Millimeter wave gesture recognition using multi-feature fusion models in complex scenes.

As a form of body language, the gesture plays an important role in smart homes, game interactions, and sign language communication, etc. The gesture recognition methods have been carried out extensively. The existing methods have inherent limitations regarding user experience, visual environment, and recognition granularity. Millimeter wave radar provides an effective method for the problems lie ahead gesture recognition because of the advantage of considerable bandwidth and high precision perception. Interfering factors and the complexity of the model raise an enormous challenge to the practical application of gesture recognition methods as the millimeter wave radar is applied to complex scenes. Based on multi-feature fusion, a gesture recognition method for complex scenes is proposed in this work. We collected data in variety places to improve sample reliability, filtered clutters to improve the signal's signal-to-noise ratio (SNR), and then obtained multi features involves range-time map (RTM), Doppler-time map (DTM) and angle-time map (ATM) and fused them to enhance the richness and expression ability of the features. A lightweight neural network model multi-CNN-LSTM is designed to gestures recognition. This model consists of three convolutional neural network (CNN) for three obtained features and one long short-term memory (LSTM) for temporal features. We analyzed the performance and complexity of the model and verified the effectiveness of feature extraction. Numerous experiments have shown that this method has generalization ability, adaptability, and high robustness in complex scenarios. The recognition accuracy of 14 experimental gestures reached 97.28%.

The endophytic microbiome response patterns of Juglans regia to two pathogenic fungi.

The endophytic microbial community reassembles to participate in plant immune balance when the host plants are stressed by pathogens. However, it remains unclear whether this assembly is pathogen-specific and how regulatory pathways are coordinated in multi-pathogens. In order to investigate the effects of infection with Colletotrichum gloeosporioides (Cg treatment) and Fusarium proliferatum (Fp treatment) on walnut leaf endophytic microbiome in their assembly, co-occurrence pattern, and on comprehensive chemical function of the internal environment of leaf, an interaction system of the walnut-pathogenic fungi was constructed using seed embryo tissue culture technology. The study showed differences in the assembly of endophytic microbial communities in walnut trees across three groups (control group, Ck; Cg; Fp) after Cg and Fp treatments. Despite changes in relative abundances, the dominant communities in phyla and genera remained comparable during the infection of the two pathogens. Endophyte fungi were more sensitive to the pathogen challenge than endophyte bacteria. Both promoted the enrichment of beneficial bacteria such as Bacillus and Pseudomonas, changed the modularity of the community, and reduced the stability and complexity of the endophyte community. Pathogenic fungi infection mainly affects the metabolism of porphyrin and chlorophyll, purine metabolism, phenylpropane metabolism, and amino acid metabolism. However, there was no significant difference in the secondary metabolites for the different susceptible plants. By screening endogenous antagonistic bacteria, we further verified that Pseudomonas psychrotolerans and Bacillus subtilis had inhibitory effects on the two pathogenic fungi and participated in the interaction between the leaves and pathogenic fungi. The antibacterial substances may be 1-methylnaphthalene, 1,3-butadiene, 2,3-butanediol, and toluene aldehyde.

Comparative Analysis of Proton Conductivity in Two Zn-Based MOFs Featuring Sulfate and Sulfonate Functional Groups.

Metal-organic frameworks (MOFs) have shown promising potential as proton-conducting materials due to their tunable structures and high porosity. In this study, two novel MOFs had been successfully synthesized, one containing sulfate groups (MOF-1; [Zn4(TIPE)2(SO4)4(H2O)]·5H2O) and the other containing sulfonate groups (MOF-2; [Zn2(TIPE)(5-sip)(NO3)0.66]·0.34NO3·17.5H2O) (TIPE = 1,1,2,2-tetrakis(4-(1H-imidazole-1-yl)phenyl)ethene, H35-sip = 5-sulfoisophthalicacid), and the effect of the two groups on the proton conductivity of Zn-based MOFs had been investigated and compared for the first time. The proton conductivity of these MOFs was systematically measured at different temperatures and humidity conditions. Remarkably, the results revealed significant differences in proton conductivity between the two sets of MOFs. At 90 °C and 98% RH, MOF-1 and MOF-2 achieved optimal proton conductivity of 4.48 × 10-3 and 5.69 × 10-2 S·cm-1, respectively. This was due to the structural differences arising from the presence of different functional groups, which subsequently affected the porosity and hydrophilicity, thereby influencing the proton conductivity. Overall, this comparative study revealed the influence of sulfate and sulfonate groups on the proton conductivity of Zn-based MOFs. This research provided a feasible idea for the development of advanced MOF materials with enhanced proton conductivity and opened up new possibilities for their application in proton devices.

Structure and properties of metal-organic frameworks modulated by sulfate ions.

Anions play a significant role in the construction of metal-organic frameworks (MOFs). Anions can affect coordination between metal ions and organic ligands, and the formation of crystal structures, thereby affecting the structure and properties of MOFs. Two novel 3D porous MOFs ({[Cd3(TIPE)2(SO4)1.6(H2O)2.4]·2.8OH·6.2H2O}n (MOF-1) and {[Cd3(TIPE)2(SO4)3(H2O)2]·10H2O}n (MOF-2)) were successfully synthesized, by introducing SO42- to design and adjust their structure and properties, in which the sulfate ions not only participated in coordination but also played a bridging role. Both MOF-1 and MOF-2 exhibited high stability and strong fluorescence properties, and their fluorescence properties also changed compared to those of previously reported 2D nonporous MOF-3 ({[Cd2(TIPE)2Cl3(ACN)]·CdCl3·3H2O}n) with an identical ligand. They could also be used in combination with MOF-3 to distinguish between Fe3+ and Cr2O72- ions, due to a change in their fluorescence properties. In this work, the structure was reshaped by introducing sulfate ions, and the role and function of the sulfate ions in the structure were studied, providing a feasible idea for the design and precise regulation of MOFs.

Embolization of unruptured wide-necked aneurysms at the MCA bifurcation using the Neuroform atlas stent-assisted coiling: a two-center retrospective study.

Background: The management of middle cerebral artery (MCA) aneurysms remains a controversial topic, and MCA aneurysms have traditionally been treated primarily by surgical clipping. The Neuroform Atlas Stent™ (NAS, available from Stryker Neurovascular, Fremont, California) represents the latest generation of intracranial stents with improved stent delivery system capabilities. Objective: This study aims to investigate the safety, feasibility and efficacy exhibited by NAS in treating unruptured aneurysms at the MCA bifurcation. Methods: This was a two-center retrospective study involving 42 patients with unruptured wide-necked aneurysms (WNAs) of the MCA treated with the NAS from October 2020 to July 2022. Results: The stent was used to treat 42 cases of unruptured WNA at the MCA bifurcation. Endovascular treatment techniques had a 100% success rate. Immediate postoperative angiography found complete aneurysm occlusion in 34 patients (80.9%) (mRRC 1), neck remnant in 7 patients (16.7%) (mRRC 2), and residual aneurysm in 1 patient (2.4%) (mRRC 3). The thromboembolic complication rate was 2.4% (1/42). The follow-up period was 8.7 months on average (3-16 months). The last angiographic follow-up results revealed complete aneurysm occlusion in 39 patients (92.9%) (mRRC 1), neck remnant in 3 (7.1%) patients (mRRC 2), no aneurysm recanalization or recurrence, and no cases of stent intimal hyperplasia. During the latest clinical follow-up, all patients had an mRS score of 0. Conclusion: Our study demonstrates that the NAS can be applied to treat unruptured WNAs at the MCA bifurcation with favorable safety, feasibility, and efficacy.

Functional Materials for Water Restoration: A "Fish Cage" for Efficient Capture of Pb(II) Ions.

In this work, a "fish cage" material for trapping Pb(II) ions has been successfully obtained, which is a novel clathrate functionalized metal-oganic framework (Cage-MOF) by introducing free adsorption sites (SO42-). The three-dimensional (3D) cage structure of Cage-MOF gives it a larger contact area and can capture "swimming fish" (Pb(II)) like a "fishing cage" in a water solution. This is the first high-efficiency adsorption material obtained by introducing free coordination groups. Cage-MOF not only has excellent water stability but also improves the selectivity and affinity for Pb(II) ions in water because of the presence of sulfate adsorption sites, and its adsorption capacity is as high as 806 mg/g. This work shows a novel and effective idea for the synthesis of water restoration materials.

Research Progress in Boron-Modified Phenolic Resin and Its Composites.

As one of the most successful modified phenolic resins, boron-modified phenolic resin (BPF) has excellent heat resistance and ablative resistance, good mechanical and wear resistance, and flame retardancy. BPF and its composites can be widely used in areas such as aerospace, weapons and equipment, automobile brakes, and fire retardants. In this review, the current state of development of BPF and its composites is presented and discussed. After introducing various methods to synthesize BPF, functionalization of BPF is briefly summarized. Particular emphasis is placed on general methods used to fabricate BPF-based composites and the heat resistance, ablative resistance, mechanical property, wear resistance, flame retardancy, and water resistance of BPF-based composites. Finally, the challenges of this research area are summarized and its future outlook is prospected.

Bleeding the Excited State Energy to the Utmost: Single-Molecule Iridium Complexes for In Vivo Dual Photodynamic and Photothermal Therapy by an Infrared Low-Power Laser.

A series of cyclometalated Ir(III) complexes with morpholine and piperazine groups are designed as dual photosensitizers and photothermal agents for more efficient antitumor phototherapy via infrared low-power laser. Their ground and excited state properties, as well as the structural effect on their photophysical and biological properties, are investigated by spectroscopic, electrochemical, and quantum chemical theoretical calculations. They target mitochondria in human melanoma tumor cells and trigger apoptosis related to mitochondrial dysfunction upon irradiation. The Ir(III) complexes, particularly Ir6, demonstrate high phototherapy indexes to melanoma tumor cells and a manifest photothermal effect. Ir6, with minimal hepato-/nephrotoxicity in vitro, significantly inhibits the growth of melanoma tumors in vivo under 808 nm laser irradiation by dual photodynamic therapy and photothermal therapy and can be efficiently eliminated from the body. These results may contribute to the development of highly efficient phototherapeutic drugs for large, deeply buried solid tumors.

Self-supervised maize kernel classification and segmentation for embryo identification.

Introduction: Computer vision and deep learning (DL) techniques have succeeded in a wide range of diverse fields. Recently, these techniques have been successfully deployed in plant science applications to address food security, productivity, and environmental sustainability problems for a growing global population. However, training these DL models often necessitates the large-scale manual annotation of data which frequently becomes a tedious and time-and-resource- intensive process. Recent advances in self-supervised learning (SSL) methods have proven instrumental in overcoming these obstacles, using purely unlabeled datasets to pre-train DL models. Methods: Here, we implement the popular self-supervised contrastive learning methods of NNCLR Nearest neighbor Contrastive Learning of visual Representations) and SimCLR (Simple framework for Contrastive Learning of visual Representations) for the classification of spatial orientation and segmentation of embryos of maize kernels. Maize kernels are imaged using a commercial high-throughput imaging system. This image data is often used in multiple downstream applications across both production and breeding applications, for instance, sorting for oil content based on segmenting and quantifying the scutellum's size and for classifying haploid and diploid kernels. Results and discussion: We show that in both classification and segmentation problems, SSL techniques outperform their purely supervised transfer learning-based counterparts and are significantly more annotation efficient. Additionally, we show that a single SSL pre-trained model can be efficiently finetuned for both classification and segmentation, indicating good transferability across multiple downstream applications. Segmentation models with SSL-pretrained backbones produce DICE similarity coefficients of 0.81, higher than the 0.78 and 0.73 of those with ImageNet-pretrained and randomly initialized backbones, respectively. We observe that finetuning classification and segmentation models on as little as 1% annotation produces competitive results. These results show SSL provides a meaningful step forward in data efficiency with agricultural deep learning and computer vision.

Sound Target Detection Under Noisy Environment Using Brain-Computer Interface.

As an important means of environmental reconnaissance and regional security protection, sound target detection (STD) has been widely studied in the field of machine learning for a long time. Considering the shortcomings of the robustness and generalization performance of existing methods based on machine learning, we proposed a target detection method by an auditory brain-computer interface (BCI). We designed the experimental paradigm according to the actual application scenarios of STD, recorded the changes in Electroencephalogram (EEG) signals during the process of detecting target sound, and further extracted the features used to decode EEG signals through the analysis of neural representations, including Event-Related Potential (ERP) and Event-Related Spectral Perturbation (ERSP). Experimental results showed that the proposed method achieved good detection performance under noisy environment. As the first study of BCI applied to STD, this study shows the feasibility of this scheme in BCI and can serve as the foundation for future related applications.

mmSafe: A Voice Security Verification System Based on Millimeter-Wave Radar.

With the increasing popularity of smart devices, users can control their mobile phones, TVs, cars, and smart furniture by using voice assistants, but voice assistants are susceptible to intrusion by outsider speakers or playback attacks. In order to address this security issue, a millimeter-wave radar-based voice security authentication system is proposed in this paper. First, the speaker's fine-grained vocal cord vibration signal is extracted by eliminating static object clutter and motion effects; second, the weighted Mel Frequency Cepstrum Coefficients (MFCCs) are obtained as biometric features; and finally, text-independent security authentication is performed by the WMHS (Weighted MFCCs and Hog-based SVM) method. This system is highly adaptable and can authenticate designated speakers, resist intrusion by other unspecified speakers as well as playback attacks, and is secure for smart devices. Extensive experiments have verified that the system achieves a 93.4% speaker verification accuracy and a 5.8% miss detection rate for playback attacks.

Mechanically Robust and Flexible GO/PI Hybrid Aerogels as Highly Efficient Oil Absorbents.

Herein, mechanically robust and flexible graphene oxide/polyimide (GO/PI) hybrid aerogels (GIAs) were fabricated by a facile method, in which the mixed suspensions of the water-soluble polyimide precursor and graphene oxide (GO) sheets were freeze-dried, which was followed by a routine thermal imidation process. The porous GIAs obtained not only exhibit excellent elasticity and extremely low density values (from 33.3 to 38.9 mg.cm-3), but they also possess a superior compressive strength (121.7 KPa). The GIAs could support a weight of up to 31,250 times of its own weight, and such a weight-carrying capacity is much higher than that of other typical carbon-based aerogels. Having such a porous structure, and high strength and toughness properties make GIAs ideal candidates for oil spill cleanup materials. The oil/organic solvents' absorption capacity ranges from 14.6 to 85, which is higher than that of most other aerogels (sponges). With their broad temperature tolerance and acidic stability, the unique multifunctional GIAs are expected to further extend their application range into extreme environments.

Two Novel Three-Dimensional Tetraphenylethylene-Based Rare Earth MOFs with Ultra-High Proton Conductivity and Performance Stability.

Invited for the cover of this issue are the groups of Lin Du and Qi-Hua Zhao at Yunnan University. The image depicts astronauts as protons moving along the hydrogen-bond network in the channel of Eu-ETTB/Gd-ETTB. Read the full text of the article at 10.1002/chem.202202154.

Two Novel Three-Dimensional Tetraphenylethylene-Based Rare Earth MOFs with Ultra-High Proton Conductivity and Performance Stability.

In this work, the two example rare earth-based metal-organic frameworks (LaIII -based MOFs), Eu-ETTB and Gd-ETTB, were obtained by self-assembly. Both materials showed extremely high proton conductivity, with the proton conductivity of Eu-ETTB being 1.53×10-2  S cm-1 at 98 % relative humidity (RH) and 85 °C and that of Gd-ETTB being 2.63×10-2  S cm-1 at 98 % RH and 75 °C. This was almost the best performance observed for three-dimensional porous MOFs without post-synthetic modification and was based on milder conditions than for most materials. Furthermore, cycle test experiments and continuous work tests showed that both materials had excellent performance both in terms of stability and durability. Water vapor adsorption experiments showed that a large number of water molecules are adsorbed the hydrogen-bond network's being rebuilt by the adsorbed water molecules in the pore channel and thus optimizing the channels for proton transfer explained the MOF's high performance.

Physiological Mechanism of Exogenous 5-Aminolevulinic Acid Improved the Tolerance of Chinese Cabbage (Brassica pekinensis L.) to Cadmium Stress.

The 5-aminolevulinic acid (ALA), a new type of plant growth regulator, can relieve the toxicity of cadmium (Cd) to plants. However, its mechanism has not been thoroughly studied. In the study, the roles of ALA have been investigated in the tolerance of Chinese cabbage (Brassica pekinensis L.) seedlings to Cd stress. The results showed that Cd significantly reduced the biomass and the length of the primary root of seedlings but increased the malondialdehyde (MDA) and the hydrogen peroxide (H2O2) contents. These can be effectively mitigated through the application of ALA. The ALA can further induce the activities of antioxidant enzymes in the ascorbate-glutathione (AsA-GSH) cycle under Cd stress, which resulted in high levels of both GSH and AsA. Under ALA + Cd treatment, the seedlings showed a higher chlorophyll content and photosynthetic performance in comparison with Cd treatment alone. Microscopic analysis results confirmed that ALA can protect the cell structure of shoots and roots, i.e., stabilizing the morphological structure of chloroplasts in leaf mesophyll cells. The qRT-PCR results further reported that ALA downregulated the expressions of Cd absorption and transport-related genes in shoots (HMA2 and HMA4) and roots (IRT1, IRT2, Nramp1, and Nramp3), which resulted in the low Cd content in the shoots and roots of cabbage seedlings. Taken together, the exogenous application of ALA alleviates Cd stress through maintaining redox homeostasis, protecting the photosynthetic system, and regulating the expression of Cd transport-related genes in Chinese cabbage seedlings.

Natural Deterioration Processes of Salix psammophila Sand Barriers in Atmospheric Exposure Section.

The atmospheric conditions of desert environments are important for the protection of Salix psammophila Sand Barrier, and these conditions can affect and change the structure and performance of the sand barrier, causing them to lose their wind proofing and sand fixing benefits. In this study, we have first examined the key environmental factors that affect the exposure of S. psammophila sand barrier. Then, we assessed how key factors in the desert atmospheric environment affect structural aging and performance. The relative crystallinity and chemical composition changes in the sand barrier were measured by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), and the main degradation factors and processes were discussed. The results showed that the degradation degree of the exposed S. psammophila sand barrier was mainly affected by moisture and ultraviolet radiation. Lignin was the main component and the source of photodegradation and photodiscoloration observed in the sand barrier. However, other polysaccharides, such as cellulose and hemicellulose, were less affected by photodegradation. The stress generated by alternating desorption-absorption was the main cause of the expansion and contraction, deformation, cracking, and warping observed in S. psammophila sand barrier. We also found a series of irreversible changes and losses that occurred, which affected the natural material properties of S. psammophila sand barrier exposed to atmospheric conditions for several years. Exposure times between 5 and 7 years were the most important turning point in time for determining the deterioration of the S. psammophila sand barrier. Our results highlighted the importance of the interactions between atmospheric factors and the exposed atmospheric sections of the S. psammophila sand barrier from the perspective of environmental effects. However, the exact mechanisms of the sand barrier deterioration still need further investigation. Nevertheless, our overall findings advanced the current understanding of the environmental effects of S. psammophila sand barrier for ecological restoration and desertification reversal, especially in stressful desert environments.

A Novel Coordination Polymer as Adsorbent Used to Remove Hg(II) and Pb(II) from Water with Different Adsorption Mechanisms.

Under the hydrothermal condition, a new type of two-dimensional coordination polymer ([Cd(D-Cam)(3-bpdb)]n, Cd-CP) has been constructed. It is composed of D-(+)-Camphoric-Cd(II) (D-cam-Cd(II)) one-dimensional chain and bridging 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (3-bpdb) ligands. Cd-CP has a good removal effect for Hg(II) and Pb(II), and the maximum adsorption capacity is 545 and 450 mg/g, respectively. Interestingly, thermodynamic studies have shown that the adsorption processes of Hg(II) and Pb(II) on Cd-CP use completely different thermodynamic mechanisms, in which the adsorption of Hg(II) is due to a strong electrostatic interaction with Cd-CP, while that of Pb(II) is through a weak coordination with Cd-CP. Moreover, Cd-CP has a higher affinity for Hg(II), and when Hg(II) and Pb(II) coexist, Cd-CP preferentially adsorbs Hg(II).

Highly efficient and selective capture Pb(II) through a novel metal-organic framework containing bifunctional groups.

The design and development of materials with a selective adsorption capacity for Pb(II) are very important for environmental governance and ecological safety. In this work, a novel 3D metal-organic framework ([Cd2H4L4Cl2SO4]·4H2O, Cd-MOF) is constructed using a multiple pyrazole heterocycles tetraphenylethylene-based ligand (H4L4) and CdSO4 which containing Pb(II) adsorption sites (SO42-). Studies have shown that the Cd-MOF has outstanding stability, and its maximum adsorption value of Pb(II) can be as high as 845.55 mg/g, which is higher than that of most MOFs or MOFs modified materials. It is worth emphasizing that the Cd-MOF have excellent recyclability due to the unique adsorption mechanism of the Cd-MOF. Thermodynamic studies have shown that Pb(II) adsorption of the Cd-MOF is a spontaneous endothermic process. Specific selective adsorption, exceptional stability and remarkable recyclability make the Cd-MOF a potential material for industrial capture and recovery of Pb(II) from water.

An AIE material with time-dependent luminescence conversion obtained by 2D coordination polymer modification via covalent post-synthetic modification.

In this study, we reported the covalent post-synthetic modification (PSM) of a luminescent complex to achieve aggregation-induced emission (AIE), prepared using the Schiff base reaction of TPE-CHO and HLC-NH2, denoted by HLC-NH2-TPE. HLC-NH2 formed a 2D luminescent complex which was constructed using 4,4'-diamino-[1,1'-biphenyl]-2,2'-dicarboxylic acid and zinc ions via a solvothermal reaction. HLC-NH2-TPE inherited the luminescence properties of HLC-NH2 and exhibited noticeable AIE properties in response to environmental viscosities and temperature changes. Interestingly, HLC-NH2-TPE displayed a time-dependent luminescence conversion phenomenon in a mixed solution of DMF/H2O (v : v/1 : 9).

Fungal community characteristics and driving factors during the decaying process of Salix psammophila sand barriers in the desert.

Wood-inhabiting fungi are crucial to wood decay and decomposition in S. psammophila sand barriers, which in turn consumingly influence nutrient dynamics in desert soils. In the case of an extremely arid desert, as opposed to forests, little of known about the fungal community composition of decaying wood and the effects of decomposing wood on soil physical and chemical properties. Combined with high-throughput gene sequencing technology, we investigated the relationships between microenvironment factors with fungal community composition and diversity during the decomposition of Salix psammophila sand barriers. The results showed that the destruction of lignocellulose components during the decay process of S. psammophila sand barrier alters the physical and chemical properties of the surrounding soil. Compared with one-year sand barrier, lignin and cellulose of seven-year S. psammophila sand barrier decreased by 40.48% and 38.33%, respectively. Soil available potassium and available nitrogen increased by 39.80% and 99.46%, respectively. We confirmed that soil available nitrogen, soil pH and soil moisture content significantly affected the fungal community distribution of S. psammophila sand barriers. Sordariomycetes are mainly affected by the positive correlation of soil pH, while Eurotiomycetes are most affected by the positive correlation of soil moisture content and soil porosity. Although our results highlighted the importance of bidirectional interactions between fungi in decayed sand barriers and soil properties, their contribution to the desert ecosystem still needs further confirmation from future studies. However, overall our findings improved the current understanding of the sand barrier-soil interactions on the process of ecological restoration.