premium for sustainably produced beef compared to the present‐biased control female participants. Future‐biased treated participants had a higher probability of being willing to pay a premium for a plant‐based meat substitute compared to the control group. We discuss the policy implications and relevance of information nudging, such as labeling, and how the effect of such nudging varies with participant characteristics.
A Silylene Stabilized by a σ‐Donating Nickel(0) Fragment
Authors: Frutos María , Parvin Nasrina , Baceiredo Antoine , Madec David , Saffon‐Merceron Nathalie , Branchadell Vicenç , Kato Tsuyoshi
Published: May 2022

A donor‐stabilized silylene 4 featuring a Ni0‐based donating ligand was synthesized. Complex 4 exhibits a pyramidalized and nucleophilic SiII center and shows a peculiar behavior due to the cooperative reactivity of Si and Ni centers. Calculations indicate that the orientation of Ni‐ligands with respect to the silylene moiety is crucial in determining the role of the Ni‐fragment (Lewis acid or Lewis base) towards silylene. Indeed, a simple 90° rotation of the Si−Ni bond, reverses the role of Ni, and transforms a classical silylene→Ni0 complex into an unprecedented Ni0→silylene complex.
Copper‐Catalyzed Radical Enantioselective Carbo‐Esterification of Styrenes Enabled by a Perfluoroalkylated‐PyBox Ligand
Authors: Nie Zaicheng , Chiou Mong‐Feng , Cui Jinfeng , Qu Yanjie , Zhu Xiaotao , Jian Wujun , Xiong Haigen , Li Yajun , Bao Hongli
Published: May 2022

Chiral lactones are found in many natural products. The reaction of simple alkenes with iodoacetic acid is a powerful method to build lactones, but the enantioselective version of this reaction has not been implemented to date. Herein, we report the efficient catalytic radical enantioselective carbo‐esterification of styrenes enabled by a newly developed CuI‐perfluoroalkylated PyBox system. Simple styrenes have been converted to useful chiral lactones, whose synthetic applications are showcased. Mechanistic studies reveal that this reaction is a rare example of an efficient ligand‐decelerated system, in which the ligand decelerates the reaction, but the reaction is still efficient with reduced amounts of ligand. This uncommon catalytic system may inspire further consideration of the effect of ligands in asymmetric catalysis.
Optochemical Control of Therapeutic Agents through Photocatalyzed Isomerization
Authors: Watson Emma E. , Russo Francesco , Moreau Dimitri , Winssinger Nicolas
Published: May 2022

A Ru(bpy)3Cl2 photocatalyst is applied to the rapid trans to cis isomerization of a range of alkene‐containing pharmacological agents, including combretastatin A‐4 (CA‐4), a clinical candidate in oncology, and resveratrol derivatives, switching their configuration from inactive substances to potent cytotoxic agents. Selective in cellulo activation of the CA‐4 analog Res‐3M is demonstrated, along with its potent cytotoxicity and inhibition of microtubule dynamics.
A Cocatalyst Strategy to Enhance Ruthenium‐Mediated Metathesis Reactivity towards Electron‐Deficient Substrates
Authors: Si Guifu , Tan Chen , Chen Min , Chen Changle
Published: May 2022

Ruthenium‐mediated olefin metathesis has been widely applied for the synthesis of various organic molecules and polymers. Inspired by the cocatalyst strategy for olefin polymerization, here we demonstrate that the abstraction of a chloride ion from various commercially available ruthenium catalysts significantly enhances their reactivity towards electron‐deficient internal olefins. This cocatalyst strategy can be implemented in ethenolysis and cross‐metathesis reactions of FG‐CH=CH‐FG type substrates bearing electron‐withdrawing groups and the synthesis of telechelic polymers that can be converted to polyethylene‐like materials with closed‐loop recycling properties. The copolymerization of cyclic substrate with cycloolefins followed by hydrogenation afforded polyolefin materials with in‐chain break points. Interestingly, switchable catalysis was achieved in the absence and presence of a cocatalyst, which allowed the polymer microstructure and material properties to be fine‐tuned.
Highly Fluorescent Bipyrrole‐Based Tetra‐BF2 Flag‐Hinge Chromophores: Achieving Multicolor and Circularly Polarized Luminescence
Authors: Cui Luxia , Shinjo Hyuga , Ichiki Takafumi , Deyama Koichi , Harada Takunori , Ishibashi Kohei , Ehara Takumi , Miyata Kiyoshi , Onda Ken , Hisaeda Yoshio , Ono Toshikazu
Published: May 2022

This study reports the facile syntheses of tetra‐boron difluoride (tetra‐BF2) complexes, flag‐hinge‐like molecules that exhibit intense green‐to‐orange luminescence in solution and yellow‐to‐red emission in the solid states. Single‐crystal structure analysis and density functional theory calculations suggested a bent structure of this series of compounds. The complexes also exhibited excellent optical properties, with quantum yields reaching 100 % and a large Stokes shift. These properties were attributed to the altered bending angle of the molecule in the S1 excited state. As the rotational motion was suppressed around the 2,2′‐bipyrrole axis, atropisomers with axial chirality were formed, which are optically resolvable into (R) and (S)‐enantiomers through a chiral column. The atropisomers thus function as circularly polarized luminescent (CPL) materials, in which the color (green, green‐yellow, and yellow) can be varied by controlling the aggregation state. This rational design of multi‐BF2 complexes can potentially realize novel photofunctional materials.
Site‐Sensitive Selective CO2 Photoreduction to CO over Gold Nanoparticles
Authors: Huang Haowei , Zhao Jiwu , Weng Bo , Lai Feili , Zhang Menglong , Hofkens Johan , Roeffaers Maarten B. J. , Steele Julian A. , Long Jinlin
Published: May 2022

We demonstrate a new case of materials–gene engineering to precisely design photocatalysts with the prescribed properties. Based on theoretical calculations, a phase‐doping strategy was proposed to regulate the pathways of CO2 conversion over Au nanoparticles (NPs) loaded TiO2 photocatalysts. As a result, the thermodynamic bottleneck of CO2‐to‐CO conversion is successfully unlocked by the incorporation of stable twinning crystal planes into face‐centered cubic (fcc) phase Au NPs. Compared to bare pristine TiO2, the activity results showed that the loading of regular fcc‐Au NPs raised the CO production by 18‐fold but suppressed the selectivity from 84 % to 75 %, whereas Au NPs with twinning (110) and (100) facets boosted the activity by nearly 40‐fold and established near unity CO selectivity. This enhancement is shown to originate from a beneficial shift in the surface reactive site energetics arising at the twinned stacking fault, whereby both the CO reaction energy and desorption energy were significantly reduced.
Maschinelles Lernen zur Vorhersage chemischer Reaktivität: Die Bedeutung “gescheiterter” Experimente
Authors: Strieth‐Kalthoff Felix , Sandfort Frederik , Kühnemund Marius , Schäfer Felix R. , Kuchen Herbert , Glorius Frank
Published: May 2022

Die quantitative Vorhersage der Ergebnisse chemischer Reaktionen ist eine zentrale Herausforderung in allen synthetischen Disziplinen. Während die darauf aufbauenden Optimierungsprobleme klassischerweise empirisch adressiert werden, birgt die datengestützte Modellierung ein enormes Potential, diese Prozesse zu beschleunigen. Für solche Vorhersagemodelle werden jedoch große Mengen hochwertiger Daten benötigt, die nur begrenzt verfügbar sind: Zu den Hauptgründen hierfür gehören experimentelle Fehler sowie besonders die menschliche Voreingenommenheit hinsichtlich der Auswahl von Experimenten und der Veröffentlichung von Ergebnissen. In einer Reihe von Fallstudien untersuchen wir die Auswirkungen dieser Verzerrungen auf die Qualität allgemeiner Schlussfolgerungen aus chemischen Reaktionsdaten, wobei die große Bedeutung von “gescheiterten” Beispielen deutlich wird. Schließlich zeigen Fallstudien zu Ansätzen der Datenerweiterung Wege auf, wie diese Einschränkungen umgangen werden können ‐ und demonstrieren somit Perspektiven für eine langfristige Verbesserung der Datenqualität in der Chemie.
Flexible Cuprous Triazolate Frameworks as Highly Stable and Efficient Electrocatalysts for CO2 Reduction with Tunable C2H4/CH4 Selectivity
Authors: Zhuo Lin‐Ling , Chen Pin , Zheng Kai , Zhang Xue‐Wen , Wu Jun‐Xi , Lin Duo‐Yu , Liu Si‐Yang , Wang Zhi‐Shuo , Liu Jin‐Yu , Zhou Dong‐Dong , Zhang Jie‐Peng
Published: May 2022

Cu‐based metal–organic frameworks have attracted much attention for electrocatalytic CO2 reduction, but they are generally instable and difficult to control the product selectivity. We report flexible Cu(I) triazolate frameworks as efficient, stable, and tunable electrocatalysts for CO2 reduction to C2H4/CH4. By changing the size of ligand side groups, the C2H4/CH4 selectivity ratio can be gradually tuned and inversed from 11.8 : 1 to 1 : 2.6, giving C2H4, CH4, and hydrocarbon selectivities up to 51 %, 56 %, and 77 %, respectively. After long‐term electrocatalysis, they can retain the structures/morphologies without formation of Cu‐based inorganic species. Computational simulations showed that the coordination geometry of Cu(I) changed from triangular to tetrahedral to bind the reaction intermediates, and two adjacent Cu(I) cooperated for C−C coupling to form C2H4. Importantly, the ligand side groups controlled the catalyst flexibility by the steric hindrance mechanism, and the C2H4 pathway is more sensitive than the CH4 one.
Rhodium‐Catalyzed Atroposelective Click Cycloaddition of Azides and Alkynes
Authors: Zeng Linwei , Li Jiaming , Cui Sunliang
Published: May 2022

The cycloaddition of azides and alkynes is the leading click chemistry technology and has been widely used in drug discovery, biology and material sciences. However, the development of a modular and scalable enantioselective click cycloaddition remains a long‐standing challenge. Herein, we report a rhodium‐catalyzed enantioselective click cycloaddition of azides and alkynes for rapid and modular access to atropisomeric triazoles in excellent yields and enantioselectivities. The process is mild, efficient and scalable, and features broad substrate scope.
Hierarchical Hollow Zinc Oxide Nanocomposites Derived from Morphology‐Tunable Coordination Polymers for Enhanced Solar Hydrogen Production
Authors: Zhu Qi , Xu Shuai , Wu Weidong , Qi Yi , Lin Zhan , Li Yuliang , Qin Yanlin
Published: May 2022

Infinite coordination‐polymer particles (CPPs) are promising materials for solar energy conversion with high efficiency. However, the range of organic ligands that may be used to create CPPs is limited, as are strategies for modification, thereby hindering the applications of such material. In this paper, competitive evolution–morphological and structural change from Zn‐based crystallites to amorphous particles is described. Controlled contribution of organic linkers selectively derived six Zn‐CPPs with multivariate characters. Based on the diversity of these substructures, hollow zinc oxide particles were initially formed by self‐pyrolysis of CPPs and effectively modified by ultrathin doped nanosheets. The obtained double‐sided heterojunctions offer fully‐covered active sites, bringing together efficient light‐excited charge‐transfer nanochannels, which exhibit an excellent solar H2‐releasing activity (e.g., 4512.5 μmol h−1 g−1) and stable cyclability.
A Fluorescent Cage for Supramolecular Sensing of 3‐Nitrotyrosine in Human Blood Serum
Authors: Pérez‐Márquez Lidia A. , Perretti Marcelle D. , García‐Rodríguez Raúl , Lahoz Fernando , Carrillo Romen
Published: May 2022

3‐Nitrotyrosine (NT) is generated by the action of peroxynitrite and other reactive nitrogen species (RNS), and as a consequence it is accumulated in inflammation‐associated conditions. This is particularly relevant in kidney disease, where NT concentration in blood is considerably high. Therefore, NT is a crucial biomarker of renal damage, although it has been underestimated in clinical diagnosis due to the lack of an appropriate sensing method. Herein we report the first fluorescent supramolecular sensor for such a relevant compound: Fluorescence by rotational restriction of tetraphenylethenes (TPE) in a covalent cage is selectively quenched in human blood serum by 3‐nitrotyrosine (NT) that binds to the cage with high affinity, allowing a limit of detection within the reported physiological concentrations of NT in chronic kidney disease.
Metal‐Free Temperature‐Controlled Regiodivergent Borylative Cyclizations of Enynes: BCl3‐Promoted Skeletal Rearrangement
Authors: Milián Ana , Fernández‐Rodríguez Manuel A. , Merino Estíbaliz , Vaquero Juan J. , García‐García Patricia
Published: May 2022

Metal‐free borylative cyclization of biphenyl‐embedded 1,3,5‐trien‐7‐ynes in the presence of simple and inexpensive BCl3 provided synthetically useful borylated building blocks. The outcome of the process depends on the reaction temperature, with borylated phenanthrenes obtained at 60 °C and phenanthrene‐fused borylated cyclobutanes formed at 0 °C. Based on DFT calculations, a mechanism for these novel transformations has been proposed, which involves an uncommon skeletal rearrangement, including migration of a methyl group and alkyne fragmentation, unprecedented in BCl3‐promoted cyclization reactions.
Rapid High‐Contrast Photoreversible Coloration of Surface‐Functionalized N‐Doped TiO2Nanocrystals for Rewritable Light‐Printing
Authors: Aleisa Rashed , Feng Ji , Ye Zuyang , Yin Yadong
Published: May 2022

Pristine titanium dioxide (TiO2) changes color from white to black when it is reduced from TiIVto TiIIIby photoexcited electrons. However, the black coloration requires substantial light energy to create, and it vanishes instantaneously upon exposure to air. This work reports the synthesis of surface‐functionalized N‐doped TiO2nanocrystals that rapidly change color (i.e., within seconds) from whitish to black under low‐power irradiation with excellent color stability in atmospheric conditions. The N‐doping plays a critical role in promoting the surface‐adsorption of polyol groups to stabilize the TiIIIspecies and accelerate the coloration process. A rewritable paper fabricated using these nanocrystals exhibits excellent writing and erasing reversibility in response to UV irradiation and oxygen exposure. The low‐cost, rapid response, excellent reversibility, and good color stability are vital advantages of N‐doped TiO2nanocrystals for color‐switching applications.
Induction of Diverse Cryptic Fungal Metabolites by Steroids and Channel Blockers
Authors: Lee Seoung Rak , Seyedsayamdost Mohammad R.
Published: May 2022

Fungi offer a deep source of natural products but remain underutilized. Most biosynthetic gene clusters (BGCs) that can be detected are silent or “cryptic” in standard lab cultures and their products are thus not interrogated in routine screens. As genetic alterations are difficult and some strains can only be grown on agar, we have herein applied an agar‐based high‐throughput chemical genetic screen to identify inducers of fungal BGCs. Using R. solani and S. sclerotiorum as test cases, we report 13 cryptic metabolites in four compound groups, including sclerocyclane, a natural product with a novel scaffold. Steroids were the best elicitors and follow‐up studies showed that plant‐steroids trigger sclerocyclane synthesis, which shows antibiotic activity against B. plantarii, an ecological competitor of S. sclerotiorum. Our results open new paths to exploring the chemical ecology of fungal‐plant interactions and provide a genetics‐free approach for uncovering cryptic fungal metabolites.
Iron‐Catalyzed Intramolecular Arene C(sp2)−H Amidations under Mechanochemical Conditions
Authors: Shi Peng , Tu Yongliang , Kong Deshen , Wu Peng , Ma Ding , Bolm Carsten
Published: May 2022

In a ball mill, FeBr3‐catalyzed intramolecular amidations lead to 3,4‐dihydro‐2(1H)‐quinolinones in good to almost quantitative yields. The reactions do not require a solvent and are easy to perform. No additional ligand is needed for the iron catalyst. Both 4‐substituted aryl and β‐substituted dioxazolones provide products with high selectivity. Mechanistically, an electrophilic spirocyclization followed by C−C migration explains the formation of rearranged products.
Novel fluorescent chemosensor sensitively detect copper (II) through the collaboration of quinoline and coumarin groups
Authors: Jiang Ji‐Quan , Zhang You‐Ming , Wei Tai‐Bao , Yao Hong , Lin Qi
Published: May 2022

Copper ion (Cu2+) plays important role in life system and industry; therefore, efficient detection of Cu2+ is very important. To improve the selectivity and sensitivity of Cu2+, herein, quinoline and coumarin groups were rationally employed into a novel fluorescent sensor CQ to efficiently sensing Cu2+ through the collaboration of these two groups. Interestingly, the CQ possesses aggregation‐induced emission (AIE) properties and shows nice selective and sensitive fluorescent response to Cu2+. The lowest limit of detection (LOD) for Cu2+ is 2.81 × 10−8 M. Moreover, the Cu2+ sensing process has good anti‐interference properties. The possible recognition mechanism was investigated by experiments and theoretical calculations, which supplied a deep insight not only on the collaboration of the quinoline and coumarin groups in the Cu2+ recognition process but also on the charge transfer induced fluorescent response mechanism. The results show that the CQ could specifically detect Cu2+ via the collaboration of the quinoline and coumarin groups through multiple coordination interactions. Importantly, test strips based on CQ were fabricated, which could act as test kits for convenient and efficient detection of Cu2+.
Application of polyhexamethylene guanidine hydrochloride to polylactic acid/polyphenylene block copolymer antibacterial composite membranes: Manufacturing technique and property evaluations
Authors: Jhang Jia‐Ci , Cheng Chiao‐Chi , Huang Chen‐Hung , Chen Yueh‐Sheng , Lin Jia‐Horng , Lou Ching‐Wen
Published: May 2022

Polylactic acid (PLA) possesses many advantages, especially biodegradability, and has subsequently been used in many regions. Unfortunately, its disadvantages, including its brittleness, become an obstacle to its application and constrain its development. In this study, Polystyrene‐b‐poly(ethylene‐co‐1‐butene)‐b‐polystyrene (SEBS) is used as the toughener and maleic anhydride grafted polypropylene (PP‐g‐MA) is used as the compatibilizer. The melt‐blending technique for polymers is employed to modify PLA in order to produce PLA/SEBS membranes. For PLA/SEBS membranes, the optimal matrices are made of a blending ratio of PLA/SEBS/PP‐g‐MA being 57/40/3. Next, polyhexamethylene guanidine hydrochloride (PHGH) is combined with the optimal membranes to form PLA/SEBS antibacterial membranes, the crystallinity, thermal properties, and antibacterial properties of which are examined to determine the effect of the PHGH content. The test results show that an appropriate content of SEBS or PHGH has a positive influence on PLA/SEBS antibacterial membranes. Moreover, the antibacterial membranes exhibit greater antibacterial efficacy against Escherichia coli (E. coli) than is gained with an increase in the PHGH content.
The Farm Hall Transcripts: The Smoking Gun That Wasn't
Authors: Dahn Ryan
Published: May 2022

Over 75 years after their creation, the Farm Hall transcripts remain a tantalizing source from the dawn of the atomic age in 1945. Declassified in 1992, the transcripts document ten prominent German nuclear physicists, including Werner Heisenberg, Carl Friedrich von Weizsäcker, and Otto Hahn, contemplating the Nazi defeat, their complicity in the German war machine, and – after the atomic bomb was dropped on Hiroshima – whether they truly intended to build a nuclear weapon for Adolf Hitler. As a written record of conversations, one might expect the transcripts to be the proverbial smoking gun that determines, once and for all, whether German physicists intended to build a nuclear weapon for the Nazi regime. Yet the Farm Hall transcripts have been used to support starkly divergent arguments. Some have used them to assert that the Germans would have willingly provided Hitler with a bomb if only they could; others view them as evidence of scientific resistance inside the Nazi regime. This article explores why the Farm Hall transcripts are not the smoking gun they appear to be.
CpPosNeg: A positive‐negative selection strategy allowing multiple cycles of marker‐free engineering of the Chlamydomonas plastome
Authors: Jackson Harry O. , Taunt Henry N. , Mordaka Paweł M. , Kumari Sujata , Smith Alison G , Purton Saul
Published: May 2022

The chloroplast represents an attractive compartment for light‐driven biosynthesis of recombinant products, and advanced synthetic biology tools are available for engineering the chloroplast genome ( = plastome) of several algal and plant species. However, producing commercial lines will likely require several plastome manipulations. This presents issues with respect to selectable markers, since there are a limited number available, they can be used only once in a serial engineering strategy, and it is undesirable to retain marker genes for antibiotic resistance in the final transplastome. To address these problems, we have designed a rapid iterative selection system, known as CpPosNeg, for the green microalga Chlamydomonas reinhardtii that allows creation of marker‐free transformants starting from wild‐type strains. The system employs a dual marker encoding a fusion protein of E. coli aminoglycoside adenyltransferase (AadA: conferring spectinomycin resistance) and a variant of E. coli cytosine deaminase (CodA: conferring sensitivity to 5‐fluorocytosine). Initial selection on spectinomycin allows stable transformants to be established and driven to homoplasmy. Subsequent selection on 5‐fluorocytosine results in rapid loss of the dual marker through intramolecular recombination between the 3′UTR of the marker and the 3′UTR of the introduced transgene. We demonstrate the versatility of the CpPosNeg system by serial introduction of reporter genes into the plastome.
Comprehensive assessment of host cell protein expression after extended culture and bioreactor production of CHO cell lines
Authors: Hamaker Nathaniel K. , Min Lie , Lee Kelvin H.
Published: May 2022

The biomanufacturing industry is advancing toward continuous processes that will involve longer culture durations and older cell ages. These upstream trends may bring unforeseen challenges for downstream purification due to fluctuations in host cell protein (HCP) levels. To understand the extent of HCP expression instability exhibited by Chinese hamster ovary (CHO) cells over these time scales, an industry‐wide consortium collaborated to develop a study to characterize age‐dependent changes in HCP levels across 30, 60, and 90 cell doublings, representing a period of approximately 60 days. A monoclonal antibody (mAb)‐producing cell line with bulk productivity up to 3 g/L in a bioreactor was aged in parallel with its parental CHO‐K1 host. Subsequently, both cell types at each age were cultivated in an automated bioreactor system to generate harvested cell culture fluid (HCCF) for HCP analysis. More than 1500 HCPs were quantified using complementary proteomic techniques, two‐dimensional electrophoresis (2DE) and liquid chromatography coupled with tandem mass spectrometry (LC‐MS/MS). While up to 13% of proteins showed variable expression with age, more changes were observed when comparing between the two cell lines with up to 47% of HCPs differentially expressed. A small subset (50 HCPs) with age‐dependent expression were previously reported to be problematic as high‐risk and/or difficult‐to‐remove impurities; however, the vast majority of these were downregulated with age. Our findings suggest that HCP expression changes over this time scale may not be as dramatic and pose as great of a challenge to downstream processing as originally expected but that monitoring of variably expressed problematic HCPs remains critical.