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Familiar strangers—individuals related through regular and repeated visual encounter occurring without verbal interaction—may reduce the risk of crime at places by increasing guardianship and internal motivation for norm compliance. This study examines the association between familiar stranger presence and incidents of theft and disorder at train stations using transit smart card and crime data for 22 stations across a six-month period. Familiar strangers are operationally defined as individual transit cards that are co-present within a 30-min temporal window on more than two occasions across a one-month period at a given train station. We apply logistic regression to estimate the likelihood of disorder and theft crimes within a 400-m radius of train stations controlling for station environmental features, co-located facilities and neighbourhood socio-demographic characteristics. Our results show that the impact of familiar strangers on crime (disorder and theft) at train stations is moderated by the neighbourhood socio-demographic context. This may suggest that macro-level norms of informal social control are important for determining crime at micro-places such as transit stations. The findings also indicate that urban design and transport policies require greater flexibility to enable intra-network variability in station design and formal security to enhance ridership.

This work highlights the importance of bis(triarylamine) redox-active linker in promoting the semiconductive and photoconductive behavior of a 2D zinc-based coordination polymer.

This study explored the sustainability of the stock market against the COVID-19 pandemic. The impacts of confirmed COVID-19 cases, COVID-19 deaths, and Movement Control Order (MCO) length on the stock market were examined. The Generalized Method of Moments (GMM) estimator was employed to analyze 57 countries’ weekly data from November 4th 2019 to July 5th 2020. The findings showed that the growth in confirmed COVID-19 cases has a significant negative effect on stock market returns, while the growth in COVID-19 deaths has a negative yet statistically insignificant influence on stock market returns. This study also found a non-linear inverted U-shaped relationship between the MCO period and stock market returns, implying that though the MCO has initial positive influences on the stock market, it negatively impacts the stock market after 5.7 weeks. Thus, this study argues that policy responses to the COVID-19 pandemic provide the most compelling explanation for its unprecedented impact on the sustainability of the stock market. Governments should therefore implement a partial lockdown to avoid deterioration of the national economy. Furthermore, government policies and plans to control the COVID-19 epidemic as well as economic stimulus packages to kickstart the economy play crucial roles in boosting economic growth and revitalizing the stock market

Contribution: Prior studies have shown that project-based learning (PBL) is an effective approach on engineering education. This study further identifies the impact of a design thinking (DT) integrated PBL approach on the college students' learning motivation and creativity. Background: A well-developed robot and its project often require interdisciplinary knowledge, such as design and technology, and interdisciplinary team collaboration to optimize the requirements of desirability and viability for developing products. The current study systematically embeds the elements of DT and PBL on a robot design course. Intended Outcomes: The DT PBL approach can improve the student's learning motivation and creativity in developing robots for engineering students. Application Design: A quasi-experimental design was used. Eighteen participants were assigned to the experimental group, whereas 23 participants were assigned to the comparison group. While the elements of DT and PBL were embedded into and delivered for the experimental group, the comparison group used a PBL-only approach. Findings: Evidence collected from quantitative survey/tests and qualitative interviews indicates that: 1) the experimental group outperformed the comparison group in overall learning motivation, and its subscales (task value and self-efficacy). The project enabled them to reflect on the insufficiency of required expertise and skills, which also helped them to learn more effectively and efficiently and 2) the experimental group outperformed the comparison group in overall creativity and its subscales (fluency, originality, and flexibility). The experimental group students can think faster, consider the problem through multiple perspectives, and come out with more creative ideas.

Background The seven-transmembrane (7TM) receptors are the largest superfamily of cell-surface receptors and are involved in various physiological processes of vertebrate species. In our previous study, a new chicken 7TM receptor (Ch-7TM) was discovered in mononuclear phagocytes (MNPs) derived from chicken peripheral blood mononuclear cells (PBMCs). To explore the functions of Ch-7TM, RNA interference (RNAi) was used to silence the Ch-7TM messenger RNA (mRNA) of MNPs, using small interface RNA (siRNA) designed with BLOCK-iT™ RNAi Designer. Results Herein we demonstrated that silencing of the Ch-7TM mRNA induced apoptosis of MNPs, suggesting that Ch-7TM contributed to the survival of MNPs. Moreover, chicken sera could inhibit the Ch-7TM-silencing-induced apoptosis in MNPs. The survival factor presented in fraction 16 (F16) of chicken sera was highly protective against the Ch-7TM-silencing-induced apoptosis in MNPs. The proteins from fraction 16 (F16) were identified as vitamin D-binding protein and apolipoprotein A-IV (ApoA-IV), which might be potential candidates for survival factors. Conclusions The protective effect of vitamin D and ApoA-IV indicated that Ch-7TM might involve the intracellular oxidation–reduction balance, although more evidence is needed to confirm this function. The siRNA screening serves as an excellent model for studying the functions of chicken MNPs receptors.

Photoconduction (PC) properties were investigated for ternary indium aluminium nitride (InxAl1-xN) nanorods (NRs) with different indium compositions (x) from 0.35 to 0.68, as grown by direct-current reactive magnetron sputter epitaxy. Cross-sectional scanning transmission electron microscopy (STEM) reveals single-crystal quality of the vertically aligned InxAl1-xN NRs. Single-rod photodetector devices with good ohmic contacts were fabricated using the focused-ion-beam technique (FIB), where the In-rich In0.68Al0.32N NR exhibits an optimal photocurrent responsivity of 1400 A W-1 and photoconductive gain of 3300. A transition from a positive photoresponse to a negative photoresponse was observed, while increasing the In composition x from 0.35 to 0.57. The negative PC was further enhanced by increasing x to 0.68. A model based on the coexistence and competition of deep electron trap states and recombination centers was proposed to explain the interesting composition-dependent PC in these ternary III-nitride 1D nanostructures. Funding Agencies|Ministry of Science and Technology. (MOST) of Taiwan [MOST 108-2628-M-011-001-MY3, MOST 109-2622-E-011-034, MOST 110-2622-E-011-017]; Swedish Research Council [2018-04198, 2021-00171, RIF21-0026]; Swedish Energy Agency [46658-1]; STINT Foundation [MG2019-8485]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; Knut and Alice Wallenberg Foundation [KAW 2020.0033]; Swedish Foundation for Strategic Research [2021-00171, RIF21-0026]

The aim of this study is to develop a titanium three-dimensional (3D) printing novel hybrid suture anchor (HSA) with wing structure mechanism which can be opened to provide better holding power for surrounding osteoporotic bone. A screw-type anchor (5.5-mm diameter and 16-mm length) was designed with wing mechanism as well as micro dual-thread in the outer cortex bone contact area and macro single-thread in the anchor body. Both side wings can be opened by an internal screw to provide better bone holding power. The suture anchor and internal screw were manufactured using Ti6Al4V 3D printing and traditional machining, respectively. Static pullout and after dynamic 300-cyclic load (150 N) pullout tests for HSA with or without the wing open and commercial solid anchor (CSA) were performed (n = 5) in severely osteoporotic bone and osteoporotic bone to evaluate failure strengths. Comparison of histomorphometrical evaluation was performed through in vivo pig implantation of HSAs with the wing open and CSAs. The failure strengths of HSA with or without the wing open were 2.50/1.95- and 2.46/2.17-fold higher than those of CSA for static and after dynamic load pullout tests in severely osteoporotic bone, respectively. Corresponding values for static and after dynamic load pullout tests were 1.81/1.54- and 1.77/1.62-fold in osteoporotic bone, respectively. Histomorphometrical evaluation revealed that the effects of new bone ingrowth along the anchor contour for CSA and HSA were both approximately 20% with no significant difference. A novel HSA with wing mechanism was developed using 3D printing and the opened wing mechanism can be used to increase bone holding power for osteoporosis when necessary. Better failure strength of HSA than CSA under static and after dynamic load pullout tests and equivalence of bone ingrowth along the anchor contours confirmed the feasibility of the novel HSA.

Photoconductivity, a crucial property, determines the potential of semiconductor materials for use in optoelectronic and photocatalytic device applications. The one-dimensional metal-organic nanotube semiconducting material [{Re(CO)

This work aims to propose a promising locally resonating system consisting of a tensioned elastic membrane and two-arch masses attached on the membrane surface. Traditional membrane-type resonators, which usually create one obvious attenuation zone at low frequencies, might not be efficient in multi-frequency vibration suppression. The proposed structure can produce an extra clear flexural attenuation region and shift bandgap frequencies below 300 Hz. By adjusting geometric parameters (thickness, width, and location) of the arch mass, the bandgap region can be tuned. Introducing a feasible analytical model for accurately predicting the first and second initial frequencies of the bandgaps for a beam structure containing membrane-arch-mass resonators is another focus of this study. The proposed theoretical framework can be used to tune the bandgap to different target frequency ranges without knowing the actual width of the bandgap. Finite-element analysis and experiments are conducted to verify the theoretical predictions. A good agreement is seen among the theoretical, finite-element analysis, and experimental results. In addition, adjacent cells with different arch-mass distributions can generate two pairs of flexural bandgaps, increasing the practicality in engineering applications. The proposed structure might be used in low-frequency vibration isolation and filters.

Fluid-coupled Lamb waves (LWs) were proposed to facilitate the self-assembling of three-dimensional (3D) photonic crystals (PCs) in this work. Numerical models were constructed for proof-of-concept, and a fabrication set-up was developed for experimental demonstration. LWs were initially generated by a piezoelectric substrate. A couplant altered the propagating direction of these LWs to form the fluid-coupled LWs at a superstrate. The coffee-ring effect (CRE) of a suspension droplet on the superstrate was thus suppressed. The suspended nanospheres formed 3D PCs after the droplet dried out. Diversified PCs were fabricated using the developed set-up. Their transmittance spectra demonstrated the corresponding bandgap clearly. Advantages of utilizing fluid-coupled LWs for self-assembling 3D PCs include flexibility in excitation frequency, fabrication cost-effectiveness, acceptance for a passively oscillating substrate, and enlargement of sample area.

Earth-abundant Cu2ZnSn(S,Se)4 (CZTSSe) is a promising nontoxic alternative compound for commercially available Cu(In,Ga)(S,Se)2 thin-film solar cells. In this study, a MoO3 nanolayer was applied as a sacrificial layer to optimize the quality of the interface between the CZTSSe and Mo back contact. MoO3 nanolayers can greatly improve CZTSSe grain growth and suppress the formation of some harmful secondary phases, especially the undesirable MoS(e)2. In terms of device performance, the series resistance was reduced from 1.83 to 1.54 Ω·cm2, and the fill factor was significantly enhanced from 42.67% to 52.12%. Additionally, MoO3 nanolayers improved CZTSSe absorber quality by lowering the defect energy levels from 228 to 148 meV. Furthermore, first-principles calculations demonstrate that the partial sulfoselenized MoO3 nanolayers may function as the (p-type) hole-selective contacts at Mo/CZTSSe interfaces, leading to an overall improvement in device performance. Lastly, a CZTSSe solar cell with about 26% improvement (compared with reference cells) in power conversion efficiency was achieved by inserting 5 nm MoO3 sacrificial layers.

This study presents a novel acoustic metasurface with a coplanar series-type Helmholtz resonator with curled necks. Using extended necks that are embedded in cavities enables one to significantly reduce the resonance frequency of the resonator. The sound absorption performance of this metasurface is investigated theoretically, numerically, and experimentally. The absorption band can be easily adjusted by altering the neck length and diameter. To achieve a wide frequency band with high absorption, two inhomogeneous units are arranged in parallel. Theoretical and finite-element predictions exhibit good agreement with the experimental measurements. The results demonstrate that the proposed acoustic metasurface with subwavelength thickness is capable of effectively absorbing low-frequency sound.

Tin monosulfide (SnS) is a promising light-harvesting material for solar cell applications, owing to its potential for large-scale production, cost-effectiveness, eco-friendly source materials, and long-term stability. However, SnS crystallizes in an orthorhombic structure, which results in a highly anisotropic charge transport behavior. Tailoring the crystallographic orientation of the SnS absorber layer plays a critical role in the enhancement of the transfer of charge carriers and the power conversion efficiency (PCE). By controlling the substrate tilting angle and temperature ramp rate in vapor transport deposition, the crystal growth orientation was tuned to a preferred direction which significantly suppressed the unfavorable (040) crystallographic plane. Through the combination of these two approaches, the PCE could be increased from 0.11% to 2%. The effect of the tilting angle was numerically simulated to investigate its role in controlling the film uniformity and directing the film growth. In addition, the correlation between the texture coefficient of the (040) plane and the charge transport properties was determined by a combination of analytical methods such as device performance studies, electrochemical impedance spectroscopy, along with transient photovoltage, space-charge-limited current, and dark current measurements. These techniques were blended together to prove that the marked improvement in PCE can be ascribed to a reduced charge recombination (in both SnS bulk and interfaces) and an enhanced hole mobility.