bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct conversion detectors: The effect of incomplete charge collection on detective quantum efficiency
Authors: Mainprize James G. , Hunt Dylan C. , Yaffe Martin J.
Published: July 2002

Direct conversion detectors offer the potential for very high resolution and high quantum efficiency for x‐ray imaging, however, variations in signal can arise due to incomplete charge collection. A charge transport model was developed to describe the signal and noise resulting from incomplete charge collection. This signal to noise ratio (SNR) reduction was incorporated into the cascaded systems model for a simple x‐ray detector. A new excess noise factor, (termed the collection noise factor) is introduced to describe the reduction in detective quantum efficiency (DQE). The DQE is proportional to the product of the quantum efficiency and the collection noise factor. If the trapping cross sections for electrons and holes are very different, and if the detector is biased improperly, the collection noise factor can drop to as low as 50%. In addition, the signal loss due to incomplete charge collection will reduce the DQE in the presence of added noise. Because of this, the DQE generally does not continue to improve with greater detector thickness. The collection noise factor and DQE are predicted for CdZnTe, and Se. The optimization of detector thickness should be based not only on quantum efficiency but also on the charge collection statistics, which are influenced by bias field and polarity.
Magnetic resonance quantification of the myocardial perfusion reserve with a Fermi function model for constrained deconvolution
Authors: Jerosch‐Herold Michael , Wilke Norbert , Stillman Arthur E. , Wilson Robert F.
Published: July 2002

The myocardial perfusion reserve, defined as the ratio of hyperemic and basal myocardial blood flow, is a useful indicator of the functional significance of a coronary artery lesion. Rapid magnetic resonance (MR) imaging for the noninvasive detection of a bolus‐injected contrast agent as a MR tracer is applied to the measurement of regional tissue perfusion during rest and hyperemia, in patients with microvascular dysfunction. A Fermi function model for the distribution of tracer residence times in the myocardium is used to fit the MR signal curves. The myocardial perfusion reserve is calculated from the impulse response amplitudes for rest and hyperemia. The assumptions of the model are tested with Monte Carlo simulations, using a multiple path, axially distributed mathematical model of blood tissue exchange, which allows for systematic variation of blood flow, vascular volume, and capillary permeability. For a contrast‐to‐noise ratio of 6:1, and over a range of flows from 0.5 to 4.0 ml/min per g of tissue, the ratio of the impulse response amplitudes for hyperemic and basal flows is linearly proportional to the ratio of model blood flows, if the mean transit time of the input function is shorter than approximately 9 s. The uncertainty in the blood flow reserve estimates grows both at low and high flows. The predictions of the Monte Carlo simulations agree with the results of MR first pass studies in patients without significant coronary artery lesions and microvascular dysfunction, where the perfusion reserve in the territory of the left anterior descending coronary artery (LAD) correlates linearly with the intracoronary Doppler ultrasound flow reserve in the LAD in agreement with previous PET studies.
Self-adjoint extensions of operators and the teaching of quantum mechanics
Authors: Bonneau Guy , Faraut Jacques , Valent Galliano
Published: July 2002

For the example of the infinite well potential, we point out some paradoxes which are solved by a careful analysis of what is a truly self-adjoint operator. We then describe the self-adjoint extensions and their spectra for the momentum and the Hamiltonian operators in different settings. Additional physical requirements such as parity, time reversal, and positivity are used to restrict the large class of self-adjoint extensions of the Hamiltonian.
Photoacoustic waves excited in liquids by fiber-transmitted laser pulses
Authors: Paltauf G. , Schmidt-Kloiber H. , Frenz M.
Published: July 2002

The acoustic wave field generated in front of a submerged fiber tip by short laser pulses is theoretically and experimentally studied by fast imaging and optical pressure measurements. It is shown that the finite size of the fiber causes strong tensile stress leading to cavitation. Depending on the absorption coefficient of the laser radiation, cavitation-induced bubble formation occurs inside (low absorption) or outside (high absorption) the volume of heat deposition. The results are used to characterize the cavitation bubble formation mechanisms and to predict possible consequences for applications of fiber-guided short-pulsed laser sources in medicine.
Classification of dolphin echolocation clicks by energy and frequency distributions
Authors: Houser D. S. , Helweg D. A. , Moore P. W.
Published: July 2002

Dolphins demonstrate an adaptive control over echolocation click production, but little is known of the manner or degree with which control is exercised. Echolocation clicks (N∼30 000) were collected from an Atlantic bottlenose dolphin (Tursiops truncatus) performing object discrimination tasks in order to investigate differential click production. Seven categories of clicks were identified using the spectral conformation and relative position of −3 and −10 dB peaks. A counterpropagation network utilizing 16 inputs, 50 hidden units, and 8 output units was trained to classify clicks using the same spectral variables. The network classified novel clicks with 92% success. Additional echolocation clicks (N>24 000) from two other dolphins were submitted to the network for classification. Classified echolocation clicks were analyzed for animal specific differences, changes in predominant click type within click trains, and task-related specificity. Differences in animal and task performance may influence click type and click train length.
Variations in the feedback of hearing aids
Authors: Hellgren Johan , Lunner Thomas , Arlinger Stig
Published: July 2002

Variations in the loop response of hearing aids caused by jaw movements, variations in acoustics outside the ear, and variations of vent size have been identified. Behind The Ear (BTE) and In The Ear Canal (ITEC) hearing aids were considered. The largest variations among the variations of the acoustics outside the ear, except when the hearing aid was partly removed, were found with the ITEC when a telephone set was placed by the ear. The variations of the loop response caused by changes in vent size were compared with the variations of a theoretical model of the feedback path. The theoretical model was also used to compare the feedback of different designs of the vent that gives the same acoustic impedance at low frequencies. The calculated feedback was less with the short vents (12 mm) than the long vents (24 mm).
A study on ultrasonic solid horns for flexural mode
Authors: Zhou Guangping , Li Mingxuan
Published: July 2002

The transfer matrix method is introduced into the analysis of ultrasonic flexural solid horns. The frequency and magnification equations of a horn are derived by using the transfer matrix method. Analyzed are the characteristics of three types of circular cross-section horns: exponent, cone, and catenary. The results are partly verified experimently.
Entrance Flows of Non-Newtonian Fluids
Authors: Duda J. L. , Vrentas J. S.
Published: July 2002

The creeping flow of a Powell-Eyring fluid through a sudden tubular contraction is considered, and finite difference solutions of the vorticity transport and stream function equations are obtained for a range of contraction ratios, fluid properties, and apparent shear rates. Calculated axial velocity profiles, excess pressure drops, and separation effects at the 90° corner of the contraction are compared with theoretical results for Newtonian fluids and with experimental data for polymer solutions and melts. The results indicate a strong influence of nonlinear viscous effects on the magnitude of the excess entrance pressure loss and on the extent of the circulation pattern at the corner of the contraction.
On the Interface Deformation in the Stratified Two-Phase Flow of Viscoelastic Fluids
Authors: Khan Ashfaq A. , Dae Han Chang
Published: July 2002

Experimental and theoretical studies were carried out to investigate the mechanism of the interface deformation in the stratified two-phase flow of viscoelastic fluids through a rectangular duct. For the experimental study, a transparent test channel was constructed to permit visual observations, from the direction perpendicular to flow, on the interface formed when two incompatible molten polymers flow between two parallel planes. Extrudate samples were also collected, and the interface shape of the extrudate cross section was examined. For the theoretical study, using the Coleman-Noll second-order fluid as the constitutive equation, an approximate solution of the equations of motion was obtained numerically. The movement of the interface from the initially flat position was determined with the use of the normal stress continuity condition across the interface. The computed results show that the more viscous component tends to push into the less viscous component, consistent with experimental observation. It has been shown that the viscosity difference between the two components predominates over the elasticity ratio in determining the interface shape in stratified two-phase flow.
Separation of Elastic and Shear Thinning Effects in the Capillary Rheometer
Authors: Boger D. V. , Binnington R.
Published: July 2002

The influence of elasticity in the absence of shear thinning on the total extra losses (end correction) in a capillary rheometer is investigated. Fluids with the unusual characteristic of being elastic but not shear thinning are used. Independent property measurements made with an R16 Weissenberg rheogoniometer are used to quantify the behavior of these fluids. The end correction in the absence of shear thinning is found to be constant with shear rate in the lower shear rate region and to decrease slightly at higher shear rates. The intercept of the end correction shear rate plot is significantly higher than the Newtonian fluid value and is shown to be directly related to the fundamental elastic properties of the fluid. The end correction is measured for a material which exhibits the properties of a second-order fluid in steady shear. The influence of shear thinning in the presence of fluid elasticity is found to increase the end correction. A method for correlating end correction data is proposed which is consistent with the results obtained by other investigators.
A New Approach to Simplifying and Harmonizing Cancer Clinical Trials—Standardizing Eligibility Criteria
Authors: Gerber David E. , Singh Harpreet , Larkins Erin , Ferris Andrea , Forde Patrick M. , Selig Wendy , Basu Roy Upal
Published: August 2022

Importance

Clinical trial sponsors rely on eligibility criteria to control the characteristics of patients in their studies, promote the safety of participants, and optimize the interpretation of results. However, in recent years, complex and often overly restrictive inclusion and exclusion criteria have created substantial barriers to patient access to novel therapies, hindered trial recruitment and completion, and limited generalizability of trial results. A LUNGevity Foundation working group developed a framework for lung cancer clinical trial eligibility criteria. The goals of this framework are to (1) simplify eligibility criteria, (2) facilitate stakeholders’ (patients, clinicians, and sponsors) search for appropriate trials, and (3) harmonize trial populations to support intertrial comparisons of treatment effects.

Observations

Clinicians and representatives from the pharmaceutical industry, the National Cancer Institute, the US Food and Drug Administration (FDA), the European Medicines Agency, and the LUNGevity Foundation undertook a process to identify and prioritize key items for inclusion in trial eligibility criteria. The group generated a prioritized library of terms to guide investigators and sponsors in the design of first-line, advanced non–small cell lung cancer clinical trials intended to support marketing application. These recommendations address disease stage and histologic features, enrollment biomarkers, performance status, organ function, brain metastases, and comorbidities. This effort forms the basis for a forthcoming FDA draft guidance for industry.

Conclusions and Relevance

As an initial step, the recommended cross-trial standardization of eligibility criteria may harmonize trial populations. Going forward, by connecting diverse stakeholders and providing formal opportunity for public input, the emerging FDA draft guidance may also provide an opportunity to revise and simplify long-standing approaches to trial eligibility. This work serves as a prototype for similar efforts now underway for other cancers.
A Lived Experience of Breast Cancer as a Scholar of Intersectionality
Authors: Tredway Kristi
Published: August 2022

This essay discusses how a diagnosis of breast cancer changed the author’s perspective on intersectionality, the interpersonal, disciplinary, structural, and especially cultural expectations of persons in marginalized social groups.
Association of Stapedotomy Volume and Patient Sex With Better Outcome
Authors: Cahill Gabrielle , Wang Annette A. , Lee Kyungmi , Sakagami Masaharu , Welling D. Bradley , Stankovic Konstantina M.
Published: August 2022

This cross-sectional study evaluates demographic characteristics, surgical characteristics, and audiometric data associated with closure of the air-bone gap to less than 10 dB or 15 dB.
Influence of Social Support, Financial Status, and Lifestyle on the Disparity Between Inflammation and Disability in Rheumatoid Arthritis
Authors: Gwinnutt James M. , Norton Sam , Hyrich Kimme L. , Lunt Mark , Combe Bernard , Rincheval Nathalie , Ruyssen‐Witrand Adeline , Fautrel Bruno , McWilliams Daniel F. , Walsh David A. , Nikiphorou Elena , Kiely Patrick D. W. , Young Adam , Chipping Jacqueline R. , MacGregor Alex , Verstappen Suzanne M. M.
Published: August 2022

Objective

To investigate how social support, financial status, and lifestyle influence the development of excess disability in rheumatoid arthritis (RA).

Methods

Data were obtained from the Étude et Suivi des Polyarthrites Indifférenciées Récentes (ESPOIR) cohort study of people with RA. A previous analysis identified groups with similar inflammation trajectories but markedly different disability over 10 years; those in the higher disability trajectory groups were defined as having “excess disability.” Self‐reported data regarding contextual factors (social support, financial situation, lifestyle) were obtained from participants, and they completed patient‐reported outcome measures (pain, fatigue, anxiety, depression) at baseline. The direct effect of the contextual factors on excess disability and the effect mediated by patient‐reported outcome measures were assessed using structural equation models. Findings were validated in 2 independent data sets (Norfolk Arthritis Register [NOAR], Early Rheumatoid Arthritis Network [ERAN]).

Results

Of 538 included ESPOIR participants (mean age ± SD 48.3 ± 12.2 years; 79.2% women), 200 participants (37.2%) were in the excess disability group. Less social support (β = 0.17 [95% confidence interval (95% CI) 0.08, 0.26]), worse financial situation (β = 0.24 [95% CI 0.14, 0.34]), less exercise (β = 0.17 [95% CI 0.09–0.25]), and less education (β = 0.15 [95% CI 0.06, 0.23]) were associated with excess disability group membership; smoking, alcohol consumption, and body mass index were not. Fatigue and depression mediated a small proportion of these effects. Similar results were seen in NOAR and ERAN.

Conclusion

Greater emphasis is needed on the economic and social contexts of individuals with RA at presentation; these factors might influence disability over the following decade.
Discovery of a 2D Hybrid Silver/Antimony‐Based Iodide Double Perovskite Photoferroelectric with Photostrictive Effect and Efficient X‐Ray Response
Authors: Wang Chang‐Feng , Li Haojin , Ji Qun , Ma Chuang , Liu Lang , Ye Heng‐Yun , Cao Bo , Yuan Guoliang , Lu Hai‐Feng , Fu Da‐Wei , Ju Ming‐Gang , Wang Jinlan , Zhao Kui , Zhang Yi
Published: August 2022

2D hybrid halide double perovskites (HHDPs) have been demonstrated to be a promising alternative to conventional lead‐based halide perovskites as a new system of photoferroelectrics, due to their unique characteristics of environmental friendliness, favorable stability, and fascinating optoelectronic properties. Herein, for the first time, a 2D iodide double perovskite photoferroelectric is reported based on Ag/Sb ions, (4,4‐DFPD)4AgSbI8 (4,4‐DFPD = 4,4‐difluoropiperidinium), which possesses a high Curie temperature of 414 K (above BaTiO3), a large spontaneous polarization of 9.6 μC cm−2, ferroelectric photovoltaic effect, and photostrictive effect. Notably, to the best of the authors’ knowledge, the discovery of photostriction in HHDP photoferroelectrics is unprecedented. Moreover, (4,4‐DFPD)4AgSbI8 exhibits an impressive X‐ray responsivity, with a sensitivity as high as 704.8 μC Gyair−1 cm−2 at 100 V bias and a detection limit as low as 0.36 μGyair s−1 at 10 V bias, both of which outperform the current all HHDP photoferroelectrics. This work enriches the photoferroelectric family, and proves that Ag/Sb‐based HHDP photoferroelectrics are a promising candidate for the next‐generation optoelectronic devices.
Unified Therapeutic‐Prophylactic Vaccine Demonstrated with a Postoperative Filler Gel to Prevent Tumor Recurrence and Metastasis
Authors: Cao Dinglingge , Guo Wen , Cai Caiyun , Tang Jingyu , Rao Weihan , Wang Yang , Wang Yaoben , Yu Lin , Ding Jiandong
Published: August 2022

Although surgical resection is currently the first choice of clinical treatment for most solid tumors, postoperative cancer recurrence and metastasis are the main causes of mortality. Herein, the authors aim to enable immunotherapy consistent with surgery. To this end, the term “therapeutic‐prophylactic vaccine (TPV)” is suggested, and a TPV‐gel is developed as a filler after resection of ≈90% tumor to eradicate residue tumor (therapeutic) and prevent recurrence and metastasis (prophylactic). The TPV‐gel is made of the matrix of blends of two poly(d,l‐lactide‐co‐glycolide)‐b‐poly(ethylene glycol)‐b‐poly(d,l‐lactide‐co‐glycolide) block copolymers and the bioactive substances of inorganic calcium salt and organic R837. The aqueous system of polymeric block blends undergoes a sol‐gel transition upon heating and thus leads to an injectable hydrogel filling the resection site; loading of CaCl2 and CaCO3 results in the release of calcium ions out of the TPV‐gel, which induces immunogenic cell death of the residual tumor cells; R837, an immune adjuvant, is dispersed in the TPV‐gel as microcrystal and can be released to awaken immune responses. The therapeutic and prophylactic efficacy of this TPV‐gel is confirmed in vitro and in vivo using a postoperative breast 4T1 mice model.
Biomimetic Aggregation‐Induced Emission Nanodots with Hitchhiking Function for T Cell‐Mediated Cancer Targeting and NIR‐II Fluorescence‐Guided Mild‐Temperature Photothermal Therapy
Authors: Yang Xing , Yang Ting , Liu Qiqi , Zhang Xiuwen , Yu Xinghua , Kwok Ryan T. K. , Hai Luo , Zhang Pengfei , Tang Ben Zhong , Cai Lintao , Gong Ping
Published: August 2022

Photothermal therapy (PTT) holds potential as an alternative approach for effective cancer treatment since it exerts minimal side effects on normal tissues. However, the photothermal stimulation increases the expression of heat shock protein (HSP) in tumor cells, rendering the tumor cells insensitive to heat and thus constraining the effects of PTT. In this study, biomimetic aggregation‐induced emission (AIE) photothermal agents with hitchhiking ability (DC@BPBBT dots) are developed by coating the nanoaggregates of the NIR AIE polymeric photothermal agents with dendritic cell (DC) membranes. Notably, the inner nanoaggregate (BPBBT dots) holds bright second‐window near infrared (NIR‐II) fluorescence (quantum yield of up to 3.47%) and a high photothermal conversion performance (photothermal conversion efficiency of up to 30.5%), and the outer cell membrane can facilitate the hitchhiking of DC@BPBBT dots on endogenous T cells and enhance the tumor delivery efficiency by about 1.2 times. Furthermore, DC@BPBBT dots can activate and stimulate T cells in vivo to secrete cytokine tumor necrosis factor α (TNF‐α), which can reduce the expression of heat shock protein 70 (HSP70) to render tumor cells more sensitive to heat. This study not only provides an alternative heat shock protein inhibition strategy based on immune cell interactions but also provides a hitchhike approach for drug delivery in cancer photothermal immunotherapy.
Bottom‐Up Growth of Graphene Nanospears and Nanoribbons
Authors: Sun Haibin , Liu Fengning , Zhang Leining , Ko Kyungmin , McLean Ben , An Hao , Kim Sungkyun , Huang Ming , Willinger Marc‐Georg , Ruoff Rodney S. , Suh Joonki , Wang Zhu‐Jun , Ding Feng
Published: August 2022

One dimensional graphene nanostructures are one of the most promising materials for next generation electronics. Here, the chemical vapor depostion growth of graphene nanoribbons (GNRs) and graphene nanospears (GNSs) on a copper surface is reported. The growth of GNRs and GNSs is enabled by a vapor–liquid–solid (VLS) mechanism guided by on‐surface propagation of a liquid Cu‐Si catalyst particle. The slow lateral growth and the fast VLS vertical growth give rise to spear head‐shaped GNSs. In situ observations further confirm that the lateral graphene growth can be completely suppressed and thus GNRs are grown. The synthesized field effect transistor (FET) devices show that the GNRs and GNSs have high carrier mobilities of ≈2000 cm2 V−1 s−1. Both FET and Kelvin probe force microscopy measurements confirm that the Fermi levels of the synthesize GNSs shift downward from the wide part to the tip is strongly p‐doped. These findings yield key insights into the growth mechanism of graphene and open a door for achieving a facile and scalable method of synthesizing free standing GNRs and GNSs and their applications, such as the Fermi‐level tunable devices.
Organic Neuroelectronics: From Neural Interfaces to Neuroprosthetics
Authors: Go Gyeong‐Tak , Lee Yeongjun , Seo Dae‐Gyo , Lee Tae‐Woo
Published: August 2022

Requirements and recent advances in research on organic neuroelectronics are outlined herein. Neuroelectronics such as neural interfaces and neuroprosthetics provide a promising approach to diagnose and treat neurological diseases. However, the current neural interfaces are rigid and not biocompatible, so they induce an immune response and deterioration of neural signal transmission. Organic materials are promising candidates for neural interfaces, due to their mechanical softness, excellent electrochemical properties, and biocompatibility. Also, organic nervetronics, which mimics functional properties of the biological nerve system, is being developed to overcome the limitations of the complex and energy‐consuming conventional neuroprosthetics that limit long‐term implantation and daily‐life usage. Examples of organic materials for neural interfaces and neural signal recordings are reviewed, recent advances of organic nervetronics that use organic artificial synapses are highlighted, and then further requirements for neuroprosthetics are discussed. Finally, the future challenges that must be overcome to achieve ideal organic neuroelectronics for next‐generation neuroprosthetics are discussed.
Roll‐To‐Roll Fabrication of Zero‐Volume‐Expansion Lithium‐Composite Anodes to Realize High‐Energy‐Density Flexible and Stable Lithium‐Metal Batteries
Authors: Luo Chao , Hu Hong , Zhang Tian , Wen Shujing , Wang Ruo , An Yanan , Chi Shang‐Sen , Wang Jun , Wang Chaoyang , Chang Jian , Zheng Zijian , Deng Yonghong
Published: August 2022

The lithium (Li)‐metal anode offers a promising solution for high‐energy‐density lithium‐metal batteries (LMBs). However, the significant volume expansion of the Li metal during charging results in poor cycling stability as a result of the dendritic deposition and broken solid electrolyte interphase. Herein, a facile one‐step roll‐to‐roll fabrication of a zero‐volume‐expansion Li‐metal‐composite anode (zeroVE‐Li) is proposed to realize high‐energy‐density LMBs with outstanding electrochemical and mechanical stability. The zeroVE‐Li possesses a sandwich‐like trilayer structure, which consists of an upper electron‐insulating layer and a bottom lithiophilic layer that synergistically guides the Li deposition from the bottom up, and a middle porous layer that eliminates volume expansion. This sandwich structure eliminates dendrite formation, prevents volume change during cycling, and provides outstanding flexibility to the Li‐metal anode even at a practical areal capacity over 3.0 mAh cm−2. Pairing zeroVE‐Li with a commercial NMC811 or LCO cathode, flexible LMBs that offer a record‐breaking figure of merit (FOM, 45.6), large whole‐cell energy density (375 Wh L−1, based on the volume of the anode, separator, cathode, and package), high‐capacity retention (> 99.8% per cycle), and remarkable mechanical robustness under practical conditions are demonstrated.
Ultrasensitive Refractive Index Sensing Based on the Quasi‐Bound States in the Continuum of All‐Dielectric Metasurfaces
Authors: Hsiao Hui‐Hsin , Hsu Yi‐Chien , Liu Ai‐Yin , Hsieh Jou‐Chun , Lin Yu‐Hsin
Published: August 2022

Symmetry‐protected quasi‐bound states in the continuum (BIC) controlled by metasurfaces with broken in‐plane symmetry are widely exploited to achieve highly surface‐sensitive and spectrally sharp resonances for nanophotonic biosensors. Through the engineering of silicon‐based asymmetric nanobar pairs, a quasi‐BIC mode is excited showing a dominant toroidal dipole (TD) and electric quadrupole (EQ) resonant feature in the near‐infrared and performs ultrahigh sensitivity in the refractometric monitoring of local environment changes. Contrary to the typical electric and magnetic Mie‐type resonances of dielectric resonators with the enhanced field mostly inside the resonator volume, the TD‐EQ quasi‐BIC mode is found to exhibit strong and tightly confined optical fields at the surface of tilted nanobar pairs, and its refractive‐index (RI) sensitivity can be dramatically increased for nanopillars with larger aspect‐ratio. The measured (simulated) sensitivity and figure of merit for nanobar pairs with a height of 450 nm reach 608 nm/RIU and 46 (612 nm/RIU and 85), respectively. Such ultrahigh sensitive all‐dielectric platform can be fabricated through complementary metal‐oxide‐semiconductor compatible process and is promising for on‐chip integration and sensor miniaturization to a wide range of diagnostic applications.
Sellotape Exfoliated Layered Quasi‐2D Perovskite Thin Film for Efficient Light‐Emitting Diodes
Authors: Liu Yanliang , Chen Fang , Jiang Zhengyan , Li Yang , Zhou Xianyong , Wu Jiawen , Chen Shi , Zhang Luozheng , Li Yaru , Liu Chang , Bae Sang‐Hoon , Lee Bo Ram , Huang Boyuan , Wang Xingzhu , Lee Yun Seog , Kim Jeehwan , Park Sung Heum , Yu Xue‐Feng , Xu Baomin
Published: August 2022

In 2004, K. S. Novoselov and A. K. Geim et al. have used sellotape to peel off the layered 2D graphite, and successfully obtained few‐layer thin graphene. Inspired by this, herein, the sellotape is initially used to exfoliate the layered Ruddlesden–Popper (RP) quasi‐2D perovskite film for efficient light‐emitting diodes application. The top surface layer of quasi‐2D perovskite film is mechanically peeled off by the sellotape without damaging the crystalline region below, which minimizes the poor conductivity issue of quasi‐2D perovskite film owing to the decreased defect density. Moreover, the exfoliated quasi‐2D film exhibits low charge traps density and enhanced energy transfer from low‐dimensional to high‐dimensional domains due to the elimination of surface defective layer and the recrystallization of quasi‐2D perovskite crystal, leading to high photoluminescence quantum yield (PLQY) up to 83.2%. Subsequently, an efficient perovskite light‐emitting diode based on the exfoliated quasi‐2D perovskite thin film is achieved with high current efficiency of 46.0 cd m−2 and excellent external quantum efficiency (EQE) up to 14.8%.
A Hole Transport Layer‐Free, More Thermally Stable, Self‐Powered CH3NH3PbBr3‐Based Multiband Imaging Photodetector with Novel Topological Insulator Bi2Te3 Electrodes
Authors: Liu Shuo , Jiao Shujie , Lu Hongliang , Yang Song , Zhao Yue , Wang Dongbo , Gao Shiyong , Wang Jinzhong , Zhao Liancheng , Li Yongfeng
Published: August 2022

The conventional forward‐structure perovskite devices typically employ organic small molecule and noble metal as the hole transport layer (HTL) and electrode, respectively, which results in poor thermal stability and high costs. To address this issue, a HTL‐free CH3NH3PbBr3 photodetector with the topological insulator bismuth telluride (Bi2Te3) electrode is developed. The device exhibits apparent sensitivity to ultraviolet/visible waveband with a peak responsivity of 97.5 mA W−1, switching ratio exceeding 104, and the detectivity is up to 1012 Jones without external bias. These figures‐of‐merit are distinguished among the reported CH3NH3PbBr3‐based devices. Impressively, this device presents a light power‐modulated near‐infrared detection thanks to the contribution of topological insulator Bi2Te3, and the underlying mechanism is elaborated in‐depth. Moreover, the novel device improves significantly in short and long‐time thermal stability. Benefiting from these distinguished properties, the photodetector is imaging‐capable and a 50 × 50 pixels’ pattern with satisfactory resolution has been achieved. This work highlights the application of topological insulators on the HTL‐free perovskite photodetector, offering new insights for the future commercialization of perovskite devices.
Quantum Linear Magnetoresistance and Nontrivial Berry Phase in High‐Mobility Elemental Tellurium
Authors: Ji Yi , Wang Bin , Li Chushan , Zuo Huakun , Yi Enkui , Jin Gangjian , Guo Donghui , Shen Bing , Zhong Dingyong , Wang Huichao
Published: August 2022

Elemental Tellurium (Te) is an important p‐type semiconductor with wide practical applications. It is currently of great interest as a chiral crystal with broken inversion and mirror symmetries, and its topological nature is under active discussion. Here the Shubnikov–de Haas (SdH) oscillations with a nontrivial π Berry phase and the quantum linear magnetoresistance (MR) in as‐synthesized high‐mobility Te single crystals are reported. The vapor transport grown Te shows a hollow hexagonal prism structure with tunable carrier density and high mobility of about 1000 cm2 V−1 s−1 at low temperature. For concentration p > 1017 cm−3, the conspicuous SdH oscillations map out the dumbbell‐shaped Fermi surface and the long‐standing peculiar amplitude change with varying magnetic field orientation is explained by careful quantitative analyses. Pulsed magnetic field measurements up to 57 T disclose a quantum linear MR beyond the quantum limit and the Landau fan diagram clearly reveals a topologically nontrivial π Berry phase. This work paves way for the synthesis of high‐mobility Te structures and sheds light onto the intrinsic nontrivial topology of the attractive elemental substance.
Off‐Axis Vortex‐Induced Asymmetric Spin‐Dependent Splitting
Authors: Zhou Xiang , Ding Yiping , Tu Jialong , Zhang Jing , Deng Dongmei
Published: August 2022

A simple and effective method to control the asymmetric spin splitting flexibly by introducing off‐axis vortex beams is reported here. Unlike the conventional spin Hall effect of light, both the value and the sign of the right‐ and left‐handed circularly polarized components can be manipulated individually by modulating the off‐axis vortex's position. Significantly, the in‐plane shifts occur when the vortex position x0 is non‐zero. In addition, it is found that this asymmetric splitting increases with increase in the topological charge. This flexibly adjustable asymmetric spin splitting provides the possibility to accelerate the development of nano‐photonic devices.
Effect of compatibilizer on the structure and property of polycarbonate/polypropylene alloys
Authors: Yu Xingxing , Ren Jifu , He Jingwei , Su Long , Liu Fang
Published: August 2022

Polycarbonate/Polypropylene (PC/PP) alloy is a typical thermodynamically incompatible system. In this work, ethylene‐methyl acrylate copolymer (EMA), methoxamine hydrochloride‐grafted POE (POE‐g‐MAH), ethylene‐butyl acrylate‐glycidyl methacrylate copolymer (EAY), a self‐made compatibilizer (PPM‐g‐GMA) of a mixture of glycidyl methacrylate grafted PP (PP‐g‐GMA) and glycidyl methacrylate‐grafted POE (POE‐g‐GMA) were selected as compatibilizer to prepare PC/PP alloys with the mass ratio of 65:30. Systematical studies of compatibilizer type, content and its effects on microstructure, mechanical properties, dielectric properties, dielectric properties and dynamic rheological properties have been carried out in this PC/PP alloys. The results demonstrated that all the compatibilizers in this article resulted in an effective improvement of the compatibility of PC/PP alloys, and the self‐made compatibilizer of PPM‐g‐GMA exhibited a significant improvement over the other three compatibilizers in notched izod impact strength, tensile strength, and bending strength. In addition, a relative low dielectric constants and dielectric losses under 2.5 GHz electric field could be obtained with the assistance of POE‐g‐MAH and PPM‐g‐GMA, indicating its possible application in dielectric materials.
Fatty acid modified cellulose: Preparation and application as green multi‐functional additive in a tyre tread formulation
Authors: Chowdhury Soumya Ghosh , Ghosh Sreedip , Pal Abhijit , Bhattacharyya Sanjay Kr. , Mukhopadhyay Rabindra
Published: August 2022

The increasing demand for biomass‐derived material and its usage in different forms in various commercial applications has become a need for sustainability. In this context, cellulose, the most abundant biodegradable material is modified (FAC) and used in tyre tread formulation. The potential of FAC is appraised against the lubricating nature of process oil due to its restricted usage for the presence of toxic polycyclic aromatic materials. In addition to that, Silane coupling agent is also replaced by FAC to assess its potency as a coupling agent. Multi‐functional nature of FAC is evaluated through morphological, rheological, physicomechanical, and dynamic‐mechanical means. Total replacement of oil with FAC has induced ~30–40% improvement in static modulus across elongation %age. Furthermore, improvement in grip properties (6%) along with a reduction in hysteresis loss (11%) is also portrayed by the composite having a complete substitution of oil by FAC. The efficacy of FAC as a potential replacement for SCA is also evaluated in this study. Replacement of 66% of SCA along with the complete substitution of oil with FAC has depicted comparable physicomechanical, dynamic as well as flow behavior with respect to the reference one. The introduction of fibrous structure along with intermolecular covalent bonding has reinforced FAC with multifunctional behavior. Thus, this multi‐functional behavior of FAC (reinforcing, dispersing, and coupling) can easily be applied in commercial tyre formulation facilitating a breakthrough in cheap and high‐performance biomass‐derived rubber composite.
Sustainability assessment of strategic asset management decisions on municipal water infrastructure systems: Framework and application
Authors: Mohammadifardi Hamed , Knight Mark , Unger Andre
Published: August 2022

Developing socially acceptable, environmentally friendly, and financially viable asset management plans (AMPs) is a major challenge for water and wastewater utilities and calls for a comprehensive Sustainability Assessment (SA). This paper proposes a novel framework that applies System Dynamics and Life Cycle Assessment tools to evaluate the long‐term sustainability of strategic asset management decisions for water and wastewater infrastructure systems. The merit of the proposed framework in dealing with the non‐linearity and dynamic behavior of the socio‐economic systems and its utility for SA of strategic asset management decisions are demonstrated in a case study of a Wastewater Collection (WWC) network system. Furthermore, the significant importance of population growth and urban densification policies in sustainability of AMP are highlighted by comparing four alternative scenarios of (1) 100% urban densification, (2) 0% urban densification, (3) 50% densification, and (4) no population growth in the case study. The results of the case study show that the greenhouse gas emission, operational and capital expenses, and bill burden of WWC and treatment services significantly reduce with urban densification.
Prüfverfahren zur Bestimmung der Trittschalldämmung von Balkon‐Anschlusselementen
Authors: Heidemann Lucas , Scheck Jochen , Zeitler Berndt
Published: August 2022

Für die thermische Trennung von Balkonen und Laubengängen von der Fassade sind bewehrte Anschlusselemente Stand der Technik. Diese Elemente beeinflussen die Trittschallübertragung und sind somit für die schalltechnische Planung von Bedeutung. Im Rahmen von Forschungsarbeiten an der HFT Stuttgart wurde ein Labor‐Prüfverfahren zur schalltechnischen Kennzeichnung solcher Anschlusselemente entwickelt. Der relativ kompakte Prüfaufbau besteht aus einem Balkon, der über das Anschlusselement mit einer Decke verbunden ist. Anhand von Körperschallmessungen wird die Trittschallminderung in Analogie zu Deckenauflagen, bzw. die Trittschallpegeldifferenz als Einfügungsdämmung mit Bezug auf die durchbetonierte Situation bestimmt. Beide Kenngrößen können für den Produktvergleich und die Prognose der Trittschallübertragung im Gebäude nach DIN EN ISO 12354‐2 verwendet werden. In diesem Beitrag wird das Prüfverfahren vorgestellt und anhand von Finite‐Elemente‐Simulationen validiert.
Vordimensionierung von Lüftungsöffnungen in Doppelfassaden
Authors: Friedrich Matthias , Schweers Klaus , Wellershoff Frank
Published: August 2022

Doppelfassaden verbessern den Schallschutz bei natürlicher Fassadenlüftung und bieten der Verschattung im Fassadenzwischenraum (FZR) einen Schutz vor hohen Windlasten. Bezüglich der natürlichen Lüftung ist jedoch zu beachten, dass die Luftströmungen zwei Fassadenebenen passieren müssen und die Luftwechselzahl nicht mit den Annahmen für einschalige Fassaden geplant werden kann. Die potenziell höheren Temperaturen im Fassadenzwischenraum erfordern zudem eine besondere Beachtung bei der Planung des sommerlichen Wärmeschutzes. An zehn Gebäuden in Hamburg mit Korridor‐Doppelfassaden und Kastenfenster‐Doppelfassaden wurden Klimadaten erfasst und Luftwechselmessungen vorgenommen. Anhand dieser Daten wurde ein Berechnungsansatz des Außenluftwechsels erstellt und in transienten thermischen Gebäudesimulationen angewandt. Erstellt wurde eine Methode, mit der in frühen Planungsphasen schnell und ohne Softwareanwendung die erforderliche Größe der Lüftungsöffnungen bestimmt werden kann.
Einsatz von Softwaretools am FG Bauphysik der Universität Kassel mit exemplarischen Aufgaben – Serie: Gebäudesimulation und Berechnungstools in der Lehre
Authors: Maas Anton , Vukadinovic Mario , Klauß Swen
Published: August 2022

Diese Artikelserie stellt den Einsatz von Computerprogrammen in der Hochschullehre der Bauphysik und Gebäudetechnik für Architekten und Bauingenieure vor.

Das Fachgebiet Bauphysik (Fachbereich Architektur Stadtplanung Landschaftsplanung) der Universität Kassel bietet im Bereich der Lehre Vorlesungen und Seminare primär für Architekturstudent:innen im Bachelor und Master an. Die Veranstaltungen sind meist auch für Student:innen der Ingenieurwissenschaften an der Universität Kassel belegbar. Je nach Studiengang und Abschluss werden Softwareprogramme abgestuft angewendet.
Wissenstransfer im Stahlbeton‐Bogenbrückenbau der 1930er‐Jahre
Authors: Pelke Eberhard , Kurrer Karl‐Eugen
Published: August 2022

Ab Mitte der 1920er‐Jahre fand der Stahlbeton auch im Großbrückenbau zu der ihm eigenen Konstruktionssprache. Dies wird im Bau von weitgespannten Bogenbrücken aufgezeigt, die in der Mitte der Inventionsphase des Stahlbetonbaus (1925–1950) ihren Höhepunkt erreichte und sich durch die folgenden Merkmale auszeichnet:

Erstens: Auflösung des im herkömmlichen Massivbrückenbau üblichen Rechteckquerschnitts, welche zur statisch‐konstruktiven Querschnittsoptimierung führte und damit eine erhebliche Steigerung der Druckspannungen induzierte.

Zweitens: Mit der Nutzung höherwertiger Zemente sowie der Trennung von Kriechen und Schwinden gelang dem Bogenbrückenbau aus Stahlbeton eine der Querschnittsoptimierung entsprechende Materialoptimierung.

Drittens: Querschnitts‐ und Materialoptimierung schließlich führten zu einer Verfeinerung der baustatischen Analyse weitgespannter Bogenbrücken aus Stahlbeton, die im Kern aus der Ermittlung des Gleichgewichts am verformten Bogensystem besteht.

Die genannten drei Merkmale werden exemplarisch an der medialen Präsentation des Wissenstransfers durch Fachzeitschriften konkret aufgezeigt. Handlungsleitend ist eine thematische Recherche der Haupt‐ und Kurzbeiträge der drei den deutschen Sprachraum prägenden Fachzeitschriften „Der Bauingenieur“, „Beton und Eisen“ und „Die Bautechnik“ zu den Sparten von Theorie, Material und Projekt. Die Überprüfung der internationalen Wertigkeit des zuvor gefilterten Themenkanons gelingt über die Veröffentlichungen der International Association for Bridge and Structural Engineering (IABSE).
Combination effect of cilengitide derivatives with gefitinib onTGF‐β1‐induced epithelial‐to‐mesenchymal transition in human non‐small cell lung cancer cells
Authors: Seo Minji , Kim Jiyeon
Published: August 2022

Cilengitide (cyclo[RGDf(NMe)V]), containing the arginine–glycine–aspartate motif, has been known to increase drug efficacy through coadministration with anticancer agents in various cancers including non‐small cell lung cancer (NSCLC), and cilengitide derivatives have also shown an epithelial‐to‐mesenchymal transition (EMT) inhibitory effect. In addition, we found that some cilengitide derivatives exert anti‐EMT effects in NSCLC cells. Especially, cilengitide derivatives cRGDwV and cRGDyV were shown to be the most effective in NSCLC cell proliferation and exerted an inhibitory effect against the transforming growth factor‐β1 (TGF‐β1)‐induced EMT phenotype changes and related signalings. In this study, we evaluated the combination effect of cRGDwV and cRGDyV with an epidermal growth factor receptor inhibitor gefitinib on the TGF‐β1‐induced EMT process in NSCLC cells. Cilengitide derivatives showed synergistic effects with gefitinib in the expression of EMT markers. Based on these results, we can suggest the potential of these peptides as coadministered drugs in cancers undergoing an EMT process.
Disparities in mortality among acute myeloid leukemia‐related hospitalizations
Authors: Alam Sara Taveras , Dongarwar Deepa , Lopez Elyse , Yellapragada Sarvari , Rivero Gustavo , Huang Quillan , Miler‐Chism Courtney , Mims Martha , Salihu Hamisu M.
Published: August 2022

Racial and socioeconomic disparities have become apparent in acute myeloid leukemia (AML) outcomes. We conducted a retrospective cohort study of hospitalizations for adults with a diagnosis of AML from 2009 to 2018 in the Nationwide Inpatient Sample (NIS). We categorized patients' ages in groups of <60 years and ≥60 years and stratified them by reported race/ethnicity. Exposures of interest were patient sociodemographics, hospital characteristics, and Elixhauser‐comorbidity Index. Outcome of interest was in‐hospital death. Statistical analyses included survey logistic regression to generate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) to quantify the independent associations between patient characteristics and mortality. Of 622,417 AML‐related hospitalizations, 57.6% were in patients ≥60 years. The overall rate of in‐hospital death was 9.4%. Compared to patients <60, older patients experienced a higher rate of in‐hospital death. In both age groups and in all ethnicities, mortality decreased over time. Differences in mortality were observed based on gender, payer, hospital location, and teaching status. For hospitalizations in patients ≥60, NH‐Black race was associated with inferior in‐hospital death outcomes (OR 1.17; CI 1.08–1.28). Urban teaching hospitals were associated with a 38% increase (OR 1.38; CI 1.06–1.80) in inpatient mortality in patients <60 and a 15% decrease (OR 0.85; CI 0.77–0.95) in inpatient mortality in patients ≥60. Our results highlight the increased need to recognize the role of race/ethnicity and socioeconomic factors and their contribution to disparate outcomes in AML.
Polyphenol Characterization of the Aqueous Extract from Hubertia ambavilla L. (Asteraceae) by HPLC‐DAD‐ESI‐MSn and Assessment of Its Antioxidant Activity
Authors: Chawech Rachid , Pesnel Sabrina , Haddada Maroua Ben , Gauvin‐Bialecki Anne , Morel Anne‐Laure
Published: August 2022

In this work, phytochemical components, and the antioxidant properties of an aqueous extract obtained from a medicinal plant Hubertia ambavilla, endemic to Reunion Island, were investigated. A total of 37 compounds were detected and identified by high‐performance liquid chromatography (UHPLC) using a photodiode‐array detector (DAD) coupled with electrospray ionization/mass spectrometry (ESI/MSn). From calibration curves, the quantity of secondary metabolites in the aqueous extract was calculated. The mean amounts of phenols, flavonoids, and condensed tannins found were 158.38±1.20 mg GAE/g DE, 60.41±1.65 mg AE/g DE and 23.77±1.36 mg CE/g DE, respectively. The in vitro antioxidant properties of the Hubertia ambavilla plant were measured using three methods: DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) and ABTS (2,2'‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) scavenging and ferric reducing antioxidant power. The results showed that crude aqueous extract of H. ambavilla had effective radical scavenging and reducing power in comparison with standard antioxidant compounds. In conclusion, the crude extract herein presented offers a natural alternative biosource of antioxidants with potential applications in food and health industries.
How to Harness Electrochemical Mediators for Photocatalysis – A Systematic Approach Using the Phenanthro[9,10‐d]imidazole Framework as a Test Case
Authors: Enders Patrick , Májek Michal , Lam Chiu Marco , Little R. Daniel , Francke Robert
Published: August 2022

In view of the frequently cited similarities between photo‐ and electrocatalysis, large overlaps are to be expected in terms of the mediators used. However, closer inspection reveals that the exchange of mediators is the exception rather than the rule. In this context, the mediator portfolio of electrosynthesis holds great potential for useful applications in photocatalysis (and vice versa). Herein, a systematic approach toward harnessing electrochemical mediators for photocatalysis is presented. Using the phenanthro[9,10‐d]‐imidazole framework (a known electrocatalytic system) as a test case, it is shown how systematic investigation and tuning of the mediator properties leads to application in photocatalysis. As a result, a much broader platform becomes accessible, one in which the redox potential in the ground and excited state can be adjusted by variation of the substituents to enable both oxidative and reductive transformations to occur simply by choosing the type of energy input (light or electricity).