0.05). The titrimetric determination of standard solution containing different levels of chloride showed recovery rates of 98.0%～103.7%, relative standard deviation was 0.16%. Conclusion Automatic potentiometric titration was easy to grasp, rapid and accurate, which was a new analytical method worthy to be applied extensively.

Objective To Study the method for determination of aluminium in water by spectrophotometry of Be ryllon Ⅲ. Methods Be ryllon Ⅲ reacts on aluminium in oppropriate temperature and acidity in water and produces a red complex compound?The red complex compound can be determined by spectrophotometry. Results The optimum reaction temperature was 85 ℃, the optimum reaction time was 5 min, pH of buffer was 6.1, Beer's law was obeyed in the concentration range of 0-0.02 mg/L for aluminium, rates of recovery were 80.0%-96.0% and RSD was 0.70%. Conclusion This method is accurate, simple, sensitive and repeatable.

Objective To evaluate the clinical significance of the axillary conservative surgery by sentinel lymph node biopsy (SLNB) using preoperative lymphoscintigraph technique with 99mTc-SC and methylene blue in early-stage breast cancer patients. Methods The sentinel lymph node (SLN) of 187 patients were located with preoperative lymphoscintigraph technique with 99mTc-SC and labeled with methylene blue during the operations. The metastasis of SLN was detected using frozen section technique. There were 51 patients whose SLN were positive having been carried with modified radical mastectomy of breast cancer and axillary lymph node dissection (ALND), 136 patients' SLN were negative,58 patients of those were carried with mammectomy or partial mastcctomy and ALND (group A),while 78 patients were carried out with mammectomy or partial mastectomy only (group B). The sentinel lymph nodes were detected with HE stain after surgery. All the patients were treated with chemotherapy,and the patients with partial mastcctomy must be treated with radiotherapy. There were 2 patients with micrometastasis in group B being treated with mammectomy or partial mastcctomy only,and carried out with ALND again. Results The number of cases with upper limb numbness, edema, dysfunction in group A were 36,8 and 45 cases, in group B were 2,0,0 case respectively. Group A compared with group B was increased significantly (P< 0.05). The number of local recurrence within 1, 3 and 5 years were 0,0,2 cases;lymphatic metastasis were 1,5,8 cases; the distant metastasis were 2,8,12 cases; the disease-free survival were 60,57,49 cases. In group B, the number of local recurrence within 1, 3 and 5 years were 0,0,6 cases, lymphatic metastasis were 3,8,12cases,the distant metastasis were 4,8,16 cases,the disease-free survival were 76,70,61 cases. There were not significant differences between the two groups(P> 0.05). Conclusion It is simple and accurate to carry out SLNB using preoperative lymphoscintigraph technique with 99mTc-SC combined with methylene blue,and the effect is reliable.

Objective To identify a aldehyde dehydrogenases positive (ALDH+) cancer stem cell subpopulation in MCF-7 cells and to investigate the proliferation and differentiation characteristics of these cells in vitro.Methods ALDH+ breast cancer stem cells were isolated from MCF-7 cells by flow cytometry and the biological property of ALDH+ breast cancer stem cells were examined by scarification test,MTT,growth curvature and Transwell migration assay.Results The ratio of CD-/low24 CD+44 cells was about 1.4 ％ in MCF-7 cells.The ratio of ALDH+ CD-/low24CD+44 cells was about 1.2 ％.The growth curvature of ALDH+ breast cancer stem cells was almost the same with that of CD-/low24 CD+44 cells.The distance between cells was obviously shorter in both CD-/low24 CD+44 cells scarification zone and ALDH+ CD-/low24 CD+44 cells scarification zone.The migration ability of CD-/low24CD+44 cells and ALDH+ CD-/low24CD+44 cells was stronger than control group cells.There were migration ability differences between CD-/low24CD+44 cells and ALDH+ CD-/low24CD+44 cells.The results of Transwell experiments were in coincidence with above results.Lots of CD-/low24CD+44 cells and ALDH+ CD-/low24CD+44 cells were through the membrane.In MTT assay,absorbance values were 1.05±0.098,1.56±0.075 and 1.67±0.032.Conclusion CD--/low24CD+44 and ALDH+ CD-/low24CD+44 breast cancer stem cell subpopulation exist in MCF-7 cells.ALDH could potentially be used as a molecular marker to identify breast cancer stem cell subpopulation.

Objective: To evaluate the dietary risk of neonicotinoid insecticides in market-sold vegetables in Guangzhou City, so as to provide insights into ensuring food safety for residents. Methods: Forty-five samples of 21 kinds of vegetables were collected from supermarkets and farmer's markets in Guangzhou City from June to September in 2022, and 10 kinds of neonicotinoid insecticides were determined using liquid chromatography-mass spectrometry (LC-MS). The vegetable consumption was obtained through the survey of food consumption and nutrients intake of residents in Guangzhou City. The dietary risk was evaluated by calculating daily exposure and non-carcinogenic risk quotients of neonicotinoid insecticides. Results: A total of 27 samples of vegetables were detected with neonicotinoid insecticides, and the detection rate was 60.00%. Among 10 kinds of neonicotinoid insecticides, 6 kinds were identified, including clothianidin, thiamethoxam, imidacloprid, acetamiprid, dinotefuranand and nitenpyram. The detection rates of clothianidin, thiamethoxam and imidacloprid were relatively high (26.67%, 11.11% and 6.67%), and some samples exceeded the standard, with the rate of 4.44%, 2.22% and 2.22%, respectively. The total exposure of neonicotinoid pesticides (IMIRPF) was 3 053.00 ng/g, and the contents and IMIRPF of imidacloprid were the highest in roots and tubers. The daily exposure of imidacloprid, acetamiprid, dinotefuran, clothianidin, thiamethoxam and nitenpyram was 34.58, 3.85, 1.20, 6.87, 7.19 and 0.86 ng/(kg·d). Non-carcinogenic risk quotients of imidacloprid, acetamiprid, dinotefuran, clothianidin, thiamethoxam and nitenpyram was 5.76×10-4, 0.55×10-4, 0.06×10-4, 0.69×10-4, 0.90×10-4 and 0.02×10-4, respectively, which was lower than 1; and the sum of non-carcinogenic risk quotients was 7.98×10-4, which was lower than 1. Conclusions The dietary risk of neonicotinoid pesticides is low in 21 kinds of market-sold vegetables in Guangzhou City; however, the contents of neonicotinoid insecticides in some vegetable samples exceed the standard. The supervision of vegetable markets should be strengthened.

80% activity rate against E.coli included piperacillin/tazobactam(93.4%)、ceftazidime(86%),and amikacin(83.3%);The susceptible rate to piperacillin/tazobactam in K.pneumoniae was 84.6%. The susceptible rate to ceftazidime decreased from 82.3% to 69.9%, which was lower than to cefepime (77.2%). Over 50% of Enterobacter cloacae were resistant to ceftazidime, cefotaxime and ceftriaxone. Susceptible rates to piperacillin/tazobactam in E. cloacae,E. aerogenes,Citrobacter freundii and Serratia marcescens (67.7%-96.4%) were higher than those to cefepime (68.8%-77.5%), cefoperazone/sulbactam (59.7%-87.5%). Susceptibility to amikacin among these 4 species (70%-83.7%) was higher than to ciprofloxacin (48.1%-79.5%). All of Morganella morganii and Proteus vulgaris isolates were susceptible to meropenem and imipenem; Over 90% of the isolates were susceptible to cefepime, cefoperazone/sulbactam and piperacillin/tazobactam.The most active agent against Pseudomonas aeruginosa was meropenem (84%), followed by amikacin, piperacillin/tazobactam, ceftazidime and imipenem (72.5%-76.6%). Mutiple-drug-resistant Acinetobacter baumannii increased from 33% in 2003 to 48% in 2004. Resistance to carbapenems increased to 18% in this species in 2004. The most active agents against Burkholderia cepacia were meropenme (64.9%), cefoperazon/sulbactam (63.2%), ceftazidime (59.6%), piperacillin/tazobactam (56.1%) and cefepime (52.6%).Conclusions Carbapenems remained very high activity against Enterobacteriaceae. Increasing resistance to 10 antimicrobials agents tested among A. baumanni brought great concern. Meropenem was 4-to 16-fold more active against common gram-negative bacilli than imipenem.

OBJECTIVE To s tudy the impr ovement effects of tilianin on the atherosclerosis （AS）model mice and its potential mechanism. METHODS Eight C 57BL/6J mice were taken as the normal group. Forty ApoE－/－ mice were randomly divided into model group ，tilianin low-dose ，medium-dose and high-dose groups [ 2.1，3.5，7.0 mg/（kg·d）] and simvastatin group [positive control drug ，3.5 mg/（kg·d）]，with 8 mice in each group. Normal group was given normal diet ，and other groups were given high-lipid diet to induce AS model. At the same time ，normal group and model group were given normal saline intragastrically ， administration groups were given relevant drug intragastrically ，once a day ，for 12 consecutive weeks. The levels of TC ，TG， LDL-C，HDL-C，Ox-LDL，IL-1β，IL-6，MCP-1 and TNF-α in plasma were determined. The pathomorphological changes of the aorta in mice were observed. The positive rate of ICAM- 1，VCAM-1 and PCNA in the aorta were determined. mRNA expressions of MMP- 2，MMP-9，TGF-β1，Smad2 and Smad 3 as well as protein expressions of TGF-β1，Smad2/3 and p-Smad 2/3 were also determined in aorta of mice. RESULTS Compared with normal group ，the plasma levels of TC ，TG，LDL-C，Ox-LDL，IL-1β， IL-6，MCP-1 and TNF-α in model group were increased significantly（P＜0.01），while HDL-C level was significantly reduced （P＜0.01）. Lipid plaques were formed in the aorta ，and the plaque area was large and caused severe stenosis of the lumen. mRNA expressions of MMP- 2，MMP-9，TGF-β1，Smad2 and Smad 3 as well as positive rate of ICAM- 1，VCAM-1，PCNA and protein expression TGF-β1，Smad2/3，and p-Smad 2/3 in the aorta were significantly increased （P＜0.01）. Compared with model group ， most of above indexes of medication groups were improved significantly （P＜0.05 or P＜0.01）. CONCLUSIONS Tilianin can inhibit the activation of TGF-β1/Smads signaling pathway and then inhibit the proliferation of vascular smooth muscle cells ，reduce ， inflammation and regulate lipid metabolism to inhibit the No.81960766） formation of AS.

Objective To understand phthalic acid esters pollution of daily consumed food in Guangzhou City，and evaluate the hazard of phthalic acid esters exposure in residents dietary. Methods Detected the content of phthalic acid esters in 10 types of food by gas chromatography-mass spectroscopy（GC-MS）methods .It combined with a survey on dietary nutrients intake of Guangzhou residents was conducted．Hazard index on the dietary exposure assessment of chemicals in food was applied. Results It showed that the highest levels of DBP，DEHP and DIBP，from the mixed diet samples in Guangzhou were 1.256，1.418，0.576 mg/kg respectively；and the exposure level of DBP，DEHP and DIBP were 2.431、5.981、2.408μg/kg.d ;HQ was respectively 0.243、0.125、0.025. HI was 0.393. Conclusion The dietary contamination of phthalic acid esters for Guangzhou was kept at a low level.But the pollution of 3 kinds of mixed samples such as meats，eggs，aquatic and products may be a certain risk of health that should attract more attention.