•We provide a whole picture about deep learning-based visual place recognition.•The differences and similarities between VPR and image retrieval are included.•We review different kinds of CNN-based ...methods, novel CNN features and datasets for VPR.•New tools such as GANs and multi-modality feature fusion are discussed for VPR.•We discuss challenges, open issues and future directions of visual place recognition.
Visual place recognition has attracted widespread research interest in multiple fields such as computer vision and robotics. Recently, researchers have employed advanced deep learning techniques to tackle this problem. While an increasing number of studies have proposed novel place recognition methods based on deep learning, few of them has provided a whole picture about how and to what extent deep learning has been utilized for this issue. In this paper, by delving into over 200 references, we present a comprehensive survey that covers various aspects of place recognition from deep learning perspective. We first present a brief introduction of deep learning and discuss its opportunities for recognizing places. After that, we focus on existing approaches built upon convolutional neural networks, including off-the-shelf and specifically designed models as well as novel image representations. We also discuss challenging problems in place recognition and present an extensive review of the corresponding datasets. To explore the future directions, we describe open issues and some new tools, for instance, generative adversarial networks, semantic scene understanding and multi-modality feature learning for this research topic. Finally, a conclusion is drawn for this paper.
High-valent iron(IV)–oxo complexes are of great significance as reactive intermediates implicated in diverse chemical and biological systems. The aqueous iron(IV)–oxo complex (Feaq IVO2+) is the ...simplest but one of the most powerful ferryl ion species, which possesses a high-spin state, high reduction potential, and long lifetime. It has been well documented that Feaq IVO2+ reacts with organic compounds through various pathways (hydrogen-atom, hydride, oxygen-atom, and electron transfer as well as electrophilic addition) at moderate reaction rates and show selective reactivity toward inorganic ions prevailing in natural water, which single out Feaq IVO2+ as a superior candidate for oxidative water treatment. This review provides state-of-the-art knowledge on the chemical properties and oxidation mechanism and kinetics of Feaq IVO2+, with special attention to the similarities and differences to two representative free radicals (hydroxyl radical and sulfate radical). Moreover, the prospective role of Feaq IVO2+ in Feaq 2+ activation-initiated advanced oxidation processes (AOPs) has been intensively investigated over the past 20 years, which has significantly challenged the conventional recognition that free radicals dominated in these AOPs. The latest progress in identifying the contribution of Feaq IVO2+ in Feaq 2+-based AOPs is thereby reviewed, highlighting controversies on the nature of the reactive oxidants formed in several Feaq 2+ activated peroxide and oxyacid processes. Finally, future perspectives for advancing the evaluation of Feaq IVO2+ reactivity from an engineering viewpoint are proposed.
Renal fibrosis commonly leads to glomerulosclerosis and renal interstitial fibrosis and the main pathological basis involves tubular atrophy and the abnormal increase and excessive deposition of ...extracellular matrix (ECM). Renal fibrosis can progress to chronic kidney disease. Stem cells have multilineage differentiation potential under appropriate conditions and are easy to obtain. At present, there have been some studies showing that stem cells can alleviate the accumulation of ECM and renal fibrosis. However, the sources of stem cells and the types of renal fibrosis or renal fibrosis models used in these studies have differed. In this review, we summarize the pathogenesis (including signaling pathways) of renal fibrosis, and the effect of stem cell therapy on renal fibrosis as described in preclinical and clinical studies. We found that stem cells from various sources have certain effects on improving renal function and alleviating renal fibrosis. However, additional clinical studies should be conducted to confirm this conclusion in the future.
Under the rapid growth of Internet of Things technology, many households are moving towards smart solutions. Addressing the inflexibility of temperature control in traditional heating systems, this ...research focuses on designing an intelligent heating system. To enhance flexibility and intelligence, an intelligent heating system based on the Internet of Things and STM32 microcontroller is proposed. Furthermore, the study identifies limitations of traditional proportional-integral-derivative control methods and establishes an optimization control model for heating system output temperature based on the Dynamic Matrix Control algorithm. Results indicate that the system's web interface successfully draws temperature curves, displaying clear data on detected temperature and humidity. The output temperature optimization control model shows a temperature rise of 2 °C and a temperature control error index of 0.0543 during the initial heating stage, and a control error index of 0.0353 during the mid-heating stage when the valve relative opening is close to 0. And the temperature control effect is better than traditional PID control, fuzzy PID control, genetic algorithm based PID control, and predictive feedback predictive control, without obvious indoor temperature overshoot phenomenon, which has certain advantages. In conclusion, the proposed system and model exhibit favorable application outcomes, offering technological support for the intelligent management of heating systems.
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•Fe(IV) is the dominant reactive intermediate in the Fe(II)/PMS system at acid pH.•Fe(IV) is also formed at circumneutral pH in the Fe(II)/PMS system.•18O labeled studies further ...verified the formation of Fe(IV)-oxo species.•Evolution of Fe(IV) in Fe(II)/persulfates systems was predicted by a kinetic model.•Evolution of Fe(IV) was monitored by a stopped-flow spectrophotometer.
Very recently, we have interestingly found that the Fe(II)-activated peroxydisulfate (PDS) process can oxidize methyl phenyl sulfoxide (PMSO) to its oxygen transfer product methyl phenyl sulfone (PMSO2), suggesting the possible occurrence of a ferryl intermediate (Fe(IV)) rather than long recognized sulfate radical (SO4−) in this process. In this work, the formation of PMSO2 was also observed when PMSO was treated by the Fe(II)/peroxymonosulfate (PMS) system over the pH range of 3–7, and the yield of PMSO2 (i.e., the molar ratio of PMSO2 formed to PMSO lost) was quantified to be approximately 100% under acidic conditions, similar to the Fe(II)/PDS system. Moreover, 18O from isotope-labeled water (H218O) was successfully incorporated into PMSO2 product when PMSO was oxidized by the Fe(II)/PDS and Fe(II)/PMS systems in H218O, likely due to the competitive oxygen exchange of Fe(IV)-oxo species with H218O. Further, Fe(IV) evolution profiles in both systems were predicted by a Fe(IV)-mediated kinetic model, and these results are in good agreement with the experimental data obtained with a stopped-flow spectrophotometer.
Understanding the impact of tillage erosion on soil organic carbon (SOC) and nitrogen (N) fractions is essential for targeted soil conservation in mountainous and hilly areas. However, little is ...known about this issue. In this study, we selected a tillage erosion-dominated hillslope from the Sichuan Basin, China, to determine the effect of tillage erosion on particulate OC (POC), dissolved OC (DOC), light fraction OC (LFOC), ammonium N (NH
-N), nitrate N (NO
-N) and alkali-hydrolysable N (AN). Additionally, we investigated the microbial activities in relation to soil C and N dynamics, including soil microbial biomass, β-glucosidase and urease activities. Tillage erosion induced serious soil loss in upper slope positions and soil deposition in lower slope positions. The observations of the various labile OC fraction distributions across the hillslope suggest that tillage erosion exerts less impact on DOC and LFOC dynamics but a notable effect on POC. The distribution pattern in total organic carbon under tillage erosion mainly depends on POC redistribution. The POC redistribution is a major factor affecting microbial activities. The AN is more prone to the tillage erosion impact than NH
-N and NO
-N. Effective soil conservation measures should be taken to weaken the adverse impacts of tillage erosion on POC and AN redistribution in sloping farmlands.
Circular RNAs are non-coding RNAs, and are enriched in the CNS. Dorsal horn neurons of the spinal cord contribute to pain-like hypersensitivity after nerve injury in rodents. Here we show that spinal ...nerve ligation is associated with an increase in expression of circAnks1a in dorsal horn neurons, in both the cytoplasm and the nucleus. Downregulation of circAnks1a by siRNA attenuates pain-like behaviour induced by nerve injury. In the cytoplasm, we show that circAnks1a promotes the interaction between transcription factor YBX1 and transportin-1, thus facilitating the nucleus translocation of YBX1. In the nucleus, circAnks1a binds directly to the Vegfb promoter, increases YBX1 recruitment to the Vegfb promoter, thereby facilitating transcription. Furthermore, cytoplasmic circAnks1a acts as a miRNA sponge in miR-324-3p-mediated posttranscriptional regulation of VEGFB expression. The upregulation of VEGFB contributes to increased excitability of dorsal horn neurons and pain behaviour induced by nerve injury. We propose that circAnks1a and VEGFB are regulators of neuropathic pain.
Infrared spectroscopy has long been used to characterize chemical compounds, but the applicability of this technique to the analysis of biological materials containing highly complex chemical ...components is arguable. However, recent advances in the development of infrared spectroscopy have significantly enhanced the capacity of this technique in analyzing various types of biological specimens. Consequently, there is an increased number of studies investigating the application of infrared spectroscopy in screening and diagnosis of various diseases. The lack of highly sensitive and specific methods for early detection of cancer has warranted the search for novel approaches. Being more simple, rapid, accurate, inexpensive, non-destructive and suitable for automation compared to existing screening, diagnosis, management and monitoring methods, Fourier transform infrared spectroscopy can potentially improve clinical decision-making and patient outcomes by detecting biochemical changes in cancer patients at the molecular level. Besides the commonly analyzed blood and tissue samples, extracellular vesicle-based method has been gaining popularity as a non-invasive approach. Therefore, infrared spectroscopic analysis of extracellular vesicles could be a useful technique in the future for biomedical applications. In this review, we discuss the potential clinical applications of Fourier transform infrared spectroscopic analysis using various types of biological materials for cancer. Additionally, the rationale and advantages of using extracellular vesicles in the spectroscopic analysis for cancer diagnostics are discussed. Furthermore, we highlight the challenges and future directions of clinical translation of the technique for cancer.
The reactions between peroxymonosulfate (PMS) and quinones were investigated for the first time in this work, where benzoquinone (BQ) was selected as a model quinone. It was demonstrated that BQ ...could efficiently activate PMS for the degradation of sulfamethoxazole (SMX; a frequently detected antibiotic in the environments), and the degradation rate increased with solution pH from 7 to 10. Interestingly, quenching studies suggested that neither hydroxyl radical (•OH) nor sulfate radical (SO4 •–) was produced therein. Instead, the generation of singlet oxygen (1O2) was proved by using two chemical probes (i.e., 2,2,6,6-tetramethyl-4-piperidinol and 9,10-diphenylanthracene) with the appearance of 1O2 indicative products detected by electron paramagnetic resonance spectrometry and liquid chromatography mass spectrometry, respectively. A catalytic mechanism was proposed involving the formation of a dioxirane intermediate between PMS and BQ and the subsequent decomposition of this intermediate into 1O2. Accordingly, a kinetic model was developed, and it well described the experimental observation that the pH-dependent decomposition rate of PMS was first-order with respect to BQ. These findings have important implications for the development of novel nonradical oxidation processes based on PMS, because 1O2 as a moderately reactive electrophile may suffer less interference from background organic matters compared with nonselective •OH and SO4 •–.