BER for a space uplink laser communication system under an actual optical distortion with a cake-cutting method.

A numerical calculating model is proposed for characterizing the BER performance of the detector working among the 2-D asymmetric distorted spot on the effects of atmospheric turbulence under weak turbulent conditions. Based on the isotropy of the beam wander effect, we introduce a beam wander vector to describe the behavior of the detector drifting among the receiving plane. Furthermore, using the cake-cutting method, the overall PDF of the light intensity is approximated by the average PDF of light intensity intercepted by the detector drifting in all different directions. The results demonstrate that the model obtains the overall PDF of the light intensity received by the detector and analyzes the BER performance of the communication system efficiently. Being an extension of the traditional 1-D calculation, our proposed model has important implications for designing the space uplink optical communication system.

Ultra-robust, Highly Stretchable, and Conductive Nanocomposites with Self-healable Asymmetric Structures Prepared by a Simple Green Method.

Flexible conductive polymer nanocomposites based on silver nanowires (AgNWs) have been extensively studied to develop the next generation of flexible electronic devices. Fiber materials with high strength and large stretching are an important part of high-performance wearable electronics. However, manufacturing conductive composites with both high mechanical strength and good stability remains challenging. In addition, the process of effectively dispersing conductive fillers into substrates is relatively complex, which greatly hampers its widespread application. Here, a simple green self-assembly preparation method in water is reported. The AgNW is evenly dispersed in aqueous, i.e., water-borne polyurethane (WPU) with water as the solvent, and a AgNW/WPU conductive nanocomposite film with an asymmetric structure is formed by self-assembly in one step. The film has high strength (≈49.2 MPa) and high strain (≈910%), low initial resistance (99.9 mΩ/sq), high conductivity (9968.1 S/cm), and excellent self-healing (93%) and adhesion. With good self-healing performance, fibers with a conductive filler spiral structure are formed. At the same time, the application of the conductive composite material with an asymmetric structure in intelligent wearability is demonstrated.

Association between toileting and falls in older adults admitted to the emergency department and hospitalised: a cross-sectional study.

OBJECTIVES: This study aimed to explore the potential risk factors associated with toileting-related falls in community-dwelling older adults who presented to the emergency department and were subsequently hospitalised. DESIGN: This was a cross-sectional study. SETTING AND PARTICIPANTS: This study was conducted in two teaching hospitals in Shanghai, China between October 2019 and December 2021 among community-dwelling adults aged ≥60 years. METHODS: In-person interviews, physical assessment and medical record review were performed to collect data on the characteristics and risk factors of falls. Associations of toileting-related falls with demographic characteristics and geriatric syndromes were examined using logistic regression models. MAIN OUTCOME MEASURES: Potential risk factors for toileting-related falls. RESULTS: This study included 419 older patients with a mean age of 73.8±9.7 years. Among 60 (14.3%) patients with toileting-related falls (mean age: 78.8±9.2 years), 63.3% of toileting-related falls, mainly occurred between 00:00 and 05:59 hours, compared with 17.3% of non-toileting-related falls, which primarily occurred during the daytime. The rate of recurrent falls (35%) was significantly higher in the toileting-related falls group than in the non-toileting-related falls group (21.2%) (p=0.02). Logistic regression showed that visual impairment (OR 2.7, 95% CI 1.1 to 7.1), cognitive impairment (OR 3.3, 95% CI 1.3 to 8.4), gait instability (OR 3.1, 95% CI 1.1 to 8.8) and urinary incontinence (OR 3.4, 95% CI 1.2 to 9.9) were strongly associated with toileting-related falls. Twenty-three (38.3%) patients in the toileting-related falls group had moderate and severe injuries, compared with 71.7% in the non-toileting-related falls group (p<0.05). CONCLUSIONS: This study revealed that patients who reported toileting-related falls were more likely to have cognitive impairment, urinary incontinence, gait instability, visual impairment than patients who fell during other activities. Social and healthcare professionals should prioritise the management of toileting activities in older patients and provide targeted interventions to those in the high-risk group.

Effect of Volume Fraction of Reinforcement on Microstructure and Mechanical Properties of In Situ (Ti, Nb)B/Ti2AlNb Composites with Tailored Three-Dimensional Network Architecture.

The mechanical properties of (Ti, Nb)B/Ti2AlNb composites were expected to improve further by utilizing spark plasma sintering (SPS) and inducing the novel three-dimensional network architecture. In this study, (Ti, Nb)B/Ti2AlNb composites with the novel architecture were successfully fabricated by ball milling the LaB6 and Ti2AlNb mixed powders and subsequent SPS consolidation. The influence of the (Ti, Nb)B content on the microstructure and mechanical properties of the composites was revealed by using the scanning electron microscope (SEM), transmission electron microscopy (TEM) and electronic universal testing machine. The microstructural characterization demonstrated that the boride crystallized into a B27 structure and the α2-precipitated amount increased with the (Ti, Nb)B increasing. When the (Ti, Nb)B content reached 4.9 vol%, both the α2 and reinforcement exhibited a continuous distribution along the prior particle boundaries (PPBs). The tensile test displayed that the tensile strength of the composites presented an increasing trend with the increasing (Ti, Nb)B content followed by a decreasing trend. The composite with a 3.2 vol% reinforcement had the optimal mechanical properties; the yield strengths of the composite at 25 and 650 °C were 998.3 and 774.9 MPa, showing an 11.8% and 9.2% improvement when compared with the Ti2AlNb-based alloy. Overall, (Ti, Nb)B possessed an excellent strengthening effect and inhibited the strength weakening of the PPBs area at high temperatures; the reinforcement content mainly affected the mechanical properties of the (Ti, Nb)B/Ti2AlNb composites by altering the α2-precipitated amount and the morphology of (Ti, Nb)B in the PPBs area. Both the continuous precipitation of the brittle α2 phase and the agglomeration of the (Ti, Nb)B reinforcement dramatically deteriorated the mechanical properties.

Atom Interferometry with Floquet Atom Optics.

Floquet engineering offers a compelling approach for designing the time evolution of periodically driven systems. We implement a periodic atom-light coupling to realize Floquet atom optics on the strontium ^{1}S_{0}-^{3}P_{1} transition. These atom optics reach pulse efficiencies above 99.4% over a wide range of frequency offsets between light and atomic resonance, even under strong driving where this detuning is on the order of the Rabi frequency. Moreover, we use Floquet atom optics to compensate for differential Doppler shifts in large momentum transfer atom interferometers and achieve state-of-the-art momentum separation in excess of 400 ℏk. This technique can be applied to any two-level system at arbitrary coupling strength, with broad application in coherent quantum control.

One-pot synthesis of tri- and di-fluoromethylated bis(indolyl)methanols via Friedel-Crafts-type acylation and alkylation.

A simple and efficient methodology for the first synthesis of tri- and di-fluoromethyl-bis(indolyl)methanols has been demonstrated through a one-pot Friedel-Crafts-type acylation-alkylation of readily available indoles and fluorinated acids. This simple protocol was successfully performed under metal-, additive-, toxic-solvent-, and protective-gas-free conditions, and delivered a wide range of tri- and di-fluoromethyl-bis(indolyl)methanols in moderate to high yields. Notably, this reaction can tolerate diverse vital and reactive functional groups. Furthermore, this one-pot Friedel-Crafts-type acylation-alkylation can be readily expanded to the gram scale with no obvious decrease in the yield, demonstrating its high application potential.

Nanocellulose with unique character converted directly from plants without intensive mechanical disintegration.

TEMPO oxidized nano-fibrillated cellulose (TONFC) has been used in different applications including biomedical, packing materials, paints and cosmetics because of its higher transparency, mechanical properties and better biocompatibility. However, pulping is always required to remove lignin and hemicellulose, and high-energy homogenization is required to defibrillate cellulose bundle into filament. Therefore, it is desirable to find a novel way to get TONFC with high carboxyl content without intensive mechanical disintegration. In this work, nanocellulose (TOHOLO) with higher carboxyl groups (2.2 ± 0.2 mmol/g) and smaller size (length = 400-685 nm and diameter = 5.9 nm) was prepared by a two-step strategy without intensive mechanical homogenization. In addition to the advantages in terms of diameter and carboxyl groups, TOHOLO showed better transparency and re-dispersibility as well as higher mechanical properties (122.8 MPa) compared to previous reports. Furthermore, for high carboxyl group and dispersibility, the TOHOLO can be used as a reinforcing filler to fabricate nanocomposites. The reinforced PVA fibers show a tensile strength of 484.4 MPa, which is about 170 % higher than comparison samples (PVA/TOCN-M, 291.9 MPa).

Scalable Nano Building Blocks of Waterborne Polyurethane and Nanocellulose for Tough and Strong Bioinspired Nanocomposites by a Self-Healing and Shape-Retaining Strategy.

Nature has given us significant inspiration to reproduce bioinspired materials with high strength and toughness. The fabrication of well-defined three-dimensional (3D) hierarchically structured nanocomposite materials from nano- to the macroscale using simple, green, and scalable methods is still a big challenge. Here, we report a successful attempt at the fabrication of multidimensional bioinspired nanocomposites (fiber, films, plates, hollow tubes, chair models, etc.) with high strength and toughness through self-healing and shape-retaining methods using waterborne polyurethane (WPU) and nanocellulose. In our method, the prepared TEMPO oxide cellulose nanofiber (TOCNF)-WPU hybrid films show excellent moisture-induced self-healing and shape-retaining abilities, which can be used to fabricate all sorts of 3D bioinspired nanocomposites with internal aligned and hierarchical architectures just using water as media. The tensile and flexural strength of the self-assembled plate can reach 186.8 and 193.2 MPa, respectively, and it also has a high toughness of 11.6 MJ m-3. Because of this bottom-up self-assembly strategy, every multidimensional structure we processed has high strength and toughness. This achievement would provide a promising future to realize a large-scale and reliable production of various sorts of bioinspired multidimensional materials with high strength and toughness in a sustainable manner.

Strategy to Fabricate a Strong and Supertough Bio-Inspired Fiber with Organic-Inorganic Networks in a Green and Scalable Way.

Green and scalable production of some fibrous materials with higher fracture energy has long been the goal of researchers. Although some progress has been made in recent years in the research of materials with high fracture energy, inspired by the fiber structure of spider silk, it is still a great challenge to produce artificial fibers with extremely high toughness using a simple and green process. Here, we use the molecular and nanoscale engineering of calcium phosphate oligomers (CaP, < 1 nm) and waterborne polyurethanes (WPU) macromolecules that have strong interactions to form organic-inorganic networks just like ß-sheet crystalline and flexible amorphous regions in spider silk. Through a simple and green route based on widespread paper string processing techniques, we fabricate a strong and supertough bioinspired fiber with a high strength (442 MPa), which is 7-15 times higher than the strength of counterpart PU (20-30 MPa), and a super toughness (640 MJ m-3), which is 2-3.5 times higher than the toughness of spider dragline silk. This technique provides a strategy for industrially manufacturing spider fiber-like artificial fibers with a super toughness.

Preparation of self-reinforced starch films for use as hard capsule material.

A strategy for preparation of self-reinforced starch films for use as hard capsule material is introduced. In this study, the hydroxypropylated-crosslinked potato starch (HCPS) was prepared and used to reinforce the hydroxypropylated-hydrolyzed potato starch (HHPS) films. The paste properties of starch samples and the morphology of starch films were investigated by a rapid visco analyzer (RVA) and scanning electron microscope (SEM), respectively. It was found that the matrix/particle interface was greatly improved after the hydroxypropylation of crosslinked starch. The strain and toughness of the starch composite films were increased by about 30% and 50% after addition of 10 wt% HCPS particles, respectively. In addition, the self-reinforced starch film also had good oxygen barrier property, with its oxygen permeating coefficient (OPC) at 5.09 × 10-12 cm3·cm/cm2·s·cmHg (50% RH). The fragmentation rate of starch capsules has also decreased, indicating it is an alternative material for the preparation of hard capsules.

Iron-catalyzed alkylation of carbazole derivatives via hydroarylation of styrenes.

The first direct and selective 3,6-di-alkylation of carbazoles via iron-catalyzed hydroarylation of styrenes is demonstrated. This simple, general and efficient method could deliver a wide range of di-benzyl-carbazoles with high chemo- and regio-selectivity at room temperature in up to 96% yield with no need for a noble-metal catalyst, directing group or additives.

Substrate-Controlled Regiodivergent Synthesis of Fluoroacylated Carbazoles via Friedel-Crafts Acylation.

A general, efficient, and substrate-controlled regiodivergent trifluoroacetylation of carbazoles has been developed through Friedel-Crafts acylation. This strategy was applicable to a wide scope of readily available substituted carbazoles at air atmosphere without using a metal catalyst, affording the corresponding trifluoroacetylated carbazoles in up to 99% yield. The divergency of the products and the orientation rules have been illustrated based on different substituents on carbazole rings. This method could also be extended to the synthesis of chlorodifluoroacetylated and pentafluoropropionylated carbazoles, which have been achieved for the first time.

Fe(OTf)3- and γ-Cyclodextrin-Catalyzed Hydroamination of Alkenes with Carbazoles.

A Fe(OTf)3- and γ-cyclodextrin catalyzed hydroamination of alkenes with carbazoles is demonstrated. This biomimetic-catalyst-oriented sustainable and green method could deliver a wide scope of N-alkylated carbazoles and N-alkylated-carbazole-fused aromatics in up to 97% yield. The salient features of this transformation include simple and benign reaction conditions with no need for a strong base, additive, or the irradiation of light.

Large Momentum Transfer Clock Atom Interferometry on the 689 nm Intercombination Line of Strontium.

We report the first realization of large momentum transfer (LMT) clock atom interferometry. Using single-photon interactions on the strontium ^{1}S_{0}-^{3}P_{1} transition, we demonstrate Mach-Zehnder interferometers with state-of-the-art momentum separation of up to 141 ℏk and gradiometers of up to 81 ℏk. Moreover, we circumvent excited state decay limitations and extend the gradiometer duration to 50 times the excited state lifetime. Because of the broad velocity acceptance of the interferometry pulses, all experiments are performed with laser-cooled atoms at a temperature of 3 µK. This work has applications in high-precision inertial sensing and paves the way for LMT-enhanced clock atom interferometry on even narrower transitions, a key ingredient in proposals for gravitational wave detection and dark matter searches.

Reliability and validity of the Mandarin version of the Continuity Assessment Record and Evaluation for older people who are transferred between hospitals and nursing homes in China.

To date, assessment tools for older people are different between hospitals and nursing homes in China. The difference between assessment tools can lead to poor communication of information between hospitals and nursing homes, which causes discontinuity of care and adverse outcomes when older people are transferred between these different settings. Continuity Assessment Record and Evaluation (CARE) is a comprehensive geriatric assessment tool developed in the United States of America. This study aimed to evaluate the reliability and validity of the Mandarin Version of CARE for older people who are transferred between hospitals and nursing homes. Using a convenience sampling method, 120 older people in hospitals and 120 older people in nursing homes in Shanghai were selected to test the internal consistency, interrater reliability and criterion-related validity of CARE from May to November 2017. When used among hospital, 70.0% (7/10) of the subscales had a Cronbach's alpha coefficients of greater than 0.7, 94.3% (50/53) of the items had an intraclass correlation coefficient (ICC) of greater than 0.75. When used in nursing homes, 90.0% (9/10) of the subscales had a Cronbach's alpha coefficients of greater than 0.7, 94.3% (50/53) of the items had an ICC of greater than 0.75. For both settings, the correlation coefficients of the subscales with their corresponding instruments for criterion-related validity were all greater than 0.8 (p < .01). The Mandarin version of CARE exhibits good reliability and validity. It can be used as an assessment tool for transition between hospitals and nursing homes.

Synergistic effect of graphene oxide/montmorillonite-sodium carboxymethycellulose ternary mimic-nacre nanocomposites prepared via a facile evaporation and hot- pressing technique.

Montmorillonite (MMT) and graphene oxide (GO), as important building block materials, are becoming hot candidates to construct biomimetic hierarchical structure materials. In this work, we fabricated integrated strong and stiff cellulosed-based nanocomposites via a simple water-solution evaporation and hot-pressing technique. It is found there are synergistic effect among the MMT, GO and carboxymethycellulose-Na (CMC-Na) under hot-pressing. Interestingly, it is also proved that there is chemical crosslinking between MMT and GO except hydrogen bonds under our experiment condition. The tensile strength and toughness of graphene oxide/montmorillonite-sodium carboxymethycellulose (GO/MMT-CMC) hybrid films reach up to 320.11 ± 12.22 MPa and 7.79 ± 1.78 MJ/m3, respectively, which were about 2.37 and 4.33 times higher than that of pure nacre; In addition, the artificial composites show excellent oxygen gas barrier and flame resistance properties. When the GO content is about 1.4 wt%, the oxygen permeability of GO/MMT-CMC is 0.94 × 10-12 cm³·cm/cm2·s·cmHg, which is 50.79% lower than that of pure CMC films. Meanwhile, the GO/MMT-CMC ternary nanopapers demonstrate excellent self-extinguishing performance which attract interest in fire-shielding coating.

Genetic dissection of seedling vigour in a diverse panel from the 3,000 Rice (Oryza sativa L.) Genome Project.

Seedling vigour (SV) is important for direct seeding rice (Oryza sativa L.), especially in a paddy-direct seeding system, but the genetic mechanisms behind the related traits remain largely unknown. Here, we used 744 germplasms, having at least two subsets, for the detection of quantitative trait loci (QTLs) affecting the SV-related traits tiller number, plant height, and aboveground dry weight at three sampling stages, 27, 34, and 41 d after sowing. A joint map based on GAPIT and mrMLM produced a satisfying balance between type I and II errors. In total, 42 QTL regions, containing 18 (42.9%) previously reported overlapping QTL regions and 24 new ones, responsible for SV were detected throughout the genome. Four QTL regions, qSV1a, qSV3e, qSV4c, and qSV7c, were delimited and harboured quantitative trait nucleotides that are responsible for SV-related traits. Favourable haplotype mining for the candidate genes within these four regions, as well as the early SV gene OsGA20ox1, was performed, and the favourable haplotypes were presented with donors from the 3,000 Rice Genome Project. This work provides new information and materials for the future molecular breeding of direct seeding rice, especially in paddy-direct seeding cultivation systems.

An approach for reinforcement of paper with high strength and barrier properties via coating regenerated cellulose.

The applications of cellulose are increasing rapidly attributing to their biodegradability and renewability. However, most of these cellulose-based materials possess poor mechanical performance, which restrict their advanced applications. In this study, a facile method was applied to fabricate composite paper with excellent mechanical and barrier properties via simple coating dissolved cellulose in ionic liquid. Subsequently, the surface wettability, oxygen permeability and mechanical properties of the resulting composites were investigated. Remarkable, both the dry and wet tensile strength of the composite papers was dramatically increased up to 101 and 14.17 MPa, which was greater than controlled paper (63.98 and 1.15 MPa). Moreover, with only 2% weight loading of regenerated cellulose, million times decline of oxygen permeability coefficient was obtained. Though the composite papers showed enhanced hydrophilicity, it exhibited strong water-resistant and shape-retaining properties in water. Therefore, the resultant composite papers showed great potential in packaging application with higher humidity.

High-strength and morphology-controlled aerogel based on carboxymethyl cellulose and graphene oxide.

Composite aerogels with excellent mechanical properties were prepared by using carboxymethyl cellulose (CMC) as raw materials, 2D graphene oxide (GO) nanosheets as reinforcement, boric acid (BA) as cross-linker. By controlling the heat transfer rate, composite aerogels with isotropy and anisotropy structure were prepared, the mechanical and heat insulation properties were studied. The isotropy composite aerogel had compression strength of 110 kPa at 60% compression, which was 5 times of the axial and 14 times of the radial of anisotropy structure composite aerogels, and thermal conductivity was also lower than those of two directions of anisotropy composite aerogel. Besides, the mechanical properties of isotropy composite aerogels increased with the increase of GO content. When GO content was up to 5 wt%, the compressive strength and Young's modulus of composite aerogels reached 349 kPa and 1029 kPa, which were 1.6 and 4.5 times that of CMC aerogels, respectively.

Synthesis of hollow Cu1.8S nano-cubes for electromagnetic interference shielding.

The applications of inorganic semiconductor nano-structures as electromagnetic interference (EMI) shielding materials have been scarcely researched. Herein, we have designed hollow Cu1.8S nano-cubes via a mild anion exchange and etching process. These 30 wt% hollow Cu1.8S nano-cubes loaded in wax can display 30 dB of EMI shielding effectiveness (SE) in the whole tested frequency range of 2-18 GHz with a sample thickness of only 1 mm. This good EMI shielding performance can be attributed to the high electric conductivity, which leads to a high dielectric constant. This research opens up the possibility for the applications of inorganic semiconductor nano-structures as lightweight EMI shielding materials, especially in the areas of aerospace, automobile and sophisticated electronics.