The study about using water sources in diet in community was performed at 3 provinces of Mekong Delta in January 2002. The total number of investigated households were 1639, the samples were collected by investigating 30 groups method. The investigating about major water source using diet showed that on average, about 70% (35-92%) of households used river water, 17.6% (2.0-48%) used tap water and 10.8% (0-20.8%) used rain water. 40% of points used the river water to supply water with community, far latrine-fishpond from 10m, 26% was closed cattle-breeding cage (under 10m). The river water-processing method was alum accumulation, the pasteurization rate without chloramine was nearly 80% and about 20% of households used non-boiled drinking-water. The rate of households used boring well was very low (2-4%), 10% of households entered using processed river water because they were very poor
Water ; epidemiology ; diet ; Alum Compounds ; Chloramines

OBJECTIVETo introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination.

METHODSIndicator microorganisms such as Escherichia coli, Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination.

RESULTSThe sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy.

CONCLUSIONSThe possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.

Chloramines ; chemistry ; pharmacology ; Chlorine ; chemistry ; Disinfection ; methods ; Halogenation ; Water ; chemistry ; Water Microbiology ; Water Purification ; methods

OBJECTIVE: To assess the effect of disinfectant (Cavicide) with benzethon chloramine and isopropanol as main active ingredients disinfectant on dental impression accuracy. METHODS: The effect of Cavicide on three impression materials (alginate, polyether and vinylpolysiloxane) were assessed using a standard model. The standard model was digitized by an extraoral scanner (IScan D103i, Imetric). For each kind of impression materials, thirty impressions were taken following the manufactures' instruction in the same conditions. Subsequently, the impressions were randomly divided into three groups, with ten impressions in each group. After the impression taking was completed, the three groups underwent pure water rinse for 1 min (blank control, BC), 2% glutaraldehyde solution immersion disinfection for 30 min (glutaraldehyde, GD), and Cavicide solution spray disinfection for 5 min (Cavicide, CC), respectively. All the impressions were digitized by the extraoral scanner (IScan D103i, Imetric) after disinfection and exported to a dedicated three-dimensional analysis software (Geomagic Qualify 2014, Geomagic, USA). In the software, the digital models of the impressions were trimmed to teeth and then superimposed with the digitized standard model via best-fit alignment. Root mean square (RMS) was used to evaluate the deviations between the impression and the standard model. The deviation in the anterior and posterior regions was evaluated respectively. One-way ANOVA test and the LSD post-hoc test were used to compare the deviations between the three groups (P < 0.05). The color map of each superimposition was saved for visual analysis. RESULTS: For the polyether and vinylpolysiloxane materials, the difference between the three groups was not statistically significant (P=0.933, P=0.827). For the alginate material, the difference in posterior region between group GD and group BC, as well as group GD and group CC were statistically significant (GD vs. BC, P=0.001; GD vs. CC, P=0.002), while the difference between group BC and group CC was not statistically significant (P=0.854). The visual analysis showed an obvious deviation in the buccal-lingual direction in group GD. CONCLUSION Disinfectant (Cavicide) with benzethon chloramine and isopropanol as main active ingredients using spray disinfection has no effect on the accuracy of the alginate, polyether and vinylpolysiloxane impressions.
2-Propanol ; Chloramines ; Dental Impression Materials ; Dental Impression Technique ; Disinfectants ; Disinfection ; Models, Dental

OBJECTIVETo introduce a new sequential chlorination disinfection process in which short-term free chlorine and chloramine are sequentially added.

METHODSPilot tests of this sequential chlorination were carried out in a drinking water plant.

RESULTSThe sequential chlorination disinfection process had the same or better efficiency on microbe (including virus) inactivation compared with the free chlorine disinfection process. There seemed to be some synergetic disinfection effect between free chlorine and monochloramine because they attacked different targets. The sequential chlorination disinfection process resulted in 35.7%-77.0% TTHM formation and 36.6%-54.8% THAA5 formation less than the free chlorination process. The poorer the water quality was, the more advantage the sequential chlorination disinfection had over the free chlorination.

CONCLUSIONThis process takes advantages of free chlorine's quick inactivation of microorganisms and chloramine's low disinfection by-product (DBP) yield and long-term residual effect, allowing simultaneous control of microbes and DBPs in an effective and economic way.

Bacteria ; drug effects ; Chloramines ; chemistry ; Chlorine ; chemistry ; Disinfection ; methods ; Viruses ; drug effects ; Water ; chemistry ; Water Microbiology ; Water Purification ; methods

OBJECTIVETo establish a labeling method for a specific lung cancer-targeting small molecule peptide cNGQGEQc with ¹³¹I and observe the radioactivity distribution of the labeled peptide in rabbits using single-photon emission computed tomography (SPECT).

METHODSChloramine-T method was used for ¹³¹I labeling of the tyrosine amino group on cNGQGEQc, and the labeling efficiency and radiochemical purity of ¹³¹I-cNGQGEQc were determined with paper chromatography. The stability of ¹³¹I-cNGQGEQc in saline and human serum was assessed after incubation in water bath at 37 degrees celsius; for 24 h. The octanol-water partition coefficient lg P (the radioactivity counting ratio of ¹³¹I-cNGQGEQc dissolved in 100 µl octanol or in 100 µl saline) was calculated. SPECT was performed in 3 male New Zealand white rabbits after intravenous injection of ¹³¹I-cNGQGEQc to observe the dynamic distribution of the peptide with the time-radioactivity curve (T-A curve) of the region of interest (ROI).

RESULTSWith a labeling efficiency of 90%, ¹³¹I-cNGQGEQc showed a radiochemical purity of was 95% after purification with HPLC. The radiochemical purity of ¹³¹I-cNGQGEQc was (93.12 ± 1.18)% and (88.34 ± 5.43)% after intubation in saline and human serum for 24 h, respectively. The octanol-water partition coefficient lg P of ¹³¹I-cNGQGEQc was -1.75, suggesting its hydrosolubility. In rabbits with intravenous injection of ¹³¹I-cNGQGEQc, SPECT visualized the kidneys at 1 min after the injection; the imaging of the heart and liver became attenuated at 5 min when the bladder was visualized with an increasing radioactivity. The radioactivity of the soft tissues began to fade at 30 min. No gallbladder visualization was detected, and the radioactivity of the abdomen remained low. No obvious radioactivity concentration was observed in the thyroid and stomach. The T-A curves of the ROI of all the tissues and organs descended over time.

CONCLUSIONRadiolabeling of cNGQGEQc with ¹³¹I is simple and highly efficient. ¹³¹I-cNGQGEQc has good stability in vitro and good distribution characteristics for in vivo imaging, and is cleared mainly by renal excretion due to its hydrosolubility. These results provide experimental basis for further studies of diagnosis and therapy of lung cancer with targeting polypeptide.

Animals ; Antineoplastic Agents ; pharmacokinetics ; Chloramines ; Humans ; Iodine Radioisotopes ; chemistry ; Lung Neoplasms ; Male ; Peptides ; pharmacokinetics ; Rabbits ; Radiopharmaceuticals ; pharmacokinetics ; Tissue Distribution ; Tomography, Emission-Computed, Single-Photon ; Tosyl Compounds

OBJECTIVETo compare the antimicrobial efficacy of four endodontic irrigants using an in vitro model infected by Enterococcus faecalis (Ef).

METHODSThe root canals of fifty extracted teeth were infected by Ef in vitro. The test groups were irrigated with 3% H(2)O(2), 2.5% sodium hypochlorite (SH), 2% chloramine-T (CR), and 2% chlorhexidine (CHX), respectively, and the control group was irrigated with 0.9% NaCl. The concentration of Ef in canals of each group was calculated before and after irrigation. The residual bacteria within the dentinal tubules and vitalities of the residual bacteria were also examined.

RESULTSAll chemical irrigants were significantly more effective than 0.9% NaCl (P < 0.05); 2.5% SH and 2% CHX were statistically more effective than 3% H(2)O(2) (P < 0.05). Residual bacteria could be found in the dentinal tubules and propagated 72 h after.

CONCLUSIONS2% CR and 2% CHX had almost the equivalent antimicrobial effect as 2.5% SH, but 3% H(2)O(2) was less effective.

Chloramines ; pharmacology ; Chlorhexidine ; pharmacology ; Dental Pulp Cavity ; microbiology ; Enterococcus faecalis ; drug effects ; Humans ; Hydrogen Peroxide ; pharmacology ; In Vitro Techniques ; Root Canal Irrigants ; pharmacology ; Sodium Hypochlorite ; pharmacology ; Tosyl Compounds ; pharmacology

OBJECTIVETo define the influence of some parameters, including assimilable organic carbon (AOC), chloramine residual, etc. on the bacterial growth in drinking water distribution systems.

METHODSThree typical water treatment plants in a northern city (City T) of China and their corresponding distribution systems were investigated. Some parameters of the water samples, such as heterotrophic plate content (HPC), AOC, COD(Mn), TOC, and phosphate were measured.

RESULTSThe AOC in most water samples were more than 100 microg/L, or even more than 200 microg/L in some cases. The HPC in distribution systems increased significantly with the decrease of residual chlorine. When the residual chlorine was less than 0.1 mg/L, the magnitude order of HPC was 10(4) CFU/mL; when it was 0.5-0.7 mg/L, the HPC was about 500 CFU/mL.

CONCLUSIONFor controlling the biostability of drinking water, the controlling of AOC and residual chlorine should be considered simultaneously. The influence of phosphors on the AOC tests of water is not significant. Phosphors may not be the limiting nutrient in the water distribution systems.

Bacteria ; drug effects ; growth & development ; Carbon ; analysis ; metabolism ; China ; Chloramines ; pharmacology ; Chlorine ; pharmacology ; Disinfectants ; pharmacology ; Drug Stability ; Organic Chemicals ; analysis ; Phosphates ; analysis ; metabolism ; Phosphorus ; pharmacology ; Population Dynamics ; Water Microbiology ; Water Purification ; methods ; Water Supply