Spatial distribution and influencing factors of rural tourism: A case study of Henan Province.

Rural tourism is a powerful way to revitalize the countryside, and its spatial pattern is crucial for sustainable development. This paper analyzes the spatial distribution of rural tourism characteristic villages in Henan Province by taking 723 villages as the research object and using the nearest neighbor index, kernel density analysis, and spatial autocorrelation. It investigates the influencing factors utilizing the optimal parameters-based geographical detector (OPGD) model. The results show that, firstly, the overall spatial distribution of the rural tourism characteristic villages in Henan Province is characterized by aggregation and unbalanced distribution, and the overall spatial distribution density demonstrates the aggregation characteristics of "four cores and one belt". Secondly, the rural tourism characteristic villages can be divided into four primary categories, agricultural industry, rural culture, and featured villages and towns. The spatial distributions of the four main categories are all clustered. Thirdly, the primary factors affecting the differences in the spatial distribution of the rural tourism characteristic villages are the topographic features, economic development level, tourism market potential, traffic capacity, and relevant policies, among which the critical factor is the number of A-class scenic spots in the tourism market potential. To promote the optimisation of the spatial pattern of rural tourism, it is necessary to strengthen resource integration. Furthermore, it is important to conduct in-depth exploration of more factors in order to provide comprehensive guidance for the sustainable development of rural tourism.

Research on care preferences for the elderly and influencing factors in Zhejiang Province: A statistical and geographical approach.

The aging of the population is becoming an increasingly severe issue. How can we develop caring services for the elderly and promote healthy aging? Investigating care preferences is an essential step in addressing this issue. A self-designed questionnaire was employed to collect data online. The impact of personal circumstances on care preferences was ascertained using the chi-squared test and multivariate logistic regression. An optimal parameters-based geographical detector was introduced to examine the influence of spatially heterogeneous regional factors on care preferences. The online survey produced 1178 valid questionnaires. Home-based elderly care was the preference of 91.9% of respondents, followed by community-based care and medical-nursing care; institutional care was the least preferred alternative. Age, education, living style, and health states of the elderly significantly influenced the preferred care option. When compared to home-based elderly care, older respondents (odds ratio [OR] = 3.776) preferred institutional care, highly educated respondents preferred community-based care (higher education: OR = 5.206; secondary education: OR = 3.049) and medical-nursing care (higher education: OR = 4.484); the elderly living alone (OR = 0.101) excluded institutional care, and the elderly living with their children excluded non-family care method of institutional care (OR = 0.031) and medical-nursing care (OR = 0.391). Regional medical resources and old-age security significantly affect the preferences of the elderly (q-statistic [q] > 0.5); local economic development significantly affects community-based care (q > 0.6); the availability of financial subsidies significantly affects home-based care and medical-nursing care (q > 0.9); and the availability of institutional resources significantly affects the preference for institutional care (q > 0.8). We found that it is necessary to improve the level of medical care given by non-family members and care facilities, vigorously develop new methods of elderly care, promote humanistic care in non-family care settings, and increase available regional medical resources, financial subsidies, and social security. This study integrates economic and social perspectives to examine and analyze retirement willingness, thereby broadening the scope of social surveys and research methodologies, and offering valuable insights with potential directive implications.

Zero-Dimensional Ignition Model of Boron Agglomerates.

Boron primarily exists in the form of agglomerates in ramjet combustion chambers. However, the model used to predict the ignition time of boron agglomerates is usually based on the single-particle assumption, resulting in inaccurate predictions. This study aims to develop a numerical model that can accurately describe the ignition of boron agglomerates. The model is based on the ignition model of a single particle boron proposed by the group of Kuo. Thiele modulus and effectiveness factor are introduced to represent the diffusion resistance of reaction gases in the pores of boron agglomerates. The model includes the necessary physical processes to accurately predict the ignition time. The rates of evaporation and heterogeneous reactions involved in the oxide layer removal process are corrected based on the fact that the diffusion rate of (BO)n in the liquid oxide layer equals to its consumption rate at the oxide-air interface. To evaluate the accuracy of the model, the obtained results for ignition time are compared with experimental data, showing reasonable consistency between them. The model is then applied to investigate the ignition characteristics of boron agglomerates. Parameters, such as initial average pore diameter, oxide layer thicknesses, initial particle diameter, O2 concentration, H2O concentration, and environmental pressure, are studied for their effects on the ignition time. In summary, the boron ignition model established in this study is a powerful tool to investigate the ignition mechanisms and characteristics of boron agglomerates. It can be further coupled with flow analysis for the detailed simulation of turbulent combustion in ramjet combustors.

Seed coating with micronutrients improves germination, growth, yield and microelement nutrients of maize (Zea mays L.).

Soil and foliar application are the most widely used methods for adding micronutrients to maize. High quality micronutrient fertilizers, however, are difficult to obtain in developing countries; micronutrient seed coatings are an attractive and practical alternative. We applied this approach to maize (Zea mays L.) to demonstrate the effects of boron (B), iron (Fe), manganese (Mn), molybdenum (Mo) and zinc (Zn) sulfates on maize germination, vigor, seedling growth, seed yield and seed quality as well as on seed microelement concentration. Seed coating was tested on three representative Chinese soil types (sandy, purple and lime soils). Compared to untreated controls, coating maize seeds with micronutrients significantly increased the seed emergence rate, seedling height, leaf length, leaf width, leaf area, main root length, root number, above ground fresh biomass, above ground dry biomass, underground fresh biomass, underground dry biomass, ear thickness and yield in sandy, purple and lime soils. Coating maize seeds with micronutrients also significantly increased the yield and quality of maize seed compared to untreated controls including ear barren tip, ear length, ear thickness, grains/row, hundred seed weigh, and rows/ear. Also, B, Zn, Fe, Mn and Mo microelements accumulated in maize seed after coating the seed with micronutrients. Our findings indicate that micronutrient seed coating may improve nutrient uptake and production of maize hybrids.

Solvent-Free Hydrogenation of 5-Hydroxymethylfurfural and Furfural to Furanyl Alcohols and their Self-Condensation Polymers.

2,5-Bis(hydroxymethyl)furan (BHMF) as well as furfuryl alcohol (FFA) are considered as highly valuable biomass-derived alcohols resembling aromatic monomers in polymer synthesis. Herein, a series of cobaltic nitrogen-doped carbon (Co-NC) catalysts calcinated at different temperatures were synthesized and tested for the solvent-free hydrogenation of 5-hydroxymethylfurfural (HMF) to prepare BHMF. It was found that the Co-NC catalyst calcinated at 600 °C (Co-NC-600) exhibited a superior catalytic activity in the hydrogenation reaction mainly due to the doping of graphitic N, which probably facilitated the polarization of H2 to afford H+ and H- . Consequently, Co-NC-600 offered a high BHMF/FFA yield greater than 90 % with a nearly complete conversion of HMF/furfural (FF) at the optimal conditions (80 °C, 4 h, and 5 MPa H2 ). After the hydrogenation reaction, Co-NC catalyst was facilely recycled by magnetic separation, and the obtained BHMF/FFA was then successfully transformed into hypercrosslinked polymers with an excellent CO2 /H2 storage capacity comparable to aromatic hydroxymethyl polymers. Therefore, this is a novel and facile two-step pathway for the conversion of biomass-derived HMF/FF towards functional polymers from both industrial and environmental perspectives.

Synthesis of bio-based 2-thiothiophenes.

While the synthesis of bio-based compounds containing carbon, oxygen and (to a lesser extent) nitrogen is well studied, the production of organosulfur compounds from biomass has received virtually no attention, despite their widespread application throughout the chemical industry. Herein, we demonstrate that a range of bio-based 2-thiothiophenes are available from the biopolymer cellulose, proving that functionally diverse small-molecule organosulfurs can be prepared independent of fossil carbon. This article is part of the theme issue 'Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)'.

Earth-abundant 3d-transition-metal catalysts for lignocellulosic biomass conversion.

Transformation of biomass to chemicals and fuels is a long-term goal in both science and industry. However, high cost is one of the major obstacles to the industrialization of this sustainable technology. Thus, developing catalysts with high activity and low-cost is of great importance for biomass conversion. The last two decades have witnessed the increasing achievement of the use of earth-abundant 3d-transition-metals in catalysis due to their low-cost, high efficiency and excellent stability. Here, we aim to review the fast development and recent advances of 3d-metal-based catalysts including Cu, Fe, Co, Ni and Mn in lignocellulosic biomass conversion. Moreover, present research trends and invigorating perspectives on future development are given.

Catalytic Conversion of Biomass to Furanic Derivatives with Deep Eutectic Solvents.

Biomass is the only renewable organic carbon resource in nature, and the transformation of abundant biomass into various chemicals has received immense spotlight. As a novel generation of designer solvents, deep eutectic solvents (DESs) have been widely used in biorefinery due to their excellent properties including low cost, easy preparation, and biodegradability. Although there have been some reports summarizing the performance of DESs for the transformation of biomass into various chemicals, few Reviews illuminate the relationship between the functional structure of DESs and catalytic conversion of biomass. Hence, this Minireview comprehensively summarizes the effects of the types of functional groups in DESs on catalytic conversion of biomass into furanic derivatives, such as carboxylic acid-based hydrogen-bond donors (HBDs), carbohydrate-based HBDs, polyalcohol-based HBDs, amine/amide-based HBDs, spatial structure of HBDs, and various hydrogen-bond acceptors (HBAs). It also further summarizes the effects of adding different additives into the DESs on the synthesis of high value-added chemicals, including water, liquid inorganic acids, Lewis acids, heteropoly acids, and typical solid acids. Moreover, current challenges and prospects for the application of DESs in biomass conversion are provided.

Green Process for 5-(Chloromethyl)furfural Production from Biomass in Three-Constituent Deep Eutectic Solvent.

5-(Chloromethyl)furfural (CMF), a versatile bio-platform molecule, was first synthesized in a three-constituent deep eutectic solvent (3c-DES) including choline chloride, AlCl3 ⋅ 6H2 O, and oxalic acid. In particular, 3c-DES was conducive for the production of CMF from glucose and provided a CMF yield of 70 % at 120 °C within 30 min. In addition, CMF yields reached up to 86, 80, 30, 29, and 35 % from fructose, sucrose, cellulose, bamboo, and bamboo pulp, respectively. This study opens new avenues for the preparation of CMF.

One-Pot Synthesis of Renewable Phthalic Anhydride from 5-Hydroxymethfurfural by using MoO3 /Cu(NO3 )2 as Catalyst.

Herein, a synthetic pathway to renewable phthalic anhydride (PA) from 5-hydroxymethfurfural (HMF) in one pot is reported. The commonly available catalysts MoO3 and Cu(NO3 )2 play a crucial role in integrating the multiple steps of the reaction, namely decarbonylation of HMF to active furyl intermediate (AFI), oxidation of HMF to maleic anhydride (MA), Diels-Alder cycloaddition of AFI and MA, and subsequent dehydration, in one pot. Under mild reaction conditions, a 63.2 % yield of PA is obtained from HMF. Compared with the currently reported route to renewable PA based on the Diels-Alder cycloaddition of biomass-derived MA and furan, this convenient one-pot synthesis represents a great improvement in efficiency.

Synthesis of MCM-41-Supported Metal Catalysts in Deep Eutectic Solvent for the Conversion of Carbohydrates into 5-Hydroxymethylfurfural.

A series of MCM-41 supported metal catalysts (denoted M/D41) were prepared by using the deep eutectic solvent (DES)-mediated ionothermal synthesis strategy. Al/D41 was found to have excellent performance in the conversion of carbohydrates into 5-hydroxymethylfurfural (HMF). Furthermore, the production of HMF from glucose could be performed at high concentrations in choline chloride aqueous solution (CAS; 32 wt %, relative to the reaction phase) and as a result, CAS is a more promising solvent than water and DES for HMF production.

Synthesis of 5-aminolevulinic acid with nontoxic regents and renewable methyl levulinate.

Synthesis of 5-aminolevulinic acid (5-ALA) was presented with novel bromination of biobased methyl levulinate (ML), followed by ammoniation and hydrolysis. Copper bromide (CuBr2) was employed as the bromination reagent with higher selectivity and activity instead of the conventional liquid bromine (Br2). 5-ALA was obtained in a high yield (64%) and purity (>95%) by optimum design, which is of great potential in industrialization.

Development of Betaine-Based Sustainable Catalysts for Green Conversion of Carbohydrates and Biomass into 5-Hydroxymethylfurfural.

Renewable and sustainable betaine-based catalysts (BX) derived from the betaine sugar industry or ChCl were developed for the production of 5-hydroxymethylfurfural (HMF) from various carbohydrates. The HMF yields in the BX-based media reached up to 88 %, 66 %, 37 % and 53 %, for the conversion of fructose, glucose, cellulose, and lignocellulosic biomass, respectively. In addition, choline-O-sulfate was synthesized and demonstrated to be an efficient catalyst for the conversion of fructose to HMF. From the perspective of green and sustainable chemistry, this work demonstrates benefits not only in the preparation of sustainable catalysts but also the green production of HMF from biomass.

[Effects of shade-humid environment on the growth characteristics of different maize (Zea mays) hybrids].

The growth traits of 18 maize hybrids were studied in natural and artificial simulation shade-humid environments. Significant differences were observed between the natural and shade-humid environments, and the air relative humidity in the shade-humid environment increased 15.0%-16.4%, the soil moisture increased 27.0%-78.4%, the illumination intensity decreased 72.9%-77.9%, and the quantum decreased 72.8%-79.6%. Shade did not affect the ambient temperature. The 7th leaf width, effective functional leaves, plant total leaves, tassel branch number, stem diameter, plant height, ear height, ear length, ear diameter, rows per ear, kernels per row, 100-grain mass and grain yield per plant under the shade-humid environment showed negative variations (reduction in phenotypic values), with the grain yield per plant and plant height being reduced by 72.3% and 7.1% respectively, and the declining changes of the remaining traits ranging from 14.8%-53.8%. However, the 7th leaf length, 7th leaf length-width ratio, anthesis to silking (ASI) duration, southern leaf blight (SLB) index and sheath blight index showed positive variations (increase in phenotypic values), with increases by 39.8%, 80.5%, 114.3%, 73.0% and 54.8%, respectively. The comprehensive shade-humid-tolerant coefficient calculated from the seven traits of ASI, tassel branches, plant total leaves, plant height, individual grain yield, southern leaf blight and sheath blight index could be easily and reliably used to evaluate the shade-humid-tolerant ability of the maize hybrids. According to this coefficient, the 18 hybrids could be classified into three categories, strongly-resistant, moderately-resistant and weakly-resistant to the shade-humid environment.

Iron increases liver injury through oxidative/nitrative stress in diabetic rats: Involvement of nitrotyrosination of glucokinase.

Excessive tissue iron levels are associated with the increase of oxidative/nitrative stress which contributes to tissue damage that may elevate the risk of diabetes. Therefore, we investigated the effects of iron on diabetes-associated liver injury and whether iron-related tyrosine nitration participated in this process. Rats were randomly divided into four groups: control, iron overload (300 mg/kg iron dextran, i.p.), diabetic (35 mg/kg of streptozotocin i.p. after administration of a high-fat diet) and diabetic simultaneously treated with iron. Iron supplement markedly increased diabetes-mediated liver damage and hepatic dysfunction by increasing liver/body weight ratio, serum levels of aspartate and alanine aminotransferase, and histological examination, which were correlated with elevated levels of lipid peroxidation, protein carbonyls and tyrosine nitration, oxidative metabolism of nitric oxide, and reduced antioxidant capacity. Consequently, the extent of oxidized/nitrated glucokinase was markedly increased in the iron-treated diabetic rats that contribute to a decrease in its expression and activity. Further studies revealed a significant contribution of iron-induced specific glucokinase nitration sites to its inactivation. In conclusion, iron facilitates diabetes-mediated elevation of oxidative/nitrative stress, simultaneously impairs liver GK, and can be a link between enzymatic changes and hepatic dysfunction. These findings may provide new insight on the role of iron in the pathogenesis of diabetes mellitus.

Ferric citrate CYP2E1-independently promotes alcohol-induced apoptosis in HepG2 cells via oxidative/nitrative stress which is attenuated by pretreatment with baicalin.

In the case of alcoholic liver injury, an iron overload is always present. Both alcohol and iron can individually induce oxidative stress in liver. However, the combined effect of physiological concentrations of alcohol and iron on oxidative stress in hepatocytes remains unknown. Baicalin has been demonstrated to be an antioxidant or iron chelator in animal experiments. In this study, we investigated the injury to hepatocytes CYP2E1-independently induced by the combination of alcohol and iron and the protective effect of baicalin. Compared with cells treated with ethanol alone, ferric citrate enhanced the accumulation of reactive oxygen and nitrogen species, increased the occurrence of protein carbonylation/nitration and the levels of 4-hydroxy-2-nonenal, changed the distribution of iNOS, and eventually resulted in apoptosis. However, pretreatment with baicalin inhibited the oxidative stress induced by the combination of alcohol and iron, mainly by chelating iron. Our findings therefore suggest that iron could CPY2E1-independently enhance the oxidative stress induced by alcohol, which probably contributes to the pathogenesis of alcoholic liver disease. Baicalin is a promising phytomedicine for preventing alcoholic liver disease.