Conformational equilibria in acrolein-CO2: the crucial contribution of n → π* interactions unveiled by rotational spectroscopy.

Using gas phase Fourier-transform microwave spectroscopy complemented by theoretical analysis, this study delivers a comprehensive depiction of the physical origin of the 'n → π* interaction' between CO2 and acrolein, one of the most reactive aldehydes. Three distinct isomers of the acrolein-CO2 complex, linked through a C⋯O tetrel bond (or n → π* interaction) and a C-H⋯O hydrogen bond, have been unambiguously identified in the pulsed jet. Relative intensity measurements allowed estimation on the population ratio of the three isomers to be T1/T2/C1 ≈ 25/5/1. Advanced theoretical analyses were employed to elucidate the intricacies of the noncovalent interactions within the examined complex. This study not only sheds light on the molecular underpinnings of n → π* interactions but also paves the way for future exploration in carbon dioxide capture and utilization, leveraging the fundamental principles uncovered in the study of acrolein-carbon dioxide interactions.

Dyslipidemia and hyperuricemia: a cross-sectional study of residents in Wuhu, China.

BACKGROUND: While dyslipidemia has been recognized as a potential risk factor for hyperuricemia, there is currently a dearth of large-scale data specifically focused on studying the relationship between these two conditions. To address this gap, the present study analyzed a dataset of 298,891 physical examination records to investigate in greater detail the clinical classification and compositional relationship between hyperuricemia and dyslipidemia. METHODS: For this investigation, a cross-sectional research design was utilized to analyze physical examination data that was gathered from Yijishan Hospital in Wuhu, China between 2011 and 2016. Logistic regression was employed to examine the association between hyperuricemia and dyslipidemia. Furthermore, the association between hyperuricemia and dyslipidemia was evaluated based on the clinical classifications of dyslipidemia and its components. RESULTS: A total of 298,891 participants from China (124,886 [41.8%] females) were included in the study, with an age range of 18 to 90 years (mean [SD]: 47.76 [13.54] years). In multivariate analysis, the odds of hyperuricemia was 1.878 times higher in patients with dyslipidemia compared to those without dyslipidemia (95% confidence interval [CI]: 1.835-1.922). In the clinical classification of dyslipidemia, individuals with hypertriglyceridemia and mixed hyperlipidemia had 1.753 times (95% CI: 1.706-1.802) and 1.925 times (95% CI: 1.870-1.982) higher odds of hyperuricemia, respectively, compared to those without dyslipidemia. Among the components of dyslipidemia, the odds ratios for hyperuricemia in individuals in the fourth quartile compared to those in the first quartile were 3.744 (95% CI: 3.636-3.918) for triglycerides, 1.518 (95% CI: 1.471-1.565) for total cholesterol, and 1.775 (95% CI: 1.718 - 1.833) for non-high-density lipoprotein cholesterol. CONCLUSIONS: Dyslipidemia has been independently linked with hyperuricemia. Moreover, the elevation of triglycerides or total cholesterol levels, including conditions such as hypertriglyceridemia and mixed hyperlipidemia, have been observed to have a positive association with the development of hyperuricemia.

Mutation of mpv17 results in loss of iridophores due to mitochondrial dysfunction in tilapia.

Mpv17 (mitochondrial inner membrane protein MPV17) deficiency causes severe mitochondrial DNA depletion syndrome in mammals and loss of pigmentation of iridophores and a significant decrease of melanophores in zebrafish. The reasons for this are still unclear. In this study, we established an mpv17 homozygous mutant line in Nile tilapia. The developing mutants are transparent due to loss of iridophores and aggregation of pigment granules in the melanophores and disappearance of the vertical pigment bars on the side of the fish. Transcriptome analysis using skin of fish at 30 dpf (days post fertilization) revealed that the genes related to purine (especially pnp4a) and melanin synthesis were significantly downregulated. However, administration of guanine diets failed to rescue the phenotype of the mutants. In addition, no obvious apoptosis signals were observed in the iris of the mutants by TUNEL staining. Significant downregulation of genes related to iridophore differentiation was detected by qPCR. Insufficient ATP, as revealed by ATP assay, α-MSH treatment and adcy5 mutational analysis, might account for the defects of melanophores in mpv17 mutants. Several tissues displayed less mtDNA and decreased ATP levels. Taken together, these results indicated that mutation of mpv17 led to mitochondrial dTMP deficiency, followed by impaired mtDNA content and mitochondrial function, which in turn, led to loss of iridophores and a transparent body color in tilapia.

Mild heat stress promotes the differentiation of odontoblast-like MDPC-23 cells via yes-associated protein.

PURPOSE: Dentin hypersensitivity (DH) is a prevalent condition, but long-term effective treatments are scarce. Differentiation of odontoblast-like cells is promising for inducing tertiary dentinogenesis and ensuring sustained therapeutic efficacy against DH. This study examined the effects and mechanism of action of mild heat stress (MHS) on the differentiation of odontoblast-like MDPC-23 cells. METHODS: We used a heating device to accurately control the temperature and duration, mimicking the thermal microenvironment of odontoblast-like cells. Using this device, the effects of MHS on cell viability and differentiation were examined. Cell viability was assessed using the MTT assay. The expression and nucleoplasmic ratio of the yes-associated protein (YAP) were examined by western blotting and immunofluorescence. The gene expression levels of heat shock proteins (HSPs) and dentin matrix protein-1 (DMP1) were measured using qPCR. Dentin sialophosphoprotein (DSPP) expression was evaluated using immunofluorescence and immunoblotting. Verteporfin was used to inhibit YAP activity. RESULTS: Mild heat stress (MHS) enhanced the odontoblast differentiation of MDPC-23 cells while maintaining cell viability. MHS also increased YAP activity, as well as the levels of HSP25 mRNA, HSP70 mRNA, HSP90α mRNA, DMP1 mRNA, and DSPP protein. However, after YAP inhibition, both cell viability and the levels of HSP90α mRNA, DMP1 mRNA, and DSPP protein were reduced. CONCLUSION: YAP plays a crucial role in maintaining cell viability and promoting odontoblast differentiation of MDPC-23 cells under MHS. Consequently, MHS is a potential therapeutic strategy for DH, and boosting YAP activity could be beneficial for maintaining cell viability and promoting odontoblast differentiation.

Energy transfer enhanced photoluminescence of 2D/3D CsPbBr3 hybrid assemblies.

Energy transfer has been proven to be an effective method to optimize optoelectronic conversion efficiency by improving light absorption and mitigating nonradiative losses. We prepared 2D/3D CsPbBr3 hybrid assemblies at different reaction temperatures using the hot injection method and found that the photoluminescence quantum yields (PLQYs) of these hybrids were greatly enhanced from 53.4% to 72.57% compared with 3D nanocrystals (NCs). Femtosecond transient absorption measurements were used to study the PLQY enhancement mechanisms, and it was found that the hot carrier lifetime improved from 0.36 to 1.88 ps for 2D/3D CsPbBr3 hybrid assemblies owing to the energy transfer from 2D nanoplates to 3D NCs. The energy transfer benefits the excited carrier accumulation and prolonged hot carrier lifetime in 3D NCs in hybrid assemblies, as well as PLQY enhancement in materials.

A Geomagnetic/Odometry Integrated Localization Method for Differential Robot Using Real-Time Sequential Particle Filter.

Geomagnetic matching navigation is extensively utilized for localization and navigation of autonomous robots and vehicles owing to its advantages such as low cost, wide-area coverage, and no cumulative errors. However, due to the influence of magnetometer measurement noise, geomagnetic localization algorithms based on single-point particle filters may encounter mismatches during continuous operation, consequently limiting their long-range localization performance. To address this issue, this paper proposes a real-time sequential particle filter-based geomagnetic localization method. Firstly, this method mitigates the impact of noise during continuous operation while ensuring real-time performance by performing real-time sequential particle filtering. Then, it enhances the long-range positioning accuracy of the method by rectifying the trajectory shape of the odometry through odometry calibration parameters. Finally, by performing secondary matching on the preliminary matching results via the MAGCOM algorithm, the positioning error of the method is further minimized. Experimental results show that the proposed method has higher positioning accuracy compared to related algorithms, resulting in reductions of over 28.58%, 37.11%, and 0.77% in RMSE, max error, and error at the end, respectively.

The Longitudinal Effect of Peer-Nominated Popularity on Defending Behaviors in Chinese Adolescents: The Moderating Role of Manipulative Traits, Desired Popularity, and Gender.

The factors influencing popular adolescents to defend victims require further exploration, particularly concerning their traits and the desire for higher peer status. In this one-year longitudinal study, 2464 Chinese adolescents (48.50% girls, Mage = 13.40 years, SD = 0.61) were investigated to examine the relationship between peer-nominated popularity, manipulative traits, desired popularity, and defending behaviors. The results revealed that peer-nominated popularity had a positive predictive effect on Chinese adolescents' defending behaviors. Furthermore, this longitudinal association was accentuated by desired popularity and manipulative traits in girls but was not in boys. Specifically, popular girls with high desired popularity demonstrated a higher likelihood of engaging in defending behaviors compared to other girls. These findings carry significant implications for understanding the influencing factors behind peer status and adolescents' defending behaviors.

Triglyceride-glucose index as a marker of adverse cardiovascular prognosis in patients with coronary heart disease and hypertension.

BACKGROUND: The triglyceride-glucose (TyG) index has been proposed as a potential predictor of adverse prognosis of cardiovascular diseases (CVDs). However, its prognostic value in patients with coronary heart disease (CHD) and hypertension remains unclear. METHODS: A total of 1467 hospitalized patients with CHD and hypertension from January 2021 to December 2021 were included in this prospective and observational clinical study. The TyG index was calculated as Ln [fasting triglyceride level (mg/dL) × fasting plasma glucose level (mg/dL)/2]. Patients were divided into tertiles according to TyG index values. The primary endpoint was a compound endpoint, defined as the first occurrence of all-cause mortality or total nonfatal CVDs events within one-year follow up. The secondary endpoint was atherosclerotic CVD (ASCVD) events, including non-fatal stroke/transient ischemic attack (TIA) and recurrent CHD events. We used restricted cubic spline analysis and multivariate adjusted Cox proportional hazard models to investigate the associations of the TyG index with primary endpoint events. RESULTS: During the one-year follow-up period, 154 (10.5%) primary endpoint events were recorded, including 129 (8.8%) ASCVD events. After adjusting for confounding variables, for per standard deviation (SD) increase in the TyG index, the risk of incident primary endpoint events increased by 28% [hazard ratio (HR) = 1.28, 95% confidence interval (CI) 1.04-1.59]. Compared with subjects in the lowest tertile (T1), the fully adjusted HR for primary endpoint events was 1.43 (95% CI 0.90-2.26) in the middle (T2) and 1.73 (95% CI 1.06-2.82) in highest tertile (T3) (P for trend = 0.018). Similar results were observed in ASCVD events. Restricted cubic spline analysis also showed that the cumulative risk of primary endpoint events increased as TyG index increased. CONCLUSIONS: The elevated TyG index was a potential marker of adverse prognosis in patients with CHD and hypertension.

Conformational equilibria and interaction preference in the complex of isoprene-maleic anhydride.

The rotational spectrum of the isoprene-maleic anhydride complex has been investigated by pulsed jet Fourier transform microwave spectroscopy and interpreted with complementary quantum chemical calculations. Theoretical predictions have yielded four plausible isomers, all residing within an energy window of 12 kJ mol-1. However, two distinct isomers characterized by a π-π stacked configuration have been experimentally observed in pulsed jets, which have differed in the orientation of isoprene over maleic anhydride. The relative population ratio of the two detected isomers has been estimated to be NI/NII ≈ 3/1 from rigorous measurements of the relative intensity on a set of µc-type transitions. Remarkably, this study underscores the pivotal role played by the interaction between the CC bonding orbital (π) of isoprene and the CC antibonding orbital (π*) of maleic anhydride in stabilizing the target complex.

The V-shaped curve relationship between fasting plasma glucose and human serum albumin in a large health checkup population in China.

BACKGROUND: This study aimed to investigate the relationship between fasting plasma glucose (FPG) and human serum albumin (HSA) in a large health checkup population in China. METHODS: In this cross-sectional health checkup study, we enrolled a population of 284,635 subjects from Wuhu between 2011 and 2016. All participants completed the physical examination, blood biochemical examination, and blood routine examination. RESULTS: The prevalence of diabetes in men and women was 6.11% and 2.98%, respectively. The average level of HSA and FPG was significantly higher in men than in women (48.44 ± 3.25 vs. 47.14 ± 3.22, P < 0.0001; 5.50 ± 1.26 vs. 5.26 ± 0.94, P < 0.0001). There were significant differences in blood biochemistry and blood routine values by gender. After adjusting for confounding factors, the results showed that FPG and HSA were a V-shaped curve, and the threshold value of HSA was 40.7 mmol/L. FPG and HSA still showed a V-shaped curve after stratification by gender and age. In the male group, FPG decreased with HSA when HSA<42.3 mmol/L, and increased when HSA ≥ 42.3 mmol/L. In the female group, FPG decreased with HSA when HSA<35.7 mmol/L, and increased when HSA ≥ 35.7 mmol/L. In the age<65 group, FPG decreased with HSA when HSA<37.5 mmol/L, and increased when HSA ≥ 37.5 mmol/L. In the age ≥ 65 group, FPG decreased with HSA when HSA<43.2 mmol/L, and increased when HSA ≥ 43.2 mmol/L. CONCLUSIONS: A V-shape relationship exists between fasting plasma glucose and human serum albumin among the Chinese health checkup population studied.

Developmental interactions between peer victimization and depressive symptoms in adolescents: A latent change score analysis.

Peer victimization and depressive symptoms are highly relevant risks during adolescence. Understanding the dynamic patterns of interactions between peer victimization and depressive symptoms as well as gender differences in these variables can improve intervention strategies for adolescents navigating this critical transition period. In the present study, a large sample of Chinese adolescents reported peer victimization and depressive symptoms in four survey waves at six-month intervals. A total of 2534 adolescents (51.9% boys, M = 12.98 ± 0.60 years) were included in the latent change score (LCS) analysis. The results supported the reciprocal effects model obtained in the full sample. Changes in peer victimization were influenced by prior changes in depressive symptoms over time, and changes in depressive symptoms were influenced by prior levels of peer victimization. There were also gender differences, with boys exhibiting depressive symptom-driven effects on peer victimization, while girls exhibiting peer victimization-induced depressive symptoms. The dynamic relationships between peer victimization and depressive symptoms that promote and constrain each other in adolescents are elucidated in this study. Differentiating effects on boys and girls is crucial for enhancing the effectiveness of practical interventions.

Planning a water-constrained ecological restoration pattern to enhance sustainable landscape management in drylands.

Ecological restoration is an important approach to improving landscape sustainability. However, ecological restoration in drylands is strongly limited by water resources. Therefore, a technical route for ecological restoration in drylands that creates sustainable landscapes based on those water constraints is needed. In this study, we develop a spatially explicit framework named "Constraint-Pattern-Benefit" to plan ecological restoration patterns in Inner Mongolia, China. Based on a prediction of the ecosystem service (ES) increase under limited evapotranspiration as a water constraint, we constructed 5 landscape sustainability-related strategies with 100 ecological restoration scenarios, which considered fragmentation of restoration locations, distance to city, water consumption, and the allocation scale to determine the spatial arrangement of ecological restoration. Results show that the ES increase potential of ecological restoration under water constraints is distributed in the center of Inner Mongolia. The multi-objective scenario simultaneously achieves 59.1% water yield, 74.2% soil conservation, 57.2% sand fixation, and 52.8% carbon sequestration with 50% restored landscape. Considering the indicators of fragmentation, water consumption, and distance to city decreases the restored landscape fragmentation from 0.44 to 0.26, improves the restoration efficiency by 14.41%, and increases the beneficiary population by 35.5%, respectively. Small-scale allocation can further increase the ES realization efficiency, which is on average 4.8% higher at the city scale than at the provincial scale. Moreover, this approach focuses on the sustainable effect of the spatial arrangement on dryland landscapes at different scales, which provides methodological support for improving the sustainability of drylands.

A Comprehensive Review on Metal Catalysts for the Production of Cyclopentanone Derivatives from Furfural and HMF.

The catalytic transformation of biomass-based furan compounds (furfural and HMF) for the synthesis of organic chemicals is one of the important ways to utilize renewable biomass resources. Among the numerous high-value products, cyclopentanone derivatives are a kind of valuable compound obtained by the hydrogenation rearrangement of furfural and HMF in the aqueous phase of metal-hydrogen catalysis. Following the vast application of cyclopentanone derivatives, this reaction has attracted wide attention since its discovery, and a large number of catalytic systems have been reported to be effective in this transformation. Among them, the design and synthesis of metal catalysts are at the core of the reaction. This review briefly introduces the application of cyclopentanone derivatives, the transformation mechanism, and the pathway of biomass-based furan compounds for the synthesis of cyclopentanone derivatives. The important progress of metal catalysts in the reaction since the first report in 2012 up to now is emphasized, the characteristics and catalytic performance of different metal catalysts are introduced, and the critical role of metal catalysts in the reaction is discussed. Finally, the future development of this transformation process was prospected.

Clique Hierarchy Moderates the Association between Social Preference and Defending Behaviors in Early Adolescence: The Role of Gender Differences.

Although social preference promotes adolescents' defending behaviors, its potential mechanisms across gender cliques remain unclear from the group dynamic perspective. This study investigated 2470 Chinese early adolescents (49% girls, Mage = 14.40, SD = 0.58) to explore how social preference and clique hierarchy are associated with defending behaviors and whether these associations differ across gender-specific cliques. The results revealed that social preference was positively related to defending behaviors in boys' cliques, but negatively in girls' cliques. Furthermore, the association was strengthened by hierarchization in boys' cliques but was weakened in girls' cliques, while the status structure strengthened the association in boys' but not girls' cliques. These findings hold crucial implications for understanding and promoting defending behaviors among adolescents.

Selective ortho-C-H Activation in Arenes without Functional Groups.

Aromatic C-H activation in alkylarenes is a key step for the synthesis of functionalized organic molecules from simple hydrocarbon precursors. Known examples of such C-H activations often yield mixtures of products resulting from activation of the least hindered C-H bonds. Here we report highly selective ortho-C-H activation in alkylarenes by simple iridium complexes. We demonstrate that the capacity of the alkyl substituent to override the typical preference of metal-mediated C-H activation for the least hindered aromatic C-H bonds results from transient insertion of iridium into the benzylic C-H bond. This enables fast iridium insertion into the ortho-C-H bond, followed by regeneration of the benzylic C-H bond by reductive elimination. Bulkier alkyl substituents increase the ortho selectivity. The described chemistry represents a conceptually new alternative to existing approaches for aromatic C-H bond activation.

Spinal NLRP3 inflammasome activation mediates IL-1ß release and contributes to remifentanil-induced postoperative hyperalgesia by regulating NMDA receptor NR1 subunit phosphorylation and GLT-1 expression in rats.

BACKGROUND: Trafficking and activation of N-methyl-D-aspartate (NMDA) receptors play an important role in initiating and maintaining postoperative remifentanil-induced hyperalgesia (RIH). Activation of the NOD-like receptor protein 3 (NLRP3) inflammasome has been linked to the development of inflammatory and neuropathic pain. We hypothesized that activation of NLRP3 inflammasome mediates IL-1ß release and contributes to RIH in rats by increasing NMDA receptor NR1 (NR1) subunit phosphorylation and decreasing glutamate transporter-1 (GLT-1) expression. METHODS: Acute exposure to remifentanil (1.2 µg/kg/min for 60 min) was used to establish RIH in rats. Thermal and mechanical hyperalgesia were tested at baseline (24 h before remifentanil infusion) and 2, 6, 24, and 48 h after remifentanil infusion. The levels of IL-1ß, GLT-1, phosphorylated NR1 (phospho-NR1), and NLRP3 inflammasome activation indicators [NLRP3, Toll-like receptor 4 (TLR4), P2X purinoceptor 7 (P2X7R), and caspase-1] were measured after the last behavioral test. A selective IL-1ß inhibitor (IL-1ß inhibitor antagonist; IL-1ra) or three different selective NLRP3 inflammasome activation inhibitors [(+)-naloxone (a TLR4 inhibitor), A438079 (a P2X7R inhibitor), or ac-YVADcmk (a caspase-1 inhibitor)] were intrathecally administered immediately before remifentanil infusion into rats. RESULTS: Remifentanil induced significant postoperative hyperalgesia, increased IL-1ß and phospho-NR1 levels and activated the NLRP3 inflammasome by increasing TLR4, P2X7R, NLRP3, and caspase-1 expression, but it decreased GLT-1 expression in the L4-L6 spinal cord segments of rats, which was markedly improved by intrathecal administration of IL-1ra, (+)-naloxone, A438079, or ac-YVADcmk. CONCLUSION: NLRP3 inflammasome activation mediates IL-1ß release and contributes to RIH in rats by inducing NMDA receptor NR1 subunit phosphorylation and decreasing GLT-1 expression. Inhibiting the activation of the NLRP3 inflammasome may be an effective treatment for RIH.

CRISPR Knockouts of pmela and pmelb Engineered a Golden Tilapia by Regulating Relative Pigment Cell Abundance.

Premelanosome protein (pmel) is a key gene for melanogenesis. Mutations in this gene are responsible for white plumage in chicken, but its role in pigmentation of fish remains to be demonstrated. In this study, we found that most fishes have 2 pmel genes arising from the teleost-specific whole-genome duplication. Both pmela and pmelb were expressed at high levels in the eyes and skin of Nile tilapia. We mutated both genes in tilapia using CRISPR/Cas9. Homozygous mutation of pmela resulted in yellowish body color with weak vertical bars and a hypopigmented retinal pigment epithelium (RPE) due to significantly reduced number and size of melanophores. In contrast, we observed an increased number and size of xanthophores in mutants compared to wild-type fish. Homozygous mutation of pmelb resulted in a similar, but milder phenotype than pmela-/- mutants. Double mutation of pmela and pmelb resulted in loss of additional melanophores compared to the pmela-/- mutants, and also an increase in the number and size of xanthophores, producing a golden body color. The RPE pigmentation of pmela-/-;pmelb-/- was similar to pmela-/- mutants, with much less pigmentation than pmelb-/- mutants and wild-type fish. Taken together, our results indicate that, although both pmel genes are important for the formation of body color in tilapia, pmela plays a more important role than pmelb. To our knowledge, this is the first report on mutation of pmelb or both pmela;pmelb in fish. Studies on these mutants suggest new strategies for breeding golden tilapia, and also provide a new model for studies of pmel function in vertebrates.

Response Characteristics of Contactless Impedance Detection (CID) Sensor on Slug Flow in Small Channels: The Investigation on Slug Separation Distance.

In recent years, CID sensors have displayed great development potential in parameter measurement of gas-liquid two-phase flow in small channels. However, the fundamental/mechanism research on the response characteristics of CID sensors is relatively insufficient. This work focuses on the investigation of the influence of separation distance between slugs on the impedance (real part, imaginary part and amplitude) response characteristics of slug flow in small channels. Experiments were carried out with the CID sensors in four small channels with inner pipe diameters of 1.96 mm, 2.48 mm, 3.02 mm and 3.54 mm, respectively. The experimental results show that for a CID sensor, the slug separation distance has significant influence on the impedance response characteristics. There is a critical value of slug separation distance. When the slug separation distance is larger than the critical value, the impedance response characteristics of each slug can be considered independent of each other, i.e., there is no interaction between the slugs. When the slug separation distance is less than the critical value, the impedance response characteristics show obvious interaction between the slugs. It is indicated that the ratios of the critical values to the pipe inner diameters are approximate 100.

An Improved Trilateration Positioning Algorithm with Anchor Node Combination and K-Means Clustering.

As a classic positioning algorithm with a simple principle and low computational complexity, the trilateration positioning algorithm utilizes the coordinates of three anchor nodes to determine the position of an unknown node, which is widely applied in various positioning scenes. However, due to the environmental noise, environmental interference, the distance estimation error, the uncertainty of anchor nodes' coordinates, and other negative factors, the positioning error increases significantly. For this problem, we propose a new trilateration algorithm based on the combination and K-Means clustering to effectively remove the positioning results with significant errors in this paper, which makes full use of the position and distance information of the anchor nodes in the area. In this method, after analyzing the factors affecting the optimization of the trilateration and selecting optimal parameters, we carry out experiments to verify the effectiveness and feasibility of the proposed algorithm. We also compare the positioning accuracy and positioning efficiency of the proposed algorithm with those of other algorithms in different environments. According to the comparison of the least-squares method, the maximum likelihood method, the classical trilateration and the proposed trilateration, the results of the experiments show that the proposed trilateration algorithm performs well in the positioning accuracy and efficiency in both light-of-sight (LOS) and non-light-of-sight (NLOS) environments. Then, we test our approach in three realistic environments, i.e., indoor, outdoor and hall. The experimental results show that when there are few available anchor nodes, the proposed localization method reduces the mean distance error compared with the classical trilateration, the least-squares method, and the maximum likelihood.

A Distributed Localization Method for Wireless Sensor Networks Based on Anchor Node Optimal Selection and Particle Filter.

In wireless sensor networks, due to the significance of the location information of mobile nodes for many applications, location services are the basis of many application scenarios. However, node state and communication uncertainty affect the distance estimation and position calculation of the range-based localization method, which makes it difficult to guarantee the localization accuracy and the system robustness of the distributed localization system. In this paper, we propose a distributed localization method based on anchor nodes selection and particle filter optimization. In this method, we first analyze the uncertainty of error propagation to the least-squares localization method. According to the proportional relation between localization error and uncertainty propagation, anchor nodes are selected optimally in real-time during the movement of mobile nodes. Then we use the ranging and position of the optimally selected anchor nodes to obtain the location information of the mobile nodes. Finally, the particle filter (PF) algorithm is utilized to gain the optimal estimation of the localization results. The experimental evaluation results verified that the proposed method effectively improves the localization accuracy and the robustness of the distributed system.