bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Solutions to the Integral-Approximate Thermal Boundary Layer Equations for a Flat Plate
Authors: Lewins J. D.
Published: February 2013

The flat plate in fluid flow is the paradigm of heat transfer problems. The polynomial approximation of Pohlhausen to the Blasius solution for the flow leads to messy expressions in the integral formulation for the associated heat transfer between plate and flow, together with a continuation of the paradoxical results that the termination in the approximate solution implies. If the distribution is approximated in exponential form, the required integrals are easy — and may safely be attempted by a lecturer at the board or screen — and the anomalies eliminated. The results are perhaps less accurate than the Pohlhausen approximation but in either case would be replaced with exact values of the flow equations, obtained with considerably more difficulty.
Investigation of Elastic Constraint Non-Linearity
Authors: Karavashkin Sergey B. , Karavashkina Olga N.
Published: February 2013

This paper shows a solution for non-linear vibrations in a homogeneous elastic line consisting of three elements connected by non-linear elastic constraints. The solution obtained is a functional spectral series, each harmonic of which is determined analytically on the basis of a system of equations describing the vibration process when the same linear system is acted on by a series of forces. The process forces depend on the degree of elastic constraint non-linearity and on the vibration amplitude of the lowest-order harmonics. We show that the boundary frequency of each harmonic decreases in proportion to the order of harmonic, and the resonance spectrum of harmonics of the dynamic process contains a spectrum of natural frequencies lower than the natural boundary frequency and the spectrum of frequencies of lower-order harmonics located between the natural boundary frequency and the boundary frequency of the first harmonic. It is shown that the method of recurrent determination of the spectrum of a non-linear dynamic process can be extended to models with non-linear resistance and to the case of a complex-spectrum external force.
Integration of Case Study Technical Investigations in Honours/Masters Engineering Courses
Authors: Gray Tom
Published: February 2013

The main aim of the development described in this paper is to establish a practice whereby undergraduate engineering students exercise their growing technical knowledge and analytical capability in the context of real engineering problems. This is done by setting ‘technical investigations’, which are based on actual industrial or consulting problems. In the present case, these case studies are set within a relatively conventional, ‘engineering science’ course on the theme of structural integrity, but the principle and the benefits to learning would be equally valid if applied to other engineering themes. The background needs which have prompted the introduction of this element and the strategies used to integrate and assess such work in a conventional lecture course are discussed and concrete examples of suitable case studies are given. Technical investigations have now been developing over three academic sessions in the author's department and information from feedback questionnaires in the first and most recent periods is included. The conclusion is that the integration of such exercises has several benefits, in terms of mastery of the subject area and in relation to the development of professional skills.
Assessing the Awareness of Risk Concepts by New Engineering Students
Authors: Schleyer Graham , Duan Rui Fang , Williamson Julian , Stacey Nicola
Published: February 2013

There is an indication that across higher-education engineering courses in the UK, the extent and content of risk education varies, and is not always commensurate with the level of risk that undergraduates could be responsible for in their subsequent professional lives. Consequently, a project was set up to incorporate risk education into the curriculum of an undergraduate engineering course in a UK university for the 2005/06 academic year. A set of learning outcomes was developed from a template of topic areas in consultation with key stakeholders. These learning outcomes formed the basis of a questionnaire that was designed to assess students' awareness of risk issues. This paper describes the development of the questionnaire, the interpretation of the results, and how the questionnaire will be used to help achieve the desired learning outcomes.
Outstanding Women in Mechanical Engineering
Authors: Hoh Yin Kiong
Published: February 2013

The article aims to sensitise teachers to their perception of engineers and scientists. It also highlights the life and achievements of one outstanding woman mechanical engineer, namely Ilene J. Busch-Vishniac, and summarises the achievements of other outstanding women in mechanical engineering. Teachers can use the examples of these outstanding female engineers as role models to inspire their students.
Post-Buckling of a Cantilever Column: A More Accurate Linear Analysis of a Classical Nonlinear Problem
Authors: Beléndez A. , Hernández A. , Gallego S. , Ortuño M. , Neipp C. , Beléndez T.
Published: February 2013

A more accurate analytical approximate expression for the slope at any point of the elastic curve of a slender cantilever column is obtained by using a heuristic but pedagogical derivation. This derivation is based on the linearization of the nonlinear differential equation that governs the post-buckling of the cantilever column. The expression proposed depends on two unknown parameters, which are obtained by comparing, term by term, the power series expansions of the approximate and exact expressions for the total length of the column. The results obtained with this new approximate expression are compared with the exact ones and with two approximations previously published in the literature. The numerical results show that the two previous approximations are not nearly as accurate as the new expression presented in this paper.
Demonstrating the Identification of Nonlinear Vibrating Systems to Undergraduate Students
Authors: Dimitriadis G. , Vio G. A.
Published: February 2013

The identification of nonlinear dynamic systems is increasingly becoming a necessary part of vibration testing and there is significant research effort devoted to it. However, as the current methodologies are still not suitable for the identification of general nonlinear systems, the subject is rarely introduced to undergraduate students. In this paper, recent progress in developing an expert approach to the identification of nonlinear systems is used in order to demonstrate the subject within the context of an undergraduate course or as an introductory tool for postgraduate students. The demonstration is based around a software package of an expert system designed to apply systematically a wide range of identification approaches to the system under investigation. It is shown that the software can be used to demonstrate the need for identification of nonlinear systems, the complexity of the procedure, the possibility of failure and the good chances of success when enough physical information about the system is available.
Symbolic Analysis of Continuous Beams
Authors: Al-Gahtani Husain Jubran
Published: February 2013

The study presents a direct method for obtaining symbolic solutions for continuous beams. The external applied concentrated forces, distributed forces and moment couples are represented by step/singular functions. The integration of the governing differential equation and the solution of the boundary and support conditions are performed using Mathematica. The output of the code produces closed-form symbolic solutions for the beam deflection and its derivatives, as well as all support reactions and moments. Several examples are presented to illustrate the capability of the proposed procedure.
Control-Volume Momentum Flux: Getting the Sign Correct
Authors: Schwing Kyle M. , Neitzel G. Paul
Published: February 2013

When describing the application of control-volume analysis to linear-momentum-balance problems, students are cautioned that there are two different things to take into consideration when determining the proper sign for the momentum-flux term. This decision can be simplified through reliance on the choice of the coordinate system and control surface to determine the sign.
On the Commutativity of Sequential Finite Rotations
Authors: Choudhury Alamgir A. , Keil Mitchel J. , Rodriguez Jorge
Published: February 2013

Non-commutativity of finite rotations is a fundamental issue that needs to be addressed in mathematical models dealing with sequential finite rotations. Comprehending rotational motions required to orient a rigid link or associated reference frames in a three-dimensional space can be quite challenging for beginning students. In this paper we present the problem of non-commutativity of finite rotations and a constraint to allow their commutativity. The constraint, in the form of a chain rule, consists of a lemma for forward and backward propagation of the prescribed rotations. The proposed scheme has been implemented using a commercial graphics package for visual demonstration of a rigid body going through three identical finite rotations but in different sequences. The unique final orientation of the body in each of the cases confirms the commutative nature of the constrained rotations. Using this method, sequential finite rotation becomes easy to comprehend and can be used as a tool for learning the concepts associated with finite rotations as well as for kinematical analysis involving sequential rotations.
Network Graph Theory Perspective on Skeletal Structures for Theoretical and Educational Purposes
Authors: Ta'aseh Nevo , Shai Offer
Published: February 2013

The paper introduces an approach to the analysis of skeletal structures in which they are represented by a discrete mathematical model called graph representation. The paper shows that the reasoning upon the structure can be performed solely upon the representation, which, besides the theoretical value, presents a powerful educational tool. Students can learn skeletal structures entirely through the graph representations and derive advanced structural topics, including the conjugate theorem and the unit force method from the theorems and principles of network graph theory. The graph representations used in the paper for structures have also been applied to represent systems from different engineering disciplines. This provides students with a multidisciplinary perspective on analysis of engineering systems in general, and skeletal structures in particular.
Boundary Layers Explained: An Undergraduate Laboratory Using an Aerofoil with Leading-Edge Slat
Authors: Lock G. D. , Holland E. C. , Cranston G. R. , Kakade V. , Lewis P. R. , Pilbrow R. G.
Published: February 2013

A new undergraduate laboratory exercise is described which explores the generation of lift over an aerofoil with and without a leading-edge slat. The experiment emphasises a fundamental understanding of the fluid-dynamic boundary layer and supports a second-year lecture course in fluid mechanics. A NACA 2415 aerofoil is used by the undergraduates in a simple open-return circuit wind tunnel at a Reynolds number of 2 × 105. Measurements of inviscid and viscous aerodynamic characteristics of the aerofoil are validated against cambered aerofoil theory and published NACA data. Oil surface-shear flow visualisation and the differences in the pressure distribution around the NACA 2415 with and without the leading-edge slat demonstrate the governing influence of the boundary layer on aerodynamic stall and the lift generated by the aerofoil. The new laboratory format was introduced to the undergraduates in 2007 and the response from student evaluation questionnaires confirmed that their understanding of basic fluid dynamics was greatly enhanced by the wind tunnel experiment.
A Simple Experiment to Demonstrate the Effect of Axial Force on Natural Frequency of Transverse Vibration of a Beam
Authors: Nandi A. , Neogy S. , Roy D.
Published: February 2013

An axial tension (compression) increases (decreases) the natural frequency of transverse vibration of a beam. The primary objective of the present work is to demonstrate this effect using a universal testing machine, an impact hammer, an accelerometer, an oscilloscope with spectrum facility and a mild steel specimen of circular cross-section. The above equipments are among the essential facilities available in a typical material testing and vibration laboratory. Therefore the proposed experimentation demands no special specific set-up and can be performed at no extra cost.
Aerothermal Design of a Multi-Stage Axial Flow Gas Turbine with Air Cooling
Authors: Alghamdi Abdullah S. , Najjar Yousef S. H. , Al-Beirutty Mohammad H.
Published: February 2013

The gas turbine engine is gaining acceptance throughout the world as a reliable, flexible and efficient base-load power generation plant. This is in addition to the fact that it has been the unrivalled working horse in aeroengines for decades. The more advanced the technology, the higher the turbine inlet temperature (TIT) is, which increases power, reduces weight and improves efficiency. This demands the use of advanced materials and cooling technology, and hence deeper understanding of aerothermal design becomes a premium. The study reported here shows how a simplified model for the flow in the annulus of the gas turbine can produce accurate results in relation to blade cooling. In this design, the axial, tangential and radial components of velocities are included, together with the compressibility effect and probability of introducing resonant forcing frequencies. This design exercise of finding the particulars of the geometry, gas angles, degree of reaction and cooling configuration represents the first step towards further analysis of heat transfer and overall performance. This could be carried out as a senior course project associated with a course on gas turbines and turbomachines.
Design and Manufacture of a Museum-Grade Children's Indoor Trebuchet by Mechanical Engineering Students
Authors: Hennessey Michael P. , Johnson Michael D.
Published: February 2013

The trebuchet, a medieval siege weapon, can play an important role in stimulating and maintaining interest in engineering and the physical sciences. We discuss our experience with use of a specialty trebuchet design project in engineering education and service learning. In particular, mechanical engineering juniors in a machine design and synthesis course designed and manufactured (based on formal specifications) trebuchets for use by children 5–12 years of age in an indoor museum environment. The entire process entailed brainstorming of ideas, concept selection, dynamic analysis, design for assembly (DFA) analysis, along with manufacture and testing. Throughout the process, feedback was solicited from the community partner, a local technology discovery center, or museum (‘The Works’). In the end, a total of six children's indoor trebuchets were manufactured and installed in the local technology center. The results presented are reproducible for use by other interested instructors.
Newton's Laws and a Dynamic Force-Field Analogy for Analyzing Organizational Changes
Authors: Lee H. P.
Published: February 2013

A dynamic force-field analogy for analyzing organizational change is presented. Instead of just analyzing the driving and restraining forces in the traditional force-field analysis, which is similar to the static analysis in solid mechanics, the forces opposing change can be modeled in terms of viscous or frictional forces that may be encountered. Some analogies between organizational change and the dynamic motion of a body using solid mechanics are presented and discussed. The analogy is then extended to excitation at the resonant state of a mechanical system to examine the optimal or ideal conditions for enforcing organizational change.
The Safety Factor: Case Studies in Engineering Judgment
Authors: Musto Joseph C.
Published: February 2013

While the concept of the safety factor in mechanical analysis and design is introduced early and reinforced throughout the typical mechanical engineering curriculum, it is often misunderstood and misinterpreted by engineering students. This is especially evident in ‘capstone design’ experiences, when the safety factor ceases to be a ‘given’ and becomes yet another design variable that must be selected and justified by the student design team. This paper reviews the concept of the safety factor from a variety of viewpoints, each of which can provide some insight to the student of mechanical design, and addresses some of the classical misconceptions and misuses of the safety factor by undergraduate students. It also proposes teaching tools that can be used to highlight the concept of the safety factor as a design variable, whose specification requires analysis, insight, and engineering judgment.
Applying Physics to an Undergraduate Design for an Unmanned Aerial System
Authors: Byers Lynn , Bellocchio Andrew , Crawford Bobby
Published: February 2013

The Department of Civil and Mechanical Engineering at the United States Military Academy requires its graduates to complete an integrative capstone design in their senior year. One of these projects involves the design, construction, testing, and demonstration of a small, highly autonomous, unmanned aerial system (UAS). This particular capstone option was added to the list of available capstone projects in the fall of 2005. In the past, while students have been able to complete the design process relatively well, an area of deficiency for all capstone design teams has been the physical modeling of their design before construction. This paper describes the progression of physical modeling and analysis for the systems' air vehicles over the course of the three years of the project's existence. In the first year, the two teams did little or no modeling. During the second year of the project, with three different teams, some modeling was attempted, but not verified through testing once the designs were constructed. At the start of the third year, one of the faculty advisors developed a detailed procedure for aerodynamic modeling and performance analysis, called the ‘Alpha .60 Laboratory’. To augment the previous year's design pedagogy with an inductive learning component, the students were required to complete the laboratory on an existing airframe. They were then required to apply the same analysis to each alternative developed through the engineering design process. Upon selection and construction of their final design, the students were required to validate their analytical predictions through flight testing. Preliminary results have shown marked improvement in the detail of the analysis and the level of the students' understanding of the underlying physics. An assessment of the laboratory's impact on the following year's designs is also presented.
Collisions and Mechanical Wave Propagation in Elastic Rods
Authors: Fazio Claudio , Guastella Ivan , Tarantino Giovanni
Published: February 2013

Some results from experiments intended to measure the propagation speed of sound waves produced by collisions between small bodies and metallic rods are analysed. Elementary models of elastic collision and of the reflection and transmission of waves at media boundaries are discussed and tested with experimental data, in the framework of a workshop on mechanical wave propagation that featured at the University of Palermo in a two-year graduate programme for prospective physics teachers and in courses for undergraduate engineering and physics students.
Local and National Belonging in A Globalised World
Authors: Inglis Tom , Donnelly Susie
Published: February 2013

The question of place is becoming more important in an increasingly globalised, cosmopolitan world. Has the global flow of culture and the movement of people around the world meant a decline in the importance of place as a form of identity? Have local, regional and national identities lost their significance for people? The article begins to explore these key issues. In particular it looks at Ireland which, from the 1990s, moved from being relatively insular and homogeneous to becoming one of the most globalised societies. The authors use a mixed method approach. First they examine data from the International Social Survey Project (ISSP) to see if there is any evidence of a decline in identity with place, how this varies between rural and urban dwellers, and levels of age and education. They then use findings from a qualitative study to examine the complex ways in which people talk about and identify with place, where they were brought up, where they live now and being Irish. The findings show that level of identity with place is still strong in Ireland and in some cases is increasing. The authors argue that increased identification with the local is an equal and opposite reaction to globalisation.
Autologous Tissue Repair and Total Face Restoration
Authors: Zan Tao , Wang Wenjin , Li Haizhou , Liu Caiyue , Zhu Hainan , Xie Yun , Zhou Shuangbai , Gao Yashan , Huang Xin , Gu Shuchen , Liu Kai , Gu Bin , Xie Feng , Pu Lee L. Q. , Li Qingfeng
Published: July 2024

Importance

Total face restoration remains a challenge in modern reconstructive surgery. After 17 years of experiments and preliminary clinical studies, a new concept of face prefabrication was developed for face restoration with autologous tissue.

Objective

To evaluate the long-term results of face restoration with autologous tissue and report a finalized and standardized approach of face prefabrication.

Design, Setting, and Participants

In this single-center long-term retrospective study, 32 patients who underwent total face restoration between 2005 and 2022 were reviewed. These patients underwent total facial reconstruction, which included flap prefabrication, 3-dimensional printing, tissue expansion, and flap transfer with aid of indocyanine green angiography (IGA). The flap first undergoes prefabrication by transferring vascularized fascia under the skin of the selected chest. A tissue expander is then placed under the fascia to create a large, thin, reliable skin flap after expansion. Once completed, the flap is transferred to the face during the second stage of the reconstruction. Intraoperative IGA is performed to guide the design of subsequent openings for facial fissures. Data were analyzed from July to September 2023.

Main Outcomes and Measures

Flap healing, reconstructive outcome, and patient recovery were assessed during follow-up. Three questionnaires, including the 36-Item Short Form Health Survey (SF-36), Aesthetic and Functional Status Score of Facial Soft-Tissue Deformities/Defects, and the EuroQoL Health-Related Quality of Life (EQ-5D-5L), were used to evaluate the quality of life and satisfaction with facial aesthetic and functional status.

Results

Of 24 included patients, 14 (58%) were male, and the mean (range) age was 32.9 (8-62) years. The mean (range) follow-up was 5.6 (2-12) years. All patients reported a significant improvement in quality of life (SF-36), especially in mean (SD) social functioning (preoperative score, 53.65 [34.51]; postoperative score, 80.73 [19.10]) and emotional stability (preoperative score, 56.67 [25.55]; postoperative score, 71.17 [18.51]). A total of 22 patients (92%) went back to work. Mean (SD) facial aesthetic status (preoperative score, 4.96 [3.26]; postoperative score, 11.52 [3.49]; P < .001) and functional status (preoperative score, 11.09 [3.51]; postoperative score, 15.78 [3.26]; P < .001) also improved. In addition, there was a significant increase in overall satisfaction and self-reported health status (preoperative score, 8.13 [1.52]; postoperative score, 3.58 [2.31]).

Conclusions and Relevance

In this study, 5-year follow-up results suggested that this innovative approach to total face restoration offered a safe and valid option for indicated patients, with acceptable reconstructive and cosmetic outcomes.
Circulating tumor cells: advancing personalized therapy in small cell lung cancer patients
Authors: Shrestha Prajwol , Kao Steven , Cheung Veronica K. , Cooper Wendy A. , van Zandwijk Nico , Rasko John E. J. , Yeo Dannel
Published: July 2024

Small cell lung cancer (SCLC) is a highly aggressive cancer with a dismal 5‐year survival of < 7%, despite the addition of immunotherapy to first‐line chemotherapy. Specific tumor biomarkers, such as delta‐like ligand 3 (DLL3) and schlafen11 (SLFN11), may enable the selection of more efficacious, novel immunomodulating targeted treatments like bispecific T‐cell engaging monoclonal antibodies (tarlatamab) and chemotherapy with PARP inhibitors. However, obtaining a tissue biopsy sample can be challenging in SCLC. Circulating tumor cells (CTCs) have the potential to provide molecular insights into a patient's cancer through a “simple” blood test. CTCs have been studied for their prognostic ability in SCLC; however, their value in guiding treatment decisions is yet to be elucidated. This review explores novel and promising targeted therapies in SCLC, summarizes current knowledge of CTCs in SCLC, and discusses how CTCs can be utilized for precision medicine.
Intelligent fault diagnosis of rolling bearings in strongly noisy environments using graph convolutional networks
Authors: Wei Lunpan , Peng Xiuyan , Cao Yunpeng
Published: July 2024

Rolling bearings often function under complex and non‐stationary conditions, where significant noise interference complicates fault diagnosis by obscuring fault characteristics. This paper presents an innovative fault diagnosis technique using graph convolutional networks (GCN) to address these challenges. Vibration signals are first transformed into the frequency domain through fast Fourier transform (FFT), creating a detailed graph where nodes and edges encapsulate fault signals. The GCN method then extracts complex node features from this graph, enabling a classifier, comprising a fully connected layer and Softmax function, to accurately identify fault types. Experimental results demonstrate the superior performance of the proposed GCN‐based fault diagnosis method, achieving an accuracy of 99.79%. This significantly surpasses traditional machine learning methods (85.4%), deep learning models (92.3%), and other graph neural network approaches (94.1%). Notably, the method shows exceptional resilience to noise, maintaining high accuracy even with 20% added noise, underscoring its robustness for practical industrial applications. The transformation of vibration signals into the frequency domain using FFT, followed by constructing a detailed graph structure, enables the GCN to effectively capture and represent intricate fault characteristics, thus enhancing accurate fault classification. These findings highlight the method's practical applicability and potential for deployment in advanced industrial settings characterized by high noise levels and complexity.
Robust Systemic and Mucosal Immune Responses to Coxsackievirus B3 Elicited by Spider Silk Protein Based Nanovaccines via Subcutaneous Immunization
Authors: Qi Xingmei , Wei Guoqiang , Li Yanan , Xiong Sidong , Chen Gefei
Published: July 2024

Coxsackievirus B3 (CVB3) is a member of the enterovirus genus and linked to several diseases, including myocarditis, which can progress to dilated cardiomyopathy. Despite ongoing preclinical efforts, no clinically approved vaccines against CVB3 are currently available, highlighting the urgent need for effective prophylactic solutions. In this study, a nanovaccine platform based on spider minor ampullate silk protein (MiSp) is introduced. This platform utilizes protein nanoparticles engineered from chimeric proteins that incorporate CVB3 antigenic peptides into customized MiSp, subsequently loaded with all‐trans retinoic acid (RA). These functional nanovaccines are capable of eliciting both mucosal and systemic immune responses following subcutaneous administration and demonstrate significant protective effects against CVB3 infection in mice. This study signifies an approach in peptide‐based parenteral vaccine strategies, utilizing engineered MiSp nanoparticles combined with RA. This methodology represents a promising pathway for preventing enterovirus infections by leveraging the unique immunomodulatory properties of spidroins and RA to combat these pathogens effectively.
Terahertz Sensing Based on Floating Bilayer Metasurface with Toroidal Dipole Resonance Toward Ultra‐High Sensitivity
Authors: Liu Xiaoxuan , Xiao Binggang , Qin Jianyuan
Published: July 2024

Metasurface structures have proven to be effective in enhancing terahertz sensing signals and can thus be used as sensors to improve terahertz detection sensitivity. However, the sensitivity is limited by the poor spatial overlap between the analytes and the local electric field of the metasurface. In this work, a novel design of a floating bilayer metasurface structure for terahertz sensing is proposed and investigated. This structure supports a sharp toroidal dipole resonance and can concentrate near‐field energy on the analyte and metal atoms rather than on the substrate surface by floating the metal atoms. Consequently, the sensitivity is significantly improved to as high as 362 GHz RIU−1; theoretically, this is approximately 2.6 times higher than that of the common metasurface. The ability of the floating bilayer metasurface to quantitatively detect chlorothalonil is experimentally demonstrated. The resonance peak shows a significant frequency shift of 7 GHz for a change of 0.0001 mg dL−1 in chlorothalonil concentration, reaching up to 86 GHz when the change in chlorothalonil concentration is 100 mg dL−1; this is approximately 6.6 times higher than that of the common metasurface. This work provides opportunities for metasurface to realize ultrasensitive sensing in the terahertz regime.
Watt‐Level Second‐Order Topological Charge Ultrafast Green Vortex Laser with Quasi ‐2D PEA2(CsPbBr3)n‐1PbBr4 Perovskite Films Saturable Absorber
Authors: Liu Zehua , Li Jingzhen , Zhang Ling , Zhang Yu , Yang Song , Bai Zhenxu , Wang Yulei , Lu Zhiwei , Yan Dapeng , Qi Yaoyao , Zhang XingWang
Published: July 2024

Ultrafast vortex beams have significant scientific and practical value because of their unique phase properties in both the longitudinal and transverse modes, enabling multi‐dimensional quantum control of light fields. Directly generating watt‐level ultrafast vortex beams with large angular momentum has remained a major challenge due to the limitations of mode‐locked materials and existing spatiotemporal mode‐locking generation methods. In this study, quasi‐2D PEA2(CsPbBr3)n‐1PbBr4 perovskite films are prepared by an anti‐solvent method and employed for the first time in a mode‐locked resonator operating in free space. Utilizing the angle‐based non‐collinear pumping and frequency doubling techniques, the second‐order ultrafast green vortex beams with a power of up to 1.05 W and a duration of 373 ps are generated. Experimental findings demonstrate the strong nonlinear saturable absorption properties of quasi‐2D PEA2(CsPbBr3)n‐1PbBr4 perovskite films at high power levels, highlighting their considerable potential in ultrafast laser technology and nonlinear optics.
Broadband Complex Amplitude‐Modulated Metasurfaces for Nanoprinting and Vectorial Hologram with Continuously Varying Linear Polarization Distributions
Authors: Zhang Song , Lin Peicheng , Huo Pengcheng , Wang Yilin , Zhang Yanzeng , Liu Mingze , Xu Ting
Published: July 2024

The multi‐dimensional light‐field manipulation capability of metasurfaces positions them as promising candidates for displaying nanoprinting and holographic images at ultra‐short distances with subwavelength resolution. In recent years, merging nanoprinting and holographic images into a single‐layer metasurface has emerged as a research focus to enhance information storage capacity. However, existing multi‐channel metasurface designs often limit the number of polarization states available for the holographic image. Here, a scheme is proposed and demonstrated to encode both a continuous grayscale image and a vectorial hologram with a continuously varying linear polarization distribution onto a complex amplitude‐modulated metasurface. The nanoprinting and holographic images generated from dielectric metasurface exhibit broadband response for the visible light. This method paves the way for compact optical devices tailored for applications in information encoding, high‐density optical storage, and information anti‐counterfeiting.
Alveolar Microdynamics during Tidal Ventilation in Live Animals Imaged by SPring‐8 Synchrotron
Authors: Kim Min Woo , Yu Seung Hyeon , Yang Un , Nukiwa Ryota , Cho Hyeon Jung , Kwon Nam Seop , Yong Moon Jung , Kim Nam Ho , Lee Sang Hyeon , Lee Jun Ho , Lim Jae Hong , Kohmura Yoshiki , Ishikawa Tatsuya , Henry Frank S. , Imai Yumiko , Oh Seung Soo , Hwang Hyung Ju , Tsuda Akira , Je Jung Ho
Published: July 2024

It is self‐evident that our chests expand and contract during breathing but, surprisingly, exactly how individual alveoli change shape over the respiratory cycle is still a matter of debate. Some argue that all the alveoli expand and contract rhythmically. Others claim that the lung volume change is due to groups of alveoli collapsing and reopening during ventilation. Although this question might seem to be an insignificant detail for healthy individuals, it might be a matter of life and death for patients with compromised lungs. Past analyses were based on static post‐mortem preparations primarily due to technological limitations, and therefore, by definition, incapable of providing dynamic information. In contrast, this study provides the first comprehensive dynamic data on how the shape of the alveoli changes, and, further, provides valuable insights into the optimal lung volume for efficient gas exchange. It is concluded that alveolar micro‐dynamics is nonlinear; and at medium lung volume, alveoli expand more than the ducts.
VIK‐Mediated Auxin Signaling Regulates Lateral Root Development in Arabidopsis
Authors: Shang Erlei , Wei Kaijing , Lv Bingsheng , Zhang Xueli , Lin Xuefeng , Ding Zhihui , Leng Junchen , Tian Huiyu , Ding Zhaojun
Published: July 2024

The crucial role of TIR1‐receptor‐mediated gene transcription regulation in auxin signaling has long been established. In recent years, the significant role of protein phosphorylation modifications in auxin signal transduction has gradually emerged. To further elucidate the significant role of protein phosphorylation modifications in auxin signaling, a phosphoproteomic analysis in conjunction with auxin treatment has identified an auxin activated Mitogen‐activated Protein Kinase Kinase Kinase (MAPKKK) VH1‐INTERACTING Kinase (VIK), which plays an important role in auxin‐induced lateral root (LR) development. In the vik mutant, auxin‐induced LR development is significantly attenuated. Further investigations show that VIK interacts separately with the positive regulator of LR development, LATERAL ORGAN BOUNDARIES‐DOMAIN18 (LBD18), and the negative regulator of LR emergence, Ethylene Responsive Factor 13 (ERF13). VIK directly phosphorylates and stabilizes the positive transcription factor LBD18 in LR formation. In the meantime, VIK directly phosphorylates the negative regulator ERF13 at Ser168 and Ser172 sites, causing its degradation and releasing the repression by ERF13 on LR emergence. In summary, VIK‐mediated auxin signaling regulates LR development by enhancing the protein stability of LBD18 and inducing the degradation of ERF13, respectively.
Enhanced Ferromagnetism and Tunable Magnetic Anisotropy in a van der Waals Ferromagnet
Authors: Gao Xin , Zhai Kun , Fu Huixia , Yan Junxin , Yue Dongdong , Ke Feng , Zhao Ying , Mu Congpu , Nie Anmin , Xiang Jianyong , Wen Fusheng , Wang Bochong , Xue Tianyu , Wang Lin , Yuan Hongtao , Liu Zhongyuan
Published: July 2024

2D van der Waals (vdW) magnets have recently emerged as a promising material system for spintronic device innovations due to their intriguing phenomena in the reduced dimension and simple integration of magnetic heterostructures without the restriction of lattice matching. However, it is still challenging to realize Curie temperature far above room temperature and controllable magnetic anisotropy for spintronics application in 2D vdW magnetic materials. In this work, the pressure‐tuned dome‐like ferromagnetic‐paramagnetic phase diagram in an iron‐based 2D layered ferromagnet Fe3GaTe2 is reported. Continuously tunable magnetic anisotropy from out‐of‐plane to in‐plane direction is achieved via the application of pressure. Such behavior is attributed to the competition between intralayer and interlayer exchange interactions and enhanced DOS near the Fermi level. The study presents the prominent properties of pressure‐engineered 2D ferromagnetic materials, which can be used in the next‐generation spintronic devices.
Feasibility and predictive factors on the completion of docetaxel plus S‐1 adjuvant chemotherapy in pathological stage III gastric cancer
Authors: Terayama Masayoshi , Ohashi Manabu , Yamaguchi Kensei , Takahari Daisuke , Makuuchi Rie , Hayami Masaru , Ida Satoshi , Kumagai Koshi , Sano Takeshi , Nunobe Souya
Published: July 2024

Background

The standard adjuvant chemotherapy regimen for stage III gastric cancer is docetaxel plus S‐1 (DS) based on the results of the START‐II trials. However, in clinical practice some patients could not continue this intensive doublet chemotherapy because of limited tolerability. This study aimed to assess the practical feasibility of DS and elucidate the predictive factors for the completion of adjuvant DS therapy.

Methods

Data from consecutive patients who underwent radical gastrectomy between 2018 and 2021 and were diagnosed with histopathologically confirmed stage III gastric cancer were retrospectively collected. First, the completion rate and adverse effects of DS were assessed. Second, the association between DS incompletion and patient backgrounds including body weight, skeletal muscle index (SMI), and intramuscular adipose content (IMAC) were examined.

Results

Of 87 patients, 59 patients (67.8%) completed DS and dose reduction was required in 18 patients (20.6%). Neutropenia of grade 3 or higher was the most common hematological toxicity observed (17.2%). The most frequent nonhematological toxicity of grade 3 or higher was fatigue (6.9%), followed by diarrhea (5.7%), nausea (4.5%), and anorexia (4.5%). In a multivariate analysis, low SMI (p = 0.005) and high IMAC (p = 0.004) were significant risk factors for DS incompletion.

Conclusions

DS adjuvant chemotherapy after radical gastrectomy for pathological stage III gastric cancer is acceptable, even in clinical practice, with respect to completion and toxicity. Additionally, the body composition factors such as SMI and IMAC might be useful in predicting incompletion of DS. These findings will help us to preoperatively select patients for DS.
Steric hindrance induced low exciton binding energy enables low‐driving‐force organic solar cells
Authors: Hu Tianyu , Zheng Xufan , Wang Ting , Saparbaev Aziz , Gao Bowen , Wu Jingnan , Xiong Jingyi , Wan Ming , Cong Tingting , Li Yuda , Wang Ergang , Wang Xunchang , Yang Renqiang
Published: July 2024

Exciton binding energy (Eb) has been regarded as a critical parameter in charge separation during photovoltaic conversion. Minimizing the Eb of the photovoltaic materials can facilitate the exciton dissociation in low‐driving force organic solar cells (OSCs) and thus improve the power conversion efficiency (PCE); nevertheless, diminishing the Eb with deliberate design principles remains a significant challenge. Herein, bulky side chain as steric hindrance structure was inserted into Y‐series acceptors to minimize the Eb by modulating the intra‐ and intermolecular interaction. Theoretical and experimental results indicate that steric hindrance‐induced optimal intra‐ and intermolecular interaction can enhance molecular polarizability, promote electronic orbital overlap between molecules, and facilitate delocalized charge transfer pathways, thereby resulting in a low Eb. The conspicuously reduced Eb obtained in Y‐ChC5 with pinpoint steric hindrance modulation can minimize the detrimental effects on exciton dissociation in low‐driving‐force OSCs, achieving a remarkable PCE of 19.1% with over 95% internal quantum efficiency. Our study provides a new molecular design rationale to reduce the Eb.
High‐Performance Textile‐Based Capacitive Strain Sensors via Enhanced Vapor Phase Polymerization of Pyrrole and Their Application to Machine Learning‐Assisted Hand Gesture Recognition
Authors: Kateb Pierre , Fornaciari Alice , Ahmadizadeh Chakaveh , Shokurov Alexander , Cicoira Fabio , Menon Carlo
Published: July 2024

Sensors based on everyday textiles are extremely promising for wearable applications. The present work focuses on high‐performance textile‐based capacitive strain sensors. Specifically, a conductive textile is obtained via vapor‐phase polymerization of pyrrole, in which the usage of methanol co‐vapor and the addition of imidazole to the iron chloride oxidant solution are shown to maximize conductivity. A technique to provide insulation and mechanical resistance using thermoplastic polyurethane and polystyrene‐block‐polyisoprene‐block‐polystyrene/barium titanate composite is developed. Such insulated conductive elastics are then used to fabricate highly sensitive twisted yarn capacitive sensors. A textile glove is subsequently embedded with such sensors. The wireless measurement and transmission system demonstrate efficacy in capturing capacitance variations upon strain and monitoring hand motions. A machine learning model to recognize 12 gestures is implemented—100% classification accuracy is obtained.
Carbonic Anhydrase Variants Catalyze the Reduction of Dialkyl Ketones with High Enantioselectivity
Authors: Chen Reichi , Kayrouz Colby S. , McAmis Eli , Clark Douglas S. , Hartwig John F.
Published: July 2024

Human carbonic anhydrase II (hCAII) naturally catalyzes the reaction between two achiral molecules—water and carbon dioxide—to yield the achiral product carbonic acid through a zinc hydroxide intermediate. We have previously shown that a zinc hydride, instead of a hydroxide, can be generated in this enzyme to create a catalyst for the reduction of aryl ketones. Dialkyl ketones are more challenging to reduce, and the enantioselective reduction of dialkyl ketones with two alkyl groups that are similar in size and electronic properties, is a particularly challenging transformation to achieve with high activity and selectivity. Here, we show that hCAII, as well as a double mutant of it, catalyzes the enantioselective reduction of dialkyl ketones with high yields and enantioselectivities, even when the two alkyl groups are similar in size. We also show that variants of hCAII catalyze the site‐selective reduction of one ketone over the other in an unsymmetrical aliphatic diketone. Computational docking of a dialkyl ketone to variants of hCAII containing the zinc hydride provides insights into the origins of the reactivity of various substrates and the high enantioselectivity of the transformations and show how a confined environment can control the enantioselectivity of an abiological intermediate.
Taming Two‐Dimensional Polymerization by a Machine‐Learning Discovered Crystallization Model
Authors: Tian Jiaxin , Treaster Kiana A. , Xiong Liangtao , Wang Zixiao , Evans Austin M. , Li Haoyuan
Published: July 2024

Rapidly synthesizing high‐quality two‐dimensional covalent organic frameworks (2D COFs) is crucial for their practical applications. While strategies such as slow monomer addition have been developed based on an empirical understanding of their formation process, quantitative guidance remains absent, which prohibits precise optimizations of the experimental conditions. Here, we use a machine‐learning approach that overcomes the challenges associated with bottom‐up model derivation for the non‐classical 2D COF crystallization processes. The resulting model, referred to as NEgen1, establishes correlations among the induction time, nucleation rate, growth rate, bond‐forming rate constants, and common solution synthesis conditions for 2D COFs that grow by a nucleation‐elongation mechanism. The results elucidate the detailed competition between the nucleation and growth dynamics in solution, which has been inappropriately described previously by classical, empirical models with assumptions invalid for 2D COF polymerization. By understanding the dynamic processes at play, the NEgen1 model reveals a simple strategy of gradually increasing monomer addition speed for growing large 2D COF crystals. This insight enables us to rapidly synthesize large COF‐5 colloids, which could only be achieved previously by prolonged reaction times or by introducing chemical modulators. These results highlight the potential for systematically improving the crystal quality of 2D COFs, which has wide‐reaching relevance for many of the applications where 2D COFs are speculated to be valuable.
Symmetric Anion Mediated Dynamic Kinetic Asymmetric Knoevenagel Reaction for N−C and N−N Atropisomers Synthesis
Authors: Qu Hongyu , Huo Chenyang , Ge Jimeng , Xue Xiaoping , Gu Zhenhua , Deng Ruixian
Published: July 2024

A symmetric anion mediated dynamic kinetic asymmetric Knoevenagel reaction was established as a general and efficient method for accessing both N−C and N−N atropisomers. The resulting highly enantio‐pure pyridine‐2,6(1H,3H)‐diones exhibit diverse structures and functional groups. The key to excellent regio‐ and remote enantiocontrol could be owed to the hydrogen bond between the enolate anion and triflamide block of the organocatalyst. This connected the enolate anion and iminium cation by a chiral backbone. The mechanism investigation via control experiments, correlation analysis, and density functional theory calculations further revealed how the stereochemical information was transferred from the catalyst into the axially chiral pyridine‐2,6(1H,3H)‐diones. The synthetic applications also demonstrated the reaction's potential.
Synthesis and performance evaluation of low‐damage variable viscosity integrated drag reducer
Authors: Fan Yuheng , Yu Weichu , Shu Wenming , Zhang Ying , Ju Yiwen , Fan Pingtian
Published: July 2024

To solve problems such as inadequate proppant carrying capacity, a complex viscosity changing process, and limited environmental friendliness associated with traditional slick water fracturing fluids, a variable viscosity friction reducer called Jianghan friction reducer (JHFR) with low damage, high drag reduction, and strong proppant‐carrying capacity is prepared by inverse emulsion polymerization. The properties of JHFR are investigated by viscometer, JHFR‐II high‐temperature and high‐pressure slick water drag reduction rate tester, surface tension meter, and JHCQ Core dynamic damage evaluation device. The result shows that the dissolution time of JHFR is less than 120 s. The drag reduction of 0.08 wt% JHFR (4.83 mPa s) is 80.3%. When the concentration of JHFR increases from 0.08 to 0.8 wt %, the viscosity of the JHFR increases from 4.83to 97.41 mPa s. After sheared at 90°C and 170 s−1 for 60 min, the viscosity of 0.8 wt% JHFR still maintains 51 mPa s. The damage rate of JHFR to core matrix permeability is lower than 30%. JHFR also shows the advantages of easy breakage and low residue. It provides guidance for the design and selection of fracturing fluid for unconventional oil and gas reservoir development.