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1.
Front Public Health ; 12: 1329234, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38463162

RESUMO

China's rural residents have basically solved the problem of subsistence, but due to aging, the prevalence of sarcopenia (abbreviated as sarcopenia) has been increasing year by year, especially the skeletal muscle health of the rural older residents has not been sufficiently paid attention to, so analyses of the impact of income level on the skeletal muscle health of the older people in rural areas of China are of great practical significance. Based on the annual data of the China Health and Nutrition Survey (CHNS) in 2006, 2009, and 2011, we introduced the mediator variable of dietary knowledge and used the Probit model regression, mediation effect model, and instrumental variable regression to assess the skeletal muscle health status of the rural older people in China and explore the mechanism of the influence of the income level on the skeletal muscle health of the rural older residents in China. The primary objectives of this study were to evaluate the impact of income level on the skeletal muscle health status of older adults living in rural areas of China and to investigate the underlying mechanisms. By analyzing the findings of this study, our aim is to establish a correlation between the economic status and skeletal muscle health of older adults in rural communities, as well as elucidate the influence of income level and dietary knowledge on their skeletal muscle health. Through the attainment of these objectives, we hope to provide valuable insights and recommendations for enhancing skeletal muscle health among the rural older population in China. Based on our research findings, it can be inferred that there was a significant association between the financial status of rural older adults and their skeletal muscle health. Additionally, the prevalence of sarcopenia was lower among individuals with higher income levels, and there was a negative correlation between the prevalence of sarcopenia and the level of dietary knowledge among rural older individuals. The knowledge of dietary knowledge level of rural older people plays a mediating role in the income level and the prevalence of sarcopenia. Moreover, with the change in income level and the increase in age, the change in skeletal muscle health status showed obvious heterogeneity, in which the effect on the relatively younger (65-70 years old) samples was greater. Therefore, sustained income growth remains an effective way to improve the skeletal muscle health of older rural residents. At the same time, improving dietary knowledge and dietary quality among the older people is important in preventing a decline in muscle strength and physical function and in preventing the onset of sarcopenia.


Assuntos
Sarcopenia , Humanos , Idoso , Sarcopenia/epidemiologia , População Rural , Músculo Esquelético/fisiologia , Dieta , Força Muscular/fisiologia
2.
Foods ; 13(2)2024 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-38254491

RESUMO

In rural areas, the aging of households is becoming increasingly severe, and the issue of dietary imbalance among the elderly is becoming increasingly prominent. Using data from the China Health and Nutrition Survey (CHNS), the negative binomial regression method was used to investigate the impact of household income level on dietary imbalance among rural elderly people, and to explore the heterogeneity of household income structure and its role in the relationship between the two. Research has found that an increase in total household income significantly improves the dietary quality of rural elderly people, and the income structure variable enhances its negative pulling effect on dietary imbalance. For elderly people with moderate dietary imbalance, the effect of increased family income is most significant. In different income groups, the impact of total household income on dietary imbalance in the high-income group is greater than that in the low-income group, and there is also a significant difference in the role played by the proportion of net income from agricultural operations. Therefore, it is necessary to increase the non working income of the elderly, strengthen social responsibility for elderly care, and alleviate the problem of dietary imbalance among rural elderly people.

3.
PLoS One ; 18(2): e0280626, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36821546

RESUMO

Vertical integration is conducive to the realization of complementary interests and sustainable development of pig industry. The outbreak of African swine fever (ASF) in 2018 has disrupted many activities along pig industry chain in China. The production capacity of breeding pigs has dropped rapidly, and the supply of pig is tight. The vertical integration of pig industry chain is the main driving force to ensure food supply. Based on the data of 12 listed pig companies from 2012 to 2019, we examine the ways and reasons for vertical integration of pig companies when external shocks increase by taking ASF as an example, breakpoint regression and Tobit model are used to analyze differences and determinants of the forward and backward integration of pig industry chain under ASF. The empirical results showed that the forward integration of the feed processing link and slaughter circulation link is higher than the backward integration. ASF had different effects on the vertical integration degree of each link. ASF promoted forward integration. The main factors have different influences on the vertical integration of pig industry in China. Forward integration increased mainly depending on previous asset specificity, legal system environment, market demand, and transaction frequency. The findings of the study imply that pig industry chain is taking the forward integration to cope with the ASF shock. The combination of feed link and breeding link reduces feed cost and ensures pig supply. Pig companies tend to reduce transaction costs by strengthening the control of downstream supply.


Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Suínos , Animais , Febre Suína Africana/epidemiologia , Vírus da Febre Suína Africana/genética , Criação de Animais Domésticos/métodos , Sus scrofa , Indústrias , Surtos de Doenças
4.
Front Vet Sci ; 9: 1028460, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36504846

RESUMO

The pig industry is primarily a domestic industry in China is focused on ensuring the domestic pork supply. This paper analyzed changes in Chinese pork imports following the outbreaks of African Swine Fever (ASF) and COVID-19 between January 2017 to November 2020 and evaluated the impact of imported pork on the development of the swine industry in China. The results demonstrated that the shortage of domestic pork supply changed the import volume. ASF transformed imported pork from a complementary product to meet the diversified needs of domestic consumers into a critical substitute required to fill the supply gap. Following the COVID-19 outbreak, the substitution effect of imported pork decreased. ASF, has caused the supply capacity of pork in China to decrease, the price of pork to increase, leading to increased pork import in January 2019. At the end of 2019, pig slaughter decreased, while China cut tariffs on imported pork. The COVID-19 outbreak did not reduce China's pork imports in China, which declined after the global COVID-19 outbreak. Imported pork has made up for the supply gap during COVID-19, not impacting the level of production of the swine industry in China.

5.
Medicine (Baltimore) ; 101(42): e31143, 2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36281095

RESUMO

To explore the epidemic, clinical, and laboratory characteristics of dengue patients in Zhejiang and the possible mechanism. Epidemic, clinical and laboratory data of 231 dengue patients admitted to the Second Affiliated Hospital of Zhejiang Traditional Chinese Medicine University between August 2017 and December 2019 were collected. GSE43777 dataset was downloaded from the Gene Expression Omnibus database and was used for the immune cell infiltration analysis, logistic regression analysis, and nomogram construction. Gene set enrichment analysis (GSEA) was performed to explore the possible regulatory pathways in dengue infection. Further, the receiver operating characteristic curve analysis and decision curve analysis were conducted to evaluate the value of related immune cells in predicting dengue severity. Among the 231 patients, the gender ratio was 1:1.1 (male/female). The patients in the <60 years age group, 60 to 80 years age group, and >80 years age group were 47.2%, 45.5%, and 7.3%, respectively. The major symptoms were fever (100%), weak (98.3%), anorexia (76.6%), muscle and joint pain (62.3%), and nausea (46.8%). In dengue patients, 98.7% of serum samples had decreased platelet levels, 96.5% of them had decreased white blood cell (WBC) levels, 97.8% had elevated aspartate aminotransferase levels, 82.3% had elevated lactate dehydrogenase levels, 49.4% had increased creatinine levels, and 35.5% had increased creatine kinase levels. Pneumonia, pleural effusion, and bilateral pleural reaction were observed in 16.5%, 8.2%, and 4.8%, respectively of dengue patients. Gallbladder wall roughness and splenomegaly accounted for 6.1% and 4.3% of all cases. Moreover, the levels of T cell, B cell, and dendritic cells were significantly higher in the convalescent group and they were involved in immune- and metabolism-related pathways. Of note, low levels of these 3 immune cells correlated with high dengue infection risk, while only dendritic cells exhibited satisfactory performance in predicting dengue severity. Dengue fever patients often onset with fever, accompanied by mild abnormalities of the blood system and other organ functions. Moreover, T cells, B cells, and dendritic cells might be involved in dengue infection and development.


Assuntos
Dengue , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Dengue/epidemiologia , Creatinina , Estudos Retrospectivos , China/epidemiologia , Febre , Aspartato Aminotransferases , Lactato Desidrogenases , Creatina Quinase
6.
Front Psychol ; 13: 966653, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35967618

RESUMO

This study explores the relationship between capability reconfiguration and firm innovation performance by analyzing a sample of 375 manufacturing firms in China. The results suggest that the relationship between capability reconfiguration and innovation performance is affected by both the catch-up stage and the mode of capability reconfiguration (evolution or substitution). The catch-up stage of enterprises significantly impacts the moderating effects of innovation magnitude on the relationship between capability substitution and firm innovation performance, however, it has no obvious effects on the moderation of innovation magnitude on the relationship between capability evolution and innovation performance. This study contributes to the theory of dynamic capability and catch-up by revealing how innovation magnitude affects capability reconfiguration and subsequent innovation performance in different catch-up stages. The implication of this study is to remind managers to take full account of the innovation magnitude and catch-up stage in their decision-making.

7.
PLoS One ; 17(4): e0266687, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35472219

RESUMO

Integrating pig production stability and pollution control is a matter of social livelihood and green development. This paper estimates the policy effectiveness of environmental regulation based on the big data of Chinese government websites and combines the pig production data of various provinces in China from 2008 to 2018 to construct a mediating effect model, empirically analyzing the relationship between environmental regulations, herd structure, and pig production. Research shows: (1) Improving environmental regulations in the short term will increase the slaughter of pigs, but in the long run it will decrease first and then increase; (2) At this stage, environmental regulations can increase the slaughter of pigs by changing the herd structure; (3) Reasonable adjustment of the herd structure can effectively increase the slaughter of pigs; (4) The herd structure can be used as a supplementary monitoring indicator to stabilize the supply of pigs. Combine it with the change rate of sow stock to provide early warning of fluctuations in pig production, and the early warning herd structure values are 0.0980 and 0.1135. There are two key initiatives to achieve supply and price stability in the pig industry that taking into account environmental protection: first, an industrial regulation instrument based on the herd structure needs to be established; second, an early warning system for pig production fluctuations should be established with reference to the early warning system for pork price fluctuations.


Assuntos
Doenças dos Suínos , Animais , China , Feminino , Suínos , Doenças dos Suínos/prevenção & controle
8.
PLoS One ; 16(12): e0261240, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34898638

RESUMO

The hog industry is the core industry in the field of agriculture and animal husbandry in China, which development is related to the improvement of people's quality of life. The production of the hog industry has been restricted by environmental regulations, which needs to reduce costs and improve efficiency. Based on the data of 29 provinces from 2008 to 2019, this paper aims to use the stochastic frontier analysis method to calculate the cost efficiency of fattening pigs, sows, and piglets in three stages of pig production and focuses on the impact of environmental regulation policies on cost efficiency. The study found that the cost efficiency of fattening pigs, sows, and piglets in China were 0.77, 0.79, and 0.53, respectively, and the efficiency losses were 23%, 21%, and 47%, respectively. The impact of environmental regulation policies on the cost efficiency of fattening pigs showed an ' N ' trend, and the impact on the cost efficiency of sows and piglets showed an inverted ' N ' trend. For fattening pigs, increasing the intensity of environmental regulation, and exceeding the second inflection point of the ' N ' curve can achieve the dual goals of environmental governance and cost reduction and efficiency increase. For sows, reducing the intensity of environmental regulation appropriately can avoid cost-efficiency loss. For piglets, environmental regulation policies have not effectively incentives the cost efficiency of piglets. In addition, raising the level of technology investment in fattening pigs and sows can achieve cost efficiency gains, and can farmers use emerging financial product tools such as ' insurance + futures ' to avoid market risks and efficiency losses.


Assuntos
Ração Animal/economia , Criação de Animais Domésticos/métodos , Suínos/crescimento & desenvolvimento , Criação de Animais Domésticos/economia , Animais , China , Conservação dos Recursos Naturais , Análise Custo-Benefício/métodos , Política Ambiental , Comportamento Alimentar/fisiologia
9.
Opt Express ; 29(10): 15478-15496, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33985247

RESUMO

As the star sensor works under high dynamic conditions, the spot formed by the star on the imaging plane will become a tail, which directly reduces the accuracy of centroid positioning. In addition, the imaging quality of the star sensor is seriously hit by the rolling shutter effect in the rolling shutter exposure mode, which further increases positioning error. Considering the diffusion radius and the dynamic tailing of the star spot, the imaging trajectory and the energy distribution models of the star spot under the rolling shutter exposure mode are established in this paper. Furthermore, based on the purposed models, the influence of the starting positions of stars and the dispersion of star spots to the centroid positioning error are analyzed by numerical simulation respectively, from which the variation laws of the two kinds of errors are obtained. Then, the laboratory experiments are implemented to evaluate the latter error; it indicates from the experimental results that the variation of the latter error is consistent with the simulation results, which is simultaneously proved that it cannot be ignored in practical engineering application. These results can be a valuable reference for developing a high precision star sensor. The models proposed in this paper can describe the star imaging process and evaluate the centroid positioning accuracy under the roller shutter exposure mode effectively, which lays a foundation for further eliminating the rolling shutter effect in the following research and improving the dynamic performance of star sensors.

10.
Transl Cancer Res ; 10(1): 349-360, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35116265

RESUMO

BACKGROUND: Hepatic carcinoma is one of the most malignant cancers worldwide. Salvador 1 (SAV1) plays a key role in a variety of human carcinogenesis. This study investigated the role of SAV1 and HERC4 in hepatocellular carcinoma (HCC). METHODS: SAV1 and HERC4 expressions in HCC tissues were examined using RT-qPCR assay. The regulatory effect of HERC4 on SAV1 was verified by co-immunoprecipitation (Co-IP), RT-qPCR, Western blot, and immunofluorescent assays in HEP3B and Huh 7 cell lines. In addition, functional experimental verification was performed through Edu staining, colony formation, and Transwell assay. Finally, Xenograft tumor model was finally used in nude mice. RESULTS: Clinical features showed significant difference with SAV1 and HERC4 expression. HERC4 was found to be upregulated, while SAV1 was downregulated in HCC. Patients with high HERC4 or low SAV1 had a worse prognosis. Results showed that HERC4 could notably decreased the expression level of SAV1 in HCC cells. Our results showed that overexpression HERC4 could reverse the inhibitory effects of SAV1 on HCC cell proliferation, migration, and invasion. SAV1 overexpression repressed tumor growth and enhance caspase 3 expression. CONCLUSION: SAV1 can be directly downregulated by HERC4, indicating that the HERC4/SAV1 axis might have great promise for targeted therapies of HCC.

11.
Sensors (Basel) ; 20(19)2020 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-33020392

RESUMO

To achieve photogrammetry without ground control points (GCPs), the precise measurement of the exterior orientation elements for the remote sensing camera is particularly important. Currently, the satellites are equipped with a GPS receiver, so that the accuracy of the line elements of the exterior orientation elements could reach centimeter-level. Furthermore, the high-precision angle elements of the exterior orientation elements could be obtained through a star camera which provides the direction reference in the inertial coordinate system and star images. Due to the stress release during the launch and the changes of the thermal environment, the installation matrix is variable and needs to be recalibrated. Hence, we estimate the cosine angle vector invariance of a remote sensing camera and star camera which are independent of attitude, and then we deal with long-term on-orbit data by using batch processing to realize the accurate calibration of the installation matrix. This method not only removes the coupling of attitude and installation matrix, but also reduces the conversion error of multiple coordinate systems. Finally, the geo-positioning accuracy in planimetry is remarkably higher than the conventional method in the simulation results.

12.
Opt Express ; 28(14): 21318-21335, 2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32680176

RESUMO

The calibration method based on integrated modeling with intrinsic and extrinsic parameters is widely used for star sensors. However, the unified optimization of parameters results in the coupling between intrinsic and extrinsic parameters in this method, further influencing the calibration accuracy of the intrinsic parameters and causing certain limitations for the practical applications involving precise extrinsic parameters. A novel calibration method for star sensors with separation of intrinsic and extrinsic parameters is proposed in this paper to solve the issue. Firstly, the coupling form of intrinsic and extrinsic parameters in the integrated calibration model is analyzed, and the coupling degree is analyzed through the partial correlation coefficient (PCC). Then, on the basis of the analysis results, combined with the applications of star sensors in satellites and missiles, the extrinsic parameters coupled with the intrinsic parameters are separated individually, and the intrinsic and extrinsic parameters without coupling are optimized nonlinearly as a whole. The experimental results verify the validity of the proposed method.

13.
Sensors (Basel) ; 19(18)2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31491930

RESUMO

When a missile is launched, the plume generated by the propulsion system will produce a lot of fake stars in the star image, which will affect the normal work of the missile-borne star sensor. A plume noise suppression algorithm based on star point shape and angular distance between stars is proposed in this paper, which is a preprocessing algorithm for star identification. Firstly, principal component analysis is used to extract the shape features of star points. Secondly, the authenticity of star points is evaluated based on length-width ratios. Thirdly, in two consecutive frames of star images, according to the shape features of star points, the optimal matching window is determined to achieve accurate matching of the corresponding star points. Finally, the rapid elimination of fake stars is completed by the principle of invariant angular distance between true stars. Simulation experiment results show that the proposed algorithm is quite robust and fast, and the elimination ratio is high even if the number of fake stars reaches four times more than true stars. Compared with the existing star identification algorithms, when the number of fake stars is large, the advantage of the proposed algorithm is obvious. Experimentation on actual star images verifies that the proposed algorithm can meet the requirements of spacecraft even if there are a large number of fake stars in the star image.

14.
PLoS One ; 14(3): e0212707, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30830928

RESUMO

Certain attributes of the hog industry increase the production risk in nodal enterprises of the hog supply chain, leading to high financing costs and eventually resulting in liquidity constraints. When the hog supply chain node enterprises are subjected to external shocks, on the basis of the commercial credit relationship in the supply chain, the entire supply chain generates liquidity risks and systemic risks. We analyze the input and output of the hog supply chain node enterprises under the constraint of liquidity, construct the mathematical model, discuss the dynamic differences of liquidity constraints in different situations, and measures the commercial credit risk and anti-risk ability of the pig supply chain node enterprises. If the external shock is less than a certain value, the current profits of the hog enterprise can entirely make up for the loss caused by external shocks, and the production of the firm will return to its state of equilibrium. If the external shock is large enough, liquidity constraints will seriously restrict the production input of the enterprise, which then leads to a deceleration of production input and may ultimately result in bankruptcy. We believe that the structure of the hog industry supply chain should be constantly adjusted to optimize the industrial upgrading and organizational form of the hog supply chain.


Assuntos
Abastecimento de Alimentos/economia , Modelos Econômicos , Carne Vermelha , Animais , Carne Vermelha/economia , Carne Vermelha/provisão & distribuição , Suínos
15.
Sensors (Basel) ; 18(9)2018 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-30154307

RESUMO

The most accurate star centroiding method for star sensors is the Gaussian fitting (GF) algorithm, because the intensity distribution of a star spot conforms to the Gaussian function, but the computational complexity of GF is too high for real-time applications. In this paper, we develop the fast Gaussian fitting method (FGF), which approximates the solution of the GF in a closed-form, thus significantly speeding up the GF algorithm. Based on the fast Gaussian fitting method, a novel star centroiding algorithm is proposed, which sequentially performs the FGF twice to calculate the star centroid: the first FGF step roughly calculates the Gaussian parameters of a star spot and the noise intensity of each pixel; subsequently the second FGF accurately calculates the star centroid utilizing the noise intensity provided in the first step. In this way, the proposed algorithm achieves both high accuracy and high efficiency. Both simulated star images and star sensor images are used to verify the performance of the algorithm. Experimental results show that the accuracy of the proposed algorithm is almost the same as the GF algorithm, higher than most existing centroiding algorithms, meanwhile, the proposed algorithm is about 15 times faster than the GF algorithm, making it suitable for real-time applications.

16.
17.
Front Microbiol ; 8: 1156, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28680421

RESUMO

Ranked among the top10 infectious causes of death worldwide, group A Streptococcus (GAS) causes small- and large-scale outbreaks, depending on the trigger as transmission of a GAS strain or expansion of predominant clones. In China, GAS infections other than scarlet fever are not notifiable. In Shanghai, an epidemiological investigation was initiated after two successive severe pneumonia cases with one death in a digital factory, from where outbreaks are less widely reported. The investigation was performed using emm typing, pulsed-field gel electrophoresis (PFGE) typing, superantigen profiling, and genome analysis. This enabled characterization of relatedness among the outbreak isolates and identification of the mobile genetic elements present. Among 57 patients with respiratory symptoms investigated in the factory, emm5 GAS strains were isolated from 8 patients. The eight GAS infection cases comprising one fatal severe pneumonia case, six influenza-like illness cases, and one pharyngitis case. Two risk factors were identified: adult with an age of 18-20 years and close contact with a GAS patient or carrier. GAS attack rate was 14.0% (8/57), and GAS carriage rate was probably around 2.7% (14/521) based on surveys in two nearby districts. All the 10 outbreak associated isolates were assigned to emm5 and sequence type ST-99 (emm5/ST-99), harbored superantigen genes speC, speG, and smeZ, and were assigned to two similar PFGE patterns (clones). Among the outbreak associated isolates, all carried ermA with resistance to erythromycin and inducible resistance to clindamycin, and eight (80%) carried a tetM gene with resistance to tetracycline. Among the 14 carriage isolates, 12 were emm12/ST-36, and 2 were emm1/ST-28, all with superantigen genes speC, speG, ssa, and smeZ. All the carriage isolates harbored ermB and tetM with resistance to erythromycin, clindamycin, and tetracycline. Genome analysis showed the two outbreak clones were closely related and possessed new prophages carrying virulence gene sdc and antibiotic resistance genes of ermA and tetM, which were not found in the emm5 reference strain Manfredo. This is the first report of a GAS outbreak in this type of workplace. The outbreak was caused by two closely related emm5 clones that differed from the predominant emm types circulating in China.

18.
PLoS One ; 12(2): e0172009, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28241024

RESUMO

Although frequent fluctuations in domestic hog prices seriously affect the stability and robustness of the hog supply chain, hog futures (an effective hedging instrument) have not been listed in China. To better understand hog futures market hedging, it is important to study the steady state of intersubjective bidding. This paper uses evolutionary game theory to construct a game model between hedgers and speculators in the hog futures market, and replicator dynamic equations are then used to obtain the steady state between the two trading entities. The results show that the steady state is one in which hedgers adopt a "buy" strategy and speculators adopt a "do not speculate" strategy, but this type of extreme steady state is not easily realized. Thus, to explore the rational proportion of hedgers and speculators in the evolutionary stabilization strategy, bidding processes were simulated using weekly average hog prices from 2006 to 2015, such that the conditions under which hedgers and speculators achieve a steady state could be analyzed. This task was performed to achieve the stability critical point, and we show that only when the value of λ is satisfied and the conditions of hog futures price changes and futures price are satisfied can hedgers and speculators achieve a rational proportion and a stable hog futures market. This market can thus provide a valuable reference for the development of the Chinese hog futures market and the formulation and guidance of relevant departmental policies.


Assuntos
Comércio/métodos , Investimentos em Saúde/economia , Suínos , Algoritmos , Animais , Evolução Biológica , China , Previsões , Teoria do Jogo , Carne , Modelos Econômicos , Modelos Teóricos
19.
Inorg Chem ; 54(23): 11314-22, 2015 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-26579936

RESUMO

In order to evaluate the impact of bridge conformation on electronic coupling in donor-bridge-acceptor triad systems, two Mo2 dimers, [Mo2(DAniF)3]2[µ-1,4-{C(O)NH}2-Naph] (1, DAniF = N,N'-di(p-anisyl)formamidinate and Naph = naphthalenyl) and [Mo2(DAniF)3]2[µ-1,4-(CS2)2-2,5-Me2C6H2] (2), have been synthesized and structurally characterized. These two compounds feature a large dihedral angle (>60°) between the central aromatic ring and the plane defined by the Mo-Mo bond vectors, which is distinct from the previously reported phenylene bridged analogues [Mo2(DAniF)3]2[µ-1,4-{C(O)NH}2-ph] (I) and [Mo2(DAniF)3]2[µ-1,4-(CS2)2-C6H4] (II), respectively. Unusual optical behaviors are observed for the mixed-valence (MV) species (1(+) and 2(+)), generated by single-electron oxidation. While 2(+) exhibits a weak intervalence charge transfer (IVCT) absorption band in the near-IR region, the IVCT band is absent in the spectrum of 1(+), which is quite different from what observed for I(+) and II(+). Optical analyses, based on superexchange formalism and Hush model, indicate that, in terms of Robin-Day classification, mixed-valence species 1(+) belongs to the electronically uncoupled Class I and complex 2(+), with Hab = 220 cm(-1), is assigned to the weakly coupled Class II. Together with I(+) and II(+), the four MV complexes complete a transition from Class I to Class II-III borderline as a result of manipulating the geometric topology of the bridge. Given the structural and electronic features for the molecular systems, the impacts of electrostatic interaction (through-space) and electron resonance (through-bond) on electronic coupling are discussed.

20.
Sensors (Basel) ; 15(8): 18526-49, 2015 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-26230697

RESUMO

Interference alignment (IA) is a novel technique that can effectively eliminate the interference and approach the sum capacity of wireless sensor networks (WSNs) when the signal-to-noise ratio (SNR) is high, by casting the desired signal and interference into different signal subspaces. The traditional alternating minimization interference leakage (AMIL) algorithm for IA shows good performance in high SNR regimes, however, the complexity of the AMIL algorithm increases dramatically as the number of users and antennas increases, posing limits to its applications in the practical systems. In this paper, a novel IA algorithm, called directional quartic optimal (DQO) algorithm, is proposed to minimize the interference leakage with rapid convergence and low complexity. The properties of the AMIL algorithm are investigated, and it is discovered that the difference between the two consecutive iteration results of the AMIL algorithm will approximately point to the convergence solution when the precoding and decoding matrices obtained from the intermediate iterations are sufficiently close to their convergence values. Based on this important property, the proposed DQO algorithm employs the line search procedure so that it can converge to the destination directly. In addition, the optimal step size can be determined analytically by optimizing a quartic function. Numerical results show that the proposed DQO algorithm can suppress the interference leakage more rapidly than the traditional AMIL algorithm, and can achieve the same level of sum rate as that of AMIL algorithm with far less iterations and execution time.

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