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Elderly patients in immunosuppressive status may have an increased occurrence of illness and risk of poor prognosis. It is a generally overlooked population that we should pay more attention to their risk factors of sickness and mortality.Eight hundred and nine patients who were diagnosed with bloodstream infection in immunosuppressive states during accepting treatment in our hospital were selected from 2015 to 2019.The demographic data, underlying diseases, comorbidity, inducement, complications, pathogen sources, etiologies, and the antibiotics therapy were analyzed between ages 65 years groups and ages 65 years groups.The clinical characteristics of totally 809 immunosuppressed people diagnosed with bloodstream infection were analyzed, and among those people about 371 were ages 65 years. By univariate logistic regression analysis and multivariate logistic regression analysis, we found that hypertension (OR: 2.864, 95% CI 2.024-4.051, P 0.0001), cerebral Infarction (OR: 4.687, 95% CI 2.056-10.686, P 0.0001), coronary heart disease (OR: 1.942, 95% CI 1.168-3.230, P = 0.011), acute pancreatitis (OR: 3.964, 95% CI 2.059-7.632, P 0.0001), infective endocarditis (OR: 6.846, 95% CI 1.828-25.644, P = 0.004), aortic dissection (OR: 9.131, 95% CI 3.190-26.085, P 0.0001), chemotherapy (OR: 3.462, 95% CI 1.815-6.603, P 0.0001), transplant status (OR: 20.031, 95% CI 4.193-95.697, P 0.0001), and respiratory tract infection (OR: 2.096, 95% CI 1.269-3.461, P = 0.004) were significantly different between ages 65 years groups and ages 65 years groups.Hypertension, cerebral Infarction, coronary heart disease, acute pancreatitis, infective endocarditis, aortic dissection, chemotherapy, transplant status, and pathogen source of respiratory tract were the independent risk factors of ages 65 years in immunosuppressed patients, which would have the benefit to discriminate the prognostic factors in immunosuppressive elderly people with bloodstream infection.

It is of great significance to quickly detect underwater cracks as they can seriously threaten the safety of underwater structures. Research to date has mainly focused on the detection of above-water-level cracks and hasn’t considered the large scale cracks. In this paper, a large-scale underwater crack examination method is proposed based on image stitching and segmentation. In addition, a purpose of this paper is to design a new convolution method to segment underwater images. An improved As-Projective-As-Possible (APAP) algorithm was designed to extract and stitch keyframes from videos. The graph convolutional neural network (GCN) was used to segment the stitched image. The GCN’s m-IOU is 24.02% higher than Fully convolutional networks (FCN), proving that GCN has great potential of application in image segmentation and underwater image processing. The result shows that the improved APAP algorithm and GCN can adapt to complex underwater environments and perform well in different study areas.

Background and objectives Lumbar ligamentum flavum cyst is a rare spinal condition that can cause significant morbidity and neurological deficits. Traditional surgical treatment involves open surgery, which can be associated with prolonged recovery time and significant morbidity. In recent years, endoscopic treatment of lumbar ligamentum flavum cyst has emerged as a minimally invasive and effective alternative to open surgery, but only a few cases have been reported in the literature. This paper describes our experience with endoscopic resection of an L4/5 ligamentum flavum cyst through an interlaminar approach and reviews the literature on the treatment of lumbar ligamentum flavum cyst. Methods An 87-year-old man presented with lameness in the left leg, and magnetic resonance imaging (MRI) showed nerve compression by a ligamentum flavum cyst at the L4/5 intervertebral plane. The patient underwent endoscopic resection of the ligamentum flavum cyst through a left interlaminar approach with the facet joint preserved. The present study was approved by the Ethics Committee of our hospital. The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request. Text regarding patient consent is not applicable for this case. Results Postoperative clinical results improved significantly, and postoperative MRI showed complete cyst resection. Conclusion Total endoscopic resection via an interlaminar approach provides a new minimally invasive approach for the surgical treatment of lumbar ligamentum flavum cyst, which can be used as a reference by clinicians.

Carbonic Anhydrase 1 (CAR1) is a zinc-metalloenzyme that catalyzes the hydration of carbon dioxide, and the alteration of CAR1 has been implicated in neuropsychiatric disorders. However, the mechanism underlying the role of CAR1 in major depressive disorder (MDD) remains largely unknown. In this study, we report the decreased level of CAR1 in MDD patients and depression-like model rodents. We found that CAR1 is expressed in hippocampal astrocytes and CAR1 regulates extracellular bicarbonate concentration and pH value in the partial hilus. Ablation of the CAR1 gene increased the activity of granule cells via decreasing their miniature inhibitory postsynaptic currents (mIPSC), and caused depression-like behaviors in CAR1-knockout mice. Astrocytic CAR1 expression rescued the deficits in mIPSCs of granule cells and reduced depression-like behaviors in CAR1 deficient mice. Furthermore, pharmacological activation of CAR1 and overexpression of CAR1 in the ventral hippocampus of mice improved depressive behaviors. These findings uncover a critical role of CAR1 in the MDD pathogenesis and its therapeutic potential.

Background Cervical cancer (CC) is the 3rd most common cancer in women and the 4th leading cause of deaths in gynaecological malignancies, yet the exact progression of CC is inconclusive, mainly due to the high complexity of the changing tumour microenvironment (TME) at different stages of tumorigenesis. Importantly, a detailed comparative single-nucleus transcriptomic analysis of tumour microenvironment (TME) of CC patients at different stages is lacking. Methods In this study, a total of 42,928 and 29,200 nuclei isolated from the tumour tissues of stage-I and II CC patients and subjected to single-nucleus RNA sequencing (snRNA-seq) analysis. The cell heterogeneity and functions were comparatively investigated using bioinformatic tools. In addition, label-free quantitative mass spectrometry based proteomic analysis was carried out. The proteome profiles of stage-I and II CC patients were compared, and an integrative analysis with the snRNA-seq was performed. Results Compared with the stage-I CC (CCI) patients, the immune response relevant signalling pathways were largely suppressed in various immune cells of the stage-II CC (CCII) patients, yet the signalling associated with cell and tissue development was enriched, as well as metabolism for energy production suggested by the upregulation of genes associated with mitochondria. This was consistent with the quantitative proteomic analysis that showed the dominance of proteins promoting cell growth and intercellular matrix development in the TME of CCII group. The interferon-α and γ responses appeared the most activated pathways in many cell populations of the CCI patients. Several collagens, such as COL12A1, COL5A1, COL4A1 and COL4A2, were found significantly upregulated in the CCII group, suggesting their roles in diagnosing CC progression. A novel transcript AC244205.1 was detected as the most upregulated gene in CCII patients, and its possible mechanistic role in CC may be investigated further. Conclusions Our study provides important resources for decoding the progression of CC and set the foundation for developing novel approaches for diagnosing CC and tackling the immunosuppressive TME.

Wide transmittance range is an essential factor for the design of infrared optical materials. Traditionally, the designs of mid-far infrared crystals have focused on oxygen-free systems of chalcogenides and pnictides. Nevertheless, the introduction of elements with large atomic numbers, such as the lone-pair cation Pb2+ and halogen anion I−, based on the oxyhalides, can broaden the infrared transmittance range. Thus, two new polymorphs of Pb(II)-containing oxyhalides, Pb14O8I12 (α-POI) and Pb7O4I6 (β-POI), are successfully synthesized via the high-temperature solution method. Interestingly, they crystallize in the same space group, $$P\bar 1$$ , and present unprecedented [O8Pb14] clusters from the perspective of oxo-centered [OPb4] basic units. Remarkably, POI exhibits a quite wide transparent range (0.47–16.0 µm), which enlightens the oxyhalides with prominent infrared optical properties. Additionally, the first principles calculations show that they have large birefringence (0.139 and 0.108 for α- and β-POI at 1064 nm, respectively), which makes POI promising infrared optical materials.

Switch/sucrose-nonfermenting (SWI/SNF) complexes play a key role in chromatin remodeling. Recent studies have found that SMARCC2, as the core subunit of the fundamental module of the complex, plays a key role in its early assembly. In this study, we found a unique function of SMARCC2 in inhibiting the progression of glioblastoma by targeting the DKK1 signaling axis. Low expression of SMARCC2 is found in malignant glioblastoma (GBM) compared with low-grade gliomas. SMARCC2 knockout promoted the proliferation of glioblastoma cells, while its overexpression showed the opposite effect. Mechanistically, SMARCC2 negatively regulates transcription by dynamically regulating the chromatin structure and closing the promoter region of the target gene DKK1, which can be bound by the transcription factor EGR1. DKK1 knockdown significantly reduced the proliferation of glioblastoma cell lines by inhibiting the PI3K–AKT pathway. We also studied the functions of the SWIRM and SANT domains of SMARCC2 and found that the SWIRM domain plays a more important role in the complete chromatin remodeling function of SMARCC2. In addition, in vivo studies confirmed that overexpression of SMARCC2 could significantly inhibit the size of intracranial gliomas in situ in nude mice. Overall, this study shows that SMARCC2, as a tumor suppressor, inhibits the proliferation of glioblastoma by targeting the transcription of the oncogene DKK1 through chromatin remodeling, indicating that SMARCC2 is a potentially attractive therapeutic target in glioblastoma.

Background Meningeal carcinomatosis is mainly associated with breast cancer, lung cancer, and melanoma. However, meningeal carcinomatosis secondary to a neurenteric cyst with malignant features is extremely rare. Case presentation We report the case of a 35-year-old woman who was admitted to the hospital with a 10-month history of headache, 6-month history of diplopia, 4-month history of hearing loss, and 1-month history of back pain, suggesting a diagnosis of chronic meningitis. Notably, enhanced brain and spinal cord magnetic resonance imaging (MRI) revealed extensive lesions with enhancement signals in the pia mater of the pons and cervical, thoracic, and lumbar spinal cord. The cerebral spinal fluid profile showed that pressure was significantly elevated, with a slight increase in leukocytes that mostly comprised mononuclear cells and decreased glucose concentration. Cytology evaluation showed a small cluster of atypical nuclei, which were suspected to be tumor cells arising from the epithelium. However, no primary tumor was found through comprehensive body and skin screening. After a histopathological biopsy of subarachnoid meninx of the thoracic spinal canal, the cause of meningeal carcinomatosis of this patient was determined as neurenteric cysts with malignant features, which is extremely rare. Conclusion This is the first case to ever report neurenteric cysts as a cause of leptomeningeal carcinomatosis and the first ever report of neurenteric cysts presenting as leptomeningeal carcinomatosis without typical cyst visible on brain MRI. This extremely rare case provided a novel view on the pathogenesis of meningeal carcinomatosis and clinical presentation of neurenteric cysts, highlighting the value of meningeal biopsy in chronic meningitis of unknown causes.

Maintaining a proper balance between the glutamate receptor-mediated neuronal excitation and the A type of GABA receptor (GABAAR) mediated inhibition is essential for brain functioning; and its imbalance contributes to the pathogenesis of many brain disorders including neurodegenerative diseases and mental illnesses. Here we identify a novel glutamate-GABAAR interaction mediated by a direct glutamate binding of the GABAAR. In HEK293 cells overexpressing recombinant GABAARs, glutamate and its analog ligands, while producing no current on their own, potentiate GABA-evoked currents. This potentiation is mediated by a direct binding at a novel glutamate binding pocket located at the α+/β− subunit interface of the GABAAR. Moreover, the potentiation does not require the presence of a γ subunit, and in fact, the presence of γ subunit significantly reduces the potency of the glutamate potentiation. In addition, the glutamate-mediated allosteric potentiation occurs on native GABAARs in rat neurons maintained in culture, as evidenced by the potentiation of GABAAR-mediated inhibitory postsynaptic currents and tonic currents. Most importantly, we found that genetic impairment of this glutamate potentiation in knock-in mice resulted in phenotypes of increased neuronal excitability, including decreased thresholds to noxious stimuli and increased seizure susceptibility. These results demonstrate a novel cross-talk between excitatory transmitter glutamate and inhibitory GABAAR. Such a rapid and short feedback loop between the two principal excitatory and inhibitory neurotransmission systems may play a critical homeostatic role in fine-tuning the excitation-inhibition balance (E/I balance), thereby maintaining neuronal excitability in the mammalian brain under both physiological and pathological conditions.

Electron beam additive manufacturing is an effective method for the fabrication of complex metallic components. With rapid solidification, the characteristics of microsegregation within the interdendritic region are interesting and important for the subsequent phase transformation and final mechanical properties. However, in view of the microsecond lifetime and the small length scale of the molten pool, experimentally investigating microsegregation is challenging, even with electron probe micro-analysis. In this study, a multiphase-field model coupled with the real thermodynamic data of Ti6Al4V alloy was successfully developed and applied to simulate the rapid solidification of columnar β grains via electron beam additive manufacturing. The thermal gradient (G) and cooling rate (R) were obtained from a 3D powder-scale multiphysics simulation and provided as inputs to a multiphase-field model. The effects of the electron beam process parameters and thermal conditions on the columnar β grains were investigated. Liquid films and droplets were observed to have solute enrichment in the intercellular region. The size of the liquid film increased at a lower scanning speed and energy power. Increasing the scanning speed and energy power refined the columnar β grains and decreased the liquid film size. The extent of microsegregation considerably increased at lower energy power, whereas the change in scanning speed had little effect on the microsegregation. The results also indicate that solute vanadium results in significant solute trapping and microsegregation during the rapid solidification of the Ti6Al4V alloy.

Glycosylated PD-L1 is a more reliable biomarker for immune checkpoint therapy and plays important roles in tumor immunity. Glycosylation of PD-L1 hinders antibody-based detection, which is partially responsible for the inconsistency between PD-L1 immunohistochemical results and therapeutic treatment response. Herein, we present a proximity ligation assay mediated rolling circle amplification (PLA-RCA) strategy for amplified imaging of glycosylated PD-L1 in situ. The strategy relies on a pair of DNA probes: an aptamer probe to specifically recognize cellular surface protein PD-L1 and a glycan conversion (GC) probe for metabolic glycan labeling. Upon proximity ligation of sequence binding to the two probes, the proximity ligation-triggered RCA occurs. The feasibility of the as-proposed strategy has been validated as it realized the visualization of PD-L1 glycosylation in different cancer cells and the monitoring of the variation of PD-L1 glycosylation during drug treatment. Thus, we envision the present work offers a useful alternative to track protein-specific glycosylation and potentially advances the investigation of the dynamic glycan state associated with the disease process.

Results of long-term explorations in the Kongqueting region, located in an East China Sea depression, suggest that the strong fault activity during the sedimentary period of the Pinghu formation significantly influenced the development of the sedimentary system. However, the aggregation and enrichment of the sand body under a tectonic background has become a problem that requires an immediate solution. Considering research outcomes of previous studies, this study used three-dimensional seismic and logging data to identify Y- or H-type and the en echelon distribution patterns of the fault plane, as well as identify the locations wherein the fault growth index value is greater than 1 in the study region, indicating the tectonic background of the fault transfer zone in the region. Second, the development type of the fault transfer zone was studied, and the sand body enrichment site was identified based on seismic inversion data and the development position of the fault transfer point. This helps clarify the evolution of sedimentary facies of the Pinghu formation combined with the sedimentary environment of the braided-river delta. Finally, after summarizing the coupling relationship between the synsedimentary fault systems and the sand body enrichment patterns, three sand-control models were determined, namely, the flexural-parallel, the en echelon collinear, and the torsional-reformed superimposed transfer zones. The findings of this study lay a foundation for the subsequent search of tectonic lithologic oil and gas reservoirs.

Numerous Bacillus spp. in soils show strong plant growth-promotion effects, but the molecular mechanism of most of these bacteria interacting with plants remains unknown. Uncovering the interaction pattern is of considerable importance for potential applications in agriculture. In the present study, we isolated the bacterium Bacillus megaterium strain WW1211 from the rhizosphere of Arabidopsis and investigated the mechanism of WW1211 on plant growth promotion at the cellular and molecular levels. Our results showed that inoculation of WW1211 substantially promoted shoot biomass and lateral root initiation but inhibited primary root growth. The promotion effect of WW1211 was counteracted by the addition of auxin biosynthesis or transport inhibitors, indicating an auxin-dependent pattern. The expression of auxin response and biosynthesis genes in Arabidopsis seedlings and the concentration of indole-3-acetic acid in Arabidopsis roots were enhanced by WW1211 inoculation. Furthermore, the meristematic zone length and the cell division in primary roots were inhibited by WW1211 inoculation. Auxin was enriched in the quiescent center, and the expression of auxin efflux and influx genes in the root tips was suppressed, indicating that WW1211 inhibited the growth of primary roots by modification of the auxin cycle and redistribution in the root meristem. Our results suggest that B. megaterium strain WW1211 induces auxin biosynthesis and simultaneously regulates auxin redistribution in plant shoots and roots, thus stimulating plant growth and lateral root initiation.

Zwitterionic hydrogels exhibit eminent nonfouling and hemocompatibility. Several key challenges hinder their application as coating materials for blood-contacting biomedical devices, including weak mechanical strength and low adhesion to the substrate. Here, we report a poly(carboxybetaine) microgel reinforced poly(sulfobetaine) (pCBM/pSB) pure zwitterionic hydrogel with excellent mechanical robustness and anti-swelling properties. The pCBM/pSB hydrogel coating was bonded to the PVC substrate via the entanglement network between the pSB and PVC chain. Moreover, the pCBM/pSB hydrogel coating can maintain favorable stability even after 21 d PBS shearing, 0.5 h strong water flushing, 1000 underwater bends, and 100 sandpaper abrasions. Notably, the pCBM/pSB hydrogel coated PVC tubing can not only mitigate the foreign body response but also prevent thrombus formation ex vivo in rats and rabbits blood circulation without anticoagulants. This work provides new insights to guide the design of pure zwitterionic hydrogel coatings for biomedical devices.

Purpose Pancreatic cancer is one of the deadliest cancers worldwide. The extracellular matrix (ECM) microenvironment affects the drug sensitivity and prognosis of pancreatic cancer patients. This study constructed an 8-genes pancreatic ECM scoring (PECMS) model, to classify the ECM features of pancreatic cancer, analyze the impact of ECM features on survival and drug sensitivity, and mine key molecules that influence ECM features in pancreatic cancer. Methods GSVA score calculation and clustering were performed in TCGA-PAAD patients. Lasso regression was used to construct the PECMS model. The association between PECMS and patient survival was analyzed and validated in the CPTAC-3 dataset of TCGA and our single-center retrospective cohort. The relationships between PECMS and features of the matrix microenvironment were analyzed. Finally, PECMS feature genes were screened and verified in pancreatic cancer specimens to select key genes associated with the ECM microenvironment. Result The survival of the PECMS-high group was significantly worse. The PECMS-high group showed higher oxidative stress levels, lower levels of antigen presentation- and MHC-I molecule-related pathways, and less immune effector cell infiltration. Data from IMvigor-210 cohort suggested that PECMS-low group patients were more sensitive to immune checkpoint blockers. The PECMS score was negatively correlated with chemotherapy drug sensitivity. The negative association of PECMS with survival and drug sensitivity was validated in our retrospective cohort. KLHL32 expression predicted lower oxidative stress level and more immune cells infiltrate in pancreatic cancer. Conclusion PECMS is an effective predictor of prognosis and drug sensitivity in pancreatic cancer patients. KLHL32 may play an important role in the construction of ECM, and the mechanism is worth further study.

Increased glycolysis is considered as a hallmark of cancer. Yet, cancer cell metabolic reprograming during therapeutic resistance development is under-studied. Here, through high-throughput stimulated Raman scattering imaging and single cell analysis, we find that cisplatin-resistant cells exhibit increased fatty acids (FA) uptake, accompanied by decreased glucose uptake and lipogenesis, indicating reprogramming from glucose to FA dependent anabolic and energy metabolism. A metabolic index incorporating glucose derived anabolism and FA uptake correlates linearly to the level of cisplatin resistance in ovarian cancer (OC) cell lines and primary cells. The increased FA uptake facilitates cancer cell survival under cisplatin-induced oxidative stress by enhancing beta-oxidation. Consequently, blocking beta-oxidation by a small molecule inhibitor combined with cisplatin or carboplatin synergistically suppresses OC proliferation in vitro and growth of patient-derived xenografts in vivo. Collectively, these findings support a rapid detection method of cisplatin-resistance at single cell level and a strategy for treating cisplatin-resistant tumors.

High-entropy alloys have attracted broad research interests due to their unique and intriguing mechanical properties. As a category of high-entropy alloys, eutectic high-entropy alloys combine the advantages of eutectic and high-entropy alloys, with excellent mechanical properties and casting properties. Some eutectic high-entropy alloys have been developed and shown exciting properties. In this paper, based on the physical metallurgy of eutectic high-entropy alloy, medium-entropy alloy Fe2NiCrNbx was designed. The as-cast alloy is composed of FCC and Laves phases, Nb element promotes the formation of primary Laves phase, and the hardness of the alloy increases with the increase in Nb element. Among the four alloys, the eutectic chemical composition at eutectic point is Fe2NiCrNb0.34; the alloy has a good strength and plastic balance. The ultimate comprehensive strength is 2267MPa, and the fracture strain is 30.8%. The experiment data and analyses identified the eutectic points and the excellent mechanical behavior. Moreover, the expensive Co element was replaced by Fe element. This cheap medium-entropy alloy has promising prospect in the consideration of the cost performance ratio.

Recrystallization has been a major method to induce heterogeneous grain structure for improving the strength–ductility combination of single-phase high-entropy alloys (HEAs). However, the recrystallization kinetics, which are the guideline for controlling the recrystallization behavior, of single-phase HEAs are relatively less explored. Here, we uncover the recrystallization behaviors of typical single-phase NiCoCrFe and Ni2CoCrFe HEAs. Our results showed that the two investigated HEAs exhibit almost similar recrystallization activation energy around 230 kJ·mol−1, but distinctively different recrystallization kinetics. This abnormal difference is attributed to the deformation twins of NiCoCrFe. These findings indicate that, except for textbook factors, deformation twinning significantly enhances the recrystallization behavior of HEAs.

Ti-15Nb-25Zr-(0, 4, 8)Fe (mol.%) alloys were prepared via spark plasma sintering (SPS) for 10 min at 800, 1000, and 1200 °C to study the effect of sintering temperatures and Fe content on the mechanical properties of alloys. The main phase of the alloys sintered at 800 °C is α phase. When the temperature is increased to 1000 and 1200 °C, the alloys are mainly β phase. Raising the sintering temperature can promote the diffusion of elements. Therefore, high strength and high plasticity are obtained in the alloys sintered at high temperature. The compressive strength of Ti-15Nb-25Zr sintered at 1200 °C is 1604 MPa, and the fracture strain is around 35%. The strength and plasticity are influenced by the complex effects of elemental diffusion, grain boundary and solid-solution strengthening. Adding Fe can improve the diffusion of elements, promote the formation of β grains and supply solid-solution strengthening effect. As the sintering temperature is increased, the compressive strength of Ti-15Nb-25Zr-4Fe shows an increasing trend and the plasticity is almost not changed. The Fe content is excessive in Ti-15Nb-25Zr-8Fe, which leads to some disadvantages including intermetallic compounds formation and grain boundary coarsening. The mechanical properties of Ti-15Nb-25Zr-8Fe are not always better than those of Ti-15Nb-25Zr-4Fe. The compressive strength of Ti-15Nb-25Zr-8Fe shows an increasing trend and the plasticity firstly increases and then decreases when the temperature is raised from 800 up to 1200 °C. Although the sintering time of SPS is short, Ti-15Nb-25Zr-(4, 8)Fe sintered at 1000 °C and Ti-15Nb-25Zr-(0, 4)Fe sintered at 1200 °C show good combination of strength and plasticity.

Rockfalls are a major hazard in mountain areas and along engineering slopes. It is important to fully understand the characteristics and processes of rockfall movements, both for hazard assessment and countermeasure design. This study focused on the movement characteristics and disaster processes of rockfalls by three-dimensional discontinuous deformation analysis (3D-DDA), the effectiveness of which was verified by outdoor experiments. An apparatus specifically built for the experiments was established, which included a releasing device and a binocular camera stereovision system. Blocks of three different shapes and sizes were released on slopes with three different inclinations on the campus of Tibet University. The indices of the movement characteristics of the blocks, such as lateral deviation, resting position, jumping height, and kinetic energy evolution, were investigated. The experimental results were compared with those of the 3D-DDA, so as to study the rockfall movement characteristics. On this basis, the 3D-DDA was applied to simulate a large-scale slope rockfall on the Tibetan Plateau, and the rockfall failure processes and movement characteristics were further analyzed. The results showed that the 3D-DDA method could effectively simulate the entire rockfall process in time and space, including instability and movement. Through the 3D-DDA numerical simulations, rockfall phenomena and behaviors could be fully understood. Furthermore, by analyzing the trajectories and kinetic energies of a rockfall, the prediction of rockfall disasters and the reasonable design of protective countermeasures could be realized.

In this work, a selective wet etching process of Si to Si0.7Ge0.3 with TMAH solution to fabricate SiGe nanowires is systematically investigated. Initially, the 2.3% TMAH solution at 20 °C is applied for the as grown Si0.7Ge0.3/Si multilayers stack and a “rectangular” profile is achieved at the Si0.7Ge0.3 extremity due to its high selectivity. However, the reduction of Ge concentration due to the Ge interdiffusion caused by the high temperature anneal treatment will attain a reduced selectivity of Si to Si0.7Ge0.3 and a “rounding” Si0.7Ge0.3 extremity profile. Moreover, the profile of the upper Si0.7Ge0.3 extremity is clearly worse than the bottom one. This is because the Ge concentration of upper Si0.7Ge0.3 is 1.5% lower and the Ge interdiffusion of the upper Si0.7Ge0.3 is slightly worse. After increasing the TMAH concentration to 25%, both the upper and bottom Si0.7Ge0.3 extremity can achieve a “rectangular” extremity profile with an almost the same Si0.7Ge0.3 loss ~ 1.5 nm per side. Compared with 2.3% TMAH concentration, the Ge concentration of the etching off SiGe film can be reduced from lower than 29% to lower than 24% using the 25% TMAH solution at 20 °C. Therefore, the 25% TMAH solution at 20 °C is chosen as the optimal selective etching condition for the thermal treated Si0.7Ge0.3/Si multilayers stack samples. Finally, a vertical stacked double SiGe nanowire structure is successfully prepared by utilizing this optimal process condition. This indicates that it is a practicable technique for the selective wet etching of Si in fabricating SiGe nanowires.

In the robotic polishing system for the wheel hubs, initial point alignment is a very important procedure before the robot starts to polish. Since the surface shapes of the wheel hubs are complex, traditional contact sensors are not suitable for the initial point alignment. Therefore, this paper presents a vision-based initial point alignment control method due to the merits of non-contact and high precision of the vision sensor. The main procedures of the new proposed initial point alignment methods are as follows. Firstly, the center point of the wheel hub is computed based on the growth of sampled points (GSP) method. Secondly, the center lines of the spokes of the wheel hub are extracted based on the edges of the spokes. Based on the center point and the center lines of the spokes, the needed rotation angle of the wheel hub denoting the current and target initial points can be computed. Thirdly, an alignment controller is designed to align the current initial point with the target one. Finally, experiments are well conducted to demonstrate the effectiveness of the proposed initial point alignment control method for the wheel hubs.