Nitric oxide sensor NsrR is the key direct regulator of magnetosome formation and nitrogen metabolism in Magnetospirillum.

Nitric oxide (NO) plays an essential role as signaling molecule in regulation of eukaryotic biomineralization, but its role in prokaryotic biomineralization is unknown. Magnetospirillum gryphiswaldense MSR-1, a model strain for studies of prokaryotic biomineralization, has the unique ability to form magnetosomes (magnetic organelles). We demonstrate here that magnetosome biomineralization in MSR-1 requires the presence of NsrRMg (an NO sensor) and a certain level of NO. MSR-1 synthesizes endogenous NO via nitrification-denitrification pathway to activate magnetosome formation. NsrRMg was identified as a global transcriptional regulator that acts as a direct activator of magnetosome gene cluster (MGC) and nitrification genes but as a repressor of denitrification genes. Specific levels of NO modulate DNA-binding ability of NsrRMg to various target promoters, leading to enhancing expression of MGC genes, derepressing denitrification genes, and repressing nitrification genes. These regulatory functions help maintain appropriate endogenous NO level. This study identifies for the first time the key transcriptional regulator of major MGC genes, clarifies the molecular mechanisms underlying NsrR-mediated NO signal transduction in magnetosome formation, and provides a basis for a proposed model of the role of NO in the evolutionary origin of prokaryotic biomineralization processes.

Does in-vehicle automation help individuals with Parkinson's disease? A preliminary analysis.

Introduction: PD is a progressive neurodegenerative disorder that affects, according to the ICF, body systems (cognitive, visual, and motor), and functions (e.g., decreased executive functions, decreased visual acuity, impaired contrast sensitivity, decreased coordination)-all which impact driving performance, an instrumental activity of daily living in the domain of "Activity" and "Participation" according to the ICF. Although there is strong evidence of impaired driving performance in PD, few studies have explored the real-world benefits of in-vehicle automation technologies, such as in-vehicle information systems (IVIS) and advanced driver assistance systems (ADAS), for drivers with PD. These technologies hold potential to alleviate driving impairments, reduce errors, and improve overall performance, allowing individuals with PD to maintain their mobility and independence more safely and for longer periods. This preliminary study aimed to fill the gap in the literature by examining the impact of IVIS and ADAS on driving safety, as indicated by the number of driving errors made by people with PD in an on-road study. Methods: Forty-five adults with diagnosed PD drove a 2019 Toyota Camry equipped with IVIS and ADAS features (Toyota Safety Sense 2.0) on a route containing highway and suburban roads. Participants drove half of the route with the IVIS and ADAS systems activated and the other half with the systems deactivated. Results: The results suggest that systems that assume control of the driving task, such as adaptive cruise control, were most effective in reducing driving errors. Furthermore, individual differences in cognitive abilities, particularly memory, were significantly correlated with the total number of driving errors when the systems were deactivated, but no significant correlations were present when the systems were activated. Physical capability factors, such as rigidity and bradykinesia, were not significantly correlated with driving error. Discussion: Taken together, these results show that in-vehicle driver automation systems can benefit drivers with PD and diminish the impact of individual differences in driver cognitive ability.

Highly Stable Supercapacitors Enabled by a New Conducting Polymer Complex PEDOT:CF3 SO2(x) PSS(1-x).

Herein, a novel conducting polymer complex PEDOT:CF3 SO2(x) PSS(1-x) [denoted as S-PEDOT:CF3 SO2(x) PSS(1-x) , where PEDOT is poly(3,4-ethylenedioxythiophene) and PSS is poly(styrene sulfonate)], is fabricated with the assistance of zinc di[bis(trifluoromenthylsulfonyl) imide][Zn(TFSI)2 ] (CFE). The introduction of CF3 SO2 - group is expected to bring better stability of PEDOT:CF3 SO2 than PEDOT:PSS due to its strong Coulomb force. Electrochemical measurement shows that a high specific capacitance of 194 F cm-3 was achieved from the novel complex S-PEDOT:CF3 SO2(x) PSS(1-x) , the highest value reported so far. An all-solid-state supercapacitor assembly with a structure of S-PEDOT:CF3 SO2(x) PSS(1-x) /H2 SO4 :polyvinyl alcohol (PVA)/S-PEDOT:CF3 SO2(x) PSS(1-x) shows a record specific capacitance of 70.9 F cm-3 and a maximum energy density of 6.02 mWh cm-3 at a power density of 397 mW cm-3 . This supercapacitor device demonstrates excellent electrochemical stability with a capacitance retention rate of 98 % after 10 000 cycles and extreme air stability of 96 % capacitance retention rate after 10 000 cycles, even if the device is exposed to air over 2880 h, much better than that of PEDOT:PSS based supercapacitors. Excellent capacitance can be achieved from PEDOT:CF3 SO2(x) PSS(1-x) electrode under electrolyte-free conditions. This work provides a novel method for high performance stable supercapacitors and may pave the way for the commercialization of PEDOT based supercapacitors.

Distraction From Smartphones Changed Pedestrians' Walking Behaviors in Open Areas.

The prevalence of phone use has become a major concern for pedestrian safety. Using smartphones while walking reduces pedestrians' ability to perceive the environment by increasing their cognitive, manual, and visual demands. The purpose of this study was to investigate the effect of common phone tasks (i.e., reading, tapping, gaming) on walking behaviors during outdoor walking. Nineteen young adults were instructed to complete four walking conditions (walking only, walking-reading, walking-tapping, and walking-gaming) along an open corridor. Results showed that all three phone tasks increased participants' neck flexion (i.e., neck kyphosis) during walking. Meanwhile, the reading task showed a greater influence on the temporal aspect during the early phases of a gait cycle. The tapping task lowered the flexion angles of the middle and lower back (i.e., torso lordosis) and induced a longer terminal double support. And the gaming task resulted in a decrease in middle back flexion, a shorter stride length, and a longer terminal double support while walking. Findings from the study confirmed our hypothesis that phone tasks changed pedestrians' physical responses to smartphone distraction while walking. To avoid potential risks caused by the observed posture and gait adaptations, safety precautions (e.g., roadside/electronic warning signals) might be imposed depending on the workload expected by different phone tasks.

Small-Molecule Electron Transport Layer with Siloxane-Functionalized Side Chains for Nonfullerene Organic Solar Cells.

Active layer materials with silicone side chains have been broadly reported to have excellent long-term stability in harsh environments. However, the application of conjugated materials with silicone side chains in electron transport layers (ETLs) has rarely been reported. In this research, we synthesized for the first time a siloxane-modified perylene-diimide derivative (PDI-OSi) consisting of a side-chain substituent of siloxane and a conjugated group of perylene-diimide (PDI). The inserted siloxane functional groups not only can strengthen the light transmittance of PDI-OSi but also can remarkably expand its solubility and improve the film-forming ability and air stability of the material. Second, introducing siloxane-containing side chains can dramatically lower the work function and interfacial barrier of the electrode, thereby achieving a favorable ohmic contact. In addition, the moderate surface energy of siloxane functional groups makes PDI-OSi hydrophobic, which is conducive to forming excellent miscibility with hydrophobic active layers to promote charge transfer. When PDI-OSi is used as an ETL in organic solar cells (OSCs), operative exciton dissociation and more favorable surface morphology enable OSCs to realize a power conversion efficiency (PCE) of 13.99%. These results indicate that side-chain engineering with siloxane pendants is a facile strategy for constructing efficient OSCs.

In vitro magnetosome remineralization for silver-magnetite hybrid magnetosome biosynthesis and used for healing of the infected wound.

BACKGROUND: Magnetosomes (BMPs) are organelles of magnetotactic bacteria (MTB) that are responsible for mineralizing iron to form magnetite. In addition, BMP is an ideal biomaterial that is widely used in bio- and nano-technological applications, such as drug delivery, tumor detection and therapy, and immunodetection. The use of BMPs to create multifunctional nanocomposites would further expand the range of their applications. RESULTS: In this study, we firstly demonstrate that the extracted BMP can remineralize in vitro when it is exposed to AgNO3 solution, the silver ions (Ag+) were transported into the BMP biomembrane (MM) and mineralized into a silver crystal on one crystal plane of Fe3O4. Resulting in the rapid synthesis of an Ag-Fe3O4 hybrid BMP (BMP-Ag). The synergy between the biomembrane, Fe3O4 crystal, and unmineralized iron enabled the remineralization of BMPs at an Ag+ concentration ≥ 1.0 mg mL-1. The BMP-Ag displayed good biocompatibility and antibacterial activity. At a concentration of 2.0 mg/mL, the BMP-Ag and biomembrane removed Ag-Fe3O4 NPs inhibited the growth of gram-negative and gram-positive bacteria. Thus using BMP-Ag as a wound dressing can effectively enhance the contraction of infected wounds. CONCLUSIONS: This study represents the first successful attempt to remineralize organelles ex vivo, realizing the biosynthesis of hybrid BMP and providing an important advancement in the synthesis technology of multifunctional biological nanocomposites.

Biomanufacturing Biotinylated Magnetic Nanomaterial via Construction and Fermentation of Genetically Engineered Magnetotactic Bacteria.

Biosynthesis provides a critical way to deal with global sustainability issues and has recently drawn increased attention. However, modifying biosynthesized magnetic nanoparticles by extraction is challenging, limiting its applications. Magnetotactic bacteria (MTB) synthesize single-domain magnetite nanocrystals in their organelles, magnetosomes (BMPs), which are excellent biomaterials that can be biologically modified by genetic engineering. Therefore, this study successfully constructed in vivo biotinylated BMPs in the MTB Magnetospirillum gryphiswaldense by fusing biotin carboxyl carrier protein (BCCP) with membrane protein MamF of BMPs. The engineered strain (MSR-∆F-BF) grew well and synthesized small-sized (20 ± 4.5 nm) BMPs and were cultured in a 42 L fermenter; the yield (dry weight) of cells and BMPs reached 8.14 g/L and 134.44 mg/L, respectively, approximately three-fold more than previously reported engineered strains and BMPs. The genetically engineered BMPs (BMP-∆F-BF) were successfully linked with streptavidin or streptavidin-labelled horseradish peroxidase and displayed better storage stability compared with chemically constructed biotinylated BMPs. This study systematically demonstrated the biosynthesis of engineered magnetic nanoparticles, including its construction, characterization, and production and detection based on MTB. Our findings provide insights into biomanufacturing multiple functional magnetic nanomaterials.

Excellent rate capability supercapacitor based on a free-standing PEDOT:PSS film enabled by the hydrothermal method.

For the first time, herein, the hydrothermal method with H2SO4 as the solvent is introduced to enhance the rate capability of free-standing pristine PEDOT:PSS films. The film with a record conductivity of 3188 S cm-1 displays a rectangular characteristic at an ultrahigh scan rate of 1300 mV s-1 and a stable specific capacitance of 110 F cm-3 from 0.1 to 100 A cm-3, with a capacitance retention of up to 94.8%. The flexible supercapacitor based on the films delivers a comparable energy density of 2.96 mW h cm-3 even at a high power density of 36 685 mW cm-3. This study provides an effective method to prepare PEDOT:PSS films with outstanding electrochemical properties and potentially expand its applications in flexible devices.

Recent Advances and Prospects of Small Molecular Organic Thermoelectric Materials.

Thermoelectric (TE) materials possess unique energy conversion capabilities between heat and electrical energy. Small organic semiconductors have aroused widespread attention for the fabrication of TE devices due to their advantages of low toxicity, large area, light weight, and easy fabrication. However, the low TE properties hinder their large-scale commercial application. Herein, the basic knowledge about TE materials, including parameters affecting the TE performance and the remaining challenges of the organic thermoelectric (OTE) materials, are initially summarized in detail. Second, the optimization strategies of power factor, including the selection and design of dopants and structural modification of the dope-host are introduced. Third, some achievements of p- and n-type small molecular OTE materials are highlighted to briefly provide their future developing trend; finally, insights on the future development of OTE materials are also provided in this study.

Strategy for Avoiding Protein Corona Inhibition of Targeted Drug Delivery by Linking Recombinant Affibody Scaffold to Magnetosomes.

PURPOSE: Nanoparticles (NPs) decorated with functional ligands are promising candidates for cancer diagnosis and treatment. However, numerous studies have shown that chemically coupled targeting moieties on NPs lose their targeting capability in the biological milieu because they are shielded or covered by a "protein corona". Herein, we construct a functional magnetosome that recognizes and targets cancer cells even in the presence of protein corona. METHODS: Magnetosomes (BMPs) were extracted from magnetotactic bacteria, M. gryphiswaldense (MSR-1), and decorated with trastuzumab (TZ) via affibody (RA) and glutaraldehyde (GA). The engineered BMPs are referred to as BMP-RA-TZ and BMP-GA-TZ. Their capacities to combine HER2 were detected by ELISA, the quantity of plasma corona proteins was analyzed using LC-MS. The efficiencies of targeting SK-BR-3 were demonstrated by confocal laser scanning microscopy and flow cytometry. RESULTS: Both engineered BMPs contain up to ~0.2 mg TZ per mg of BMP, while the quantity of HER2 binding to BMP-RA-TZ is three times higher than that binding to BMP-GA-TZ. After incubation with normal human plasma or IgG-supplemented plasma, GA-TZ-containing BMPs have larger hydrated radii and more surface proteins in comparison with RA-TZ-containing BMPs. The TZ-containing BMPs all can be targeted to and internalized in the HER2-overexpressing breast cancer cell line SK-BR-3; however, their targeting efficiencies vary considerably: 50-75% for RA-TZ-containing BMPs and 9-19% for GA-TZ-containing BMPs. BMPs were incubated with plasma (100%) and cancer cells to simulate human in vivo environment. In this milieu, BMP-RA-TZ uptake efficiency of SK-BR-3 reaches nearly 80% (slightly lower than for direct interaction with BMP-RA-TZ), whereas the BMP-GA-TZ uptake efficiency is <17%. CONCLUSION: Application of the RA scaffold promotes and orients the arrangement of targeting ligands and reduces the shielding effect of corona proteins. This strategy improves the targeting capability and drug delivery of NP in a simulated in vivo milieu.

Risk perception and distraction engagement with smart devices in different types of walking environments.

OBJECTIVE: The present study aims to: 1) determine whether the risks associated with distracted walking are influenced by walking environment by estimating the incidence and severity of phone-related distracted walking injuries; and 2) investigate individuals' perceptions of distracted walking risk within different walking environments to understand whether individuals are aware of the potential risks and the manner in which they understand those risks. BACKGROUND: Distracted walking has been increasingly considered a public safety issue over the past few years. Research has focused on understanding the many factors that may influence pedestrians' engagement with smart-devices in order to address this issue. Risk perception may be one factor that guides engagement decisions but has not been widely studied in the context of distracted walking. Risk perception and the consequences of distracted walking are likely to be impacted by the walking environment, however, current research has typically focused on a subset of locations- streets and intersections. METHOD: This study used the National Electronic Injury Surveillance System (NEISS), a national database of injuries due to consumer products, to understand the number and severity of distracted walking injuries and locations where it occurred. Phone related injury cases from 2011 to 2019 were extracted and categorized by two independent raters in terms of cause of injury and location of injury. An online questionnaire, N = 207, was used to understand how individuals' perception of risk in five different walking environments (intersections, stairwells, hallways, pedestrian plazas, and parking lots) were related to distraction engagement. Risk perception was measured through three different framings: risk of distracted walking (i.e., overall risk of engaging with the behavior), risk of collision and risk of falls (e.g., risks associated with the consequences of engaging with the behavior). RESULTS: The NEISS analysis showed an upward trend of distracted walking injuries from 2011 (2184 incidents) to 2019 (4711 incidents) and that the number of injuries differed across the different walking environments. The survey results showed that individuals varied their risk perception levels (risk of distracted walking, collision, and falls) based on the walking environment and distraction status (distraction and no distraction). The relationship between overall risk of distracted walking and the risks of the different consequences (falls & collision) differed by walking environment. Finally, significant negative correlations were found between risk perception and actual distraction engagement for each location.

Novel Protein Mg2046 Regulates Magnetosome Synthesis in Magnetospirillum gryphiswaldense MSR-1 by Modulating a Proper Redox Status.

Magnetotactic bacteria (MTB) are a large, polyphyletic group of aquatic microorganisms capable of absorbing large amounts of iron and synthesizing intercellular nano-scaled nanoparticles termed magnetosomes. In our previous transcriptomic studies, we discovered that a novel gene (MGMSRv2_2046, termed as mg2046) in Magnetospirillum gryphiswaldense strain MSR-1 was significantly up-regulated during the period of magnetosome synthesis. In the present study, we constructed a MSR-1 mutant strain with deletion of mg2046 (termed Δmg2046) in order to evaluate the role of this gene in cell physiological status and magnetosome formation process. In comparison with wild-type MSR-1, Δmg2046 showed similar cell growth, but much lower cell magnetic response, smaller number and size of magnetosomes, and reduced iron absorption ability. mg2046 deletion evidently disrupted iron uptake, and redox equilibrium, and strongly inhibited transcription of dissimilatory denitrification pathway genes. Our experimental findings, taken together with results of gene homology analysis, indicate that Mg2046 acts as a positive regulator in MSR-1 under microaerobic conditions, responding to hypoxia signals and participating in regulation of oxygen metabolism, in part as a co-regulator of dissimilatory denitrification pathway with oxygen sensor MgFnr (MGMSRv2_2946, termed as Mg2946). Mg2046 is clearly involved in coupled regulation of cellular oxygen, iron and nitrogen metabolism under micro-aerobic or anaerobic conditions. Our findings help explain how MSR-1 cells initiate dissimilatory denitrification pathway and overcome energy deficiency under microaerobic conditions, and have broader implications regarding bacterial survival and energy metabolism strategies under hypoxia.