[Energy-saving and Emission Reduction Path for Road Traffic in Key Coastal Cities of Guangdong, Fujian and Zhejiang].

The rapid development of society and economy has resulted in a substantial increase in energy consumption, consequently exacerbating pollution issues. Current research predominantly focuses on energy-saving and emission reduction in road transportation within individual cities or the three major economic regions of China:the Yangtze River Delta, the Pearl River Delta, and the Beijing-Tianjin-Hebei Region. However, there is a dearth of studies addressing the southeastern coastal economic region. Located at the heart of China's southeastern coastal economic development, the provinces of Guangdong, Fujian, and Zhejiang unavoidably face challenges associated with energy consumption and emissions while pursuing economic growth. To address these challenges, this study employed a LEAP model to construct various scenarios for road transportation in the key coastal cities of Guangdong, Fujian, and Zhejiang from 2015 to 2035. These scenarios included a baseline scenario (BAU), an existing policy scenario (EPS), and an improved policy scenario (MPS). The MPS and EPS encompassed vehicle structure optimization (VSO), improved fuel economy (IFE), and reduced annual average mileage (RDM). By simulating and evaluating these scenarios, the energy-saving and emission reduction potentials of road transportation in the key coastal cities were assessed. The results indicated that, in the primary scenario, the MPS exhibited the most significant improvements in energy-saving, carbon reduction, and pollutant reduction effects. By 2035, the MPS achieved a remarkable 75% energy-saving rate compared to that in the baseline scenario, accompanied by reductions of 68%, 59%, 66%, 70%, and 64% in CO2, CO, NOx, PM2.5, and SO2 emissions, respectively. In the secondary scenario, the improved scenario of enhancing fuel economy achieved a notable 30% reduction in energy consumption. Additionally, the scenarios involving vehicle structure adjustment (yielding reductions of 36%, 30%, 36%, 26%, and 40%) and annual average mileage reduction (resulting in reductions of 37%, 37%, 36%, 37%, and 36%) demonstrated significant reductions in CO2, CO, NOx, PM2.5, and SO2 emissions.

Divergent Synthesis of Highly Substituted Tetrahydroquinolines and Cyclopentenes via Lewis Base Catalyzed Switchable [4 + 2] and [3 + 2] Annulations of MBH-Carbonates with Activated Olefins.

A highly selective and divergent synthesis which enabled access to various complex compounds is highly attractive in organic synthesis and medicinal chemistry. Herein, we developed an effective method for divergent synthesis of highly substituted tetrahydroquinolines via Lewis base catalyzed switchable annulations of Morita-Baylis-Hillman carbonates with activated olefins. The reaction displayed switchable [4 + 2] or [3 + 2] annulations via catalyst or substrate control, providing a diverse range of architectures which contained highly substituted tetrahydroquinolines or cyclopentenes with three contiguous stereocenters bearing a quaternary carbon center in high yields with excellent diastereoselectivities and regioselectivities. Furthermore, synthetic utility of this strategy was further highlighted by gram-scale experiments and simple transformations of the products.

Highly regioselective synthesis of lactams via cascade reaction of α,ß-unsaturated ketones, ketoamides, and DBU as a catalyst.

Herein, the aldol/Michael cascade reaction on the ß,γ-positions of α,ß-unsaturated ketones with ketoamides to construct bicyclic lactams via DBU catalysis has been developed. The substrates were well-tolerated with high regio- and diastereoselectivities in moderate to good yields (32 examples). The control experiments revealed that the hydrogen of the amide was the key factor.

[3 + 2] cycloaddition of nonstabilized azomethine ylides and 2-benzothiazolamines to access imidazolidine derivatives.

A simple and practical method for the construction of 1,3,5-trisubstituted imidazolidine derivatives via [3 + 2] cycloaddition reaction has been developed. This reaction could smoothly proceed between nonstabilized azomethine ylides generated in situ and 2-benzothiazolamines to deliver a wide scope of differently substituted imidazolidines in high yields (up to 98%). The structure of one example was confirmed by X-ray single-crystal structure analysis.

Substrate-Controlled Regioselectivity Switchable [3 + 2] Annulations To Access Spirooxindole Skeletons.

The additive-free [3 + 2] annulation from isatins, amino acids with 2-styrylbenzoxazoles, was described, providing a series of functional and structurally complex 3,3'-pyrrolidinyl-spirooxindole derivatives containing four contiguous and two quaternary stereogenic centers in high yields (up to 95%) and excellent diastereoselectivities (up to >25:1 dr). Interestingly, the reaction exhibits switchable regioselectivity depending on the substrate of amino acids. With proline or thioproline as the substrate, the reaction afforded α-regioselective spirooxindole skeletons. In contrast, when piperidine acid is the substrate, the reaction provided γ-regioselective spirooxindole skeletons.

A copper iodide-catalyzed coupling reaction of benzofuran-3(2H)-ones with amines: an approach to α-ketoamides.

A CuI-catalyzed coupling reaction of benzofuran-3(2H)-ones with amines has been well established for the direct synthesis of α-ketoamides. This process involves C-O bond cleavage and C[double bond, length as m-dash]O/C-N bond formation. Mechanism studies indicated that this α-ketoamide formation reaction may involve a free radical process.

1,3-Dipolar cycloaddition of isatin N,N'-cyclic azomethine imines with α,ß-unsaturated aldehydes catalyzed by DBU in water.

A simple and green procedure was established by [3 + 3] cycloaddition reaction of isatin derived cyclic imine 1,3-dipoles with α,ß-unsaturated aldehydes, giving the desired spiro heterocyclic oxindoles with aza-quaternary centers in good yields and diastereoselectivities. It should be noted that water can be employed as a suitable solvent for the improvement of diastereoselectivity.

Dearomative [3 + 2] cycloaddition reaction of nitrobenzothiophenes with nonstabilized azomethine ylides.

A highly diastereoselective dearomative [3 + 2] 1,3-dipolar cycloaddition reaction of nitrobenzothiophenes with an in situ-generated nonstabilized azomethine ylides has been developed. The transformation provides a series of functionalized fused tricyclic benzo[4,5]thieno[2,3-c]pyrroles in good yields (up to 92%) under mild reaction conditions. In addition, a gram-scale experiment and the synthetic transformation of the cycloadduct further highlighted the synthetic utility. The relative configurations of the typical products were clearly confirmed by X-ray crystallography.

Synthesis of γ-Lactones by TBAI-Promoted Intermolecular Carboesterification of Carboxylic Acids with Alkenes and Alcohols.

A novel tetrabutylammonium iodide (TBAI)-promoted three-component reaction of carboxylic acid with alkene and alcohol has been developed, which represents facile and straightforward access to polysubstituted γ-lactone skeletons in moderate-to-good yields. This methodology is distinguished by the use of a commercial catalyst and readily available starting materials, wide substrate scope, and operational simplicity. Mechanistic studies suggested that this transformation went through a radical process.

Cross 1,3-dipolar cycloadditions of C,N-cyclic azomethine imines with an N-benzyl azomethine ylide: facile access to fused tricyclic 1,2,4-hexahydrotriazines.

A cross 1,3-dipolar cycloaddition of two different ylides between C,N-cyclic azomethine imines with an in situ-generated nonstabilized azomethine ylide from an N-benzyl precursor was realized. The reactions afforded a clean and facile access to diverse fused tricyclic 1,2,4-hexahydrotriazines in high yields (up to 96%). The chemical structures of the typical compounds were confirmed by X-ray single-crystal structure analysis.

N-Heterocyclic Carbene/Lewis Acid Dual Catalysis for the Divergent Construction of Enantiopure Bridged Lactones and Fused Indenes.

The chiral triazole carbene and Ti(OPr-i)4 cocatalyzed reaction between α,ß-unsaturated aldehydes and 2-(aroylvinyl)benzaldehydes was systematically studied. A divergence in reaction pathways was observed under different reaction conditions. In benzene solvent and at ambient temperature, the reaction produced 4,5-dihydro-1,4-methanobenzo[c]oxepin-3-ones, the bridged caprolactones, as the major products in moderate yields with excellent enantioselectivity. The same reaction in dichloroethane and at 50 °C, however, gave 2,8-dihydrocyclopenta[a]indenes as the major products in most cases. The application of the method developed was demonstrated by the transformation of the bridged lactone products into enantiopure 4-hydroxy-1,2,3,4-tetrahydronaphthalene-2-carboxylic acids.

The Reaction of 2-Aroylvinylcinnamaldehydes with Aromatic Aldehydes by Dual Catalysis with a Chiral N-Heterocyclic Carbene and a Lewis Acid: Enantioselective Construction of Tetrahydroindeno[1,2-c]furan-1-ones.

The cooperative chiral N-heterocyclic carbene and Lewis acid catalyzed reactions between 2-aroylvinylcinnamaldehydes and various aromatic aldehydes produced multifunctional tetrahydroindeno[1,2-c]furan-1-ones with excellent enantioselectivity. This work developed a versatile and efficient method for highly enantioselective construction of chiral tetrahydroindeno[1,2-c]furan-1-one, which are not easily prepared by other synthetic methods.

Chiral N-heterocyclic carbene/Lewis acid cooperative catalysis of the reaction of 2-aroylvinylcinnamaldehydes: a switch of the reaction pathway by Lewis acid activation.

The chiral N-heterocyclic carbene/Lewis acid co-catalyzed reaction of 2-aroylvinylcinnamaldehydes produced good yields of indeno[1,2-c]furan-1-one derivatives with excellent enantioselectivity and diastereoselectivity. A switch of intramolecular cyclization to intermolecular dimerization was achieved by the cooperative catalysis of chiral triazole carbene and Ti(OPr-i)4 catalysts.

N-Heterocyclic Carbene-Catalyzed Oxidative Annulations of α,ß-Unsaturated Aldehydes with Hydrazones: Selective Synthesis of Optically Active 4,5-Dihydropyridazin-3-ones and Pyridazin-3-ones.

A novel and efficient method for the highly enantioselective synthesis of chiral 4,5-dihydropyridazin-3-one derivatives has been developed based on the chiral N-heterocyclic carbene-catalyzed oxidative annulation between α,ß-unsaturated aldehydes and hydrazones. Meanwhile, the selective synthesis of either 4,5-dihydropyridazin-3-ones or pyridazin-3-one derivatives from the same reactants has been achieved by simply varying catalytic and reaction conditions.

N-heterocyclic carbene-catalyzed diastereoselective and enantioselective reaction of 2-aroylvinylcinnamaldehydes with α,ß-unsaturated imines: complete control and switch of diastereoselectivity by N-substituents of catalysts.

Highly diastereoselective and enantioselective reactions between 2-aroylvinylcinnamaldehydes and α,ß-unsaturated imines were achieved under asymmetric catalysis of chiral triazole carbene catalysts. In the presence of N-anisylindeno[2,1-b]triazolo[4,3-d][1,4]oxazinium salt, the reaction of 2-aroylvinylcinnamaldehydes with α,ß-unsaturated imines afforded indeno[2,1-c]pyran-1-one derivatives 4 with 90%-99% ee, while enantiopure indenocyclopentan-1-ones 5 (>99% ee) were obtained under the catalysis of N-mesitylindeno[2,1-b]triazolo[4,3-d][1,4]oxazinium salt. A slight variation of an N-substituent on triazole carbenes was found to switch completely the diastereoselectivity of the reaction for the formation of indeno[2,1-c]pyran-1-ones.

Palladium-catalyzed Suzuki-Miyaura coupling of aryl sulfamates with arylboronic acids.

Readily available NHC-Pd(II)-Mp complexes 2 showed efficient catalytic activity toward the Suzuki-Miyaura coupling of aryl sulfamates with arylboronic acids or potassium phenyltrifluoroborate, giving the expected coupling products in good to high yields. It should be noted that this is the first example so far of the phosphine-free, NHC-Pd(II) complexes catalyzed Suzuki-Miyaura coupling of aryl sulfamates with arylboronic acids.

Quantitative detection of Streptococcus mutans and bacteria of dental caries and no caries groups in permanent teeth from a north China population.

BACKGROUND: Streptococcus mutans (S. mutans) is the prime pathogen of dental caries. There are few reports that studied the relationship between S. mutans, bacteria and dental caries in permanent teeth when compared to those in primary teeth. This study aimed to detect S. mutans and bacteria of dental caries and non-caries groups in permanent teeth from a north China population by real-time polymerase chain reaction (PCR) and compare the relationship between the number of these bacteria and the prevalence of dental caries in permanent teeth. METHODS: Human saliva samples were collected from 142 subjects with permanent teeth. According to their dental tooth (DT), 142 subjects were divided into a dental caries group (DT ≥ 1) and a non-caries group (DT = 0). With specific primers for S. mutans and 16S rRNA, the total number of S. mutans and total bacteria of 142 saliva samples were detected by real-time PCR and statistically analyzed. RESULTS: There was no significant difference between the detection rates of S. mutans (P = 0.118) and medians of S. mutans (P = 0.115). The ratio of S. mutans to total bacteria in people with dental caries was significantly higher than in those without caries (P < 0.001), but the total number of bacteria in people with dental caries was significantly lower than in those without caries (P < 0.001). CONCLUSIONS: S. mutans had different effects on caries in the permanent teeth of several individuals from a north China population. The ratios of S. mutans to total bacteria in saliva detected by real-time PCR with Sm479F/R and 16S RNA primers were closely associated with the prevalence of dental caries in the same population. These assays may be useful for the assessment of an individual's risk of dental caries.

N-heterocyclic carbene-palladium(II)-1-methylimidazole complex-catalyzed Suzuki-Miyaura coupling of aryl sulfonates with arylboronic acids.

A well-defined NHC-Pd(II)-Im complex 1 was found to be an effective catalyst for the Suzuki-Miyaura coupling of aryl sulfonates including tosylates and phenylsulfonates with arylboronic acids, giving the desired coupling products in good to high yields. Acceptable yields can also be achieved even by using the less reactive mesylates as the substrates. It is worthy of noting here that this is the first example of NHC-Pd(II) complex-catalyzed Suzuki-Miyaura coupling of aryl sulfonates with arylboronic acids, enriching an inexpensive, convenient, and alternative method for the synthesis of biaryl compounds.

[A family associated outbreak of Mycoplasma pneumoniae infection in a hospital ward].

OBJECTIVE: To describe the epidemiological and serological features on a family associated outbreak caused by Mycoplasma pneumoniae (MP) infection occurred in Beijing in August 2007. METHODS: Mutual exposure of the family members was investigated and retrospective medical record was reviewed for the hospitalized patients. Serum antibodies to MP were measured and chest X-rays were taken for all the family members. RESULTS: This family consisted of 5 members, with fixed members as the boy (13 years old), his father (43 years old) and mother (44 years old), grandmother (64 years old) and uncle (32 years old) who was involved in taking care of the sick boy and his father. During 23 days of the event, four of all the five family members were ill. Three (boy, father and uncle) had radiographic pneumonia, whose paired sera all showed a ≥ fourfold increase in antibody titer, and two of them were confirmed by chest X-ray on day 2 after onset of fever. The grandmother suffered from bronchitis, with positive (PA) serum antibody to MP. Serum MP-IgG from the father and uncle was positive, 3 days and 2 days after the onset of fever. The chances of contact between grandmother with the boy and uncle with the father were both only in the hospital wards. Only the mother remained asymptomatic, with her serum MP-IgM(-) and MP-IgG(+) for which the blood sample was collected 37 days after close contact with the boy. The longest time of exposure to the patients was between mother and the boy but only the mother did not increase her total workload or feeling for fatigue. RESULTS: of MP-IgG from post-infection did not completely defend against the repeated MP infection. Combined risk factors as index patients with severe cough, prolonged close contact, poorly ventilation of the environment, and family members with excessive fatigue might work as the causes of this family MP outbreak.

[Quantitative detection of Streptococcus mutans in different people with dental caries by real-time polymerase chain reaction].

OBJECTIVE: To establish a quantity detection method of Streptococcus mutans (Sm) and bacteria and compare the relationship between the number of these bacteria and the prevalence of dental caries in different people. METHODS: With specific primers for a unique sequence in a 14 kb HaeIII restriction fragment consistently presenting during detecting Sm by chromosomal DNA fingerprints, the total number of Sm and bacteria of 99 saliva samples were detected by real-time polymerase chain reaction (PCR) and statistically analyzed. RESULTS: The primers were specific for Sm and the minimum detectable level by real-time PCR was 0.1 microg/L. The total number of bacteria in the dental caries and people without caries was 51.4 x 10(8) cell copies/L and 221.6 x 10(8) cell copies/L respectively, in which the ratio of Sm to bacteria was 0.0193 and 0.0059 respectively. The differences were significantly different between the people with dental caries and those without caries in the total number of bacteria and the ratio of Sm to bacteria. CONCLUSIONS: The primers can be used to detect the Sm by real-time PCR. The ratio of Sm to bacteria was closely associated with the prevalence of dental caries.