An Autonomous Path Planning Method for Unmanned Aerial Vehicle based on A Tangent Intersection and Target Guidance Strategy

Unmanned aerial vehicle (UAV) path planning enables UAVs to avoid obstacles and reach the target efficiently. To generate high-quality paths without obstacle collision for UAVs, this paper proposes a novel autonomous path planning algorithm based on a tangent intersection and target guidance strategy (APPATT). Guided by a target, the elliptic tangent graph method is used to generate two sub-paths, one of which is selected based on heuristic rules when confronting an obstacle. The UAV flies along the selected sub-path and repeatedly adjusts its flight path to avoid obstacles through this way until the collision-free path extends to the target. Considering the UAV kinematic constraints, the cubic B-spline curve is employed to smooth the waypoints for obtaining a feasible path. Compared with A*, PRM, RRT and VFH, the experimental results show that APPATT can generate the shortest collision-free path within 0.05 seconds for each instance under static environments. Moreover, compared with VFH and RRTRW, APPATT can generate satisfactory collision-free paths under uncertain environments in a nearly real-time manner. It is worth noting that APPATT has the capability of escaping from simple traps within a reasonable time

First realization of macroscopic Fourier ptychography for hundred-meter distance sub-diffraction imaging

Fourier ptychography (FP) imaging, drawing on the idea of synthetic aperture, has been demonstrated as a potential approach for remote sub-diffraction-limited imaging. Nevertheless, the farthest imaging distance is still limited around 10 m even though there has been a significant improvement in macroscopic FP. The most severely issue in increasing the imaging distance is FoV limitation caused by far-field condition for diffraction. Here, we propose to modify the Fourier far-field condition for rough reflective objects, aiming to overcome the small FoV limitation by using a divergent beam to illuminate objects. A joint optimization of pupil function and target image is utilized to attain the aberration-free image while estimating the pupil function simultaneously. Benefiting from the optimized reconstruction algorithm which effectively expands the camera's effective aperture, we experimentally implement several FP systems suited for imaging distance of 12 m, 90 m, and 170 m with the maximum synthetic aperture of 200 mm. The maximum imaging distance and synthetic aperture are thus improved by more than one order of magnitude of the state-of-the-art works with a fourfold improvement in the resolution. Our findings demonstrate significant potential for advancing the field of macroscopic FP, propelling it into a new stage of development

Sensitization of fullerenes by covalent attachment of a diketopyrrolopyrrole chromophore

In an effort to develop new materials for organic solar cell applications, we have synthesized triads of 3,6-dithien-2-yl-2,5-dialkylpyrrolo[3,4-c]pyrrole-1,4-dione (DTDPP) covalently linked at the nitrogen positions to two [6,6]-phenyl-C61-butyric acid ester (PCB) units via alkyl chains of different lengths. We present here the excited-state properties of the compounds in solution, as investigated by (time-resolved) spectroscopy. The absorption spectra of the triads are the composite of the ones recorded with the separate fullerene and DTDPP parent molecules, indicating weak electronic coupling between the sub-units. However, the fluorescence quantum yield drops from 74% in pure DTDPP to <1% in the triads, in both polar o-dichlorobenzene (DCB) and non-polar toluene (TOL). According to the energy levels determined by cyclic voltammetry for the parent compounds, charge separation (CS) or excitation energy transfer (EET) could be responsible for the quenching. However, femtosecond-resolved transient absorption (TA) measurements revealed the quenching mechanism to be highly efficient EET from the DTDPP to the PCB moieties. Ultrafast fluorescence spectroscopy showed multiphasic EET dynamics, due to different molecular conformations induced by the flexibility of the alkyl linkers, with time constants ranging from the sub-picosecond to the 100–150 ps scale. The DTDPP chromophore thus acts as a sensitizer (or light-absorbing antenna) to channel light towards the fullerenes, which have low absorbance in the visible range. The ultrafast time scale of the EET leading to fast population of the PCB singlet excited state is particularly interesting for potential use of the systems to increase light harvesting in photovoltaic devices containing fullerenes

Association of vitamin D deficiency and subclinical diabetic peripheral neuropathy in type 2 diabetes patients

BackgroundDiabetic peripheral neuropathy (DPN) contributes to disability and imposes heavy burdens, while subclinical DPN is lack of attention so far. We aimed to investigate the relationship between vitamin D and distinct subtypes of subclinical DPN in type 2 diabetes (T2DM) patients.MethodsThis cross-sectional study included 3629 T2DM inpatients who undertook nerve conduction study to detect subclinical DPN in Zhongshan Hospital between March 2012 and December 2019. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D (25(OH)D) level &lt; 50 nmol/L.Results1620 (44.6%) patients had subclinical DPN and they were further divided into subgroups: distal symmetric polyneuropathy (DSPN) (n=685), mononeuropathy (n=679) and radiculopathy (n=256). Compared with non-DPN, DPN group had significantly lower level of 25(OH)D (P &lt; 0.05). In DPN subtypes, only DSPN patients had significantly lower levels of 25(OH)D (36.18 ± 19.47 vs. 41.03 ± 18.47 nmol/L, P &lt; 0.001) and higher proportion of vitamin D deficiency (78.54% vs. 72.18%, P &lt; 0.001) than non-DPN. Vitamin D deficiency was associated with the increased prevalence of subclinical DPN [odds ratio (OR) 1.276, 95% confidence interval (CI) 1.086-1.501, P = 0.003] and DSPN [OR 1. 646, 95% CI 1.31-2.078, P &lt; 0.001], independent of sex, age, weight, blood pressure, glycosylated hemoglobin, T2DM duration, calcium, phosphorus, parathyroid hormone, lipids and renal function. The association between vitamin D deficiency and mononeuropathy or radiculopathy was not statistically significant. A negative linear association was observed between 25(OH)D and subclinical DSPN. Vitamin D deficiency maintained its significant association with subclinical DSPN in all age groups.ConclusionsVitamin D deficiency was independently associated with subclinical DSPN, rather than other DPN subtypes

Calycosin Attenuates Lipopolysaccharide-Induced Acute Lung Injury in Mice through the miR-375-3p/ROCK2 Axis

Objective: Septic patients are especially vulnerable to acute lung injury (ALI). Calycosin (CAL) has various promising pharmacological activities. This paper aims to expound on the role of CAL in mice with sepsis-induced ALI and the associated mechanisms. Methods: Mouse models of sepsis-induced ALI were established using lipopolysaccharide (LPS). Pulmonary histopathological changes were observed by HE staining. Cell apoptosis was assessed by TUNEL staining. Pulmonary edema was evaluated by measuring wet/dry weight. Bronchoalveolar lavage fluid (BALF) was collected to count inflammatory cells. In vitro LPS models were established using MLE-12 cells. miR-375-3p expression was determined by RT-qPCR. Cell viability and apoptosis were assessed by MTT assay and flow cytometry. Levels of inflammatory cytokines were determined by ELISA. The target relationship between miR-375-3p and ROCK2 was analyzed by the dual-luciferase assay. ROCK2 protein level was determined by Western blot. Results: miR-375-3p was weakly-expressed in mice with sepsis-induced ALI, and CAL treatment elevated miR-375-3p expression. CAL treatment mitigated pulmonary tissue damage and edema, decreased apoptosis and inflammatory cells, downregulated levels of pro-inflammatory cytokines, and upregulated levels of anti-inflammatory cytokines in mice with sepsis-induced ALI. CAL treatment increased MLE-12 cell viability and decreased apoptosis and inflammation in MLE-12 cells. Inhibition of miR-375-3p partially abrogated CAL-mediated protective action on MLE-12 cells. miR-375-3p attenuated LPS-induced MLE-12 cell injury by targeting ROCK2. Conclusion: CAL upregulates miR-375-3p to target ROCK2, thus protecting against sepsis-induced ALI in mice

Spatial Diffusion of E-Commerce in China’s Counties: Based on the Perspective of Regional Inequality

In recent decades, China has been on a new journey toward a digital economy of which e-commerce accounts for a substantial proportion. Despite some controversy, the innovation diffusion hypothesis and efficiency hypothesis of online shopping have been tested in research on the urban–rural dual structure. However, research on the spatial diffusion model of online business is sparse. Based on the online business and online shopping index released by the Ali Research Institute, this article compares the spatial diffusion model of online shopping and online business in the core–periphery structure based on the inequality between the eastern and western regions of China. Our study suggests that online business trends are in line only with the innovation diffusion hypothesis, with marginal counties having lower levels of online business. Online shopping, on the other hand, is in line with the innovation diffusion hypothesis and partially with the efficiency hypothesis, with a higher index of online shopping in the core regions and some peripheral counties. The discrepancy in the spatial diffusion mode is due to the differences in aims and supporting elements between online business and online shopping. Apart from infrastructure, the diffusion of online business is largely constrained by the regional industrial base, while online shopping is influenced by income and savings levels, which is the main reason for the differences in the spatial diffusion of online business and online shopping. We argue that the diffusion of online business has not led to the ability to balance regional inequalities at the national scale, while online shopping has the potential to bridge core and peripheral disparities better than online businesses, not in terms of the ability to bridge economic disparities, but in terms of the potential to reduce spatial consumption inequalities and welfare gains