Enantiospecific Analysis of Carboxylic Acids Using Cinchona Alkaloid Dimers as Chiral Solvating Agents.

Cinchona alkaloid derivatives as Brønsted base catalysts have attracted considerable attention in the field of asymmetric catalysis. However, their potential application as chiral solvating agents has not been described. In this research, we investigated the use of the Cinchona alkaloid dimer, namely, (DHQ)2PHAL, as a chiral solvating agent for discerning various mandelic acid derivatives through 1H NMR spectroscopy. The addition of catalytic amounts of DMAP facilitated this process. Our experimental results demonstrate that dimeric (DHQ)2PHAL exhibits remarkable chiral discrimination properties regarding the diagnostic split protons of 1H NMR signals (including 24 examples, up to 0.321 ppm). Furthermore, it serves as an excellent chiral discriminating agent and provides good resolution for racemic chiral phosphoric acid as determined by 31P NMR spectroscopy. The quality of enantiodifferentiation has also been evaluated by means of the parameter "resolution (Rs)". Significantly, this class of CSAs based on (alkaloid)2linker systems with an azaaromatic linker can be directly employed, which is commercially available in an enantiopure form at very low cost and exhibits promising potential in determining the enantiopurity of α-hydroxy acids by chemoselective and biocatalytic reactions.

[Distribution of Four Artificial Sweeteners in Water Treatment and Water Supply System in City H of Zhejiang Province].

Taking the sewage and drinking water treatment system of two cities in Zhejiang Province as the main research target, a systematic investigation on the common artificial sweeteners was carried out by solid phase extraction-high performance liquid chromatography (SPE-HPLC). The results showed that SPE-HPLC can accurately determine micro acesulfame (ACE), saccharin (SAC), aspartame (ASP), and neotame (NEO) in water. The detection limits were 57, 120, 170, and 47 µg·L-1, and the quantification limits were 190, 400, 567, and 157 µg·L-1, respectively. After optimization of the solid phase extraction procedure when using PWAX columns, the recoveries of ACE and SAC were enhanced to 86.5% and 97.7%; however, it slightly decreased to 66.5% for NEO. The occurrence rates of ACE, SAC, and NEO in domestic sewage were 100.0%, and it was only 33.3% for ASP. The highest concentrations of four aforementioned artificial sweeteners in domestic sewage were 0.83, 4.52, 1.22, and 7.57 µg·L-1, respectively. The highest concentrations of acesulfame, saccharin, aspartame, and neotame in source water were 22.94, 39.17, 0.73, and 8.92 µg·L-1, respectively, and detection rates were 72.7%, 90.9%, 18.2%, and 90.9%, respectively. Most artificial sweeteners were removed by the prozone process; the removal efficiencies of ACE, SAC, and NEO ranged from 67.7% to 100.0%, and the removal efficiencies of ACE, SAC, and NEO by the advanced treatment process ranged from 73.7% to 100.0%, which effectively reduced the risk of drinking water quality. The four artificial sweeteners were not detected in the water supply network.

[Immunological mechanisms of Neisseria gonorrhoeae infection: An update].

Neisseria gonorrhoeae (NG), as a pathogen of gonorrhea, is strictly limited to growth on the human host. In case of gonococcal infection, the body may recruit such inflammatory cells as neutrophils to resist the invasion of NG or initiate its adaptive immune response by antigen presentation to eliminate the pathogen. However, a series of immune escape mechanisms of NG make it difficult to clear up the infection. In the innate immune system, NG can not only secrete thermonuclease to degrade neutrophile granulocytes, inhibit respiratory burst to resist killing by neutrophils, activate NLRP3 to prompt the pyronecrosis of inflammatory cells, but also regulate the differentiation of macrophages to reduce the inflammatory response, combine with factor H to evade complement-mediated killing. NG infection can hardly give rise to effective adaptive immune response and immune memory, but can promote TGF-ß production to inhibit Th1/Th2-mediated adaptive immune response, bind to CEACAM1 on the B cell surface to promote apoptosis in B cells, and combine with CEACAM1 on the T cell surface to inhibit helper T cell proliferation, which makes it difficult for B cells to produce high-affinity specific antibodies. With the increasing drug-resistance of NG, immunological studies may play a significant role in the development of novel therapies and effective vaccines against the infection.

[Analysis on variance of common pathogenic bacteria and drug resistance in children in Chengdu area from 2001 to 2006].

OBJECTIVE: To investigate the variance and drug resistance of pathogenic bacteria isolated from children with infectious diseases seen between 2001 and 2006 in Chengdu area. METHODS: A total of 2888 pathogenic bacterial strains isolated from children in Chengdu Children's Hospital from 2001 to 2006 were analyzed. Tests were performed according to the guidelines of National Committee for Clinical Laboratory Standards (NCCLS) of the United States. RESULT: (1) Of the 2888 strains, 1845 (63.9%) were Gram negative bacteria. The main pathogenic bacteria included Escherichia coli (Ec, 718 strain, 24.9%), Hemophilus (H, 476 strain, 16.5%), Streptococcus pneumoniae (Sp, 412 strain, 14.3%), Klebsiella pneumoniae (Kp, 369 strain, 12.8%), Staphylococcus aureus (Sa, 353 strain, 12.2%), Staphylococcus epidermidis (Se, 278 strain, 9.6%), Pseudomonas aeruginosa (Pa, 146 strain, 5.1%) and other non-zymocyte (Onz, 136 strain, 4.7%). (2) The common pathogens found in blood specimen were 158 strain, which included Se (78 strain, 49.4%), Ec (23 strain, 14.6%), Kp (17 strain, 10.8%), Sa (14 strain, 8.9%), Onz (14 strain, 8.9%), Sp (7 strain, 4.4%) and Pa (5 strain, 3.2%). (3) The number of common pathogens isolated from patients with lower respiratory tract infection was 2018, including Ec (441 strains, 21.9%), H (430 strains, 21.3%), Sp (368 strains, 18.2%), Kp (253 strains, 12.5%), Sa (207 strains, 10.3%), Se (149 strains, 7.3%), Pa (97 strains, 4.8%) and Onz (73 strains, 3.6%). (4) There were 120 strains of common pathogens isolated from urine specimens, including Ec (78 strains, 65%), Kp (25 strains, 20.8%), Onz (7 strains, 5.8%), Pa (5 strains, 4.2%) and Se (5 strains, 4.2%). (5) There were 497 strains of common pathogens found in pus specimens, including Ec 167 strains, (33.6%), Sa (126 strains, 25.4%), Se (46 strains, 9.3%), H (44 strains, 8.9%), Onz (37 stains, 7.4%), Kp (31 strains, 6.2%), Sp (26 strains, 5.2%) and Pa (20 strain, 4.0%). The trend of drug resistance of pathogenic bacteria to antibiotics deteriorated. The proportion of methicillin-resistant Staphylococcus aureus (MRSA) was 6.7% and the methicillin-resistant coagulase-negative Staphylococci (MRCNS) rate was 20% in 2001 - 2003. The total proportion of extended-spectrum beta-lactamase stains (ESBL(S)) in Ec and Kp was 21.8%, and the rate of beta-lactamase production stains of Hemophilus influenzae (Hi) was 19.4% in 2001 - 2003.The proportion of MRSA was 17.2% and the MRCNS rate was 70.2%, the total proportion of ESBL(S) in Ec and Kp was 43.8%, and the rate of beta-lactamase producing stains of Hi was 39.7% in 2004 - 2006. CONCLUSION: The distribution of common pathogenic bacteria seen in Chengdu Children's Hospital has changed and the trend of drug resistance of pathogenic bacteria to antibiotics deteriorated in recent three years. Regionally monitoring the changes in pathogenic bacteria and the trend of drug resistance to antibiotics is paramount in guiding the pediatric clinical treatment.

[Study on liposome preparation technique of Bupleurum chinense volatile oil for injection].

OBJECTIVE: To study the preparation technique of the liposome of Bupleurum chinense volatile oil. METHOD: The composition, entrapment ratio of volatile oil, availability of freeze-drying and the changes of finger prints were studied. RESULT: Entrapment ratio reached 81.9%. After freeze-dried, the remaining ratio of the oil entrapped in the liposome reached 88.6%. CONCLUSION: It is practicable to make B. chinense injection into freeze-dried liposome powder.