bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic radiation from membranes at high frequencies: The quantum chaos regime
Authors: Delande Dominique , Sornette Didier
Published: July 2002

An efficient and reliable numerical scheme is developed to compute the radiation directivity and total power radiated by isolated eigenmodes and by finite bandwidth excitations of a membrane of arbitrary shape over the whole frequency domain. Results are presented for the case of a membrane having the shape of a stadium, this shape having been studied intensively in the literature concerned with the correspondence between classical geometrical ray trajectories and high-frequency vibrations, the so-called “quantum chaos” problem. Localization of the radiation directivity is shown to be due to “scars” of eigenmodes made by resonance on periodic ray orbits. The dependence of the radiation efficiency as a function of the ratio cM/c of the membrane wave velocity cM over the air sound speed c and its important fluctuations from mode-to-mode is explained by the theory of random matrices.
Acceptance limits for the duration of pre-Helmholtz transients in bowed string attacks
Authors: Guettler Knut , Askenfelt Anders
Published: July 2002

The attack of most bowed notes shows an initial part before Helmholtz triggering occurs (the pre-Helmholtz transient), during which the stick-slip interaction promotes frequencies other than that of the string’s fundamental. Depending on the particular combination of bowing parameters, this state is characterized either by periods that are prolonged, or by a division of the period into two or more parts, multiple flyback. An onset with perfectly periodic motion (Helmholtz triggering) directly from the very start is also possible. A sample of violin tones representing these three classes of attacks, and with different duration of the pre-Helmholtz transient, has been collected by the use of a computer-controlled bowing machine. The tones were evaluated by 20 advanced string students and professionals in a listening test, judging the acceptance and quality of the attacks. The maximum acceptable duration of the pre-Helmholtz transient was estimated to 50 ms (⩽10 nominal periods, open G string, violin) for attacks with prolonged periods, and 90 ms (⩽18 periods) for multiple-flyback attacks. These values refer to a neutral start in a neutral context, such as when practicing a scale. A playing test, in which the performances of two professional violinists were analyzed, confirmed these results, and showed that the same limits apply to a larger group of bowing styles as well.
Subjective effects of peak clipping and compression limiting in normal and hearing-impaired children and adults
Authors: Stelmachowicz P. G. , Lewis D. E. , Hoover B. , Keefe D. H.
Published: July 2002

Despite many advances in hearing-aid signal processing, compression limiting and peak clipping are still used. To date, perceptual studies have been conducted only with adults. The current study was designed to investigate the clarity of peak-clipped and compressed speech for both adults and children. Subjects were 30 normal-hearing and 30 hearing-impaired individuals in three age ranges (7–9, 10–12, and 16–50 years). Stimuli were processed at 60, 70, 75, and 80 dB SPL using peak clipping and at 80 dB SPL using compression limiting. Paired-comparison measures were used to assess the clarity of sentences, and a signal-to-distortion ratio (SDR) based on a measure of coherence between input and output was computed for each condition. For the peak-clipping conditions, there was a decrease in perceived clarity as the input increased from 60 to 80 dB SPL. This perceptual continuum was most apparent for the normal-hearing adults. The normal-hearing 10–12 year olds and the hearing-impaired adults showed a similar, but less pronounced, pattern. In contrast, the remaining three subject groups showed minimal differences in perceived clarity across conditions. Surprisingly, only the two oldest normal-hearing groups showed a clear preference for compression limiting over peak clipping at the highest input level, and only their results were consistent with the pattern of coherence across stimuli. Judgments of clarity by the normal-hearing subjects correlated best with the SDR in the 500–2000-Hz range, while clarity judgments of the hearing-impaired subjects correlated best with the SDR below 1000 Hz.
A theoretical study of duct noise control by flexible panels
Authors: Huang Lixi
Published: July 2002

Theoretical exploration is undertaken for passive noise control by flush-mounted panels in an otherwise rigid duct. For a plane sound wave traveling in the flexible segment, the wall compliance renders a wave speed less than the isentropic speed of sound in air. Scattering and reflection occur at the upstream edge of the panel while the energy flux of the transmitted wave is partitioned between the wall flexural waves and the sound in air. For a lossless panel these waves are scattered and reflected again by the downstream edge forming standing waves responsible for the undesirable passbands. For panels with substantial structural damping, however, both flexural and sound waves diminish with distance, eliminating the passbands. It is estimated that the wave dissipation by panel materials like rubber could outperform typical fibrous duct lining. The combination of wave reflection, dissipation, and slowing down allows broadband, low-frequency noise reduction over a short distance.
The bi-azimuthal scattering distribution of an abyssal hill
Authors: Makris Nicholas C. , Chia Chin Swee , Fialkowski Laurie T.
Published: July 2002

High-resolution bistatic images of a typical abyssal hill on the western flank of the Mid-Atlantic Ridge are made with a low-frequency towed-array system operating remotely at 1/2 convergence zone (∼33.3 km) stand-off. Comparison with modeled images, generated from high-resolution supporting bathymetry sampled at 5-m intervals, roughly the wavelength scale, reveals that steep scarps return the strongest echoes because they project the largest area along the acoustic path from the source to receiver. Prominent returns deterministically image scarp morphology when the cross-range axis of the system’s resolution footprint runs along the scarp axis. Statistical fluctuations inherent in the scattered field prevent the system from distinguishing smaller-scale anomalies on the scarps, such as canyons and gullies (∼100–200 m scale), that would otherwise be resolvable in range, in certain bistatic geometries. The mean bi-azimuthal scattering distributions of the two major scarps on the abyssal hill are identical and have strengths equal to the constant −17 dB±8 dB. This suggests that long-range reverberation from prominent geomorphological features of the world’s mid-ocean ridges can be adequately modeled as Lambertian with albedo π/101.7, given supporting bathymetry sampled with sufficient frequency to resolve the projected area of these features.
Reconstruction of bowing point friction force in a bowed string
Authors: Woodhouse J. , Schumacher R. T. , Garoff S.
Published: July 2002

A method is presented for reconstructing the friction force and the velocity at the bowing point of a string excited by a rosined bow sliding transverse to the string. Two versions of the method of reconstruction are presented, each approximate in different ways, but both capable of sufficient accuracy to allow useful application to problems of understanding frictional interactions in this dynamical system. The method is illustrated with simulated data to verify its accuracy, and results are shown for two contrasting cases of observed stick-slip string motion. As has been found in other investigations, the friction force during sliding is not determined by the instantaneous sliding speed. The results seem to be compatible with a thermally based model of rosin friction.
X-ray powder diffraction analysis of adducts triglycine fluoroberyllic acid and triglycine selenic acid for pyroelectric application
Authors: Che Yunxia , Zheng Jimin , Hao Jianmin , Chu Lianqing
Published: July 2002

Two adducts (NH2CH2COOH)3⋅H2BeF4(TGFb) and (NH2CH2COOH)3⋅H2SeO4(TGSe) were obtained and characterized by X-ray powder diffraction. The samples were indexed using the TREOR program [Werner, Z. Kristallogr. Kristallogeom. Kristallphys. Kristallchem. 120, 375–387 (1964)] on a monoclinic unit cell. The lattice parameters of adducts TGFb and TGSe were refined by a least-squares method using the Lattice Constant Refinement Program of the Rikagu software. The refined lattice parameters are a=9.1589(9) Å, b=12.6204(13) Å, c=5.6966(8) Å, β=105.451(9)° for TGFb. The Smith and Snyder figure [Smith and Snyder, J. Appl. Crystallogr. 12, 60–65 (1979)] is F30=39.4(0.0141,54). The refined lattice parameters a=9.5063(11) Å, b=12.8281(10) Å, c=5.8682(7) Å, β=110.353(77)° for TGSe. The Smith and Snyder figure is F30=39(0.0106,73). The powder diffraction results are in agreement with those obtained from single crystal structure data.
Analysis of School-Level Vaccination Rates by Race, Ethnicity, and Geography in New York City
Authors: Elbel Brian , Zhou Geng Eric , Lee David C. , Chen Willy , Day Sophia E. , Konty Kevin J. , Schwartz Amy Ellen
Published: September 2022

This cross-sectional study of New York City school data examines differences in COVID-19 vaccination rates by race, ethnicity, and borough.
Subclinical Risk Factors for Heart Failure With Preserved and Reduced Ejection Fraction Among Black Adults
Authors: Zhao Li , Zierath Rani , John Jenine E. , Claggett Brian Lee , Hall Michael E. , Clark Donald , Butler Kenneth R. , Correa Adolfo , Shah Amil M.
Published: September 2022

Importance

Sparse data exist regarding the contributions of subclinical impairments in cardiovascular and noncardiovascular function to incident heart failure (HF) with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF) among Black US residents, limiting understanding of the etiology of HF subtypes.

Objectives

To identify subclinical cardiovascular and noncardiovascular risk factors associated with HFrEF and HFpEF in Black US residents.

Design, Setting, and Participants

This cohort study used cross-sectional and time-to-event analysis with data from the community-based Jackson Heart Study (JHS), a longitudinal cohort study with baseline data collected from 2000 to 2004 (visit 1) and 10-year follow-up for incident HF. Black US residents from the Jackson, Mississippi, metropolitan area enrolled in JHS; those with prevalent HF, with moderate or greater aortic or mitral valve diseases on visit 1, who died before 2005, and who had missing HF status on follow-up were excluded. The analysis included 4361 participants and was performed between June 2020 to August 2021.

Exposures

Quantitative measures of cardiovascular (left ventricular mass index [LVMI], left ventricular ejection fraction [LVEF], left atrial [LA] diameter, and pulse pressure) and noncardiovascular (percent predicted forced expiration volume in 1 second [FEV1 (percent predicted)], estimated glomerular filtration rate (eGFR), waist circumference, and hemoglobin A1c [HbA1c] level) organ function.

Main Outcomes and Measures

Incident HF, HFrEF, and HFpEF over 10-year follow-up.

Results

The 4361 participants had a mean (SD) age of 54 (13); 2776 (64%) were women; and there were 163 HFpEF and 146 HFrEF events. In multivariable models incorporating measures reflecting each organ system, factors associated with incident HFpEF included greater LA diameter (hazard ratio [HR], 1.23; 95% CI, 1.03-1.47; P = .02), higher pulse pressure (HR, 1.23; 95% CI, 1.05-1.44; P = .009), lower FEV1 (percent predicted) (HR, 1.22; 95% CI, 1.04-1.43; P = .02), lower eGFR (HR, 1.43; 95% CI, 1.19-1.72; P < .001), higher HbA1c level (HR, 1.25; 95% CI, 1.07-1.45; P = .005), and higher waist circumference (HR, 1.41; 95% CI, 1.18-1.69; P < .001). Factors associated with incident HFrEF included greater LVMI (HR, 1.25; 1.07-1.46; P = .005), lower LVEF (HR, 1.65; 95% CI, 1.42-1.91; P < .001), lower FEV1 (percent predicted) (HR, 1.19; 95% CI, 1.00-1.42; P = .047), and lower eGFR (HR, 1.27; 95% CI, 1.04-1.55; P = .02).

Conclusions and Relevance

In this community-based cohort study of Black US residents, subclinical impairments in cardiovascular and noncardiovascular organ function were differentially associated with risk of incident HFpEF and HFrEF.
An Overview of Clinical Development of Agents for Metastatic or Advanced Breast Cancer Without ERBB2 Amplification (HER2-Low)
Authors: Prat Aleix , Bardia Aditya , Curigliano Giuseppe , Hammond M. Elizabeth H. , Loibl Sibylle , Tolaney Sara M. , Viale Giuseppe
Published: September 2022

Importance

Erb-b2 receptor tyrosine kinase 2 (ERBB2; formerly HER2 [human epidermal growth factor receptor 2]) is an important prognostic and predictive factor in breast cancer. Anti-ERBB2 therapies have improved outcomes in ERBB2-positive breast cancer. However, based on current definitions, tumors with low ERBB2 expression are included in the ERBB2-negative subtype, and therefore, are ineligible for anti-ERBB2 therapies; patients with ERBB2-low (immunohistochemistry [IHC] 1 positive [+] or IHC 2+/in situ hybridization [ISH] negative [−]) tumors account for up to approximately 50% of breast cancer cases. Although the prognostic role of ERBB2-low needs to be defined, ERBB2 offers a potential therapeutic target in these patients.

Observations

Most breast cancer tumors have some ERBB2 expression, with ERBB2-low being more common in hormone receptor–positive than in hormone receptor–negative breast cancer. Although an early clinical study failed to demonstrate benefit of adjuvant trastuzumab for ERBB2-low disease, several novel anti-ERBB2 therapies have shown efficacy in ERBB2-low breast cancer, including the antibody-drug conjugate trastuzumab deruxtecan in a phase 3 trial, and trastuzumab duocarmazine and the bispecific antibody zenocutuzumab in early-phase studies. Although reports are conflicting, some differences in biology and patient outcomes have been found between ERBB2-low and ERBB2 IHC-0 breast cancer. Currently, no established guidelines exist for scoring ERBB2-low expression in breast cancer because the focus has been on binary classification as ERBB2-positive or ERBB2-negative. Additional interpretive cutoffs may be needed to select patients for treatment with effective agents in ERBB2-low breast cancer, along with standardized laboratory quality assurance programs to ensure consistent patient identification for eligibility for ERBB2-low targeting agents.

Conclusions and Relevance

This review suggests that ERBB2-low may be a distinct, clinically relevant breast cancer entity warranting reassessment of traditional diagnostic and therapeutic paradigms. Ongoing clinical trials and further investigations may provide optimized strategies for diagnosing and treating ERBB2-low breast cancer, including reproducible, consistent definitions to identify patients in this diagnostic category and demonstration of benefits of emerging therapies.
Pirellulaceae
Authors: Lage Olga Maria , Calisto Rita , Vitorino Inês , Øvreås Lise
Published: September 2022

Pi.rel.lu.la.ce'ae. N.L. fem. n.
Pirellula
, type genus of the family; suff. –
aceae
ending to denote a family; N.L. fem. pl. n.
Pirellulaceae
the
Pirellula
family.

Planctomycetota / Planctomycetia / Pirellulales / Pirellulaceae

The family
Pirellulaceae
belongs to the order
Pirellulales
of the class
Planctomycetia
and the phylum
Planctomycetota,
which is part of the PVC superphylum. The family
Pirellulaceae
accommodates 40 species, which belong to 13 genera with validly published names and 3 genera whose names remain to be validated. Members of the family display variable colony color and cell shape. Cells occur singly or organized in aggregates, rosettes, or chains. Mobility can occur. Division occurs by polar or lateral budding. Preference for neutral pH, mesophilic or tolerance to psychrophylic conditions, aerobic or microaerophilic or anaerobic lifestyle as well as heterotrophy are main physiological characteristics. Vitamin B
12
may be required. Phosphatidylcholine, diphosphatidylglycerol and phosphatidylglycerol, oleic/elaidic acid (C
18:1
ω9), and palmitic acid (C
16:0
) are the main polar lipids and the major fatty acids (respectively). Menaquinone 6 (MK‐6) is the most common quinone. Members of the family were isolated from a broad range of habitats. The genome size varies between 6.1 and 11.0 Mb. The type genus is
Pirellula
.

DNA G + C content (mol%)
: 49.5–63.6 (genome analysis).

Type genus
:
Pirellula
Schlesner and Hirsch 1987
VP
emend. Schlesner et al. 2004.
Klugiella
Authors: Trujillo Martha E. , Riesco Raúl
Published: September 2022

Klugiella
(Klu.gi.el'la. N.L. fem. n.
Klugiella
named after Michael J. Klug, an American entomologist/microbiologist who, along with S. Kotarski, first described the microbial community of
Tipula abdominalis
larval gut, from which strain 44C3
T
was isolated).

Actinomycetota / Actinomycetia / Micrococcales / Microbacteriaceae / Klugiella

Gram‐stain positive, aerobic, rod‐shaped actinobacteria. Nonmotile and non‐spore‐forming. Colonies are circular, convex, and yellow. Catalase positive and oxidase negative. Grows between 4–30°C, at pH 6–11 and on media supplemented with 1% NaCl. Chemoorganotrophic. Acid production for several carbohydrates is reported. Chemotaxonomic markers include a type B peptidoglycan and major menaquinones MK‐11 and MK‐12.
Klugiella
is phylogenetically related to the genera
Cryobacterium
,
Alpinimonas,
and
Lysinibacter
, all members of the family
Microbacteriaceae
. The closest neighbors are
Cryobacterium luteum
CGMCC1.11210
T
,
Cryobacterium aureum
Hh31
T
, and
Cryobacterium levicorallinum
Hh34
T
. The genus is represented by the single species
Klugiella xanthotipulae
, represented by strain 44C3
T
.

DNA G
 + 
C content (mol%)
: 62.7 (WGS).

Type species
:
Klugiella xanthotipulae
Cook et al. 2008
VP
.
Association Between Change in Body Mass Index and Knee and Hip Replacements: A Survival Analysis of Seven to Ten Years Using Multicohort Data
Authors: Salis Zubeyir , Sainsbury Amanda
Published: September 2022

Objective

To define the association between change in body mass index (BMI) and the risk of knee and hip replacement.

Methods

We used data from 3 independent cohort studies: the Osteoarthritis Initiative (OAI), the Multicenter Osteoarthritis Study (MOST), and the Cohort Hip and Cohort Knee (CHECK) study, which collected data from adults (45–79 years of age) with or at risk of clinically significant knee osteoarthritis. We conducted Cox proportional hazards regression analysis with clustering of both knees and hips per person to determine the association between change in BMI (our exposure of interest) and the incidence of primary knee and hip replacement over 7–10 years’ follow‐up. Change in BMI (in kg/m2) was calculated between baseline and the last follow‐up visit before knee or hip replacement, or for knees and hips that were not replaced, the last follow‐up visit.

Results

A total of 16,362 knees from 8,181 participants, and 16,406 hips from 8,203 participants, were eligible for inclusion in our knee and hip analyses, respectively. Change in BMI was positively associated with the risk of knee replacement (adjusted hazard ratio [HRadj] 1.03 [95% confidence interval (95% CI) 1.00–1.06]) but not hip replacement (HRadj1.00 [95% CI 0.95–1.04]). The association between change in BMI and knee replacement was independent of participants’ BMI category at baseline (i.e., normal, overweight, or obese).

Conclusion

Public health strategies incorporating weight loss interventions could reduce the burden of knee but not hip replacement surgery.
Amorphous Ultra‐Small Fe‐Based Nanocluster Engineered and ICG Loaded Organo‐Mesoporous Silica for GSH Depletion and Photothermal‐Chemodynamic Synergistic Therapy
Authors: Li Jiaqi , Tian Haina , Zhu Fukai , Jiang Suhua , He Maomao , Li Yang , Luo Qiang , Sun Wen , Liu Xiaolong , Wang Peiyuan
Published: September 2022

Intracellular oxidative amplification can effectively destroy tumor cells. Additionally, Fe‐mediated Fenton reaction often converts cytoplasm H2O2 to generate extensive hypertoxic hydroxyl radical (•OH), leading to irreversible mitochondrion damage for tumor celleradication, which is widely famous as tumor chemodynamic therapy (CDT). Unfortunately, intracellular overexpressed glutathione (GSH) always efficiently scavenges •OH, resulting in the significantly reduced CDT effect. To overcome this shortcoming and improve the oxidative stress in cytoplasm, Fe3O4 ultrasmall nanoparticle encapsulated and ICG loaded organo‐mesoporous silica nanovehicles (omSN@Fe‐ICG) are constructed to perform both photothermal and GSH depletion to enhance the Fenton‐like CDT, by realizing intracellular oxidative stress amplification. After this nanoagents are internalized, the tetrasulfide bonds in the dendritic mesoporous framework can be decomposed with GSH to amplify the toxic ROS neration by selectively converting H2O2 to hydroxyl radicals through the released Fe‐based nanogranules. Furthermore, the NIR laser‐induced hyperthermia can further improve the Fenton reaction rate that simultaneously destroyed the mitochondria. As a result, the GSH depletion and photothermal assisted CDT can remarkably improve the tumor eradication efficacy.
Synthesis of Ambient Copolymerization CQAS Hydrogel Composite Membrane with Enhanced Antifouling
Authors: Li Yamin , Chen Chen
Published: September 2022

Hydrogel molecular structure contained massive hydrophilic groups, which can capture water molecules to form the rejection layer of natural organic matter (NOM). Aiming at introducing the excellent properties of hydrogels into the water treatment separation membrane, a new kind of positive charged ambient self‐crosslinking chitosan quaternary ammonium salt (CQAS) hydrogel is designed and applied to prepare a hydrogel composite membrane via surface coating method. Effects of the amount of initiator on the ambient self‐cross‐linking time of CQAS hydrogels is discussed, as well as the impacts of coating amount of ambient self‐cross‐linking CQAS pre‐gel solution on the comprehensive properties of the composite membranes is also studied. The membrane structure and morphology is characterized by FT‐IR, FE‐SEM, AFM, and the membrane properties are evaluated by dynamic contact angle and membrane performance evaluation instrument. The obtained CQAS hydrogel composite membrane exhibited super hydrophilicity, high, and stable separation performance of monovalent and divalent cations, excellent long‐term tolerance, and resistance to NOM contaminants. Specifically, in the dynamic antifouling test, the stable flux recovery rate of the CQAS hydrogel membrane to the simulative contaminants BSA, HA, and SA are 82.95%, 92.89%, and 73.37%, respectively.
Carbon Nanotube‐Based Strain Sensors: Structures, Fabrication, and Applications
Authors: Wang Rui , Sun Luanfa , Zhu Xiaoyang , Ge Wensong , Li Hongke , Li Zhenghao , Zhang Houchao , Huang Youqi , Li Zengcheng , Zhang Yuan‐Fang , Zhao Jiawei , Xu Quan , Lan Hongbo
Published: September 2022

Flexible strain sensors have received widespread attention because of their great potential in many fields. Carbon nanotubes (CNTs) have been used as conductive materials for flexible strain sensors due to their excellent electrical and mechanical properties, and the fabricated flexible strain sensors have excellent sensing performance. This paper systematically summarizes the advances in flexible resistance‐type strain sensors based on CNTs. The strain sensing mechanisms are introduced, including crack extension, tunneling effect, and disconnection of overlapping materials. The performance parameters of the sensors, including sensitivity, stretchability, linearity, hysteresis, dynamic durability, and transparency, are discussed comprehensively. The coating methods, 3D printing techniques, chemical vapor deposition, transfer methods, and spinning processes used to fabricate CNT strain sensors are highlighted. The effect of isolated and porous internal conductive structures, folded and microcracked surface structures, films and fabrics macroscopic structures on sensor performance were systematically analyzed. The applications of the sensors in medical health, motion monitoring, gesture recognition, human–computer interaction, and soft robotics are provided in detail. Finally, the future challenges of CNT flexible strain sensors are summarized and the outlook is presented. Although CNT strain sensors have made great progress so far, there are still many problems that need researchers’ attention and solutions.
Achieving Small Temperature Coefficients in Carbon‐Based Perovskite Solar Cells by Enhancing Electron Extraction
Authors: Zhang Xian , Guan Yan , Zhang Yangyang , Yu Wenjin , Wu Cuncun , Han Jiaheng , Zhang Yafei , Chen Cong , Zheng Shijian , Xiao Lixin
Published: September 2022

Hole transport layer (HTL)‐free carbon electrode‐based perovskite solar cells (C‐PSCs) have drawn great attention due to their excellent stability and simple fabrication process. However, the photovoltaic parameters of C‐PSCs usually exhibit large negative temperature coefficients (TCs). Herein, the TCs of C‐PSCs can be suppressed by enhancing electron extraction. An efficient electron transport layer (ETL), [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM)‐coated nanoneedle‐like brookite TiO2 (ND‐B‐TiO2) is used as ETL to prepare HTL‐free pure FAPbI3‐based C‐PSCs. Compared with bare ND‐B‐TiO2, PCBM@ND‐B‐TiO2 shows higher electron mobility, and better band alignment with formamidinium lead triiodide (FAPbI3) perovskite, as well as improved contact with perovskite, which leads to enhanced electron extraction and transportation. Consequently, the power conversion efficiency (PCE) of HTL‐free carbon‐based FAPbI3 PSC can reach up to 14.55%, which is one of the highest efficiencies for FAPbI3‐based planar C‐PSCs so far. More importantly, the optimized device is less sensitive to the operating temperature due to the boosted carrier extraction and passivated interface defects, showing a small TC(PCE) of only ≈−0.11%/°C between 25 °C and 85 °C. The work demonstrates that enhancing electron extraction is an effective way to achieve high‐performance C‐PSCs and high‐temperature solar cells.
Gold Catalysis: 2,3‐ or 1,4‐Addition to Butadiynes
Authors: Stein Philipp M. , Pascher Jonas , Stracke Jonas , Levacher Victor S. , Wagner Josefine A. , Rominger Frank , Oeser Thomas , Rudolph Matthias , Hashmi A. Stephen K.
Published: September 2022

In the past, numerous impressive methodologies have been developed in homogeneous gold catalysis, typically using alkynes, allenes, or different non‐conjugated diyne systems as starting materials. While there are applications catalyzed by other transition metals, the use of 1,3‐butadiyne derivatives has been largely neglected in gold catalysis. In this work we present an efficient gold‐catalyzed method focusing on the functionalization of this specific type of diynes. The starting materials can be synthesized via simple Glaser Coupling, starting from cheap, highly variable, terminal alkynes. These homocoupling products, which are often observed as undesirable side‐products in Sonogashira reactions, can be converted into versatile 1,3‐butadiene derivatives in alcohol as a solvent and nucleophile under mild conditions. The possible field of application of the 1,3‐butadiene derivatives known from the literature is very broad and ranges from a use as transistor or OLED material to a use as an enzyme inhibitor. The approach presented here offers an attractive and highly effective way to versatile functionalized 1,3‐butadiene derivatives.

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Synthesis of Chiral, Fused Tricyclic Molecules by Sequential Metal‐Catalyzed Reactions of Simple Substrates
Authors: Saltó Joan , Biosca Maria , Pàmies Oscar , Diéguez Montserrat
Published: September 2022

A set of complex tricyclic compounds containing several functional groups and multiple stereogenic centers has been prepared in only two steps with excellent diastereo‐ and enantioselectivities. The synthesis takes advantage of the highly versatile and enantioselective Pd‐catalyzed allylic substitution of simple cyclic allylic acetates or carbonates to form chiral 1,6‐, 1,7‐ and 1,8‐enynes, which are then diastereoselectively transformed to the corresponding cyclopentenone‐ and cyclobutene‐based tricyclic compounds.

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Gold Nanoparticles Disrupt the IGFBP2/mTOR/PTEN Axis to Inhibit Ovarian Cancer Growth
Authors: Hossen Md. Nazir , Wang Lin , Dwivedi Shailendra Kumar Dhar , Zhang Yushan , Rao Geeta , Elechalwar Chandra Kumar , Sheth Vinit , Dey Anindya , Asfa Sima , Gulla Suresh Kumar , Xu Chao , Fung Kar‐Ming , Robertson J. David , Bieniasz Magdalena , Wilhelm Stefan , Bhattacharya Resham , Mukherjee Priyabrata
Published: September 2022

By exploiting the self‐therapeutic properties of gold nanoparticles (GNPs) a molecular axis that promotes the growth of high‐grade serous ovarian cancer (HGSOC), one of the deadliest gynecologic malignancies with poorly understood underlying molecular mechanisms, has been identified. The biodistribution and toxicity of GNPs administered by intravenous or intraperitoneal injection, both as a single dose or by repeated dosing over two weeks are first assessed; no biochemical or histological toxicity to vital organs is found. Using an orthotopic patient‐derived xenograft (PDX) model of HGSOC, the authors then show that GNP treatment robustly inhibits tumor growth. Investigating the molecular mechanisms underlying the GNP efficacy reveals that GNPs downregulate insulin growth factor binding protein 2 (IGFBP2) by disrupting its autoregulation via the IGFBP2/mTOR/PTEN axis. This mechanism is validated by treating a cell line‐based human xenograft tumor with GNPs and an mTOR dual‐kinase inhibitor (PI‐103), either individually or in combination with GNPs; GNP and PI‐103 combination therapy inhibit ovarian tumor growth similarly to GNPs alone. This report illustrates how the self‐therapeutic properties of GNPs can be exploited as a discovery tool to identify a critical signaling axis responsible for poor prognosis in ovarian cancer and provides an opportunity to interrogate the axis to improve patient outcomes.
Geometric Constraints Regulate Energy Metabolism and Cellular Contractility in Vascular Smooth Muscle Cells by Coordinating Mitochondrial DNA Methylation
Authors: Liu Han , Liu Yuefeng , Wang He , Zhao Qiang , Zhang Tao , Xie Si‐an , Liu Yueqi , Tang Yuanjun , Peng Qin , Pang Wei , Yao Weijuan , Zhou Jing
Published: September 2022

Vascular smooth muscle cells (SMCs) can adapt to changes in cellular geometric cues; however, the underlying mechanisms remain elusive. Using 2D micropatterned substrates to engineer cell geometry, it is found that in comparison with an elongated geometry, a square‐shaped geometry causes the nuclear‐to‐cytoplasmic redistribution of DNA methyltransferase 1 (DNMT1), hypermethylation of mitochondrial DNA (mtDNA), repression of mtDNA gene transcription, and impairment of mitochondrial function. Using irregularly arranged versus circumferentially aligned vascular grafts to control cell geometry in 3D growth, it is demonstrated that cell geometry, mtDNA methylation, and vessel contractility are closely related. DNMT1 redistribution is found to be dependent on the phosphoinositide 3‐kinase and protein kinase B (AKT) signaling pathways. Cell elongation activates cytosolic phospholipase A2, a nuclear mechanosensor that, when inhibited, hinders AKT phosphorylation, DNMT1 nuclear accumulation, and energy production. The findings of this study provide insights into the effects of cell geometry on SMC function and its potential implications in the optimization of vascular grafts.
Rechargeable Dual‐Carbon Batteries: A Sustainable Battery Technology
Authors: Tebyetekerwa Mike , Duignan Timothy T. , Xu Zhen , Song Zhao Xiu
Published: September 2022

Dual‐carbon batteries (DCBs) with both electrodes composed of carbon materials are currently at the forefront of industrial consideration. This is due to their low cost, safety, sustainability, fast charging, and simpler electrochemistry than lithium and other post‐lithium metal‐ion batteries. This article provides an overview of the past lessons on rechargeable DCBs and their future promises. In brief, it introduces the reader to DCBs as one of the most promising energy storage solutions for balancing sustainability, cost and performance, their history, electrochemistry and associated charge storage mechanisms. Then, the past lessons with respect to their ion intercalation are provided. These include DCB mechanisms during different anion/cation intercalation in layered carbons and their intercalation compounds and electrode structures versus electrochemical performance. This is followed by a description of the current issues affecting DCBs like capacity fading and self‐discharging, electrolyte instability, low energy densities and electrode exfoliation, together with their remedies. Finally, an insightful perspective proposing key areas requiring significant research efforts toward the success of DCBs is provided responsible for accelerating the commercialization and adoption of DCBs toward a sustainable and circular economy. This article is a simplified guide to understanding the current state and future research needed to develop sustainable DCBs.
Comparing various sulfur sources for soybean grown on an acid Oxisol in Brazil
Authors: Francisco Eros A. B. , Chien Sen H. , Ono Fabio , Gearhart Maria Mercedes , Cruz Antonio P.
Published: September 2022

A greenhouse experiment and a 2‐yr field trial were conducted to compare various S sources for soybean [Glycine max (L.) Merr.] grown on an acid Oxisol in Brazil. In the greenhouse, the sources included ammonium sulfate (AMS), monoammonium phosphate with a S ratio = 50:50 of AMS/elemental S (ES) – (AMS + ES), and ES + bentonite containing 90% ES. All sources were surface‐applied at 0, 5, 10, 20, and 40 mg S kg–1. Separately, all S sources were incorporated into the soil at 20 mg S kg–1. Yield and S uptake by the grain followed the order AMS = MAP – (AMS + ES) > ES + bentonite. No significant differences in grain yield and S uptake were observed between surface application and incorporation, except those of surface application were greater than those of incorporation with MAP – (AMS + ES). In the field trial, single superphosphate (SSP) and phosphogypsum (PG) were also included. All sources were surface‐applied at 30 kg S ha–1 yr–1. Additionally, AMS was split‐applied in equal amounts at planting and R1 stage. In both years, grain yield and S uptake followed the order AMS = MAP – (AMS + ES) = PG = SSP > ES + bentonite = control. The highest S uptake was observed with split‐application of AMS in the first but not the second year. The benefit of a split application of AMS over a one‐time application for S uptake in the first year was probably caused by reduced SO4–S leaching.
Proyecto Titi: Teaching children that cotton‐top tamarins (Saguinus oedipus) are not appropriate pets
Authors: Savage Anne , Díaz Leysthen , Pasion Johana , Torregroza Katherine , Guillen Rosamira
Published: September 2022

Cotton‐top tamarins (Saguinus oedipus) are a critically endangered species found only in Colombia. Their survival is threatened by extensive habitat destruction and the illegal pet trade. Because many people in Colombia have a low level of awareness of cotton‐top tamarins and even less understanding of the impacts that the illegal pet trade has on the species and its long‐term survival, Proyecto Tití has developed a series of programs for children in rural elementary schools that introduce children to cotton‐top tamarins. This study examines Proyecto Titi's efforts to reduce the desire to have a cotton‐top tamarin as a pet with outcomes focused specifically on (1) creating an emotional connection between people and cotton‐top tamarins, (2) identifying the feelings and understanding the challenges that cotton‐top tamarin face when they are kept as pets, and (3) empowering students to make positive choices to help cotton‐top tamarins. Both TITI KIDS and TITIRITIANDO programs helped students to (1) increase their knowledge of cotton‐top tamarins, (2) understand the damage that the pet trade has on individual animals and the long‐term survival of cotton‐top tamarins and (3) provide practical actions that they can engage in to protect cotton‐top tamarins for the future. Our hope is that students from our programs become advocates for conservation in their communities and assist in the long‐term conservation activities to protect cotton‐top tamarins in Colombia.
Multimodal Antibacterial Platform Constructed by the Schottky Junction of Curcumin‐Based Bio Metal–Organic Frameworks and Ti3C2Tx MXene Nanosheets for Efficient Wound Healing
Authors: Guo Chuanpan , Cheng Fang , Liang Gaolei , Zhang Shuai , Duan Shuxia , Fu Yingkun , Marchetti Fabio , Zhang Zhihong , Du Miao
Published: September 2022

A novel multimodal antibacterial platform is constructed by the in situ growth of a bioactive zinc‐based metal–organic framework (Zn‐MOF) using the natural antibacterial agent (curcumin) as ligand over the Ti3C2Tx nanosheets (NSs) for highly effective bacteria‐infected wound healing. As Zn nodes in Zn‐MOF can be partially exchanged by Ti sites in Ti3C2Tx NSs, a novel oxygen vacancy‐rich Schottky junction is formed at the interface between Zn‐MOF and Ti3C2Tx NSs, which can remarkably improve the separation and electron transfer efficiency of photoinduced carriers under near‐infrared light irradiation (808 nm). Consequently, it affords the Zn‐MOF@Ti3C2Tx Schottky junction abundant superoxide radicals (•O2−) and hydroxyl radicals (•OH) by electron transfer via type I mechanism and singlet oxygen (1O2) by energy transfer via type II mechanism, accompanying the superior photothermal performance and controllable release of Zn2+ ions and curcumin. The Zn‐MOF@Ti3C2Tx shows excellent biocompatibility and multimodal antibacterial ability toward Staphylococcus aureus and Escherichia coli. Based on the detailed investigations of the antibacterial mechanism, the Zn‐MOF@Ti3C2Tx Schottky junction remarkably demonstrates accelerated wound healing (wound closure ratio is >99%) infected by S. aureus.
The Linkage of Sulfonimidoyl Fluorides and Unactivated Alkenes via Hydrosulfonimidoylation
Authors: Zeng Daming , Ma Yinhao , Deng Wei‐Ping , Wang Ming , Jiang Xuefeng
Published: September 2022

Sulfur(VI) fluoride cleavage and exchanging linkage, a new generation of linkage chemistry, exhibits enormous potential for combining a range of functional molecules in an increasing number of fields. Herein, we established a metal‐free linkage of unactivated alkenes and sulfonimidoyl fluorides via hydrosulfonimidoylation to construct sulfoximines within minutes. An intermolecular hydride transfer process is the key step, and it occurs via overlap of the LUMO in the sulfonimidoyl cation and HOMO in the unactivated alkene, which was confirmed via control experiments with deuterated compounds. DFT calculations further demonstrated the concerted process involving formation of the S−C(sp3) bond and hydride transfer. Remarkably, abundant natural products and pharmaceuticals with multiple heteroatoms and sensitive functional groups have been subjected to the current linkage reaction to achieve various sulfoximine linkages, furnishing the basis for drug discovery and drug conjugation.
Dramatically Enhanced Reactivity of Fullerenes and Tetrazine towards the Inverse‐Electron‐Demand Diels–Alder Reaction inside a Porous Porphyrinic Cage
Authors: Dhamija Avinash , Gunnam Anilkumar , Yu Xiujun , Lee Hochan , Hwang In‐Chul , Ho Ko Young , Kim Kimoon
Published: September 2022

Inverse‐electron‐demand Diels–Alder reaction (IEDDA) between fullerenes and 1,2,4,5‐tetrazine generally requires harsh conditions and long reaction times due to their strong electron‐accepting nature. Herein, we report a dramatic enhancement in the reactivity of the fullerenes (C60/C70)‐tetrazine reaction inside a porous Zn‐porphyrinic cage (Zn‐PB) under sustainable conditions by installing a tetrazine‐based axle (LA) via metal‐ligand coordination bond, which modulates the cavity size to facilitate the encapsulation of fullerenes. Upon encapsulation, the close proximity of fullerenes and the tetrazine group of LA dramatically increase their reactivity towards the IEDDA reaction to form fullerene‐tetrazine adducts. Furthermore, the C60‐tetrazine adduct is rearranged upon hydration to a bent‐shaped C60‐pyrazoline adduct that can be released from the Zn‐PB cavity in the presence of excess LA, thus catalyzing the formation of C60‐pyrazoline adduct inside Zn‐PB without product inhibition.
Memory Effect in Thermoresponsive Proline‐based Polymers
Authors: Badreldin Mostafa , Le Scouarnec Rosanna , Lecommandoux Sebastien , Harrisson Simon , Bonduelle Colin
Published: September 2022

We report that synthetic polymers consisting of L‐proline monomer units exhibit temperature‐driven aggregation in water with unprecedented hysteresis. This protein‐like behavior is robust and governed by the chirality of the proline units. It paves the way to new processes, driven by either temperature or ionic strength changes, such as a simple “with memory” thermometer.
Target‐Triggered Formation of Artificial Enzymes on Filamentous Phage for Ultrasensitive Direct Detection of Circulating miRNA Biomarkers in Clinical Samples
Authors: Zeng Yan , Yue Hui , Cao Binrui , Li Yan , Yang Mingying , Mao Chuanbin
Published: September 2022

Integrating artificial enzymes onto nanostructures target‐ and site‐specifically is still a challenge. Here we show that target miRNAs trigger the formation of DNAzyme site‐specifically at the tip of filamentous phage for detecting miRNA biomarkers. Through an antibody‐modified oligonucleotide, the tip of the phage with magnetic nanoparticles on the sidewall captures a target miRNA, inducing the formation of DNAzyme that extends from the phage tip through a hybridization chain reaction. After magnetic separation, the resultant complex catalyzes a colorimetric reaction with the signal correlated to target concentrations, leading to the quantification of miRNAs with a detection limit of 5.0 fM, about 103 folds lower than the phage‐free approach. Our approach can differentiate miRNA mutants and quantify miRNA in human plasma, tumor cells, and tissues with high sensitivity, suggesting that the target‐triggered integration of enzymes and phages holds promise for searching for new catalysts.
Intramolecular Thiol‐ and Selenol‐Assisted Delivery of Hydrogen Sulfide
Authors: Hu Qiwei , Suarez S. Israel , Hankins Rynne A. , Lukesh John C.
Published: September 2022

Arylthioamides have been frequently employed to assess the chemical biology and pharmacology of hydrogen sulfide (H2S). From this class of donors, however, extremely low H2S releasing efficiencies have been reported and proper mechanistic studies have been omitted. Consequently, millimolar concentrations of arylthioamides are required to liberate just trace amounts of H2S, and via an unidentified mechanistic pathway, which obfuscates the interpretation of any biological activity that stems from their use. Herein, we report that H2S release from this valuable class of donors can be markedly enhanced through intramolecular nucleophilic assistance. Specifically, we demonstrate that both disulfide‐ and diselenide‐linked thioamides are responsive to biologically relevant concentrations of glutathione and release two molar equivalents of H2S via an intramolecular cyclization that significantly augments their rate and efficiency of sulfide delivery in both buffer and live human cells.
Discovery of a Thioxanthone–TfOH Complex as a Photoredox Catalyst for Hydrogenation of Alkenes Using p‐Xylene as both Electron and Hydrogen Sources
Authors: Kang Wen‐Jie , Li Bo , Duan Meng , Pan Guangxing , Sun Weiqiang , Ding Aishun , Zhang Yanbin , Houk K. N. , Guo Hao
Published: September 2022

Hydrogenation of alkenes is one of the most fundamental transformations in organic synthesis, and widely used in the petrochemical, pharmaceutical, and food industries. Although numerous hydrogenation methods have been developed, novel types of catalysis with new mechanisms and new hydrogen sources are still desirable. Thioxanthone (TX) is widely used in energy‐transfer photoreactions, but rarely in photoredox processes. Herein we show that a catalytic amount of TfOH as a co‐catalyst can tune the properties of TX to make it a photoredox catalyst with highly enhanced oxidative capability in the hydrogenation of carbonylated alkenes with the cheap petroleum industrial product p‐xylene serving as the hydrogen source. Deuterium can also be introduced by this method by using D2O as the D source. To the best of our knowledge, this is the first example of using p‐xylene as a hydrogen source.
Ag22 Nanoclusters with Thermally Activated Delayed Fluorescence Protected by Ag/Cyanurate/Phosphine Metallamacrocyclic Monolayers through In‐Situ Ligand Transesterification
Authors: Yuan Zhi‐Rui , Wang Zhi , Han Bao‐Liang , Zhang Cheng‐Kai , Zhang Shan‐Shan , Zhu Zhen‐Yu , Yu Jiu‐Hong , Li Tian‐Duo , Li Ying‐Zhou , Tung Chen‐Ho , Sun Di
Published: September 2022

The composition of protection monolayer exerts great influence on the molecular and electronic structures of atomically precise monolayer protected metal nanoclusters. Four isostructural Ag/cyanurate/phosphine metallamacrocyclic monolayer protected Ag22 nanoclusters are synthesized by kinetically controlled in‐situ ligand formation‐driven strategy. These eight‐electron superatomic silver nanoclusters feature an unprecedented interfacial bonding structure with diverse E‐Ag (E=O/N/P/Ag) interactions between the Ag13 core and metallamacrocyclic monolayer, and displays thermally activated delayed fluorescence (TADF), benefiting from their distinct donor‐acceptor type electronic structures. This work not only unmasks a new core‐shell interface involving cyanurate ligand but also underlines the significance of high‐electron‐affinity N‐heterocyclic ligand in synthesizing TADF metal nanoclusters. This is the first mixed valence Ag0/I nanocluster with TADF characteristic.
Spatial Well‐defined Bimetallic Two‐Dimensional Polymers with Single‐Layer Thickness for Electrocatalytic Oxygen Evolution Reaction
Authors: Fa Dejuan , Tao Yanhong , Pan Xin , Wang Dingjia , Feng Guangyuan , Yuan Jiangyan , Luo Qingqing , Song Yaru , Gao Xuejiao J. , Yang Ling , Lei Shengbin , Hu Wenping
Published: September 2022

Innovative bimetallic materials provide more possibilities for further improving the performance of oxygen evolution reaction (OER) electrocatalysts. However, it is still a great challenge to rationally design bimetallic catalysts because there is not a practical way to decouple the factors influencing the intrinsic activity of active sites from others, thus hindering in‐depth understanding of the mechanism. Herein, we provide a rational design of bimetallic Ni, Co two‐dimensional polymer model OER catalyst. The well‐defined architecture, identical density of active sites and monolayer characteristic allow us to decouple the intrinsic activity of active sites from other factors. The results confirmed that the relative position and local coordination environment has significant effect on the synergistic effect of the bimetallic centres. The highest electrocatalytic activity with the turnover frequency value up to 26.19 s−1 was achieved at the overpotential of 500 mV.