scholarly journals Contrasting the effectiveness of chloramines reduction in indoor swimming pools disinfected by ozone versus UV

2015 ◽  
Author(s):  
Iris Chan ◽  
BCIT School of Health Sciences, Environmental Health ◽  
Bobby Sidhu
Keyword(s):  
Health Hazard ◽  
Free Chlorine ◽  
Ozone Treatment ◽  
Secondary Treatment ◽  
Swimming Pools ◽  
Significant Difference ◽  
The Mean ◽  
Analysis System ◽  
Pool System ◽  
By Products

  Objectives: Chloramines are disinfection by-products that are produced between chlorine and contaminants in the pool. Exposures to chloramines at high levels or for extended durations have been found to cause mucous membrane irritations and respiratory distress in humans. To reduce chloramines production, secondary treatment in the form of UV and ozone are used in newer indoor swimming pools. This study aimed to examine whether there is a difference between UV and ozone treatment in their effectiveness in reducing chloramines in indoor pools. Killarney leisure pool and whirlpool, which utilized ozone treatment, as well as Hillcrest leisure pool and whirlpool, which utilized UV treatment, were studied. Methods: Hach Pocket Colorimeter 2 Analysis System which used a DPD method of analysis was used to determine concentrations of free chlorine and total chlorines. Concentrations of chloramines were calculated by subtracting the concentration of free chlorine from total chlorine. Thirty pool water samples for each type of pool system were analyzed on random days in the afternoons of January and February, 2015. A two sample t-test was used to compare the chloramines concentrations of the whirlpools; while a Mann-Whitney U test was used to compare the chloramines concentrations of the leisure pools. Results: There was a statistically significant difference between the mean chloramines concentration of the UV-treated whirlpool and that of the ozone-treated whirlpool (p = 0.00854). However, there was not a statistically significant difference between the mean chloramines concentration between the UV treated leisure pool and that of the ozone treated leisure pool (p = 0.882048). Conclusions: It was determined that UV was more effective than ozone in reducing chloramines concentrations in indoor public whirlpools. Therefore, in order to choose a treatment that leads to the greatest reduction of health hazard posed to pool patrons, UV is preferred. Whirlpools that intend to adopt secondary treatment may consider UV.  

scholarly journals The effectiveness of ozone-chlorine treatment for reducing chloramine concentration compared to chlorine treatment in swimming pools and whirlpools

2014 ◽  
Author(s):  
Derrick Mah ◽  
BCIT School of Health Sciences, Environmental Health ◽  
Helen Heacock
Keyword(s):  
Swimming Pool ◽  
Ozone Treatment ◽  
Concentration Limit ◽  
Upper Respiratory Tract ◽  
Swimming Pools ◽  
Chlorine Disinfection ◽  
Two Samples ◽  
Significant Difference ◽  
Analysis System ◽  
By Products

  Objectives: Chloramines are by-products of chlorine disinfected swimming pools and are hazardous to people if chloramines evaporate into the air. There is evidence that chloramines cause upper respiratory tract and eye irritation. It was suspected that ozone treatment in addition to chlorine disinfection will reduce chloramine levels in the pool. The following study compared chloramine concentration in a strictly chlorine disinfected swimming pool and whirlpool (C.G. Brown) in Burnaby, BC with an ozone-chlorine disinfected swimming pool and whirlpool (Killarney) in Vancouver, BC. The study also compared each pool and whirlpool to the 1.0 mg/L combined chlorine concentration limit in the B.C. Pool Regulation. Methods: Chloramine concentrations were determined by using a Hach Pocket Colorimeter 2 Analysis System which used a DPD method of analysis. Chloramine was determined by subtracting total chlorine by the free chlorine. Thirty pool water samples were analyzed based on two samples per pool per day for fifteen days. A two sample t-test was used to compare the ozone-chlorine treated pools with the chlorine only treated pools using the Mann-Whitney U test. A z-test was used to compare all types of swimming pools and whirlpools to the 1.0 mg/L limit. Results: The chloramine concentration in both the ozone-chlorine disinfected swimming pool and whirlpool was not statistically significantly lower than in the chlorine disinfected swimming pool (p=0.263597) and whirlpool (p=0.523672). Both types of swimming pools were found to be statistically significantly greater than the 1.0 mg/L chloramine limit (p=0.000023 in the chlorine pool and p=0.00001 for the ozone-chlorine pool). Similarly, both types of whirlpools were determined to be statistically significantly greater than the 1.0 mg/L chloramine limit (p=0.000001 for the chlorine pool and p=0.000001 for the ozone-chlorine pool). Conclusion: It was determined that there was no difference between ozone chlorine treated pools and chlorine only treated pools. Environmental Health Officers can suggest other forms of secondary treatment instead of ozone since there is no significant difference compared to chlorine only treated pools in reducing chloramine concentrations. This information is also beneficial for pool operators because they can increase their flow rates for pools that use ozonation or strictly chlorination relative to what they were originally designed for.  

scholarly journals Cost-effectiveness of using stone cone, balloon dilator, stone basket, and entrapment device in ureteroscopic laser lithotripsy for ureteric stones

2021 ◽  
Vol 49 (12) ◽  
pp. 030006052110610
Author(s):  
Kürşat Çeçen
Keyword(s):  
Laser Lithotripsy ◽  
Secondary Treatment ◽  
Auxiliary Equipment ◽  
Total Cost ◽  
End Of Treatment ◽  
Significant Difference ◽  
Total Treatment ◽  
The Mean ◽  
Mean Cost ◽  
First Time

Objective To evaluate the costs and stone-free rates of ureteroscopic laser lithotripsy (ULL) performed with and without auxiliary equipment and to compare first-time ULL with total treatment. Methods One hundred patients who underwent first-time ULL without the use of auxiliary equipment because its unavailability comprised the no-device ULL (ndULL) group. Additionally, 100 patients who underwent first-time ULL with the use of auxiliary equipment when necessary comprised the device ULL (dULL) group. Results In the ndULL and dULL groups, the stone-free rates after first-time ULL were 72% and 94% and the mean cost was US $1037 ± 15.10 and US $1452 ± 19.80 per case, respectively, with a statistically significant difference. The stone-free rates at the end of treatment were 98% and 99%, respectively, without a statistically significant difference. When secondary treatment costs were added to the first ULL costs after failed treatment, the mean total cost was US $1625 ± 12.60 in the ndULL group and US $1566 ± 11.01 in the dULL group without a statistically significant difference. Conclusions The stone-free rates and costs after first-time ULL were significantly different between the groups. However, after total treatment, there was no statistically significant difference between the two groups.

scholarly journals Analysis of Effects of Physical, Chemical and Biological Properties in Domestic Waste Water (Slugde) on Environmental Health in Abia State, Nigeria

2019 ◽  
Vol 1 (1) ◽  
pp. 14-21
Author(s):  
Egbe C.A ◽  
Dada A. A.
Keyword(s):  
Waste Water ◽  
Health Hazard ◽  
Biological Properties ◽  
Coliform Bacteria ◽  
Domestic Waste ◽  
Potential Health ◽  
Mean Values ◽  
Physical Chemical ◽  
Significant Difference ◽  
The Mean

The study analyze the physical, chemical and Biological properties of sludge (Domestic waste water) in Umuda-Isingwu, Umuahia-Ibeku and Ihie-ndume in Umuahia north local government area of Abia state. Simple random sampling technique was adopted for the study. Data obtained from laboratory analysis of the water samples was analyzed using descriptive and inferential statistical techniques notably mean, F-LSD and F -test. The mean values of the physical and chemical parameters were compared with SON’s and WHO’s permissible limits. In the chemical properties COD had a mean range of 69.03 ± 0.06 to 80.03 ± 0.06 with all the means showing significant difference among each other (P ≤ 0.05). The highest TSS was observed in Ibeku at 921.03 ± 0.06. Nickel had a range of 7.42 ± 0.01 to 8.71 ± 0.01 Mg/l with all the means showing significant difference (P ≤ 0.05). PO4 had its highest concentration in Ihie Ndume community with a mean of 54.03 ± 0.06 Mg/l. None of the means of pH was seen to be above the WHO permissible limit of 8.5, as the mean range of pH was between 6.11 ± 0.01 to 7.76 ± 0.01. The E. coli load was high at Umuda Isingwu, followed by Ibeku and then Ihie Ndume. P. aeruginos and S. aereus was not observed in Ihie Ndume. The presence of fecal coliform bacteria is an indicator that a potential health hazard exists for individuals exposed to the source of water. Nickel was found to be slightly elevated at most of the sites above WHO. Trace metals have been implicated to be responsible for certain health disorders. The PO43- levels varied along the sampling community sites with some sites values having relatively higher values. In general the quality of these waste water cannot be guaranteed as most of the indicators were higher than the WHO and SON standards. This paper assumes that waste water evaluated pose huge treat to the immediate environment and should be investigated further in addition to epidemiological evaluation of the community to rule out occurrence of water-borne diseases.

scholarly journals The Effect of Atropine Alone or Combined with Orthokeratology for Children with Myopia: A Meta-Analysis

2021 ◽  
Author(s):  
zengying wang ◽  
yifei meng ◽  
sufang qie ◽  
zhipeng yan
Keyword(s):  
Weighted Mean Difference ◽  
Meta Analysis ◽  
Cochrane Library ◽  
Moderate Degree ◽  
Axial Elongation ◽  
Low Degree ◽  
Significant Difference ◽  
The Mean ◽  
Analysis System ◽  
Myopia Control

Abstract Objective: To evaluate the effect of atropine alone or combined with orthokeratology on myopia control by meta-analysis system.Methods: The current study searched PubMed, Cochrane Library, EMBASE, MEDLINE, Web of science, Ovid to collect eligible studies. The Weighted mean difference (WMD) of mean changes in axial elongation between the atropine alone or combined with orthokeratology group and the orthokeratology (ortho-k) group was used as evaluation index. Results: Twelve studies were eventually included, involving 671 children in the atropine alone and 547 children in the atropine combined with orthokeratology（AOK） group. This meta-analysis showed that the mean axial elongation of atropine alone was faster than that of ortho-k alone. [WMD=0.06mm, 95％CI(0.02~0.10), p＜0.007]. The function of AOK for slowing axial elongation was affected by the baseline diopter of children. The WMD in -1~-3D subgroup was -0.10 mm(95％CI,-0.14~-0.05,P＜0.00001),which mens that the AOK was more effective than OK alone in retarding axial elongation. In -3~-6D, WMD is -0.04mm (95% Cl, -0.11~0.03), and there is not statistically significant between two groups (P<0.30).Conclusion: This study suggested that ortho-k monotherapy is better in slowing axial elongation than atropine monotherapy in children with myopia. For children with low degree of myopia, the combination of ortho-k and 0.01% atropine is more effective than ortho-k monotherapy in slowing axial elongation in children. But there is no significant difference between two treatments in children with moderate degree of myopia.

scholarly journals Expressions of IL-17, IL-21 and IL-23 in the Serum of Allergic Rhinitis Patients

2011 ◽  
Vol 30 (4) ◽  
pp. 323-327 ◽  
Author(s):  
Xuekun Huang ◽  
Qintai Yang ◽  
Yulian Chen ◽  
Peng Li ◽  
Gehua Zhang ◽  
...  
Keyword(s):  
Allergic Rhinitis ◽  
Healthy Subjects ◽  
Serum Levels ◽  
Interleukin 17 ◽  
Serum Samples ◽  
Significant Difference ◽  
Quantitative Immunofluorescence ◽  
The Mean ◽  
Analysis System ◽  
Inhalant Allergens

Expressions of IL-17, IL-21 and IL-23 in the Serum of Allergic Rhinitis PatientsThe present study aimed to investigate the expressions of interleukin-17 (IL-17), IL-21 and IL-23 in the serum of allergic rhinitis (AR) patients and to explore their relationship with special IgE (sFgE) in the serum. AR patients (n=24) and healthy subjects (n=12) were recruited and serum samples were collected. The serum level of IgE specific for inhalant allergens was determined using the automatic quantitative immunofluorescence analysis system, and the contents of IL-17, IL-21 and IL-23 in the serum were detected using ELISA. The level of serum IgE in the healthy individuals was categorized as grade 0 and that in the AR patients as grade 2-6. The mean contents of IL-17, IL-21 and IL-23 were 164.71 ±39.37 pg/mL, 199±97.86 pg/mL and 78.94±26.33 pg/mL, respectively, in the AR patients, and 67.75±18.24 pg/mL, 7.58±5.49 pg/mL and 13.58± 3.93 pg/mL, respectively, in the healthy subjects. Statistical analysis showed the serum levels of IL-17 and IL-23 in the AR patients were markedly higher than those in the healthy subjects, however, no significant difference was noted in the content of IL-21. Furthermore, the IL-17 level was positively related to the levels of IL-23 and IgE and the IL-23 level was positively related to the IgE level among AR patients, but no relations were observed between the IL-21 level and levels of IL-17, IL-23 and IgE. Our study indicates IL-17 and IL-23 may play an important role in the pathogenesis of AR and maybe IL-21 is not involved in the occurrence of AR.

Marginal Fit and Retention Strength of Zirconia Crowns Cemented by Self-adhesive Resin Cements

2018 ◽  
Vol 43 (2) ◽  
pp. 151-161 ◽  
Author(s):  
R Pilo ◽  
M Folkman ◽  
A Arieli ◽  
S Levartovsky
Keyword(s):  
Resin Cement ◽  
Image Analysis System ◽  
Marginal Gap ◽  
Resin Cements ◽  
Adhesive Resin ◽  
Significant Difference ◽  
Zirconia Crowns ◽  
The Mean ◽  
Analysis System ◽  
Panavia 21

SUMMARY The absolute marginal gap (AMG) precementation and postcementation and the retention of zirconia crowns cemented to standardized molar preparations (4×10) by self-adhesive resin cements (SARCs) were evaluated. The following SARCs were used: RelyX U-200 (RXU200; 3M ESPE, Seefeld, Germany), SmartCem 2 (SC2; Dentsply, Milford, DE, USA), and G-Cem Automix (GCA; GC, Alsip, IL, USA). The control adhesive resin cement was Panavia 21 (PAN; Kuraray Dental Co Ltd, Osaka, Japan). Twenty measuring locations at a constant interval along the margins were marked, and the AMG was measured by an image analysis system connected to a stereomicroscope (20×). The cemented copings were aged 270 days at 100% humidity and 37°C and then underwent 10,000 thermal cycles, 5°C-55°C. After aging, the crowns were tested for retention, and the debonded surfaces were examined at 3× magnification. The mean marginal gaps precementation and postcementation were 34.8 ± 17.4 μm and 72.1 ± 31 μm, respectively, with no statistically significant differences between the cements. A significant difference (p≤0.001) in retention between the cements was found. The highest values were obtained for SC2 and GCA (1385 Pa and 1229 Pa, respectively), but these presented no statistically significant differences. The lowest values were found for PAN and RXU200 (738 Pa and 489 Pa, respectively), but these showed no statistically significant differences. The predominant mode of failure in all of the groups was mixed, and no correlations were found between marginal gap and retention.

Vowel Recognition Threshold as a Function of Temporal Segmentations

1970 ◽  
Vol 13 (4) ◽  
pp. 715-724 ◽  
Author(s):  
Richard L. Powell ◽  
Oscar Tosi
Keyword(s):  
Normal Hearing ◽  
Recognition Threshold ◽  
Vowel Sound ◽  
Significant Difference ◽  
The Mean ◽  
Vowel Recognition ◽  
Temporal Segment

Vowels were segmented into 15 different temporal segments taken from the middle of the vowel and ranging from 4 to 60 msecs, then presented to 6 subjects with normal hearing. The mean temporal-segment recognition threshold of 15 msecs with a range from 9.3 msecs for the /u/ to 27.2 milliseconds for the /a/. Misidenti-fication of vowels was most often confused with the vowel sound adjacent to it on the vowel-hump diagram. There was no significant difference between the cardinal and noncardinal vowels.

Left Ventricular Dysfunction and Blood Glycohemoglobin Levels in Young Diabetics

1991 ◽  
Vol 30 (05) ◽  
pp. 183-188
Author(s):  
A. Aydrner ◽  
A. Oto ◽  
E. Oram ◽  
O. Gedik ◽  
C. F. Bekdik ◽  
...  
Keyword(s):  
Ejection Fraction ◽  
Left Ventricular Function ◽  
Ventricular Function ◽  
Left Ventricular ◽  
Diabetic Patients ◽  
Filling Fraction ◽  
Time To Peak ◽  
Significant Difference ◽  
The Mean ◽  
Hba1c Levels

Left ventricular function including regional wall motion (RWM) was evaluated by 99mTc first-pass and equilibrium gated blood pool ventriculography and glycohemoglobin (HbA1c) blood levels determined by a quantitative column technique in 25 young patients with insulin-dependent diabetes mellitus without clinical evidence of heart disease, and in healthy controls matched for age and sex. Phase analysis revealed abnormal RWM in 19 of 21 diabetic patients. The mean left ventricular global ejection fraction, the mean regional ejection fraction and the mean 1/3 filling fraction were lower and the time to peak ejection, the time to peak filling and the time to peak ejection /cardiac cycle were longer in diabetics than in controls. We found high HbA1c levels in all diabetics. There was no significant difference between patients with and without retinopathy and with and without peripheral neuropathy in terms of left ventricular function and HbA1c levels.

Detection of Circulating Tissue Factor and Factor VII in a Normal Population

1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Normal Population ◽  
Mean Value ◽  
Factor Vii ◽  
Significant Difference ◽  
Age Dependent ◽  
The Mean ◽  
Highly Correlated ◽  
And Gender

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.

Multi-Center Study of Thromboplastin Calibration Precision – Influence of Reagent Species, Composition, and International Sensitivity Index (ISI)

1993 ◽  
Vol 69 (01) ◽  
pp. 035-040 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Oral Anticoagulants ◽  
International Normalized Ratio ◽  
The Other ◽  
World Health ◽  
Rabbit Brain ◽  
Sensitivity Index ◽  
Bovine Plasma ◽  
Significant Difference ◽  
The Mean ◽  
International Sensitivity Index

SummaryFour thromboplastin reagents were tested by 18 laboratories in Europe, North-America, and Australasia, according to a detailed protocol. One thromboplastin was the International Reference Preparation for ox brain thromboplastin combined with adsorbed bovine plasma (coded OBT/79), and the second was a certified reference material for rabbit brain thromboplastin, plain (coded CRM 149R). The other two thromboplastin reagents were another rabbit plain brain thromboplastin (RP) with a lower ISI than CRM 149R and a rabbit brain thromboplastin combined with adsorbed bovine plasma (RC). Calibration of the latter two reagents was performed according to methods recommended by the World Health Organization (W. H. O.).The purpose of this study was to answer the following questions: 1) Is the calibration of the RC reagent more precise against the bovine/combined (OBT/79) than against the rabbit/plain reagent (CRM 149R)? 2) Is the precision of calibration influenced by the magnitude of the International Sensitivity Index (ISI)?The lowest inter-laboratory variation of ISI was observed in the calibration of the rabbit/plain reagent (RP) against the other rabbit/plain reagent (CRM 149R) (CV 1.6%). The highest interlaboratory variation was obtained in the calibration of rabbit/plain (RP) against bovine/combined (OBT/79) (CV 5.1%). In the calibration of the rabbit/combined (RC) reagent, there was no difference in precision between OBT/79 (CV 4.3%) and CRM 149R (CV 4.2%). Furthermore, there was no significant difference in the precision of the ISI of RC obtained with CRM 149R (ISI = 1.343) and the rabbit/plain (RP) reagent with ISI = 1.14. In conclusion, the calibration of RC could be performed with similar precision with either OBT/79 or CRM 149R, or RP.The mean ISI values calculated with OBT/79 and CRM 149R were practically identical, indicating that there is no bias in the ISI of these reference preparations and that these reference preparations have been stable since their original calibration studies in 1979 and 1987, respectively.International Normalized Ratio (INR) equivalents were calculated for a lyophilized control plasma derived from patients treated with oral anticoagulants. There were small but significant differences in the mean INR equivalents between the bovine and rabbit thromboplastins. There were no differences in the interlaboratory variation of the INR equivalents, when the four thromboplastins were compared.

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