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Sample records for otoscope cone disinfection

  1. Evaluation of otoscope cone cleaning and disinfection procedures commonly used in veterinary medical practices: a pilot study.

    PubMed

    Newton, Heide M; Rosenkrantz, Wayne S; Muse, Russell; Griffin, Craig E

    2006-04-01

    The objective of this study was to evaluate the relative efficacy of otoscope cone cleaning and disinfection methods commonly used in veterinary practices. Using sterile technique, 60 new gas-sterilized 4-mm otoscope cones were inoculated with a broth culture of 1.5 billion Pseudomonas aeruginosa bacteria per mL then allowed to dry for 10 min. Six study groups of 10 cones each were created. Group 1 served as positive control and received no cleaning or disinfection. Group 2 cones were wiped with sterile cotton-tipped applicators and gauze then rinsed with water. Group 3 cones were wiped with 70% isopropyl alcohol. Group 4 cones were scrubbed in a speculum cleaner with Cetylcide II solution (Cetylite Industries, Inc., Pennsauken, NJ). Groups 5 and 6 cones were soaked for 20 min in Cetylcide II and chlorhexidine gluconate 2% solutions, respectively. Using sterile technique and after 10-15 min drying time, the cones were swabbed in a consistent pattern, and samples were submitted for quantitative culture. Culture results showed no growth from cones soaked in Cetylcide II or chlorhexidine solutions. Two of the 10 cones wiped with alcohol, 3/10 cones wiped then rinsed with water, and 3/10 cones scrubbed with the speculum cleaner showed growth of P. aeruginosa. All (10/10) cones in the control group showed heavy growth of P. aeruginosa. These results show that P. aeruginosa can survive on otoscope cones cleaned and disinfected by several commonly used methods. Further study is needed to determine practical and optimal cleaning and disinfection methods for otoscope cones.

  2. Otoscopic exam of the ear (image)

    MedlinePlus

    ... intrument which is used to look into the ear canal. The ear speculum (a cone-shaped viewing piece of the otoscope) is slowly inserted into the ear canal while looking into the otoscope. The speculum ...

  3. Otoscope examination (image)

    MedlinePlus

    An otoscope is a tool which shines a beam of light to help visualize and examine the condition of the ear canal and eardrum. Examining the ear can reveal the cause of symptoms such as an earache, the ear feeling full, or hearing loss.

  4. Comparative evaluation of tensile strength of Gutta-percha cones with a herbal disinfectant

    PubMed Central

    Mahali, Raghunandhan Raju; Dola, Binoy; Tanikonda, Rambabu; Peddireddi, Suresh

    2015-01-01

    Aim: To evaluate and compare the tensile strength values and influence of taper on the tensile strength of Gutta-percha (GP) cones after disinfection with sodium hypochlorite (SH) and Aloe vera gel (AV). Materials and Methods: Sixty GP cones of size 110, 2% taper, 60 GP cones F3 ProTaper, and 60 GP of size 30, 6% taper were obtained from sealed packs as three different groups. Experimental groups were disinfected with 5.25% SH and 90% AV gel except the control group. Tensile strengths of GP were measured using the universal testing machine. Results: The mean tensile strength values for Group IA, IIA and IIIA are 11.8 MPa, 8.69 MPa, and 9.24 MPa, respectively. Results were subjected to statistical analysis one-way analysis of variance test and Tukey post-hoc test. 5.25% SH solutions decreased the tensile strength of GP cones whereas with 90% AV gel it was not significantly altered. Conclusion: Ninety percent Aloe vera gel as a disinfectant does not alter the tensile strength of GP cones PMID:26752842

  5. 21 CFR 874.4770 - Otoscope.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4770 Otoscope. (a) Identification. An otoscope is a device intended to allow inspection of the external ear canal and tympanic membrane under...

  6. 21 CFR 874.4770 - Otoscope.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4770 Otoscope. (a) Identification. An otoscope is a device intended to allow inspection of the external ear canal and tympanic membrane under...

  7. Antimicrobial effect of three disinfecting agents on Resilon cones and their effect on surface topography: An in vitro study

    PubMed Central

    Chandrappa, Mahesh Martur; Meharwade, Prasanna Mahadevasa; Srinivasan, Raghu; Bhandary, Shreetha; Nasreen, Farhat

    2016-01-01

    Aim: The objective of this study was to evaluate the effectiveness of 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and 2% peracetic acid (PAA) in disinfecting Resilon cones and to evaluate topographical changes microscopically under scanning electron microscope (SEM) after rapid chemical disinfection. Materials and Methods: Resilon cones were disinfected in an ultraviolet (UV) light chamber for 20 min and contaminated by immersing in a microbial suspension of Enterococcus faecalis for 30 min. The contaminated cones were then immersed in the 5.25% NaOCl, 2% CHX, and 2% PAA for 1 min, 5 min, and 10 min, separately. The cones were then incubated at 37°C in thioglycollate broth for 7 days and examined for turbidity. The samples showing turbidity were subcultured on blood agar and incubated at 37°C for 48 h. Gram staining was done to confirm that the cultured bacteria were E. faecalis. Surface changes of disinfected Resilon cones were evaluated under SEM. Statistical Analysis Used: The data were analyzed statistically using Kruskal-Wallis, analysis of variance (ANOVA), and Mann–Whitney U-test. Result: In eliminating E. faecalis, 5.25% NaOCl was most effective followed by 2% PAA and 2% CHX. Topographic examination of tested Resilon cones revealed some surface deposits after disinfection with 5.25% NaOCl and 2% CHX, whereas 2% PAA caused surface erosion. Conclusion: In disinfecting Resilon cones, 5.25% NaOCl is most effective followed by 2% PAA and 2% CHX. PMID:27099418

  8. Otoscope fogging: examination finding for perforated tympanic membrane

    PubMed Central

    Naylor, Jason F

    2014-01-01

    The author reports a recently recognised physical examination finding, otoscope fogging, for perforated tympanic membrane. Otoscope fogging is defined as condensation forming in the view field of the otoscope while inspecting the ear. In the setting of occult perforation secondary to the inability to visualise the entire tympanic membrane, otoscope fogging may provide the clinician with valuable information since medical management may differ if perforation is present. PMID:24879720

  9. Disinfection.

    ERIC Educational Resources Information Center

    Gould, J. P.; Haas, C. N.

    1978-01-01

    Presents a literature review of wastewater disinfection for 1978. This review covers areas such as: (1) mechanisms of inactivation of negative microorganisms by chlorine and ozone; and (2) the effects of various treatment on over-all water quality. A list of 61 references is also presented. (HM)

  10. DISINFECTION

    EPA Science Inventory

    The primary goal of the disinfection process in drinking water treatment is the inactivation of microbial pathogens. These pathogens comprise a diverse group of organisms which serve as the etiological agents of waterborne disease. Included in this group are bacterial, viral and ...

  11. Terahertz otoscope and potential for diagnosing otitis media

    PubMed Central

    Ji, Young Bin; Moon, In-Seok; Bark, Hyeon Sang; Kim, Sang Hoon; Park, Dong Woo; Noh, Sam Kyu; Huh, Yong-Min; Suh, Jin-Seok; Oh, Seung Jae; Jeon, Tae-In

    2016-01-01

    We designed and fabricated a novel terahertz (THz) otoscope to help physicians to diagnose otitis media (OM) with both THz diagnostics and conventional optical diagnostics. We verified the potential of this tool for diagnosing OM using mouse skin tissue and a human tympanic membrane samples prior to clinical application. PMID:27446647

  12. Otoscopic, cytological, and microbiological examination of the equine external ear canal.

    PubMed

    Sargent, Sandra J; Frank, Linda A; Buchanan, Benjamin R; Donnell, Robert L; Morandi, Federica

    2006-06-01

    Otoscopic examination and cytology of the equine ear would be beneficial in diseases such as head trauma, headshaking, otitis externa secondary to otitis media, vestibular disease, aural neoplasia and aural pruritus secondary to parasites. In practice, otic examinations of horses are rarely done due to the perceived difficulty in visualizing the equine external ear canal and tympanic membrane, as well as the need for chemical restraint. In this study, the proximal external ear canal was examined in live horses using a handheld otoscope and in cadaver heads using video otoscopy. Visualization of the proximal ear canal of the sedated horse could be done with a handheld otoscope, but more sedation or general anaesthesia and a video otoscope would be required to adequately visualize the tympanic membrane in the live horse. The proximal ear canals of 18 horses were examined cytologically and cultured aerobically. In three horses, both ears were sampled. No cells or organisms were seen on cytological examination of 11/21 ears. Nine of the 21 ears were sterile when cultured. Ten of the 21 ears had mixed growth with low numbers of organisms (Corynebacterium sp. being most common). Two of the 21 ears had heavy growth of a single organism (Corynebacterium sp. and Staphylococcus intermedius, respectively). Equine cadaver heads were examined in cross-section by computed tomography (CT) imaging and histopathology in order to further understand the anatomy of the equine external ear canal. Equine practitioners should be aware that otic examination is possible and may provide important diagnostic information.

  13. Disinfection Processes.

    PubMed

    Munakata, Naoko; Kuo, Jeff

    2016-10-01

    A review of the literature published in 2015 on topics relating to disinfection processes is presented. This review is divided into the following sections: disinfection methods, disinfection byproducts, and microbiology and microbial communities. PMID:27620087

  14. Fiber optically guided CO2 laser myringotomy through an otoscope: animal experimentation

    NASA Astrophysics Data System (ADS)

    DeRowe, Ari; Ophir, Dov; Katzir, Abraham

    1992-08-01

    We have developed an otoscope which contains an optical fiber capable of transmitting CO2 laser energy. Such a hand-held unit may prove useful in the treatment of acute otitis media and otitis media with effusion. We used crystalline fibers (0.9 mm diameter) capable of transmitting CO2 laser energy. Four guinea pigs were anaesthetized. In one ear a laser myringotomy was performed using 7.5 watts for 0.1 seconds. The diameter of the myringotomy was 1.5 mm. In the other ear a similar conventional myringotomy was performed. After three weeks three laser and three conventional myringotomies were closed. On the average conventional myringotomies closed 50% sooner than laser myringotomies. Temporal bones from three guinea pigs were removed and sectioned according to accepted methods. No histological differences were found between ears. This experiment has proven the feasibility of using an otoscope for fiberoptically guided CO2 laser myringotomy.

  15. A short-wave infrared otoscope for middle ear disease diagnostics (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Carr, Jessica A.; Valdez, Tulio; Bruns, Oliver; Bawendi, Moungi

    2016-02-01

    Otitis media, a range of inflammatory conditions of the middle ear, is the second most common illness diagnosed in children. However, the diagnosis can be challenging, particularly in pediatric patients. Otitis media is commonly over-diagnosed and over-treated and has been identified as one of the primary factors in increased antibiotic resistance. We describe the development of a short-wave infrared (SWIR) otoscope for objective middle ear effusion diagnosis. The SWIR otoscope can unambiguously detect the presence of middle ear fluid based on its strong light absorption in the SWIR. This absorption causes a stark, visual contrast between the presence and absence of fluid behind the tympanic membrane. Additionally, when there is no middle ear fluid, the deeper tissue penetration of SWIR light allows the SWIR otoscope to better visualize middle ear anatomy through the tympanic membrane than is possible with visible light. We demonstrate that in healthy, adult human ears, SWIR otoscopy can image a range of middle ear anatomy, including landmarks of the entire ossicular chain, the promontory, the round window niche, and the chorda tympani. We suggest that SWIR otoscopy can provide valuable diagnostic information complementary to that provided by visible pneumotoscopy in the diagnosis of middle ear effusions, otitis media, and other maladies of the middle ear.

  16. A compact structured light based otoscope for three dimensional imaging of the tympanic membrane

    NASA Astrophysics Data System (ADS)

    Das, Anshuman J.; Estrada, Julio C.; Ge, Zhifei; Dolcetti, Sara; Chen, Deborah; Raskar, Ramesh

    2015-02-01

    Three dimensional (3D) imaging of the tympanic membrane (TM) has been carried out using a traditional otoscope equipped with a high-definition webcam, a portable projector and a telecentric optical system. The device allows us to project fringe patterns on the TM and the magnified image is processed using phase shifting algorithms to arrive at a 3D description of the TM. Obtaining a 3D image of the TM can aid in the diagnosis of ear infections such as otitis media with effusion, which is essentially fluid build-up in the middle ear. The high resolution of this device makes it possible examine a computer generated 3D profile for abnormalities in the shape of the eardrum. This adds an additional dimension to the image that can be obtained from a traditional otoscope by allowing visualization of the TM from different perspectives. In this paper, we present the design and construction of this device and details of the imaging processing for recovering the 3D profile of the subject under test. The design of the otoscope is similar to that of the traditional device making it ergonomically compatible and easy to adopt in clinical practice.

  17. Detecting tympanostomy tubes from otoscopic images via offline and online training.

    PubMed

    Wang, Xin; Valdez, Tulio A; Bi, Jinbo

    2015-06-01

    Tympanostomy tube placement has been commonly used nowadays as a surgical treatment for otitis media. Following the placement, regular scheduled follow-ups for checking the status of the tympanostomy tubes are important during the treatment. The complexity of performing the follow up care mainly lies on identifying the presence and patency of the tympanostomy tube. An automated tube detection program will largely reduce the care costs and enhance the clinical efficiency of the ear nose and throat specialists and general practitioners. In this paper, we develop a computer vision system that is able to automatically detect a tympanostomy tube in an otoscopic image of the ear drum. The system comprises an offline classifier training process followed by a real-time refinement stage performed at the point of care. The offline training process constructs a three-layer cascaded classifier with each layer reflecting specific characteristics of the tube. The real-time refinement process enables the end users to interact and adjust the system over time based on their otoscopic images and patient care. The support vector machine (SVM) algorithm has been applied to train all of the classifiers. Empirical evaluation of the proposed system on both high quality hospital images and low quality internet images demonstrates the effectiveness of the system. The offline classifier trained using 215 images could achieve a 90% accuracy in terms of classifying otoscopic images with and without a tympanostomy tube, and then the real-time refinement process could improve the classification accuracy by 3-5% based on additional 20 images. PMID:25889718

  18. Optoelectronic holographic otoscope for measurement of nano-displacements in tympanic membranes

    NASA Astrophysics Data System (ADS)

    Del Socorro Hernández-Montes, Maria; Furlong, Cosme; Rosowski, John J.; Hulli, Nesim; Harrington, Ellery; Cheng, Jeffrey Tao; Ravicz, Michael E.; Santoyo, Fernando Mendoza

    2009-05-01

    Current methodologies for characterizing tympanic membrane (TM) motion are usually limited to either average acoustic estimates (admittance or reflectance) or single-point mobility measurements, neither of which suffices to characterize the detailed mechanical response of the TM to sound. Furthermore, while acoustic and single-point measurements may aid in diagnosing some middle-ear disorders, they are not always useful. Measurements of the motion of the entire TM surface can provide more information than these other techniques and may be superior for diagnosing pathology. We present advances in our development of a new compact optoelectronic holographic otoscope (OEHO) system for full field-of-view characterization of nanometer-scale sound-induced displacements of the TM surface at video rates. The OEHO system consists of a fiber optic subsystem, a compact otoscope head, and a high-speed image processing computer with advanced software for recording and processing holographic images coupled to a computer-controlled sound-stimulation and recording system. A prototype OEHO system is in use in a medical research environment to address basic science questions regarding TM function. The prototype provides real-time observation of sound-induced TM displacement patterns over a broad frequency range. Representative time-averaged and stroboscopic holographic interferometry results in animals and human cadaver samples are shown, and their potential utility is discussed.

  19. Multiwavelength Fluorescence Otoscope for Video-Rate Chemical Imaging of Middle Ear Pathology

    PubMed Central

    2015-01-01

    A common motif in otolaryngology is the lack of certainty regarding diagnosis for middle ear conditions, resulting in many patients being overtreated under the worst-case assumption. Although pneumatic otoscopy and adjunctive tests offer additional information, white light otoscopy has been the main tool for diagnosis of external auditory canal and middle ear pathologies for over a century. In middle ear pathologies, the inability to avail high-resolution structural and/or molecular imaging is particularly glaring, leading to a complicated and erratic decision analysis. Here, we propose a novel multiwavelength fluorescence-based video-rate imaging strategy that combines readily available optical elements and software components to create a novel otoscopic device. This modified otoscope enables low-cost, detailed and objective diagnosis of common middle ear pathological conditions. Using the detection of congenital cholesteatoma as a specific example, we demonstrate the feasibility of fluorescence imaging to differentiate this proliferative lesion from uninvolved middle ear tissue based on the characteristic autofluorescence signals. Availability of real-time, wide-field chemical information should enable more complete removal of cholesteatoma, allowing for better hearing preservation and substantially reducing the well-documented risks, costs and psychological effects of repeated surgical procedures. PMID:25226556

  20. Digital holographic otoscope for measurements of the human tympanic membrane in vivo

    NASA Astrophysics Data System (ADS)

    Dobrev, I.; Harrington, E. J.; Cheng, T.; Furlong, C.; Rosowski, J. J.

    We are developing an advanced computer-controlled digital optoelectronic holographic system (DOEHS) for diagnosing middle-ear conductive disorders and investigating the causes of failure of middle-ear surgical procedures. Our current DOEHS system can provide near real-time quantitative measurements of the sound-induced nano-meter scale motion of the eardrum. The DOEHS have been deployed and is currently being tested in clinical conditions, where it is being optimized for in-vivo measurements of patients. The stability of the measurement system during examination is crucial as the non-ideal clinical environment presents disturbances larger than the measured quantities from several domains - thermal, optical, electrical and mechanical. Examples include disturbances are due to heartbeat breathing, patients head's motion as well as environment induced mechanical disturbances (0.1-60Hz, 0.01-100 μm). In this paper we focus on our current progress in the analysis and implementation of various acquisition strategies and algorithms for minimization of the measurement error due to mechanical disturbances in a clinic. We have also developed and implemented a versatile and modular otoscope head (OH) design providing a variety of capabilities for acoustic and displacement measurements of both post-mortem samples of varying sizes (1-12mm) as well as in-vivo examination of patients. The OH offers hybrid on-axis and off axis digital Furrier holographic setup for high resolution (λ/35) 4 phase step measurements as well as fast (<0.1ms) single frame measurements for improved performance in the clinical environment. We also focus on the development of a mechatronic positioning system (MOP) for aiding in the localization of the TM in patients.

  1. New formaldehyde base disinfectants.

    NASA Technical Reports Server (NTRS)

    Trujillo, R.; Lindell, K. F.

    1973-01-01

    Preparations of formaldehyde in various organic liquids - ethylene glycol, glycerol, and propylene glycol - serve as effective disinfectants towards microbial vegetative cells and spores. This disinfection is a temperature-dependent process and is manifest when these formaldehyde base disinfectants are dissolved in water. The irritating vapors associated with formaldehyde disinfection are not present in either of these new formaldehyde base disinfectants or in aqueous solutions of them.

  2. Disinfection. [Wastewater treatment

    SciTech Connect

    Haas, C.N.; McCreary, J.J.

    1982-06-01

    Methods of disinfection of wastewater including chlorination, ultraviolet radiation, ozone, and quaternary compounds are reviewed. Various analytical methods to detect residues of the disinfectants are described. The production of inorganic and nonvolatile organic compounds in conventional water treatment processes is reviewed. (KRM)

  3. Humidifier disinfectants, unfinished stories.

    PubMed

    Choi, Yeyong; Paek, Domyung

    2016-01-01

    Once released into the air, humidifier disinfectants became tiny nano-size particles, and resulted in chemical bronchoalveolitis. Families had lost their most beloved members, and even some of them became broken. Based on an estimate of two million potential victims who had experienced adverse effects from the use of humidifier disinfectants, we can say that what we have observed was only the tip of the iceberg. Problems of entire airways, as well as other systemic effects, should be examined, as we know these nano-size particles can irritate cell membranes and migrate into systemic circulation. The story of humidifier disinfectant is not finished yet. PMID:26987713

  4. The cone dystrophies.

    PubMed

    Simunovic, M P; Moore, A T

    1998-01-01

    The cone dystrophies are a heterogeneous group of inherited disorders that result in dysfunction of the cone photoreceptors and sometimes their post-receptoral pathways. The major clinical features of cone dystrophy are photophobia, reduced visual acuity and abnormal colour vision. Ganzfeld electroretinography shows reduced or absent cone responses. On the basis of their natural history, the cone dystrophies may be broadly divided into two groups: stationary and progressive cone dystrophies. The stationary cone dystrophies have received more attention, and subsequently our knowledge of their molecular genetic, psychophysical and clinical characteristics is better developed. Various methods of classification have been proposed for the progressive cone dystrophies, but none is entirely satisfactory, largely because the underlying disease mechanisms are poorly understood. Multidisciplinary studies involving clinical assessment, molecular genetics, electrophysiology and psychophysics should lead to an improved understanding of the pathogenesis of these disorders.

  5. Cold knife cone biopsy

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003910.htm Cold knife cone biopsy To use the sharing features on this page, please enable JavaScript. A cold knife cone biopsy (conization) is surgery to remove ...

  6. CHLORINE DISINFECTION OF AEROMONAS

    EPA Science Inventory

    The bacterial genus Aeromonas is currently listed on the USEPA's Candidate Contaminant List (CCL). Resistance to chemical disinfection is an essential aspect regarding all microbial groups listed on the CCL. This study was designed to determine the inactivation kinetics of Aeromo...

  7. Commercial Disinfectants During Disinfection Process Validation: More Failures than Success

    PubMed Central

    Chumber, Sushil Kumar; Khanduri, Uma

    2016-01-01

    Introduction Disinfection process validation is mandatory before introduction of a new disinfectant in hospital services. Commercial disinfection brands often question existing hospital policy claiming greater efficacy and lack of toxicity of their products. Inadvertent inadequate disinfection leads to morbidity, patient’s economic burden, and the risk of mortality. Aim To evaluate commercial disinfectants for high, intermediate and low-level disinfection so as to identify utility for our routine situations. Materials and Methods This laboratory based experiment was conducted at St Stephen Hospital, Delhi during July-September 2013. Twelve commercial disinfectants: Sanidex®, Sanocid®, Cidex®, SekuSept Aktiv®, BIB Forte®, Alprojet W®, Desnet®, Sanihygiene®, Incidin®, D125®, Lonzagard®, and Glutishield® were tested. Time-kill assay (suspension test) was performed against six indicator bacteria (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella Typhi, Bacillus cereus, and Mycobacterium fortuitum). Low and high inoculum (final concentrations 1.5X106 and 9X106 cfu/ml) of the first five bacteria while only low level of M. fortuitum was tested. Results Cidex® (2.4% Glutaraldehyde) performed best as high level disinfectant while newer quarternary ammonium compounds (QACs) (Incidin®, D125®, and Lonzagard®) were good at low level disinfection. Sanidex® (0.55% Ortho-pthalaldehyde) though mycobactericidal took 10 minutes for sporicidal activity. Older QAC containing BIB Forte® and Desnet® took 20 minutes to fully inhibit P. aeruginosa. All disinfectants effectively reduced S. Typhi to zero counts within 5 minutes. Conclusion Cidex® is a good high-level disinfectant while newer QACs (Incidin®, D125®, and Lonzagard®) were capable low-level disinfectants. PMID:27656441

  8. Cone Health and Retinoids.

    PubMed

    Kono, Masahiro

    2015-01-01

    Cones are photoreceptor cells used for bright light and color vision. Retinoids are vitamin A derivatives, one of which is the 11-cis aldehyde form that serves as the chromophore for both cone and rod visual pigments. In the visual disease, Type 2 Leber congenital amaurosis (LCA2), 11-cis-retinal generation is inhibited or abolished. Work by others has shown that patients with LCA2 have symptoms consistent with degenerating cones. In mouse models for LCA2, early cone degeneration is readily apparent: cone opsins and other proteins associated with the outer segment are delocalized and cell numbers decline rapidly within the first month. Rods would appear normal morphologically and functionally, if not for the absence of chromophore. Supplementation of mouse models of LCA2 with cis-retinoids has been shown to slow loss of cone photoreceptor cells if mice were maintained in darkness. Thus, 11-cis-retinal appears not only to have a role in the light response reaction but also to promote proper trafficking of the cone opsins and maintain viable cones. PMID:26310171

  9. Contamination of gutta-percha and Resilon cones taken directly from the manufacturer.

    PubMed

    Seabra Pereira, Osvaldo L; Siqueira, José F

    2010-06-01

    Any substance and material placed in the root canal either temporarily or definitively must be free of microbial contamination. The purpose of the present study was to evaluate the percentage of contamination of Resilon cones, a polycaprolactone-based material, and seven different brands of gutta-percha cones available in the specialized market. Cones were removed from their original manufacturer boxes and immediately transferred to tubes containing thioglycolate broth. Tests were carried out in triplicate. In addition, for quantitative analysis of possible contaminants, cones were taken from their packages, transferred to tubes containing saline solution, agitated, and aliquots of this solution were seeded onto Mueller-Hinton agar plates. No sample showed contamination in any of the tests performed. Despite the absence of detectable contamination before the first use, a rationale for routinely disinfecting cones before placing them into root canals is given.

  10. Cone sampling array models

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J., Jr.; Poirson, Allen

    1987-01-01

    A model is described for positioning cones in the retina. Each cone has a circular disk of influence, and the disks are tightly packed outward from the center. This model has three parameters that can vary with eccentricity: the mean radius of the cone disk, the standard deviation of the cone disk radius, and the standard deviation of postpacking jitter. Estimates for these parameters out to 1.6 deg are found by using measurements reported by Hirsch and Hylton (1985) and Hirsch and Miller (1987) of the positions of the cone inner segments of an adult macaque. The estimation is based on fitting measures of variation in local intercone distances, and the fit to these measures is good.

  11. Progressive cone dystrophy.

    PubMed Central

    Ripps, H; Noble, K G; Greenstein, V C; Siegel, I M; Carr, R E

    1987-01-01

    Psychophysical, reflectometric, and electrophysiological studies were performed on four members of a dominant pedigree with progressive cone dystrophy. The two youngest individuals were asymptomatic at the initial examination, and none of the subjects complained of problems associated with night vision. Absent or grossly reduced cone-mediated ERG responses revealed the widespread loss of cone function. Moderate elevations (1 log unit) in absolute threshold together with reductions in rhodopsin levels in the midperipheral retina provided evidence of a mild impairment of the rod system also, although not to the degree seen in a cone-rod dystrophy. The progressive nature of the disease was apparent from the case histories and the changes in visual performance that occurred on re-test after a 5-year interval. Likewise, the results of incremental threshold measurements at several retinal loci suggested that peripheral cones may be affected earlier and more severely than those in the central retina. PMID:3502298

  12. S-cone psychophysics.

    PubMed

    Smithson, Hannah E

    2014-03-01

    We review the features of the S-cone system that appeal to the psychophysicist and summarize the celebrated characteristics of S-cone mediated vision. Two factors are emphasized: First, the fine stimulus control that is required to isolate putative visual mechanisms and second, the relationship between physiological data and psychophysical approaches. We review convergent findings from physiology and psychophysics with respect to asymmetries in the retinal wiring of S-ON and S-OFF visual pathways, and the associated treatment of increments and decrements in the S-cone system. Beyond the retina, we consider the lack of S-cone projections to superior colliculus and the use of S-cone stimuli in experimental psychology, for example to address questions about the mechanisms of visually driven attention. Careful selection of stimulus parameters enables psychophysicists to produce entirely reversible, temporary, "lesions," and to assess behavior in the absence of specific neural subsystems. PMID:24759446

  13. Improved tympanic thermometer based on a fiber optic infrared radiometer and an otoscope and its use as a new diagnostic tool for acute otitis media

    NASA Astrophysics Data System (ADS)

    Fishman, Gadi; DeRowe, Ari; Ophir, Eyal; Scharf, Vered; Shabtai, Abraham; Ophir, Dov; Katzir, Abraham

    1999-06-01

    Clinical diagnosis of acute otitis media (AOM) in children is not easy. It was assumed that there is a difference ΔT between the Tympanic Membrane (TM) temperatures in the two ears in unilateral AOM and that an accurate measurement of ΔT may improve the diagnosis accuracy. An IR transmitting fiber, made of AgClBr, was coupled into a hand held otoscope and was used for the non-contact (radiometric) measurements of TT, the TM temperature. Experiments were carried out, first, on a laboratory model that simulated the human ear, including an artificial tympanic membrane and an artificial ear canal. Measurements carried out using commercially available tympanic thermometers shown that the temperature Tc of the ear canal affected the results. Tc did not affect the fiberoptic radiometer, and this device accurately measured the true temperature, TT of the tympanic membrane. A prospective blinded sampling of the TM temperature was then performed on 48 children with suspected AOM. The mean temperature difference between the ears, for children with unilateral AOM was ΔT = (0.68 +/- 0.27)°C. For children with bilateral AOM it was ΔT = (0.14+/-0.10)°C (p<0.001). It was demonstrated that afor unilateral AOM the difference ΔT was proportional to the systemic temperature. In conclusion, the fiberoptic interferometric measurements of the TM can be a useful non-invasive diagnostic tool for AOM, when combined with other data.

  14. Disinfectants used for environmental disinfection and new room decontamination technology.

    PubMed

    Rutala, William A; Weber, David J

    2013-05-01

    Environmental contamination plays an important role in the transmission of several key health care-associated pathogens. Effective and thorough cleaning/disinfecting of the patient environment is essential. Room decontamination units (such as ultraviolet-C and hydrogen peroxide systems) aid in reducing environmental contamination after terminal room cleaning and disinfection.

  15. The color cone.

    PubMed

    Logvinenko, Alexander D

    2015-02-01

    While the notion of a color cone can be found in writings of Maxwell, Helmholtz, Grassmann, and other scientists of the nineteenth century, it has not been clearly defined as yet. In this paper, the color cone is understood as the set of points in the cone excitation space produced by all possible lights. The spectral curve representing all the monochromatic lights is shown not to entirely belong to the color cone boundary, since its ends turn into the color cone interior. The monochromatic lights represented by the fragment of the spectral curve lying on the color cone boundary make up what is called the effective visible spectrum. The color cone is shown to be a convex hull of the conical surface through the fragment of the spectral curve representing the effective visible spectrum. The effective visible spectrum ends are shown to be determined by the photopigment spectral absorbance being independent of the prereceptor filters (e.g., the spectral transmittance of the lense and macular pigment).

  16. Growth cone collapse assay.

    PubMed

    Cook, Geoffrey M W; Jareonsettasin, Prem; Keynes, Roger J

    2014-01-01

    The growth cone collapse assay has proved invaluable in detecting and purifying axonal repellents. Glycoproteins/proteins present in detergent extracts of biological tissues are incorporated into liposomes, added to growth cones in culture and changes in morphology are then assessed. Alternatively purified or recombinant molecules in aqueous solution may be added directly to the cultures. In both cases after a defined period of time (up to 1 h), the cultures are fixed and then assessed by inverted phase contrast microscopy for the percentage of growth cones showing a collapsed profile with loss of flattened morphology, filopodia, and lamellipodia.

  17. DISINFECTION BYPRODUCTS: THE NEXT GENERATION

    EPA Science Inventory

    Disinfection of drinking water is rightly hailed as a major public health triumph of the 20th Century. Before widespread disinfection of drinking water in the U.S. and Europe, millions of people died from infectious waterborne diseases, such as typhoid and cholera. The microbia...

  18. Sanitizers and Disinfectants Guide. Revised

    ERIC Educational Resources Information Center

    Healthy Schools Network, Inc., 2012

    2012-01-01

    Sanitizers and disinfectants can play an important role in protecting public health. They are designed to kill "pests," including infectious germs and other microorganisms such as bacteria, viruses, and fungi. Unfortunately, sanitizers and disinfectants also contain chemicals that are "pesticides." Exposure to persistent toxic chemicals in…

  19. 2017 Eclipse Shadow Cones

    NASA Video Gallery

    A solar eclipse occurs when the Moon's shadow falls on the Earth. The shadow comprises two concentric cones called the umbra and the penumbra. Within the smaller, central umbra, the Sun is complete...

  20. Disinfection of pumice.

    PubMed

    Setz, J; Heeg, P

    1996-10-01

    Pumice is a potential source of infection for the dental technician and of cross-contamination between different dentures and patients. In this study, the number of microorganisms in two different combinations of pumice and disinfectant was compared with a conventional mixture of pumice and water. The results revealed that under practical conditions the mix of Steribim (pumice containing benzoic acid added by the manufacturer) with water reduced the number of bacteria by 99% compared with a mix of a conventional pumice and water. The addition of an antiseptic product that contained octenidine as active agent to conventional pumice reduced the number of microorganisms by 99.999%.

  1. Lunar cinder cones.

    PubMed

    McGetchin, T R; Head, J W

    1973-04-01

    Data on terrestrial eruptions of pyroclastic material and ballistic considerations suggest that in the lunar environment (vacuum and reduced gravity) low-rimmed pyroclastic rings are formed rather than the high-rimmed cinder cones so abundant on the earth. Dark blanketing deposits in the Taurus-Littrow region (Apollo 17 landing area) are interpreted as being at least partly composed of lunar counterparts of terrestrial cinder cones.

  2. Lunar cinder cones.

    NASA Technical Reports Server (NTRS)

    Mcgetchin, T. R.; Head, J. W.

    1973-01-01

    Data on terrestrial eruptions of pyroclastic material and ballistic considerations suggest that in the lunar environment (vacuum and reduced gravity) low-rimmed pyroclastic rings are formed rather than the high-rimmed cinder cones so abundant on the earth. Dark blanketing deposits in the Taurus-Littrow region (Apollo 17 landing area) are interpreted as being at least partly composed of lunar counterparts of terrestrial cinder cones.

  3. Occurrence and exposures to disinfectants and disinfection by-products

    SciTech Connect

    Cumming, R.B.; Jolley, R.L.

    1992-12-31

    Disinfection by-products are associated with all chemical disinfectants. The concentration and toxic nature of the disinfection byproducts (DBPs) is a direct function of the chemical nature of the disinfectant itself and/or of the chemical reactions of the disinfectant with reaction substrates in the water, especially organic constituents. A principal advantage of biological and physical water treatment processes, such as filtration, is the lack of chemical reactions producing disinfectant-related DBPs. The use of the highest quality source water available is important for minimization of DBP formation. In lieu of such high quality water, improvement of water quality by removal of DBP precursors through filtration or other means before application of chemical disinfectants is important. Most, if not all, water treatment experts are aware of these simplistic axioms. In view of the increasing knowledge being developed concerning DBPs including the identification of ``new`` DBPs, prudence dictates minimization of DBP formation. Wholesome drinking water is perhaps the biggest economic bargain available to consumers. The cost-effectiveness of water quality improvement should be evaluated with that in mind.

  4. Occurrence and exposures to disinfectants and disinfection by-products

    SciTech Connect

    Cumming, R.B.; Jolley, R.L.

    1992-01-01

    Disinfection by-products are associated with all chemical disinfectants. The concentration and toxic nature of the disinfection byproducts (DBPs) is a direct function of the chemical nature of the disinfectant itself and/or of the chemical reactions of the disinfectant with reaction substrates in the water, especially organic constituents. A principal advantage of biological and physical water treatment processes, such as filtration, is the lack of chemical reactions producing disinfectant-related DBPs. The use of the highest quality source water available is important for minimization of DBP formation. In lieu of such high quality water, improvement of water quality by removal of DBP precursors through filtration or other means before application of chemical disinfectants is important. Most, if not all, water treatment experts are aware of these simplistic axioms. In view of the increasing knowledge being developed concerning DBPs including the identification of new'' DBPs, prudence dictates minimization of DBP formation. Wholesome drinking water is perhaps the biggest economic bargain available to consumers. The cost-effectiveness of water quality improvement should be evaluated with that in mind.

  5. Ultraviolet disinfection of potable water

    SciTech Connect

    Wolfe, R.L. )

    1990-06-01

    Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection. 38 refs.

  6. Dental unit waterlines disinfection using hypochlorous acid-based disinfectant

    PubMed Central

    Shajahan, Irfana Fathima; Kandaswamy, D; Srikanth, Padma; Narayana, L Lakshmi; Selvarajan, R

    2016-01-01

    Objective: The purpose of the study was to investigate the efficacy of a new disinfectant to disinfect the dental unit waterlines. Materials and Methods: New dental unit waterlines were installed in 13 dental chairs, and biofilm was allowed to grow for 10 days. Disinfection treatment procedure was carried out in the 12 units, and one unit was left untreated. The dental unit waterlines were removed and analyzed using the scanning electron microscope (SEM) (TESCAN VEGA3 SBU). Result: On examination, SEM images showed that there was no slime layer or bacterial cells seen in any of the 12 cut sections obtained from the treated dental waterlines which mean that there was no evident of biofilm formation. Untreated dental unit waterlines showed a microbial colonization with continuous filamentous organic matrix. There was significant biofilm formation in the control tube relative to the samples. Conclusion: The tested disinfectant was found to be effective in the removal of biofilm from the dental unit waterlines. PMID:27563184

  7. The cone dysfunction syndromes

    PubMed Central

    Aboshiha, Jonathan; Dubis, Adam M; Hardcastle, Alison J; Michaelides, Michel

    2016-01-01

    The cone dysfunction syndromes are a heterogeneous group of inherited, predominantly stationary retinal disorders characterised by reduced central vision and varying degrees of colour vision abnormalities, nystagmus and photophobia. This review details the following conditions: complete and incomplete achromatopsia, blue-cone monochromatism, oligocone trichromacy, bradyopsia and Bornholm eye disease. We describe the clinical, psychophysical, electrophysiological and imaging findings that are characteristic to each condition in order to aid their accurate diagnosis, as well as highlight some classically held notions about these diseases that have come to be challenged over the recent years. The latest data regarding the genetic aetiology and pathological changes observed in the cone dysfunction syndromes are discussed, and, where relevant, translational avenues of research, including completed and anticipated interventional clinical trials, for some of the diseases described herein will be presented. Finally, we briefly review the current management of these disorders. PMID:25770143

  8. Why rods and cones?

    PubMed

    Lamb, T D

    2016-02-01

    Under twenty-first-century metropolitan conditions, almost all of our vision is mediated by cones and the photopic system, yet cones make up barely 5% of our retinal photoreceptors. This paper looks at reasons why we additionally possess rods and a scotopic system, and asks why rods comprise 95% of our retinal photoreceptors. It considers the ability of rods to reliably signal the arrival of individual photons of light, as well as the ability of the retina to process these single-photon signals, and it discusses the advantages that accrue. Drawbacks in the arrangement, including the very slow dark adaptation of scotopic vision, are also considered. Finally, the timing of the evolution of cone and rod photoreceptors, the retina, and the camera-style eye is summarised.

  9. Cap protects aircraft nose cone

    NASA Technical Reports Server (NTRS)

    Bryan, C. F., Jr.; Bryan, D. C.

    1981-01-01

    Inexpensive, easily fabricated cap protects aircraft nose cone from erosion. Made of molded polycarbonate, cap has been flight tested at both subsonic and supesonic speeds. Its strength and erosion characteristics are superior to those of fiberglass cones.

  10. Assessment of the Potential of CFC (Calcium hydroxide Flagyl Ciprofloxacin) for the Rapid Disinfection of Resilon and Gutta-Percha

    PubMed Central

    Hamza, Mariam Omer Bin; Gufran, Khalid

    2015-01-01

    Introduction Obturating materials exposed to the dental operating environment has been shown to be contaminated, making rapid chair side disinfection mandatory to ensure the sterility of the root canals. Objective The purpose of this study was to investigate the effectiveness of CFC (combination of Calcium hydroxide, Flagyl and Ciprofloxacin) for the rapid disinfection of Gutta-percha and Resilon cones. Materials and Methods Seventy new Gutta-percha and Resilon cones were randomly selected, contaminated with Enterococcus faecalis and divided into 4 group according to the irrigant used for disinfection {Group I: 5.25% Sodium Hypochlorite (NaOCl), Group II: MTAD, Group III: 2% Chlorhexidine (CHX), Group IV: CFC (a combination of Calcium hydroxide, Flagyl and Ciprofloxacin)}. All the samples were placed in a centrifuge tube with BHI broth after being washed with sterile water. The samples were then incubated for 7 days at 37oC. Samples were randomly plated on Mac Conkey agar plate and the colony count was recorded and the observations were drawn. Results A 5.25% NaOCl required 1 minute exposure for effective disinfection of all the samples. MTAD could eliminate E.faecalis from gutta-percha samples in 30 seconds whereas it required 1 minute of exposure for Resilon cones. Both 2% CHX and CFC could not disinfect the samples with 1 minute exposure and a minimum of 5 minute exposure was required. Conclusion A 5.25% NaOCl and Biopure MTAD required less chair side time to disinfect all the samples effectively when compared with 2% CHX and CFC. PMID:26557614

  11. Health effects of drinking water disinfectants and disinfection by-products

    SciTech Connect

    Condie, L.W.; Bercz, J.P.

    1986-01-01

    This paper summarizes toxicological studies conducted with drinking water disinfectants. Toxicological effects, which are associated with the disinfectants themselves as well as with the by-products formed when disinfectants react with organic material present in water, are considered. The health impact of chemical reactions occurring between residual disinfectants and nutrients in the gastrointestinal tract is also discussed. 40 references, 5 tables.

  12. 40 CFR 141.54 - Maximum residual disinfectant level goals for disinfectants.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Maximum residual disinfectant level goals for disinfectants. 141.54 Section 141.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.54 Maximum residual disinfectant level...

  13. 40 CFR 141.54 - Maximum residual disinfectant level goals for disinfectants.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Maximum residual disinfectant level goals for disinfectants. 141.54 Section 141.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.54 Maximum residual disinfectant level...

  14. 40 CFR 141.54 - Maximum residual disinfectant level goals for disinfectants.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Maximum residual disinfectant level goals for disinfectants. 141.54 Section 141.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.54 Maximum residual disinfectant level...

  15. 40 CFR 141.54 - Maximum residual disinfectant level goals for disinfectants.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Maximum residual disinfectant level goals for disinfectants. 141.54 Section 141.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.54 Maximum residual disinfectant level...

  16. 40 CFR 141.54 - Maximum residual disinfectant level goals for disinfectants.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Maximum residual disinfectant level goals for disinfectants. 141.54 Section 141.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.54 Maximum residual disinfectant level...

  17. Can pulsed xenon ultraviolet light systems disinfect aerobic bacteria in the absence of manual disinfection?

    PubMed

    Jinadatha, Chetan; Villamaria, Frank C; Ganachari-Mallappa, Nagaraja; Brown, Donna S; Liao, I-Chia; Stock, Eileen M; Copeland, Laurel A; Zeber, John E

    2015-04-01

    Whereas pulsed xenon-based ultraviolet light no-touch disinfection systems are being increasingly used for room disinfection after patient discharge with manual cleaning, their effectiveness in the absence of manual disinfection has not been previously evaluated. Our study indicates that pulsed xenon-based ultraviolet light systems effectively reduce aerobic bacteria in the absence of manual disinfection. These data are important for hospitals planning to adopt this technology as adjunct to routine manual disinfection.

  18. Disinfection of Human Teeth for Educational Purposes.

    ERIC Educational Resources Information Center

    Tate, William H.; White, Robert S.

    1991-01-01

    A study investigated the efficacy of glutaraldehyde and several other disinfectants for disinfecting teeth to be used for teaching and research, as an alternative to autoclaving for teeth with amalgam restorations. Results indicate that formalin was the only disinfectant that penetrated tooth pulp chambers in effective antimicrobial…

  19. [Drinking water decontamination with isolative sorbent disinfectants].

    PubMed

    Krasnov, M S

    2004-01-01

    Drinking water can be decontaminated with the use of isolative sorbent disinfectants. Consideration of the effectiveness of water disinfectants and the sorptive power of porous materials against bacteria and viruses attested to the favour of iodine and silver-containing disinfectants and their compositions on porous aggressive carriers to be employed in extreme conditions such as on board crewed space vehicles.

  20. Light cone matrix product

    SciTech Connect

    Hastings, Matthew B

    2009-01-01

    We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, the behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.

  1. Review of water disinfection techniques

    NASA Technical Reports Server (NTRS)

    Colombo, Gerald V.; Sauer, Richard L.

    1987-01-01

    Throughout the history of manned space flight the supply of potable water to the astronauts has presented unique problems. Of particular concern has been the microbiological quality of the potable water. This has required the development of both preflight water system servicing procedures to disinfect the systems and inflight disinfectant addition and monitoring devices to ensure continuing microbiological control. The disinfectants successfully used to date have been aqueous chlorine or iodine. Because of special system limitations the use of iodine has been the most successful for inflight use and promises to be the agent most likely to be used in the future. Future spacecraft potable, hygiene, and experiment water systems will utilize recycled water. This will present special problems for water quality control. NASA is currently conducting research and development to solve these problems.

  2. Computational modeling of ultraviolet disinfection.

    PubMed

    Younis, B A; Yang, T H

    2010-01-01

    The efficient design of ultraviolet light (UV) systems for water and wastewater treatment requires detailed knowledge of the patterns of fluid motion that occur in the disinfection channel. This knowledge is increasingly being obtained using Computational Fluid Dynamics (CFD) software packages that solve the equations governing turbulent fluid-flow motion. In this work, we present predictions of the patterns of flow and the extent of disinfection in a conventional reactor consisting of an open channel with an array of UV lamps placed with their axes perpendicular to the direction of flow. It is shown that the resulting flow is inherently unsteady due to the regular shedding of vortices from the submerged lamps. It is also shown that the accurate prediction of the hydraulic residence time and, consequently, the extent of disinfection is strongly dependent on the ability of the CFD method to capture the occurrence and strength of the vortex shedding, and its effects on the turbulent mixing processes.

  3. Shatter cones: Diagnostic impact signatures

    NASA Astrophysics Data System (ADS)

    McHone, J. F.; Dietz, R. S.

    Uniquely fractured target rocks known as shatter cones are associated with more than one half the world's 120 or so presently known impact structures. Shatter cones are a form of tensile rock failure in which a positive conical plug separates from a negative outer cup or mold and delicate ornaments radiating from an apex are preserved on surfaces of both portions. Although distinct, shatter cones are sometimes confused with other striated geologic features such as ventifacts, stylolites, cone-in-cone, slickensides, and artificial blast plumes. Complete cones or solitary cones are rare, occurrences are usually as swarms in thoroughly fractured rock. Shatter cones may form in a zone where an expanding shock wave propagating through a target decays to form an elastic wave. Near this transition zone, the expanding primary wave may strike a pebble or other inhomogeneity whose contrasting transmission properties produce a scattered secondary wave. Interference between primary and secondary scattered waves produce conical stress fields with axes perpendicular to the plane of an advancing shock front. This model supports mechanism capable of producing such shatter cone properties as orientation, apical clasts, lithic dependence, and shock pressure zonation. Although formational mechanics are still poorly understood, shatter cones have become the simplest geologic field criterion for recognizing astroblemes (ancient terrestrial impact structures).

  4. Shatter cones: Diagnostic impact signatures

    NASA Technical Reports Server (NTRS)

    Mchone, J. F.; Dietz, R. S.

    1988-01-01

    Uniquely fractured target rocks known as shatter cones are associated with more than one half the world's 120 or so presently known impact structures. Shatter cones are a form of tensile rock failure in which a positive conical plug separates from a negative outer cup or mold and delicate ornaments radiating from an apex are preserved on surfaces of both portions. Although distinct, shatter cones are sometimes confused with other striated geologic features such as ventifacts, stylolites, cone-in-cone, slickensides, and artificial blast plumes. Complete cones or solitary cones are rare, occurrences are usually as swarms in thoroughly fractured rock. Shatter cones may form in a zone where an expanding shock wave propagating through a target decays to form an elastic wave. Near this transition zone, the expanding primary wave may strike a pebble or other inhomogeneity whose contrasting transmission properties produce a scattered secondary wave. Interference between primary and secondary scattered waves produce conical stress fields with axes perpendicular to the plane of an advancing shock front. This model supports mechanism capable of producing such shatter cone properties as orientation, apical clasts, lithic dependence, and shock pressure zonation. Although formational mechanics are still poorly understood, shatter cones have become the simplest geologic field criterion for recognizing astroblemes (ancient terrestrial impact structures).

  5. New disinfection and sterilization methods.

    PubMed Central

    Rutala, W. A.; Weber, D. J.

    2001-01-01

    New disinfection methods include a persistent antimicrobial coating that can be applied to inanimate and animate objects (Surfacine), a high-level disinfectant with reduced exposure time (ortho-phthalaldehyde), and an antimicrobial agent that can be applied to animate and inanimate objects (superoxidized water). New sterilization methods include a chemical sterilization process for endoscopes that integrates cleaning (Endoclens), a rapid (4-hour) readout biological indicator for ethylene oxide sterilization (Attest), and a hydrogen peroxide plasma sterilizer that has a shorter cycle time and improved efficacy (Sterrad 50). PMID:11294738

  6. Cone rod dystrophies.

    PubMed

    Hamel, Christian P

    2007-01-01

    Cone rod dystrophies (CRDs) (prevalence 1/40,000) are inherited retinal dystrophies that belong to the group of pigmentary retinopathies. CRDs are characterized by retinal pigment deposits visible on fundus examination, predominantly localized to the macular region. In contrast to typical retinitis pigmentosa (RP), also called the rod cone dystrophies (RCDs) resulting from the primary loss in rod photoreceptors and later followed by the secondary loss in cone photoreceptors, CRDs reflect the opposite sequence of events. CRD is characterized by primary cone involvement, or, sometimes, by concomitant loss of both cones and rods that explains the predominant symptoms of CRDs: decreased visual acuity, color vision defects, photoaversion and decreased sensitivity in the central visual field, later followed by progressive loss in peripheral vision and night blindness. The clinical course of CRDs is generally more severe and rapid than that of RCDs, leading to earlier legal blindness and disability. At end stage, however, CRDs do not differ from RCDs. CRDs are most frequently non syndromic, but they may also be part of several syndromes, such as Bardet Biedl syndrome and Spinocerebellar Ataxia Type 7 (SCA7). Non syndromic CRDs are genetically heterogeneous (ten cloned genes and three loci have been identified so far). The four major causative genes involved in the pathogenesis of CRDs are ABCA4 (which causes Stargardt disease and also 30 to 60% of autosomal recessive CRDs), CRX and GUCY2D (which are responsible for many reported cases of autosomal dominant CRDs), and RPGR (which causes about 2/3 of X-linked RP and also an undetermined percentage of X-linked CRDs). It is likely that highly deleterious mutations in genes that otherwise cause RP or macular dystrophy may also lead to CRDs. The diagnosis of CRDs is based on clinical history, fundus examination and electroretinogram. Molecular diagnosis can be made for some genes, genetic counseling is always advised. Currently

  7. EPIDEMIOLOGIC STUDIES OF DISINFECTANTS AND DISINFECTANT BY-PRODUCTS

    EPA Science Inventory

    This article provides a review of the epidemiologic evidence for human health effects that may be associated with the disinfection of drinking water. An epidemiologic study attempts to link human health effects with exposure to a specific agent (e.g., DBCM), agents (e.g., THMs or...

  8. Recycled Water Poses Disinfectant Problem

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1973

    1973-01-01

    Discusses the possible health hazards resulting from released nucleic acid of inactivated viruses, chlorinated nonliving organic molecules, and overestimated reliability of waste treatment standards. Suggests the recycle system use a dual disinfectant such as chlorine and ozone in water treatment. (CC)

  9. Ultraviolet disinfection of contact lenses.

    PubMed

    Harris, M G; Fluss, L; Lem, A; Leong, H

    1993-10-01

    To evaluate the efficacy of ultraviolet (UV) radiation as a method of disinfecting contact lenses and their storage solutions, we contaminated soft lenses (Bausch & Lomb Optima 38), rigid gas permeable (RGP) lenses (Oxyflow F-30), and their storage solutions with three common bacteria. Escherichia coli (E.c.), Staphylococcus epidermis (S.e.), and Serratia marcescens (S.m.). The storage solutions used were saline solution and RGP conditioning solution. We determined the exposure times to 253.7-nm wavelength UV radiation necessary to disinfect the contact lenses and solutions. The decimal reduction values (D values) found for UV radiation were 10 to 200 hundred times shorter than reported for currently available disinfection systems. For E.c., sterilization was attained after 100 s of exposure. For S.e. and S.m., sterilization occurred after 300 s of exposure. Different contact lens solutions transmit UV radiation to various degrees, with saline solution passing more than 90% of the UV radiation. Thus, our results indicate that UV radiation is an effective and rapid method of disinfecting contact lenses and their storage solutions. PMID:8247487

  10. Ultraviolet disinfection of contact lenses.

    PubMed

    Harris, M G; Fluss, L; Lem, A; Leong, H

    1993-10-01

    To evaluate the efficacy of ultraviolet (UV) radiation as a method of disinfecting contact lenses and their storage solutions, we contaminated soft lenses (Bausch & Lomb Optima 38), rigid gas permeable (RGP) lenses (Oxyflow F-30), and their storage solutions with three common bacteria. Escherichia coli (E.c.), Staphylococcus epidermis (S.e.), and Serratia marcescens (S.m.). The storage solutions used were saline solution and RGP conditioning solution. We determined the exposure times to 253.7-nm wavelength UV radiation necessary to disinfect the contact lenses and solutions. The decimal reduction values (D values) found for UV radiation were 10 to 200 hundred times shorter than reported for currently available disinfection systems. For E.c., sterilization was attained after 100 s of exposure. For S.e. and S.m., sterilization occurred after 300 s of exposure. Different contact lens solutions transmit UV radiation to various degrees, with saline solution passing more than 90% of the UV radiation. Thus, our results indicate that UV radiation is an effective and rapid method of disinfecting contact lenses and their storage solutions.

  11. Postoutbreak disinfection of mobile equipment.

    PubMed

    Alphin, R L; Ciaverelli, C D; Hougentogler, D P; Johnson, K J; Rankin, M K; Benson, E R

    2010-03-01

    Current control strategies for avian influenza virus, exotic Newcastle disease, and other highly contagious poultry diseases include surveillance, quarantine, depopulation, disposal, and decontamination. Skid steer loaders and other mobile equipment are extensively used during depopulation and disposal. Movement of contaminated equipment has been implicated in the spread of disease in previous outbreaks. One approach to equipment decontamination is to power wash the equipment, treat with a liquid disinfectant, change any removable filters, and let it sit idle for several days. In this project, multiple disinfectant strategies were individually evaluated for their effectiveness at inactivating Newcastle disease virus (NDV) on mechanical equipment seeded with the virus. A small gasoline engine was used to simulate typical mechanical equipment. A high titer of LaSota strain, NDV was applied and dried onto a series of metal coupons. The coupons were then placed on both interior and exterior surfaces of the engine. Liquid disinfectants that had been effective in the laboratory were not as effective at disinfecting the engine under field conditions. Indirect thermal fog showed a decrease in overall virus titer or strength. Direct thermal fog was more effective than liquid spray application or indirect thermal fog application. PMID:20521731

  12. Skin disinfection in preterm infants.

    PubMed

    Malathi, I; Millar, M R; Leeming, J P; Hedges, A; Marlow, N

    1993-09-01

    Greater care and a more thorough approach to intravenous catheter site disinfection may be important for the prevention of catheter related sepsis, especially with coagulase negative staphylocci in preterm infants. The efficacy of skin disinfection was evaluated in preterm infants using a skin swabbing technique after disinfectant exposure. In the first part of the study, 25 peripheral intravascular catheter sites were quantitatively sampled immediately after routine cannula insertion. Bacterial counts greater than 100 colony forming units/cm2 were observed from 10 (40%) sites. In the second part, sampling for bacterial colony counts was done after skin cleansing with various durations of exposure of chlorhexidine/alcohol swabs or povidone iodine. The overall mean reduction in bacterial colony counts after skin cleansing ranged from 90-99%. Skin sterilisation was achieved in 33-92% of cases. The use of two consecutive 10 second exposures resulted in a significantly improved reduction in colony counts compared with a single 10 second wipe. A longer 30 second exposure also resulted in a greater reduction of bacterial numbers compared with a shorter duration of 5 or 10 seconds. Repopulation of disinfected sites occurred within 48 hours. This effect was delayed by occluding the cleansed site with a semipermeable dressing. There were no significant differences between povidone iodine and the chlorhexidine swabs in reducing bacterial numbers. This study has demonstrated that a brief exposure with a premoistened disinfectant swab is not sufficient for complete elimination of resident skin flora of newborn infants. The use of two consecutive cleanings, or a longer duration of cleansing is recommended for more effective skin sterilisation.

  13. 9 CFR 166.14 - Cleaning and disinfecting.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... disinfecting. (a) Disinfectants to be used. Disinfection required under the regulations in this Part shall be... cresylic disinfectant that is used in accordance with directions on the EPA-approved label, provided such disinfectant also meets the requirements set forth in §§ 71.10(b) and 71.11 of this chapter. (3)...

  14. 9 CFR 166.14 - Cleaning and disinfecting.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... disinfecting. (a) Disinfectants to be used. Disinfection required under the regulations in this Part shall be... cresylic disinfectant that is used in accordance with directions on the EPA-approved label, provided such disinfectant also meets the requirements set forth in §§ 71.10(b) and 71.11 of this chapter. (3)...

  15. 9 CFR 166.14 - Cleaning and disinfecting.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... disinfecting. (a) Disinfectants to be used. Disinfection required under the regulations in this Part shall be... cresylic disinfectant that is used in accordance with directions on the EPA-approved label, provided such disinfectant also meets the requirements set forth in §§ 71.10(b) and 71.11 of this chapter. (3)...

  16. 9 CFR 166.14 - Cleaning and disinfecting.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... disinfecting. (a) Disinfectants to be used. Disinfection required under the regulations in this Part shall be... cresylic disinfectant that is used in accordance with directions on the EPA-approved label, provided such disinfectant also meets the requirements set forth in §§ 71.10(b) and 71.11 of this chapter. (3)...

  17. 9 CFR 166.14 - Cleaning and disinfecting.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... disinfecting. (a) Disinfectants to be used. Disinfection required under the regulations in this Part shall be... cresylic disinfectant that is used in accordance with directions on the EPA-approved label, provided such disinfectant also meets the requirements set forth in §§ 71.10(b) and 71.11 of this chapter. (3)...

  18. The Holographic Entropy Cone

    SciTech Connect

    Bao, Ning; Nezami, Sepehr; Ooguri, Hirosi; Stoica, Bogdan; Sully, James; Walter, Michael

    2015-09-21

    We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phase space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.

  19. The Holographic Entropy Cone

    DOE PAGESBeta

    Bao, Ning; Nezami, Sepehr; Ooguri, Hirosi; Stoica, Bogdan; Sully, James; Walter, Michael

    2015-09-21

    We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phasemore » space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.« less

  20. Making An Impact: Shatter Cones

    ERIC Educational Resources Information Center

    Blank, Lisa M.; Plautz, Michael R.; Crews, Jeffrey W.

    2004-01-01

    In 1990, a group of geologists discovered a large number of shatter cones in southwestern Montana. Shatter cones are a type of metamorphosed rock often found in impact structures (the remains of a crater after a meteor impact and years of Earth activity). Scientists have discovered only 168 impact craters around the world. If rocks could talk,…

  1. DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON

    EPA Science Inventory

    The effects of the use of the alternative disinfectants on the formation of halogenated disinfection by–products (DBPs) including total organic halide, trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along ...

  2. Status report on analytical methods to support the disinfectant/disinfection by-products regulation

    SciTech Connect

    Not Available

    1992-08-01

    The U.S. EPA is developng national regulations to control disinfectants and disinfection by-products in public drinking water supplies. Twelve disinfectants and disinfection by-products are identified for possible regulation under this rule. The document summarizes the analytical methods that EPA intends to propose as compliance monitoring methods. A discussion of surrogate measurements that are being considered for inclusion in the regulation is also provided.

  3. 9 CFR 91.41 - Cleaning and disinfecting of aircraft.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... animals on the aircraft shall be cleaned and disinfected using an approved disinfectant listed in § 71.10... stowage area. The disinfectant solution must be applied with a device that creates an aerosol or mist...

  4. DRINKING WATER DISINFECTION BY-PRODUCTS: WHAT IS KNOWN

    EPA Science Inventory

    Chlorine, ozone, chlorine dioxide, and chloramine are currently the major disinfectants being used to disinfect drinking water. Although the alternative disinfectants (ozone, chlorine dioxide, and chloramine) are increasing in popularity in the United States, chlorine is still us...

  5. Micropollutants produced by disinfection of wastewater effluents

    SciTech Connect

    Jolley, R.L.; Cumming, R.B.; Lee, N.E.; Thompson, J.E.; Lewis, L.R.

    1981-01-01

    Recent research conducted with the objective of determining some of the chemical mutagenic characteristics of nonvolatile micropollutants in treated wastewater effluents is summarized. The effluents from nine wastewater plants were examined relative to the chemical effects of the disinfectants chlorine, ozone, and uv light on nonvolatile organic constituents and the formation of mutagenic constituents during disinfection. Results indicate that disinfection by chlorine or ozone can lead to an increase in the number of mutagenic materials in the effluents. (JGB)

  6. Ultra violet disinfection: A 3-year history

    SciTech Connect

    Tubesing, R.R.; Lindeke, D.R.

    1998-07-01

    The Stillwater Wastewater Treatment Facility is one of nine wastewater treatment facilities operated by the Metropolitan Council Environmental Services in the Minneapolis-St. Paul Metropolitan Area. The facility services the cities of Stillwater, Oak Park Heights, and Bayport. In 1993, an ultra violet disinfection facility began operation to provide the disinfection for the Facility. This presentation discusses the reasons for using ultra violet disinfection in lieu of chlorination/dechlorination facilities, the operating performance, and operating cost factors.

  7. Disinfection Addition and Disinfection Changes: What It Means to the LCR

    EPA Science Inventory

    This slide presentation’s general points are: Many protective pipe scales are vey dependent on ORP, and hence, state of disinfection. Adding disinfection to anoxic systems will likely cause big chemistry changes in DS and corrosion. Changing disinfectants could cause major l...

  8. Disinfecting Filters For Recirculated Air

    NASA Technical Reports Server (NTRS)

    Pilichi, Carmine A.

    1992-01-01

    Simple treatment disinfects air filters by killing bacteria, algae, fungi, mycobacteria, viruses, spores, and any other micro-organisms filters might harbor. Concept applied to reusable stainless-steel wire mesh filters and disposable air filters. Treatment used on filters in air-circulation systems in spacecraft, airplanes, other vehicles, and buildings to help prevent spread of colds, sore throats, and more-serious illnesses.

  9. Decontamination formulations for disinfection and sterilization

    DOEpatents

    Tucker, Mark D.; Engler, Daniel E.

    2007-09-18

    Aqueous decontamination formulations that neutralize biological pathogens for disinfection and sterilization applications. Examples of suitable applications include disinfection of food processing equipment, disinfection of areas containing livestock, mold remediation, sterilization of medical instruments and direct disinfection of food surfaces, such as beef carcasses. The formulations include at least one reactive compound, bleaching activator, inorganic base, and water. The formulations can be packaged as a two-part kit system, and can have a pH value in the range of 7-8.

  10. Effect of Disinfectants on Glucose Monitors

    PubMed Central

    Mahoney, John J; Lim, Christine G

    2012-01-01

    Background Monitoring blood glucose levels is an integral part of routine diabetes management. To minimize the risk of transmission of bloodborne pathogens during monitoring, the Centers for Disease Control and Prevention (CDC) recommends that glucose meters be disinfected after each use whenever they are used to test multiple patients. The objective of this study is to assess the compatibility of some common disinfectants with certain blood glucose meter systems. Methods We tested six disinfectants for adverse impact on meter performance or the exterior meter surfaces. The disinfectants tested were 0.525% sodium hypochlorite, 20% 2-propanol and 10% ethanol, 17.2% isopropanol, 55% isopropanol, 70% isopropanol, and hydrogen peroxide. To assess meter performance, we tested OneTouch® Ultra® blood glucose monitoring systems with control solution before and after application of either water or disinfectant. To assess the effect on exterior meter surfaces, we performed a soaking test to simulate long-term exposure to disinfectant. Results Paired t-test results showed that the control solution data associated with disinfectant and with water application were not significantly different for each meter type. However, most of the meter types were adversely affected by hydrogen peroxide and/or by the higher concentrations of alcohol-based disinfectants. Conclusions Although none of the six disinfectants affected meter performance, hydrogen peroxide and isopropanol >20% adversely affected the exterior surfaces of the tested meters. When complying with CDC instructions for meter disinfection, users should use caution and choose disinfectants that have been validated by the meter manufacturer. PMID:22401326

  11. Ultraviolet (UV) Disinfection for Drinking Water Systems

    EPA Science Inventory

    UV disinfection is an effective process for inactivating many microbial pathogens in water with potential to serve as stand-alone treatment or in combination with other disinfectants. USEPA provided guidance on the validation of UV reactors nearly a decade ago. Since then, lesson...

  12. Silver disinfection in water distribution systems

    NASA Astrophysics Data System (ADS)

    Silvestry Rodriguez, Nadia

    Silver was evaluated as disinfectant to maintain water quality in water distribution system. It was used to inhibit growth of two opportunistic bacteria in planktonik form and in biofilm formation in Robbins devices with stainless steel and PVC surfaces. The results of this work show that silver is a potential secondary disinfectant to be used in water distribution systems.

  13. ULTRAVIOLET DISINFECTION STUDIES WITH CCL LISTED MICROORGANISMS

    EPA Science Inventory

    Resistance to ultraviolet (UV) disinfection is an essential aspect regarding all microbial groups listed on the CCL. The U.S. drinking water industry is interested in including UV light treatment as an amendment to conventional treatment for disinfecting water supplies. UV disi...

  14. MUTAGENICITY OF DRINKING WATER FOLLOWING DISINFECTION

    EPA Science Inventory

    Many drinking water utilities in the USA are considering alternatives to chlorine for disinfection in order to comply with federal regulations regarding disinfection by-products. An evaluation is thus needed of the potential risks associated with the use of alternative disinfecta...

  15. 40 CFR 141.72 - Disinfection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Disinfection. 141.72 Section 141.72 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL... for Giardia lamblia cysts and viruses. If a system uses a disinfectant other than chlorine, the...

  16. 40 CFR 141.72 - Disinfection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Disinfection. 141.72 Section 141.72 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL... for Giardia lamblia cysts and viruses. If a system uses a disinfectant other than chlorine, the...

  17. 40 CFR 141.72 - Disinfection.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... for Giardia lamblia cysts and viruses. If a system uses a disinfectant other than chlorine, the system...) The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide, as specified in § 141.74 (a)(2) and (b)(6), cannot be...

  18. Interaction of disinfectant residues on cleanroom substrates.

    PubMed

    Kaiser, H; Klein, D; Kopis, E; Leblanc, D; McDonnell, G; Tirey, J F

    1999-01-01

    This study will determine the levels of disinfectant residues on stainless steel surfaces after simulated manual cleaning activities. Additionally, this study will determine if chemical interactions between different chemical agents, representative of commonly used cleanroom disinfectant technologies, subsequently applied to the same surfaces exist, and to what degree these interactions impact sporicidal performance of an oxidizing biocide against Bacillus subtilis.

  19. Disinfection of Bacillus spores with acidified nitrite.

    PubMed

    Szabo, Jeffrey G; Adcock, Noreen J; Rice, Eugene W

    2014-10-01

    Disinfecting water generated from a bioterrorism contamination event will require large amounts of disinfectant since the volume of water flushed from a drinking water distribution system or wash water collected from a contaminated outdoor area can accumulate quickly. Commonly used disinfectants may be unavailable in the necessary amounts, so evaluation of alternative disinfectants is needed. This study focuses on disinfection of Bacillus spores in water using acidified nitrite. The effect of varying pH (2 or 3), temperature (5°C or 24°C), nitrite concentration (0.01 or 0.1M), buffer (Butterfields or Phosphate Buffered Saline, PBS) and Bacillus species (B. globigii and B. anthracis Sterne) was evaluated. B. globigii was more resistant to disinfection under all water quality conditions. Disinfection was more effective for B. globigii and B. anthracis Sterne at 0.1M nitrite, pH 2, and 24°C. Disinfection of B. anthracis Sterne was enhanced in low ionic strength Butterfields buffer compared to PBS.

  20. Sepsis, parenteral vaccination and skin disinfection

    PubMed Central

    Cook, Ian F.

    2016-01-01

    ASBSTRACT Disinfection should be required for all skin penetrative procedures including parenteral administration of vaccines. This review analyses medically attended infectious events following parenteral vaccination in terms of their microbiological aetiology and pathogenesis. Like ‘clean’ surgical site infections, the major pathogens responsible for these events were Staphylococcal species, implicating endogenous con-tamination as a significant source of infection. As 70% isopropyl alcohol swabbing has been shown to effectively disinfect the skin, it would be medico-legally difficult to defend a case of sepsis with the omission of skin disinfection unless the very low risk of this event was adequately explained to the patient and documented prior to vaccination. There was a significant cost-benefit for skin disinfection and cellulitis. Skin disinfection in the context of parenteral vaccination represents a new paradigm of medical practice; the use of a low cost intervention to prevent an event of very low prevalence but of significant cost. PMID:27295449

  1. Quaternary Ammonium Disinfectant Issues Encountered in an Environmental Services Department.

    PubMed

    Boyce, John M; Sullivan, Linda; Booker, Arica; Baker, James

    2016-03-01

    We identified several factors affecting the use of quaternary ammonium-based (Quat) disinfectant in our facility. Microfiber wipers, cotton towels, and 1 of 2 types of disposable wipes soaked in a Quat disinfectant revealed significant binding of the disinfectant. Concentrations of Quat delivered by automated disinfectant dispensers varied widely.

  2. Disinfecting activities of non-peroxide soft contact lens cold disinfection solutions.

    PubMed

    Shih, K L; Raad, M K; Hu, J C; Gresh, W J; Jiries, S I; Caldwell, L J; Bergamini, M V

    1991-07-01

    The antimicrobial activities of three non-peroxide soft contact lens chemical disinfection systems--ReNu Multi-Purpose Solution (0.00005% polyaminopropyl biguanide), Opti-Soft Disinfecting Solution (0.001% polyquaternium-1), and Opti-Free Rinsing, Disinfecting & Storage Solution (0.001% polyquaternium-1)--were compared to Soft Mate Disinfecting Solution (0.005% chlorhexidine digluconate). Each product was separately inoculated with each of five microorganisms at approximately 10(6) microorganisms per mL. All of the solutions demonstrated excellent disinfecting activity against Pseudomonas aeruginosa and Staphylococcus epidermidis, with complete disinfection occurring within 4 hours. Only Soft Mate disinfected Serratia marcescens within 4 hours. ReNu reduced the microorganisms to 10-100 cells/mL and Opti-Soft and Opti-Free reduced the number to 10(2)-10(3) cells/mL. For the fungal species, Soft Mate showed excellent activity against Candida albicans (disinfection in 4 hours) and reduced Aspergillus fumigatus to 10(3) spores/mL in 4 hours. After 4 hours ReNu, Opti-Soft, and Opti-Free had reduced C. albicans only slightly, to 10(5) cells/mL and displayed virtually no disinfecting activity against A. fumigatus. For these newer chemical disinfection systems, diligent cleaning and rinsing of the soft contact lenses are the most important steps in the patient care regimen.

  3. Microbial resistance to disinfectants: mechanisms and significance

    SciTech Connect

    Hoff, J.C.; Akin, E.W.

    1986-11-01

    Drinking water disinfection provides the final barrier to transmission of a wide variety of potentially waterborne infectious agents including pathogenic bacteria, viruses, and protozoa. These agents differ greatly in their innate resistance to inactivation by disinfectants, ranging from extremely sensitive bacteria to highly resistant protozoan cysts. The close similarity between microorganism inactivation rates and the kinetics of chemical reactions has long been recognized. Ideally, under carefully controlled conditions, microorganism inactivation rates simulate first-order chemical reaction rates, making it possible to predict the effectiveness of disinfection under specific conditions. In practice, changes in relative resistance and deviations from first-order kinetics are caused by a number of factors, including microbial growth conditions, aggregation, and association with particulate materials. The net effect of all these factors is a reduction in the effectiveness and predictability of disinfection processes. To ensure effective pathogen control, disinfectant concentrations and contact times greater than experimentally determined values may be required. Of the factors causing enhanced disinfection resistance, protection by association with particulate matter is the most significant. Therefore, removal of particulate matter is an important step in increasing the effectiveness of disinfection processes.

  4. [Disinfection by-products reduction of combined disinfection by chlorine and monochloramines in distribution system].

    PubMed

    Liu, Jing; Chen, Chao; Zhang, Xiao-Jian

    2009-09-15

    Halogen disinfection by-products of four chlorined disinfection processes with long contact time in distribution system was compared in the work. These four disinfection processes are free chlorine, monochloramines, free chlorine disinfection in clearwelles while chloramines in distribution system, sequential chlorination disinfection with short-term free chlorine plus chloramines. According to the research, free chlorine generates most trihalomethanes (THMs) and haloacetic acids (HAAs) both in clearwells and distribution system, while monochloramines barely yield halogen DBPs. Free chlorine disinfection in clearwelles while chloramines in distribution system could reduce 9.6% of THMs and 42% of HAAs in 24 h contact time of distribution system compared with free chlorine. But free chlorine has contacted with water for 2 h in this process, halogen DBPs have been yielded substantially. Process of sequential chlorination disinfection could control DBPs more effectively due to keeping a short contact time of free chlorine and water. 48% of THMs and 72% of HAAs are reduced in 24h compared with free chlorine. In conclusion, sequential chlorination disinfection is a more effective disinfection process for controlling DBPs and water safety.

  5. [Virucidal activity of disinfectants. Influence of the serum protein upon the virucidal activity of disinfectants].

    PubMed

    Noda, M; Matsuda, S; Kobayashi, M

    2000-08-01

    Five disinfectants were tested for virucidal activity on three DNA viruses and three RNA viruses in the presence or absence of serum protein. Disinfectants of the aldehyde and halogen groups had a virucidal activity on human herpes virus, bovine rhabdo virus, human immunodeficiency virus, human adeno virus, porcine parvo virus, and polio virus. Disinfectants of the invert and amphoteric soap groups, and biganide group had a destructive effect on RNA and DNA viruses possessing an envelope. The presence of serum protein exerted great influence upon the virucidal activity of disinfectants of the invert and amphoteric soap groups. PMID:11019515

  6. Shatter cones: (Mis)understood?

    PubMed Central

    Osinski, Gordon R.; Ferrière, Ludovic

    2016-01-01

    Meteorite impact craters are one of the most common geological features in the solar system. An impact event is a near-instantaneous process that releases a huge amount of energy over a very small region on a planetary surface. This results in characteristic changes in the target rocks, from vaporization and melting to solid-state effects, such as fracturing and shock metamorphism. Shatter cones are distinctive striated conical fractures that are considered unequivocal evidence of impact events. They are one of the most used and trusted shock-metamorphic effects for the recognition of meteorite impact structures. Despite this, there is still considerable debate regarding their formation. We show that shatter cones are present in several stratigraphic settings within and around impact structures. Together with the occurrence of complete and “double” cones, our observations are most consistent with shatter cone formation due to tensional stresses generated by scattering of the shock wave due to heterogeneities in the rock. On the basis of field mapping, we derive the relationship Dsc = 0.4 Da, where Dsc is the maximum spatial extent of in situ shatter cones, and Da is the apparent crater diameter. This provides an important, new, more accurate method to estimate the apparent diameter of eroded complex craters on Earth. We have reestimated the diameter of eight well-known impact craters as part of this study. Finally, we suggest that shatter cones may reduce the strength of the target, thus aiding crater collapse, and that their distribution in central uplifts also records the obliquity of impact. PMID:27532050

  7. Shatter cones: (Mis)understood?

    PubMed

    Osinski, Gordon R; Ferrière, Ludovic

    2016-08-01

    Meteorite impact craters are one of the most common geological features in the solar system. An impact event is a near-instantaneous process that releases a huge amount of energy over a very small region on a planetary surface. This results in characteristic changes in the target rocks, from vaporization and melting to solid-state effects, such as fracturing and shock metamorphism. Shatter cones are distinctive striated conical fractures that are considered unequivocal evidence of impact events. They are one of the most used and trusted shock-metamorphic effects for the recognition of meteorite impact structures. Despite this, there is still considerable debate regarding their formation. We show that shatter cones are present in several stratigraphic settings within and around impact structures. Together with the occurrence of complete and "double" cones, our observations are most consistent with shatter cone formation due to tensional stresses generated by scattering of the shock wave due to heterogeneities in the rock. On the basis of field mapping, we derive the relationship D sc = 0.4 D a, where D sc is the maximum spatial extent of in situ shatter cones, and D a is the apparent crater diameter. This provides an important, new, more accurate method to estimate the apparent diameter of eroded complex craters on Earth. We have reestimated the diameter of eight well-known impact craters as part of this study. Finally, we suggest that shatter cones may reduce the strength of the target, thus aiding crater collapse, and that their distribution in central uplifts also records the obliquity of impact.

  8. Shatter cones: (Mis)understood?

    PubMed

    Osinski, Gordon R; Ferrière, Ludovic

    2016-08-01

    Meteorite impact craters are one of the most common geological features in the solar system. An impact event is a near-instantaneous process that releases a huge amount of energy over a very small region on a planetary surface. This results in characteristic changes in the target rocks, from vaporization and melting to solid-state effects, such as fracturing and shock metamorphism. Shatter cones are distinctive striated conical fractures that are considered unequivocal evidence of impact events. They are one of the most used and trusted shock-metamorphic effects for the recognition of meteorite impact structures. Despite this, there is still considerable debate regarding their formation. We show that shatter cones are present in several stratigraphic settings within and around impact structures. Together with the occurrence of complete and "double" cones, our observations are most consistent with shatter cone formation due to tensional stresses generated by scattering of the shock wave due to heterogeneities in the rock. On the basis of field mapping, we derive the relationship D sc = 0.4 D a, where D sc is the maximum spatial extent of in situ shatter cones, and D a is the apparent crater diameter. This provides an important, new, more accurate method to estimate the apparent diameter of eroded complex craters on Earth. We have reestimated the diameter of eight well-known impact craters as part of this study. Finally, we suggest that shatter cones may reduce the strength of the target, thus aiding crater collapse, and that their distribution in central uplifts also records the obliquity of impact. PMID:27532050

  9. RP cone-rod degeneration.

    PubMed Central

    Heckenlively, J R

    1987-01-01

    A group of patients with progressive retinal degeneration and visual field loss, who meet the basic definition of RP were investigated to better define the relationship of the findings on the ERG with clinical characteristics such as visual field size, presence or absence of scotomata or pseudo-altitudinal defects on visual field, amount of night blindness; and presence or absence of macular or optic nerve changes. These studies suggest that cone-rod degeneration patients of the RP type go through the following stages; early, the ERG has a definite cone-rod pattern where the rod ERG is larger than the cone ERG while both are abnormal. As the disease advances, there is more of a reduction in the scotopic ERG such that both the rod and cone ERGs become nearly equal. As the disease further progresses the ERG becomes non-recordable on single-flash technique, but there is good residual rod function and the final rod threshold remains good until the visual field is reduced, typically less than 10 degrees with the IV-4 isopter. Finally with advanced disease the patient becomes night blind and generally becomes very difficult to distinguished from patients who have advanced rod-cone degeneration. While it may seem logical to find that visual field size correlates with various ERG parameters; this has not been as consistent a finding in patients with rod-cone degeneration in the author's experience. The analysis shows several new pieces of information about visual field changes in cone-rod degeneration; enlarged blind spots are seen earlier in cases which have recordable cone-rod patterns (group I), and pseudo-altitudinal changes are more likely to occur in autosomal recessive patients. Patients with macular lesions and central scotomata had larger amplitudes than patients with normal appearing maculae and no central scotomata. Patients with temporal optic atrophy had an earlier onset of symptoms and significant correlation with both photopic a- and b-waves and bright flash

  10. Cone Penetrometer N Factor Determination Testing Results

    SciTech Connect

    Follett, Jordan R.

    2014-03-05

    This document contains the results of testing activities to determine the empirical 'N Factor' for the cone penetrometer in kaolin clay simulant. The N Factor is used to releate resistance measurements taken with the cone penetrometer to shear strength.

  11. UV disinfection for onsite sand filter effluent

    SciTech Connect

    Lowery, J.D.; Romatzick, S.

    1982-05-01

    The technical and economic feasibility of using ultraviolet (uv) light as a viable alternative to chlorine as the required disinfectant for onsite sand filter effluents discharged to surface waters in Maine was determined. To obtain a reliable cross section of performance for sand filters in Maine, 74 filters were selected for an effluent characterization program. The effluent characterization study allowed general conclusions to be made with regard to the potential of uv disinfection. A simple suspended lamp uv disinfection unit was designed, constructed, and tested in the laboratory and in the field. The efficiency of the uv disinfection unit was determined through field testing at 10 of the 74 sand filter sites used in the effluent characterization program.

  12. Disinfection, sterilization, and antisepsis: An overview.

    PubMed

    Rutala, William A; Weber, David J

    2016-05-01

    All invasive procedures involve contact by a medical device or surgical instrument with a patient's sterile tissue or mucous membranes. The level of disinfection or sterilization is dependent on the intended use of the object: critical (items that contact sterile tissue such as surgical instruments), semicritical (items that contact mucous membrane such as endoscopes), and noncritical (devices that contact only intact skin such as stethoscopes) items require sterilization, high-level disinfection and low-level disinfection, respectively. Cleaning must always precede high-level disinfection and sterilization. Antiseptics are essential to infection prevention as part of a hand hygiene program as well as several other uses such as surgical hand antisepsis and pre-operative skin preparation.

  13. Wastewater Disinfectants: Many Called--Few Chosen

    ERIC Educational Resources Information Center

    Smith, James W.

    1978-01-01

    Gives a comparative study of disinfectants used to rid wastewater of pathogens. Concentrates on the effects of chlorine and ozone, with some mention of ultra-violet irradiation, bromine chloride, and chlorine dioxide. (MA)

  14. Environmental Cleaning and Disinfecting for MRSA

    MedlinePlus

    ... stores and other retail stores. Check the disinfectant product’s label on the back of the container. Most, if ... check for an EPA registration number on the product’s label to confirm that it is registered). How should ...

  15. ALTERNATIVE DISINFECTION FOR DRINKING WATER TREATMENT

    EPA Science Inventory

    During a one-yr study at Jefferson Parish, La., the chemical, microbiological, and mutagenic effects os using the major drinkgin water disinfectants (chlorine, chlorine dioxide, chloramine, ozone) were evaluated. Tests were performed on samples collected from various treatment s...

  16. ALTERNATIVE DISINFECTANTS FOR DRINKING WATER TREATMENT

    EPA Science Inventory

    During a one-year study at Jefferson Parish, Louisiana the chemical, microbiological, and mutagenic effects of using the major drinking water disinfectants (chlorine, chlorine dioxide, chloramine, ozone) were evaluated. ests were performed on samples collected from various treatm...

  17. Antiviral activity of alcohol for surface disinfection.

    PubMed

    Moorer, W R

    2003-08-01

    Bacteria and viruses from the patient's mouth travel with dental splatter and spills. A surface disinfectant should possess antiviral activity as well as antibacterial action. Because of frequent and 'open' application in the dental office, such a disinfectant should be non-toxic, non-allergenic and safe for the hygienist. It now appears that high-concentration alcohol mixtures (i.e. 80% ethanol + 5% isopropanol) are not only excellent antibacterials, but quickly inactivate HIV as well as hepatitis B and hepatitis C viruses. Compared to alternative surface disinfectants, use of high-concentration alcohol for the spray-wipe-spray method of surface disinfection in dentistry appears safe and efficient. However, dried matter should be wiped and hydrated first.

  18. [Formaldehyde sediment in incubators following disinfection].

    PubMed

    Wartner, R; Kegel, M; Meyer, H D; Schlüter, G; Wegner, J; Werner, E

    1983-12-01

    Measurements in incubators revealed the presence of formaldehyde concentrations involving a health risk for premature and normal newborns kept and cared for in incubators. Prior to measurements, the incubators had been disinfected by means of formaldehyde vapours in an "Aseptor" disinfecting cabinet (Drägerwerk AG, Lübeck) and then ventilated in strict adherence to operating instructions. The elevated formaldehyde concentrations found had been due to residues of paraformaldehyde and urotropin on the surfaces of the disinfected apparatus, liberating formaldehyde by hydrolysis depending on temperature and relative humidity. There should be a basic reconsideration of the present practice of incubator disinfection. From experiments with activated-carbon filters in incubators it would seem that there is a chance of reducing such formaldehyde concentrations.

  19. 9 CFR 71.10 - Permitted disinfectants.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., Fungicide, and Rodenticide Act (7 U.S.C. 135 et seq.), with tuberculocidal claims, as disinfectants for... confusion, the product of each manufacturer and distributor shall bear a distinctive trade name or...

  20. New developments in disinfection and sterilization.

    PubMed

    Wallace, Craig A

    2016-05-01

    A review of regulatory clearances for selected new sterilization and disinfection products for the period January 2012-June 2015 indicates continued leverage of established technologies for steam and low-temperature sterilization, and high-level disinfection. New products in these areas were typically modified and improved versions of existing products, with the exception of a new combination hydrogen peroxide/ozone sterilizer. Development of new low-temperature sterilization technologies to address continued evolution of complex medical devices is expected to continue.

  1. An environmental disinfection odyssey: evaluation of sequential interventions to improve disinfection of Clostridium difficile isolation rooms.

    PubMed

    Sitzlar, Brett; Deshpande, Abhishek; Fertelli, Dennis; Kundrapu, Sirisha; Sethi, Ajay K; Donskey, Curtis J

    2013-05-01

    OBJECTIVE. Effective disinfection of hospital rooms after discharge of patients with Clostridium difficile infection (CDI) is necessary to prevent transmission. We evaluated the impact of sequential cleaning and disinfection interventions by culturing high-touch surfaces in CDI rooms after cleaning. DESIGN. Prospective intervention. SETTING. A Veterans Affairs hospital. INTERVENTIONS. During a 21-month period, 3 sequential tiered interventions were implemented: (1) fluorescent markers to provide monitoring and feedback on thoroughness of cleaning facility-wide, (2) addition of an automated ultraviolet radiation device for adjunctive disinfection of CDI rooms, and (3) enhanced standard disinfection of CDI rooms, including a dedicated daily disinfection team and implementation of a process requiring supervisory assessment and clearance of terminally cleaned CDI rooms. To determine the impact of the interventions, cultures were obtained from CDI rooms after cleaning and disinfection. RESULTS. The fluorescent marker intervention improved the thoroughness of cleaning of high-touch surfaces (from 47% to 81% marker removal; P < .0001). Relative to the baseline period, the prevalence of positive cultures from CDI rooms was reduced by 14% (P=.024), 48% (P <.001), and 89% (P=.006) with interventions 1, 2, and 3, respectively. During the baseline period, 67% of CDI rooms had positive cultures after disinfection, whereas during interventions periods 1, 2, and 3 the percentages of CDI rooms with positive cultures after disinfection were reduced to 57%, 35%, and 7%, respectively. CONCLUSIONS. An intervention that included formation of a dedicated daily disinfection team and implementation of a standardized process for clearing CDI rooms achieved consistent CDI room disinfection. Culturing of CDI rooms provides a valuable tool to drive improvements in environmental disinfection.

  2. An environmental disinfection odyssey: evaluation of sequential interventions to improve disinfection of Clostridium difficile isolation rooms.

    PubMed

    Sitzlar, Brett; Deshpande, Abhishek; Fertelli, Dennis; Kundrapu, Sirisha; Sethi, Ajay K; Donskey, Curtis J

    2013-05-01

    OBJECTIVE. Effective disinfection of hospital rooms after discharge of patients with Clostridium difficile infection (CDI) is necessary to prevent transmission. We evaluated the impact of sequential cleaning and disinfection interventions by culturing high-touch surfaces in CDI rooms after cleaning. DESIGN. Prospective intervention. SETTING. A Veterans Affairs hospital. INTERVENTIONS. During a 21-month period, 3 sequential tiered interventions were implemented: (1) fluorescent markers to provide monitoring and feedback on thoroughness of cleaning facility-wide, (2) addition of an automated ultraviolet radiation device for adjunctive disinfection of CDI rooms, and (3) enhanced standard disinfection of CDI rooms, including a dedicated daily disinfection team and implementation of a process requiring supervisory assessment and clearance of terminally cleaned CDI rooms. To determine the impact of the interventions, cultures were obtained from CDI rooms after cleaning and disinfection. RESULTS. The fluorescent marker intervention improved the thoroughness of cleaning of high-touch surfaces (from 47% to 81% marker removal; P < .0001). Relative to the baseline period, the prevalence of positive cultures from CDI rooms was reduced by 14% (P=.024), 48% (P <.001), and 89% (P=.006) with interventions 1, 2, and 3, respectively. During the baseline period, 67% of CDI rooms had positive cultures after disinfection, whereas during interventions periods 1, 2, and 3 the percentages of CDI rooms with positive cultures after disinfection were reduced to 57%, 35%, and 7%, respectively. CONCLUSIONS. An intervention that included formation of a dedicated daily disinfection team and implementation of a standardized process for clearing CDI rooms achieved consistent CDI room disinfection. Culturing of CDI rooms provides a valuable tool to drive improvements in environmental disinfection. PMID:23571361

  3. Possible monitoring requirements for the disinfectants and disinfection by-products (D/DBP) regulations

    SciTech Connect

    Not Available

    1993-01-01

    The monitoring requirements presented in the report were developed by EPA before a negotiated Disinfectants and Disinfection By-Products (D/DBP) rule was considered. The framework described herein may be substantially changed as a result of the negotiated rulemaking process. The document is useful to consider in developing various monitoring options during the negotiated rulemaking process.

  4. Journey of water in pine cones

    PubMed Central

    Song, Kahye; Yeom, Eunseop; Seo, Seung-Jun; Kim, Kiwoong; Kim, Hyejeong; Lim, Jae-Hong; Joon Lee, Sang

    2015-01-01

    Pine cones fold their scales when it rains to prevent seeds from short-distance dispersal. Given that the scales of pine cones consist of nothing but dead cells, this folding motion is evidently related to structural changes. In this study, the structural characteristics of pine cones are studied on micro-/macro-scale using various imaging instruments. Raindrops fall along the outer scales to the three layers (bract scales, fibers and innermost lignified structure) of inner pine cones. However, not all the layers but only the bract scales get wet and then, most raindrops move to the inner scales. These systems reduce the amount of water used and minimize the time spent on structural changes. The result shows that the pine cones have structural advantages that could influence the efficient motion of pine cones. This study provides new insights to understand the motion of pine cones and would be used to design a novel water transport system. PMID:25944117

  5. Journey of water in pine cones

    NASA Astrophysics Data System (ADS)

    Song, Kahye; Yeom, Eunseop; Seo, Seung-Jun; Kim, Kiwoong; Kim, Hyejeong; Lim, Jae-Hong; Joon Lee, Sang

    2015-05-01

    Pine cones fold their scales when it rains to prevent seeds from short-distance dispersal. Given that the scales of pine cones consist of nothing but dead cells, this folding motion is evidently related to structural changes. In this study, the structural characteristics of pine cones are studied on micro-/macro-scale using various imaging instruments. Raindrops fall along the outer scales to the three layers (bract scales, fibers and innermost lignified structure) of inner pine cones. However, not all the layers but only the bract scales get wet and then, most raindrops move to the inner scales. These systems reduce the amount of water used and minimize the time spent on structural changes. The result shows that the pine cones have structural advantages that could influence the efficient motion of pine cones. This study provides new insights to understand the motion of pine cones and would be used to design a novel water transport system.

  6. Reproductive effects of alternative disinfectants

    SciTech Connect

    Carlton, B.D.; Barlett, P.; Basaran, A.; Colling, K.; Osis, I.; Smith, M.K.

    1986-11-01

    Organohalides formed through the reaction of chlorine and organic compounds in natural and waste waters pose potential health hazards. For this reason, alternative water disinfectants that do not form organohalides are being investigated with great interest. In this laboratory, the authors have examined the reproductive effects of chloramine and chlorine administered by gavage in Long-Evans rats. Animals were treated for a total of 66 to 76 days. Males were treated for 56 days and females for 14 days prior to breeding and throughout the 10-day breeding period. Females were treated throughout gestation and lactation. Following breeding, the males were necropsied and evaluated for sperm parameters and reproductive tract histopathology. Adult females and some pups were necropsied at weaning on postnatal day 21. Other pups were treated postweaning until 28 or 40 days of age. These pups were evaluated for the day of vaginal patency and thyroid hormone levels. No differences were observed between control rats and those rats exposed to up to 5 mg/kg/day chlorine or 10 mg/kg/day chloramine when fertility, viability, litter size, day of eye opening, or day of vaginal patency were evaluated. No alterations in sperm count, sperm direct progressive movement percent motility, or sperm morphology were observed among adult male rats. In addition, male and female reproductive organ weights were comparable to their respective control groups, and no significant histopathologic changes were observed among chlorine- or chloramine-treated male and female rats.

  7. Formation and Occurrence of Disinfection By-Products

    EPA Science Inventory

    Disinfection by-products (DBPs) are formed when disinfectants such as chlorine, ozone, chlorine dioxide, or chloramines react with naturally occurring organic matter, anthropogenic contaminants, bromide, and iodide during the production of drinking water. There is concern about D...

  8. Study and application of herbal disinfectants in China.

    PubMed

    Chen, Zhao-Bin

    2004-12-01

    Disinfection means killing or removing pathogenic microorganisms in media to realize a harmless process. A disinfectant, which is also referred to as a disinfection medicine in relevant regulations, is the medicine used to kill microorganisms for the purpose of disinfection. The disinfectants prepared from plants (including traditional Chinese herbal medicines) and the extracts thereof are called herbal disinfectants. China has a long history of using herbal disinfectants. As early as in 533 A.D., the use of Cornel to sterilize well water was recorded in Necessary Techniques for Qi People by Jia Enxie of the Beiwei Dynasty. During the Dragon Boat Festival, people often use fumigants made of traditional Chinese herbal medicines like Chinese Atractylodes, Argy Wormwood Leaf and Red Arsenic Sulfide to smoke their houses, so as to ward off plagues and drive away evils. In fact this is now a kind of disinfection practice.

  9. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE DISINFECTION BYPRODUCTS IN DRINKING WATER

    EPA Science Inventory

    This paper discusses the identification of organic disinfection byproducts (DBPs) at a pilot plant in Evansville, IN, which uses chlorine dioxide as a primary disinfectant. Unconventional multispectral identification techniques (gas chromatography combined with high- and low reso...

  10. The History And Future Directions Of Biosolids Disinfection

    EPA Science Inventory

    This paper reviews the history of disinfection practices, emphasizing their application to human fecal material and the residuals from wastewater treatment. It discusses development of the current US sewage sludge disinfection regulations and their associated practices; discusse...

  11. The History And Future Directions Of Biosolids Disinfection (Presentation)

    EPA Science Inventory

    This paper reviews the history of disinfection practices, emphasizing their application to human fecal material and the residuals from wastewater treatment. It discusses development of the current US sewage sludge disinfection regulations and their associated practices; discusse...

  12. Study and application of herbal disinfectants in China.

    PubMed

    Chen, Zhao-Bin

    2004-12-01

    Disinfection means killing or removing pathogenic microorganisms in media to realize a harmless process. A disinfectant, which is also referred to as a disinfection medicine in relevant regulations, is the medicine used to kill microorganisms for the purpose of disinfection. The disinfectants prepared from plants (including traditional Chinese herbal medicines) and the extracts thereof are called herbal disinfectants. China has a long history of using herbal disinfectants. As early as in 533 A.D., the use of Cornel to sterilize well water was recorded in Necessary Techniques for Qi People by Jia Enxie of the Beiwei Dynasty. During the Dragon Boat Festival, people often use fumigants made of traditional Chinese herbal medicines like Chinese Atractylodes, Argy Wormwood Leaf and Red Arsenic Sulfide to smoke their houses, so as to ward off plagues and drive away evils. In fact this is now a kind of disinfection practice. PMID:15745254

  13. DISINFECTION PROCESSES AND STABILITY REFINEMENTS TO BIOSOLIDS TREATMENT TECHNOLOGIES

    EPA Science Inventory

    This paper reviews the current US sewage sludge disinfection regulations and their associated practices; discusses the limitations of the practices; discusses the criteria employed in evaluating a new (innovative or alternative) disinfection process and both notes some processes ...

  14. PARTICLE ASSOCIATION EFFECTS ON MICROBIAL INDICATOR CONCENTRATIONS AND CSO DISINFECTION

    EPA Science Inventory

    Combined sewer overflow (CSO) and wastewater disinfection effectiveness are evaluated by measuring microbial indicator concentrations before and after disinfection. The standard techniques for quantifying indicators are membrane filtration and multiple-tube fermentation/most pro...

  15. [Evaluation of surface disinfectants utilized in dentistry].

    PubMed

    Silva, Célia Regina Gonçalves e; Jorge, Antonio Olavo Cardoso

    2002-01-01

    Surface disinfection is a procedure carried out on the external parts of the dental equipment as well as on other items of the dental office. The aim of this study was to analyze the efficacy of 4 surface disinfectants utilized in dentistry: 77 degrees GL alcohol, phenolic compound (Duplofen), iodophor (PVP-I) and 77 degrees GL alcohol with 5% of chlorhexidine. Four surfaces of the equipment were analyzed in the study (the carter, the washbasin for hand-washing, the headrest of the chair and the external surface of the reflector), and the spray-wipe-spray procedure was carried out. From each surface, samples were collected by means of surface plates containing Mitis Salivarius bacitracin sucrose agar, Sabouraud Dextrose agar with chloramphenicol, MacConkey agar and blood agar, for counting mutans streptococci, Candida yeasts, gram-negative bacteria and total microorganisms, respectively (ufc/plate). The results were statistically analyzed by means of the Student's t test in order to compare the mean ufc/plate values. The most effective disinfectant was 77 degrees GL alcohol with 5% of chlorhexidine, mainly against gram-positive bacteria. Iodophor and phenolic compound were also effective in microbial reduction. 77 degrees GL alcohol was the least effective product - however, although it is not considered as a surface disinfectant, it produced, in this study, statistically significant microbial reduction after the disinfecting procedure.

  16. Inside the cone of protection

    SciTech Connect

    Stahmann, J.R.

    1983-01-01

    Although lightning cones of protection and cones of attraction have been used for over 100 years, much confusion still remains as to their effectiveness, particularly as applied to personnel protection. At Kennedy Space Center, a 1:1 cone of protection with a straight side is standard for structure or equipment protection. However, at the launch pad, where a 400-foot lightning lightning rod on top of an insulating mast is used for pad lightning protection, the idea developed that personnel within a 400-foot radius of this mast would be safe from lightning and those outside it would not. Since it is obvious that a person 395 feet (120.4 m.) from the mast is only slightly safer than one at 405 feet (123.5 m.), an investigation was initiated to calculate the probabilities of a person being struck by lightning as he moves closer to the mast inside the cone of protection. Since the risk does not go to zero outside the structure, the risk level can then be estimated. To arrive at the expected strike frequency, it was necessary to measure the strike frequencies at KSC. Krider and others have found a mean area density of cloud-to-ground lightning at KSC of about 4.6 + or - 3.1 flashes per sq km per month in the summer. An overall frequency is estimated as about 20 flashes per sq km per year. With these data, the risk of exposure at various distances from the lightning mast can be calculated. Assuming continuous exposure during thunderstorms, this risk varies from about one strike per person in 1,400 years near the tower to one stroke per person in 300 years at about 400 foot (122 m.).

  17. Cardiac cone-beam CT

    SciTech Connect

    Manzke, Robert . E-mail: robert.manzke@philips.com

    2005-10-15

    This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net.

  18. Trends in sterilization and disinfection procedures in orthodontic offices.

    PubMed

    Cash, R G

    1990-10-01

    The present survey is a repetition of a 1987 survey examining the sterilization/disinfection procedures of Georgia's orthodontists. The purpose of this study is to examine the trends in orthodontic sterilization/disinfection procedures. Orthodontists in Georgia have dramatically changed their sterilization and disinfection procedures. The major changes represented are greater use of protective barrier wear by doctor and staff members; increased heat sterilization methods for instruments, pliers, and handpieces; and increased disinfection of alginate impressions.

  19. Prescriptionless light-cone integrals

    NASA Astrophysics Data System (ADS)

    Suzuki, A. T.; Schmidt, A. G. M.

    2000-01-01

    Perturbative quantum gauge field theory as seen within the perspective of physical gauge choices such as the light-cone gauge entails the emergence of troublesome poles of the type (k\\cdot n)^{-α} in the Feynman integrals. These come from the boson field propagator, where α = 1,2,\\cdots and n^{μ} is the external arbitrary four-vector that defines the gauge proper. This becomes an additional hurdle in the computation of Feynman diagrams, since any graph containing internal boson lines will inevitably produce integrands with denominators bearing the characteristic gauge-fixing factor. How one deals with them has been the subject of research over decades, and several prescriptions have been suggested and tried in the course of time, with failures and successes. However, a more recent development at this fronteer which applies the negative dimensional technique to compute light-cone Feynman integrals shows that we can altogether dispense with prescriptions to perform the calculations. An additional bonus comes to us attached to this new technique, in that not only it renders the light-cone prescriptionless but, by the very nature of it, it can also dispense with decomposition formulas or partial fractioning tricks used in the standard approach to separate pole products of the type (k\\cdot n)^{-α}[(k-p)\\cdot n]^{-β} (β = 1,2,\\cdots ). In this work we demonstrate how all this can be done.

  20. Bursting the Taylor cone bubble

    NASA Astrophysics Data System (ADS)

    Pan, Zhao; Truscott, Tadd

    2014-11-01

    A soap bubble fixed on a surface and placed in an electric field will take on the shape of a cone rather than constant curvature (dome) when the electrical field is not present. The phenomenon was introduced by J. Zeleny (1917) and studied extensively by C.T. Wilson & G.I. Taylor (1925). We revisit the Taylor cone problem by studying the deformation and bursting of soap bubbles in a point charge electric field. A single bubble takes on the shape of a cone in the electric field and a high-speed camera equipped with a micro-lens is used to observe the unsteady dynamics at the tip. Rupture occurs as a very small piece of the tip is torn away from the bubble toward the point charge. Based on experiments, a theoretical model is developed that predicts when rupture should occur. This study may help in the design of foam-removal techniques in engineering and provide a better understanding of an electrified air-liquid interface.

  1. An insight of disinfection by-product (DBP) formation by alternative disinfectants for swimming pool disinfection under tropical conditions.

    PubMed

    Yang, Linyan; Schmalz, Christina; Zhou, Jin; Zwiener, Christian; Chang, Victor W-C; Ge, Liya; Wan, Man Pun

    2016-09-15

    Sodium hypochlorite (NaClO) is the most commonly used disinfectant in pool treatment system. Outdoor pools usually suffer from the strong sunlight irradiation which degrades the free chlorine rapidly. In addition, more pools start to adopt the recirculation of swimming pool water, which intensifies the disinfection by-product (DBP) accumulation issue. Given these potential drawbacks of using NaClO in the tropical environment, two alternative organic-based disinfectants, trichloroisocyanuric acid (TCCA, C3Cl3N3O3) and bromochlorodimethylhydantoin (BCDMH, C5H6BrClN2O2), were investigated and compared to NaClO in terms of their self-degradation and the formation of DBPs, including trihalomethanes (THMs) and haloacetic acids (HAAs), under simulated tropical climate conditions. The result reveals that halogen stabilizer, TCCA, had the advantages of slower free chlorine degradation and lower DBP concentration compared to NaClO, which makes it a good alternative disinfectant. BCDMH was not recommended mainly due to the highly reactive disinfecting ingredient, hypobromous acid (HBrO), which fails to sustain the continuous disinfection requirement. Total disinfectant dosage was the main factor that affects residual chlorine/bromine and THM/HAA formation regardless of different disinfectant dosing methods, e.g. shock dosing (one-time spiking) in the beginning, and continuous dosing during the whole experimental period. Two-stage second-order-kinetic-based models demonstrate a good correlation between the measured and predicted data for chlorine decay (R(2) ≥ 0.95), THM (R(2) ≥ 0.99) and HAA (R(2) ≥ 0.83) formation. Higher temperature was found to enhance the DBP formation due to the temperature dependence of reaction rates. Thus, temperature control of pools, especially for those preferring higher temperatures (e.g. hydrotherapy and spa), should take both bather comfort and DBP formation potential into consideration. It is also observed that chlorine competition

  2. DETECTION OF INFECTIOUS ADENOVIRUS IN TERTIARY TREATED AND UV DISINFECTED WASTEWATER DURING A UV DISINFECTION PILOT STUDY

    EPA Science Inventory

    An infectious enteric adenovirus was isolated from urban wastewater receiving tertiary treatment and ultraviolet (UV) disinfection. A pilot study was undertaken to investigate the efficacy of UV disinfection (low pressure, high intensity radiation) of total and fecal coliform bac...

  3. Integrated Disinfection By-Products Mixtures Research: Disinfection of Drinking Waters by Chlorination and Ozonation/Postchlorination Treatment Scenarios

    EPA Science Inventory

    This article describes disinfection of the same source water by two commonly used disinfection treatment scenarios for purposes of subsequent concentration, chemical analysis, and toxicological evaluation. Accompanying articles in this issue of the Journal of Toxicology and Envir...

  4. Organization of the human trichromatic cone mosaic.

    PubMed

    Hofer, Heidi; Carroll, Joseph; Neitz, Jay; Neitz, Maureen; Williams, David R

    2005-10-19

    Using high-resolution adaptive-optics imaging combined with retinal densitometry, we characterized the arrangement of short- (S), middle- (M), and long- (L) wavelength-sensitive cones in eight human foveal mosaics. As suggested by previous studies, we found males with normal color vision that varied in the ratio of L to M cones (from 1.1:1 to 16.5:1). We also found a protan carrier with an even more extreme L:M ratio (0.37:1). All subjects had nearly identical S-cone densities, indicating independence of the developmental mechanism that governs the relative numerosity of L/M and S cones. L:M cone ratio estimates were correlated highly with those obtained in the same eyes using the flicker photometric electroretinogram (ERG), although the comparison indicates that the signal from each M cone makes a larger contribution to the ERG than each L cone. Although all subjects had highly disordered arrangements of L and M cones, three subjects showed evidence for departures from a strictly random rule for assigning the L and M cone photopigments. In two retinas, these departures corresponded to local clumping of cones of like type. In a third retina, the L:M cone ratio differed significantly at two retinal locations on opposite sides of the fovea. These results suggest that the assignment of L and M pigment, although highly irregular, is not a completely random process. Surprisingly, in the protan carrier, in which X-chromosome inactivation would favor L- or M-cone clumping, there was no evidence of clumping, perhaps as a result of cone migration during foveal development. PMID:16237171

  5. Studies on Disinfection By-Products and Drinking Water

    USGS Publications Warehouse

    Rostad, Colleen E.

    2007-01-01

    Drinking water is disinfected with chemicals to remove pathogens, such as Giardia and Cryptosproridium, and prevent waterborne diseases such as cholera and typhoid. During disinfection, by-products are formed at trace concentrations. Because some of these by-products are suspected carcinogens, drinking water utilities must maintain the effectiveness of the disinfection process while minimizing the formation of by-products.

  6. MODELING DISINFECTANT RESIDUALS IN DRINKING-WATER STORAGE TANKS

    EPA Science Inventory

    The factors leading to the loss of disinfectant residual in well-mixed drinking-water storage tanks are studied. Equations relating disinfectant residual to the disinfectant's reation rate, the tank volume, and the fill and drain rates are presented. An analytical solution for ...

  7. Proteomic Adaptations to Starvation Prepare Escherichia coli for Disinfection Tolerance

    PubMed Central

    Du, Zhe; Nandakumar, Renu; Nickerson, Kenneth; Li, Xu

    2015-01-01

    Despite the low nutrient level and constant presence of secondary disinfectants, bacterial re-growth still occurs in drinking water distribution systems. The molecular mechanisms that starved bacteria use to survive low-level chlorine-based disinfectants are not well understood. The objective of this study is to investigate these molecular mechanisms at the protein level that prepare starved cells for disinfection tolerance. Two commonly used secondary disinfectants chlorine and monochloramine, both at 1 mg/L, were used in this study. The proteomes of normal and starved Escherichia coli (K12 MG1655) cells were studied using quantitative proteomics. Over 60-min disinfection, starved cells showed significantly higher disinfection tolerance than normal cells based on the inactivation curves for both chlorine and monochloramine. Proteomic analyses suggest that starvation may prepare cells for the oxidative stress that chlorine-based disinfection will cause by affecting glutathione metabolism. In addition, proteins involved in stress regulation and stress responses were among the ones up-regulated under both starvation and chlorine/monochloramine disinfection. By comparing the fold changes under different conditions, it is suggested that starvation prepares E. coli for disinfection tolerance by increasing the expression of enzymes that can help cells survive chlorine/monochloramine disinfection. Protein co-expression analyses show that proteins in glycolysis and pentose phosphate pathway that were up-regulated under starvation are also involved in disinfection tolerance. Finally, the production and detoxification of methylglyoxal may be involved in the chlorine-based disinfection and cell defense mechanisms. PMID:25463932

  8. THE TOXICOLOGY OF COMPLEX MIXTURES OF DISINFECTION BY-PRODUCTS

    EPA Science Inventory

    Chemical disinfection of water is a major public health advance that has decreased dramatically water-borne disease. Chemical disinfectants react with naturally occurring organic and inorganic matter in water to produce a wide variety of disinfection byproducts (DBPs). DBP num...

  9. A Toxicological Perspective on Disinfection ByProducts

    EPA Science Inventory

    Disinfection of water is essential for reduction of microbes harmful to human health and chemical disinfection is considered one of the major public health triumphs of the 20th Century. An unintended consequence of disinfection with oxidizing chemicals is formation of disinfectio...

  10. 21 CFR 880.6890 - General purpose disinfectants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false General purpose disinfectants. 880.6890 Section... Miscellaneous Devices § 880.6890 General purpose disinfectants. (a) Identification. A general purpose disinfectant is a germicide intended to process noncritical medical devices and equipment surfaces. A...

  11. 21 CFR 880.6890 - General purpose disinfectants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false General purpose disinfectants. 880.6890 Section... Miscellaneous Devices § 880.6890 General purpose disinfectants. (a) Identification. A general purpose disinfectant is a germicide intended to process noncritical medical devices and equipment surfaces. A...

  12. 21 CFR 880.6890 - General purpose disinfectants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false General purpose disinfectants. 880.6890 Section... Miscellaneous Devices § 880.6890 General purpose disinfectants. (a) Identification. A general purpose disinfectant is a germicide intended to process noncritical medical devices and equipment surfaces. A...

  13. 21 CFR 880.6890 - General purpose disinfectants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false General purpose disinfectants. 880.6890 Section... Miscellaneous Devices § 880.6890 General purpose disinfectants. (a) Identification. A general purpose disinfectant is a germicide intended to process noncritical medical devices and equipment surfaces. A...

  14. 21 CFR 880.6890 - General purpose disinfectants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false General purpose disinfectants. 880.6890 Section... Miscellaneous Devices § 880.6890 General purpose disinfectants. (a) Identification. A general purpose disinfectant is a germicide intended to process noncritical medical devices and equipment surfaces. A...

  15. Environmental health perspectives. Volume 46. Drinking water disinfectants - December 1982

    SciTech Connect

    Lucier, G.W.; Hook, G.E.R.

    1982-01-01

    Among subjects considered are chlorine dioxide, N-chloramines, mutagenic activity by disinfectant reaction products, trihalomethane and behavioral toxicity, and carcinogenic risk estimation. There are 27 papers on these and related topics. The volume stems from a symposium on drinking water disinfectants and disinfectant by-products.

  16. OPTIMAL SCHEDULING OF BOOSTER DISINFECTION IN WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    Booster disinfection is the addition of disinfectant at locations distributed throughout a water distribution system. Such a strategy can reduce the mass of disinfectant required to maintain a detectable residual at points of consumption in the distribution system, which may lea...

  17. 9 CFR 91.41 - Cleaning and disinfecting of aircraft.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfecting of aircraft... INSPECTION AND HANDLING OF LIVESTOCK FOR EXPORTATION Cleaning and Disinfecting of Aircraft § 91.41 Cleaning and disinfecting of aircraft. Prior to loading of animals, the stowage area of aircraft to be used...

  18. 9 CFR 91.41 - Cleaning and disinfecting of aircraft.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Cleaning and disinfecting of aircraft... INSPECTION AND HANDLING OF LIVESTOCK FOR EXPORTATION Cleaning and Disinfecting of Aircraft § 91.41 Cleaning and disinfecting of aircraft. Prior to loading of animals, the stowage area of aircraft to be used...

  19. 9 CFR 91.41 - Cleaning and disinfecting of aircraft.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Cleaning and disinfecting of aircraft... INSPECTION AND HANDLING OF LIVESTOCK FOR EXPORTATION Cleaning and Disinfecting of Aircraft § 91.41 Cleaning and disinfecting of aircraft. Prior to loading of animals, the stowage area of aircraft to be used...

  20. Disinfection of hospital wastewater by continuous ozonization.

    PubMed

    Chiang, Chow-Feng; Tsai, Ching-Tsan; Lin, Shaw-Tao; Huo, Chun-Pao; Lo, Kwang Victor

    2003-01-01

    The disinfection of hospital wastewaters using the ozonization process was studied. The concentrations of ozone required to reach a sudden drop of coliform and Pseudomonas aeruginosa in the wastewater are 4.0-7.0 and 3.0-5.0 mg L(-1), respectively. For the hospital wastewater, the disinfection efficiencies were 0.518S(-1.1) for coliforms, 0.509S(-1.06) for Pseudomonas aeruginosa and 0.254S-(1.54) for total count, respectively. As to the effects of ozone input methods on the disinfection efficiency, the continuous ozonization process was ten times higher than the batch input process. The low COD removal rate was obtained at 25.0 mgL(-1) of ozone concentration for hospital wastewater. However, more biodegradable compounds resulted in the treated mixture.

  1. Antiseptics and Disinfectants: Activity, Action, and Resistance

    PubMed Central

    McDonnell, Gerald; Russell, A. Denver

    1999-01-01

    Antiseptics and disinfectants are extensively used in hospitals and other health care settings for a variety of topical and hard-surface applications. A wide variety of active chemical agents (biocides) are found in these products, many of which have been used for hundreds of years, including alcohols, phenols, iodine, and chlorine. Most of these active agents demonstrate broad-spectrum antimicrobial activity; however, little is known about the mode of action of these agents in comparison to antibiotics. This review considers what is known about the mode of action and spectrum of activity of antiseptics and disinfectants. The widespread use of these products has prompted some speculation on the development of microbial resistance, in particular whether antibiotic resistance is induced by antiseptics or disinfectants. Known mechanisms of microbial resistance (both intrinsic and acquired) to biocides are reviewed, with emphasis on the clinical implications of these reports. PMID:9880479

  2. Fundamental conical defects: The d-cone, its e-cone, and its p-cone

    NASA Astrophysics Data System (ADS)

    Seffen, Keith A.

    2016-07-01

    We consider well-known surface disclinations by cutting, joining, and folding pieces of paper card. The resulting shapes have a discrete, folded vertex whose geometry is described easily by Gauss's mapping, in particular, we can relate the degree of angular excess, or deficit, to the size of fold line rotations by the area enclosed by the vector diagram of these rotations. This is well known for the case of a so-called "d-cone" of zero angular deficit, and we formulate the same for a general disclination. This method allows us to observe kinematic properties in a meaningful way without needing to consider equilibrium. Importantly, the simple vector nature of our analysis shows that some disclinations are primitive; and that other types, such as d-cones, are amalgamations of them.

  3. Fundamental conical defects: The d-cone, its e-cone, and its p-cone.

    PubMed

    Seffen, Keith A

    2016-07-01

    We consider well-known surface disclinations by cutting, joining, and folding pieces of paper card. The resulting shapes have a discrete, folded vertex whose geometry is described easily by Gauss's mapping, in particular, we can relate the degree of angular excess, or deficit, to the size of fold line rotations by the area enclosed by the vector diagram of these rotations. This is well known for the case of a so-called "d-cone" of zero angular deficit, and we formulate the same for a general disclination. This method allows us to observe kinematic properties in a meaningful way without needing to consider equilibrium. Importantly, the simple vector nature of our analysis shows that some disclinations are primitive; and that other types, such as d-cones, are amalgamations of them. PMID:27575208

  4. Sensitivity to disinfection of bacterial indicator organisms for monitoring the Salmonella Enteritidis status of layer farms after cleaning and disinfection.

    PubMed

    Dewaele, I; Ducatelle, R; Herman, L; Heyndrickx, M; De Reu, K

    2011-06-01

    The present study evaluated Escherichia coli, Enterococcus faecalis, and Enterococcus hirae as potential indicator organisms for the possible Salmonella Enteritidis (SE) presence in layer farms after cleaning and disinfection by comparing their susceptibility to disinfection. A quantitative suspension disinfection test according to European Standard EN1656 was performed using disinfection products CID20 and Virocid (both from CID Lines, Ieper, Belgium). In a preliminary test, the sensitivity to both disinfection products was compared between ATCC strains of SE, E. coli, En. faecalis, and En. hirae. The sensitivity of SE to disinfection was most comparable to that of E. coli. A second disinfection test compared the elimination of E. coli to SE ATCC strains as well as field strains. Results showed no significant effect regarding the strain (P > 0.05 for CID20 and Virocid), meaning that no difference was detected in sensitivity toward disinfection. When comparing the sensitivity in general at species level for all concentrations of disinfectant used, no significant difference was found between E. coli and SE in sensitivity to Virocid (P > 0.05). In conclusion, because of its similar response to disinfection in a suspension disinfection test, E. coli could be used as an indicator for possible Salmonella presence after cleaning and disinfection.

  5. [New antiseptics and disinfectants in surgery (2)].

    PubMed

    Pkhakadze TYa; Bogomolova, N S; Vinogradova, L N

    1996-01-01

    Various forms of plivasept, an agent produced by Pliva (Croatia), were studied in the laboratory and clinic and found to be highly effective. For the prevention of intrahospital infections the use of 0.02% and 0.05% water solutions of plivasept without PAV is advisable as an antiseptec for inyracavitary administration, 0.05% water solution of plivasept for disinfection of surfaces and equipment, 0.5% alcohol plivasept solution for disinfection of instruments, a plivasept tincture for surgical treatment of the skin on the hands and the injection and operative fields, and foam-forming plivasept for hygienic treatment of the hands.

  6. [Sterilization and disinfection in clinical orthodontics].

    PubMed

    Uzel, I; Haydar, B

    1989-11-01

    Recently a great deal of attention has been devoted to the spread of hepatitis b and aids viruses and the high risk of contamination of these viruses during the dental operations has made orthodontists more aware of the necessity of sterilization and disinfection. This article discusses the methods of sterilization and disinfection. Avoidance of corrosion of instruments and the use of a ultrasonic cleaner to avoid contamination has been explained. In the conclusion the measures that the orthodontist has to take in order to protect himself is discussed.

  7. Disinfectants to Fight Oral Candida Biofilms.

    PubMed

    Rodrigues, M Elisa; Henriques, Mariana; Silva, Sónia

    2016-01-01

    Oral biofilms, especially those caused by oral mycobiota, which include Candida species, are very difficult to eradicate, due to their complex structure and recalcitrance. Moreover, the mouth is prone to be colonized since it presents different types of surfaces, especially biomaterials and dental implants, often associated with a high rate of infections. Therefore, although disinfection of the oral cavity is of major importance, the number of commercially available disinfectants is not high. However, new solutions, as silver nanoparticles are being developed to help oral biofilms' eradication. PMID:27271679

  8. Disinfectants to Fight Oral Candida Biofilms.

    PubMed

    Rodrigues, M Elisa; Henriques, Mariana; Silva, Sónia

    2016-01-01

    Oral biofilms, especially those caused by oral mycobiota, which include Candida species, are very difficult to eradicate, due to their complex structure and recalcitrance. Moreover, the mouth is prone to be colonized since it presents different types of surfaces, especially biomaterials and dental implants, often associated with a high rate of infections. Therefore, although disinfection of the oral cavity is of major importance, the number of commercially available disinfectants is not high. However, new solutions, as silver nanoparticles are being developed to help oral biofilms' eradication.

  9. Isolating prompt photons with narrow cones

    NASA Astrophysics Data System (ADS)

    Catani, S.; Fontannaz, M.; Guillet, J. Ph.; Pilon, E.

    2013-09-01

    We discuss the isolation of prompt photons in hadronic collisions by means of narrow isolation cones and the QCD computation of the corresponding cross sections. We reconsider the occurence of large perturbative terms with logarithmic dependence on the cone size and their impact on the fragmentation scale dependence. We cure the apparent perturbative violation of unitarity for small cone sizes, which had been noticed earlier in next-to-leading-order (NLO) calculations, by resumming the leading logarithmic dependence on the cone size. We discuss possible implications regarding the implementation of some hollow cone variants of the cone criterion, which simulate the experimental difficulty to impose isolation inside the region filled by the electromagnetic shower that develops in the calorimeter.

  10. Cone Penetrometer Off-Surface Sensor

    SciTech Connect

    Smail, T.R.; French, p.J.; Huffman, R.K.; Hebert, P.S.

    1999-10-20

    Cone penetrometer technology accounts for approximately 50 percent of the subsurface drilling done at the Savannah River Site. This technology provides a means of collecting data for use in the characterization of the subsurface. The cone penetrometer consists of a steel cone attached to a pipe column that is hydraulically inserted into the ground. To allow researchers to accurately measure subsurface properties, without the inherent problems of cone penetrometer equipment, the Savannah River Technology Center has developed the Cone Penetrometer Off-Surface Sensor (CPOSS). The CPOSS design consists of a knife-blade mechanism mounted along the surface of a module capable of attaching to existing cone penetrometer equipment and being deployed at depths of up to 200 feet. CPOSS development is the subject of this report.

  11. Cleaning and disinfection of blenders used in hospital kitchens.

    PubMed

    Anderton, A; Aidoo, K E

    1991-03-01

    The efficiency of a range of methods used to clean and disinfect blenders was compared. Blenders with metal, plastic and glass goblets were experimentally contaminated with Klebsiella aerogenes after which they were cleaned and disinfected by (a) cold water rinse, (b) detergent wash, (c) detergent wash and disinfectant soak, (d) detergent wash and boiling water rinse and (e) autoclaving. Autoclaving was the only procedure that sterilized the blenders but this could only be used for blenders with metal goblets. A detergent wash with or without chemical disinfection followed by a boiling water rinse was found to be the most effective method of cleaning and disinfecting all three types of blender.

  12. Cone opsins, colour blindness and cone dystrophy: Genotype-phenotype correlations.

    PubMed

    Gardner, J C; Michaelides, M; Hardcastle, A J

    2016-05-25

    X-linked cone photoreceptor disorders caused by mutations in the OPN1LW (L) and OPN1MW (M) cone opsin genes on chromosome Xq28 include a range of conditions from mild stable red-green colour vision deficiencies to severe cone dystrophies causing progressive loss of vision and blindness. Advances in molecular genotyping and functional analyses of causative variants, combined with deep retinal phenotyping, are unravelling genetic mechanisms underlying the variability of cone opsin disorders.

  13. Disinfecting efficacy of three chemical disinfectants on contaminated diagnostic instruments: A randomized trial

    PubMed Central

    Ganavadiya, Rahul; Chandra Shekar, B.R.; Saxena, Vrinda; Tomar, Poonam; Gupta, Ruchika; Khandelwal, Garima

    2014-01-01

    Context: Cross infection remains one of the major challenges in the dental profession, especially in field settings. Transmission of hepatitis B, hepatitis C, and human immunodeficiency virus have raised a major concern for patients and dental staff. These risks can be eliminated by effective sterilization and disinfection techniques. Aim: The aim was to compare the disinfecting efficacy of three chemical disinfectants on contaminated diagnostic instruments. Settings and Design: This was a randomized, cross over trial conducted among three participants selected from a research laboratory, Bhopal, Madhya Pradesh, India. Materials and Methods: The study participants were examined 4 times on different days. Each time, the coded mouth mirrors of different make were used, and the disinfection was accomplished using coded disinfectants. The reduction in total viable count was compared between the three groups (2% glutaraldehyde, 6% hydrogen peroxide (H2O2) and 99.9% ethyl alcohol) with distilled water as negative control and autoclaving as a positive control. Furthermore, the predisinfection count was compared between the instruments of different make. Statistical Analysis Used: Statistical analysis was performed using paired t-test and One-way ANOVA. The statistical significance was fixed at 0.05. Results: Autoclaved instruments resulted in complete elimination of viable micro-organisms. Maximum reduction in microbial load was observed after disinfection with H2O2 followed by glutaraldehyde, ethyl alcohol and distilled water in descending order. Furthermore, maximum microbial contamination was recorded on locally manufactured mirrors, while standard plain mirrors showed least contamination. Conclusions: Although, a significant reduction in total viable count was observed with all the disinfectants evaluated in the present study, none of the disinfectants was successful in completely eliminating the viable micro-organisms. PMID:25316989

  14. Ionic emission from Taylor cones

    NASA Astrophysics Data System (ADS)

    Castro Reina, Sergio

    Electrified Taylor cones have been seen as an efficient way to generate thrust for space propulsion. Especially the pure ionic regime (PIR) combines a very high specific impulse (thrust per unit mass) and efficiency, which is very important to reduce fuel transportation costs. The PIR has been primarily based on electrosprays of liquid metals [Swatik and Hendricks 1968, Swatik 1969]. However, emissions dominated by or containing exclusively ions have also been observed from nonmetallic purely ionic substances, initially sulfuric acid [Perel et al. 1969], and more recently room temperature molten salts referred to as ionic liquids (ILs) [Romero-Sanz et al. 2003]. The recent use of the liquid metal ion source (LMIS) with ILs, becoming this "new" source to be known as ionic liquid ion source (ILIS) [Lozano and Martinez-Sanchez 2005], has shown important differences on the emission from Taylor cones with the traditional hollow capillary. This new source seems to be more flexible than the capillary [Paulo, Sergio, carlos], although its low emission level (low thrust) is an important drawback from the space propulsion point of view. Throughout the thesis I have studied some aspects of the ionic emission from ionic liquid Taylor cones and the influence of the properties of the liquids and the characteristic of source on the emission. I have unraveled the reason why ILIS emits such low currents (˜200 nA) and found a way to solve this problem increasing the current up to capillary levels (˜1000 nA) [Castro and Fernandez de la Mora 2009]. I have also tried to reduce ion evaporation while reducing the emitted droplet size in order to increase the thrust generated while keeping the efficiency relatively high and I have measured the energy of evaporation of several cations composing ionic liquids, mandatory step to understand ionic evaporation.

  15. [Test methods for surgical hand disinfection (author's transl)].

    PubMed

    Reber, H; Müntener, M; Neck, K; Lips, U

    1975-08-01

    As exemplified by a test preparation, methods for assessing the effect of hand disinfection on the resident flora are put up for discussion. The test of a method for hand disinfection must make allowance for conditions prevailing in practice. Accordingly, the following steps should be taken into consideration: A. Single use 1. Immediate disinfecting effect 2. Duration of the disinfecting effect B. Repeated use 3. Course of the initial colony count 4. Immediate disinfecting effect 5. Behaviour of colony count after interruption of the disinfecting method applied. For the purpose of comparing the total count, as with all other disinfecting methods, the colony count must be determined by fractional collection methods; to this end, Traub's procedure may be modified, possibly using the plastic bag method described by Gaschen. A careful statistical evaluation with appropriate transformation of the results is indispensable.

  16. Ultraviolet disinfection of effluent from subsurface flow constructed wetlands.

    PubMed

    Richter, A Y; Weaver, R W

    2003-09-01

    Subsurface flow constructed wetlands are becoming increasingly common for on-site treatment of domestic wastewater. Before spray application, wetland effluent must be disinfected. Traditionally, tablet chlorination has been used, but an alternative is needed to increase dependability. Consequently, we investigated the use of ultraviolet light disinfection of effluent from constructed wetlands. Two low pressure (254 nm) and two medium pressure ultraviolet bulbs (190 to 400 nm) were used for disinfection. Upon installation, all units disinfected effluent successfully. After 2 weeks in operation, three of the four units did not reduce fecal coliform populations below 200 in 100 ml of effluent due to decreased light intensity from films that developed on the bulbs. One unit consistently disinfected water to populations lower than 200 in 100 ml for 1 year without maintenance. Ultraviolet disinfection, as utilized, was not consistently suitable for disinfection of effluent from subsurface flow constructed wetlands because of coatings that developed on the bulbs and blocked the light.

  17. Nested-cone transformer antenna

    DOEpatents

    Ekdahl, C.A.

    1991-05-28

    A plurality of conical transmission lines are concentrically nested to form an output antenna for pulsed-power, radio-frequency, and microwave sources. The diverging conical conductors enable a high power input density across a bulk dielectric to be reduced below a breakdown power density at the antenna interface with the transmitting medium. The plurality of cones maintain a spacing between conductors which minimizes the generation of high order modes between the conductors. Further, the power input feeds are isolated at the input while enabling the output electromagnetic waves to add at the transmission interface. Thus, very large power signals from a pulse rf, or microwave source can be radiated. 6 figures.

  18. Nested-cone transformer antenna

    DOEpatents

    Ekdahl, Carl A.

    1991-01-01

    A plurality of conical transmission lines are concentrically nested to form n output antenna for pulsed-power, radio-frequency, and microwave sources. The diverging conical conductors enable a high power input density across a bulk dielectric to be reduced below a breakdown power density at the antenna interface with the transmitting medium. The plurality of cones maintain a spacing between conductors which minimizes the generation of high order modes between the conductors. Further, the power input feeds are isolated at the input while enabling the output electromagnetic waves to add at the transmission interface. Thus, very large power signals from a pulse rf, or microwave source can be radiated.

  19. USE OF FENTON'S REAGENT AS A DISINFECTANT

    EPA Science Inventory

    Combined sewage samples obtained from a wastewater treatment facility were disinfected by the Fenton's Reagent of several different compositions. The pre-settled samples contained both suspended solids (SS) and dissolved organic carbon (DOC) at concentrations of 28 and 290 mg/L,...

  20. Effective household disinfection methods of kitchen sponges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several household disinfecting treatments to kill bacteria, yeasts and molds on kitchen sponges were evaluated. Sponges were soaked in 10 percent bleach for 3 min, lemon juice (pH 2.9) or deionized water for 1 min; placed in a microwave oven for 1 min; or placed in a dishwasher operating with a dryi...

  1. Effective disinfection methods of kitchen sponges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pathogenic foodborne bacteria can be disseminated in households through the use of contaminated sponges. Several household disinfecting treatments to kill bacteria, yeasts and molds on sponges were evaluated. Sponges were incubated in a suspension of ground beef and tryptic soy broth to develop bact...

  2. DISINFECTION: CHLORINE, MONOCHLORAMINE, AND CHLORINE DIOXIDE

    EPA Science Inventory

    The disinfection process in the treatment of water is designed to insure the inactivation of microbial pathogens. These pathogens which serve as the etiological agents of waterborne disease comprise a diverse group of microorganisms, which include bacterial, viral and protozoan s...

  3. Microbial contamination and disinfection methods of pacifiers

    PubMed Central

    NELSON, Paulo; LOUVAIN, Márcia Costa; MACARI, Soraia; LUCISANO, Marília Pacífico; da SILVA, Raquel Assed Bezerra; de QUEIROZ, Alexandra Mussolino; GATON-HERNÁNDEZ, Patrícia; da SILVA, Léa Assed Bezerra

    2015-01-01

    Objectives To evaluate the microbial contamination of pacifiers by Mutans Streptococci (MS) and the efficacy of different methods for their disinfection. Methods Twenty-eight children were assigned to a 4-stage changeover system with a 1-week interval. In each stage, children received a new pacifier and the parents were instructed to maintain their normal habits for 1 week. After this time, the pacifiers were subjected to the following 4 disinfection methods: spraying with 0.12% chlorhexidine solution, Brushtox® or sterile tap water, and immersion in boiling tap water for 15 minutes. Microbiological culture for MS and Scanning Electron Microscopy (SEM) were performed. The results were analyzed statistically by Friedman’s non-parametric test (a=0.05). Results The 0.12% chlorhexidine spray was statistically similar to the boiling water (p>0.05) and more effective than the Brushtox® spray and control (p<0.05). The analysis of SEM showed the formation of a cariogenic biofilm in all groups with positive culture. Conclusions Pacifiers become contaminated by MS after their use by children and should be disinfected routinely. Spraying with a 0.12% chlorhexidine solution and immersion in boiling water promoted better disinfection of the pacifiers compared with a commercial antiseptic toothbrush cleanser (Brushtox®). PMID:26537723

  4. Disinfection of water distribution systems for Legionella.

    PubMed

    Lin, Y S; Stout, J E; Yu, V L; Vidic, R D

    1998-06-01

    Hospital-acquired legionnaires' disease arises from the presence of Legionella in hospital water systems. Legionella not only persists in hot water tanks but is also found in the biofilm throughout the entire water distribution system. Conditions within water systems that promote Legionella colonization include water temperature, configuration and age of the hot water tank, physicochemical constituents of the water, plumbing materials, and commensal microflora. Hospital-acquired legionnaires' disease has been prevented by instituting control measures directed at the water distribution system. These include superheat-and-flush, copper/silver ionization, ultraviolet light, instantaneous heating systems, and hyperchlorination. Each of the above disinfection methods has been proven to be effective in the short-term, but long-term efficacy has been difficult due to limitations associated with each method. The complexities of Legionella disinfection, including advantages and disadvantages of each method, are reviewed. A successful Legionella prevention program requires cooperation and communication among hospital administrative personnel, engineers, and infection control staff. Routine environmental surveillance cultures for Legionella are the critical component for successful long-term disinfection. Culture results document the efficacy of the disinfection method and alert the hospital staff to consider Legionella in hospitalized patients with pneumonia. PMID:9643393

  5. 40 CFR 141.72 - Disinfection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration... heterotrophic bacteria plate count (HPC) is measured; c=number of instances where the residual disinfectant... system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured...

  6. 40 CFR 141.72 - Disinfection.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration... heterotrophic bacteria plate count (HPC) is measured; c=number of instances where the residual disinfectant... system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured...

  7. Identification of appropriate cone length to avoid positive cone margin in high grade cervical intraepithelial neoplasia

    PubMed Central

    Tsuda, Naotake; Nishio, Shin; Ushijima, Kimio

    2016-01-01

    Objective To identify key factors for predicting positive cone margin and appropriate cone length. Methods We retrospectively reviewed the margin status of patients who received conization with high grade cervical intraepithelial neoplasia, along with other factors such as patient age, parity, preoperative cytology, size of disease, type of transformation zone, and cone length from patient records. Cut-off value of cone length was analyzed in women younger than 40 years old because we design conization with minimum length especially for women who wish for future pregnancy. Cut-off value of cone length was defined as length corresponds to estimated probability of positive cone margin equal to 0.1 by logistic regression analysis with variables selected by stepwise methods. Results Among 300 patients, 75 patients had positive cone margin. Multivariable analysis revealed that squamous cell carcinoma at preoperative cytology (p=0.001), 2 or more quadrant disease (p=0.011), and shorter cone length (p<0.001) were risk factors for positive cone margin. Stepwise methods identified cone length and size of lesion as important variables. With this condition, cut-off value of cone length was estimated as 15 mm in single quadrant disease and 20 mm in 2 or more quadrant disease, respectively. Conclusion We identified the independent risk factors of positive cone margin and identified the cut-off value of cone length to avoid positive cone margin in women younger than 40 years old. Conization should be performed not only according to colposcopic findings including type of transformation zone but size of disease and cone length. PMID:27401478

  8. The structure and emplacement of cinder cone fields

    NASA Technical Reports Server (NTRS)

    Settle, M.

    1979-01-01

    The paper examines the structure and emplacement of cinder cone fields. Terrestrial cinder cone fields occur in volcanic provinces upon the flanks of major volcanoes or within relatively flat-lying volcanic fields. Measurements of cone shape and distribution were made in three volcano cone fields and three platform cone fields, and it was found that modal average values of cone basal diameter are on the order of 300 to 400 m within volcano cone fields and 900 to 1000 m within platform cone fields. The average morphometric parameters for the six fields indicate that cone diameter is positively correlated with cone separation distance, and that the size and spacing of cinder cones formed on the flanks of volcanoes is less than the size and spacing of cones constructed in volcanic fields.

  9. Efficacy of various disinfectants against SARS coronavirus.

    PubMed

    Rabenau, H F; Kampf, G; Cinatl, J; Doerr, H W

    2005-10-01

    The recent severe acute respiratory syndrome (SARS) epidemic in Asia and Northern America led to broad use of various types of disinfectant in order to control the public spread of the highly contagious virus. However, only limited data were available to demonstrate their efficacy against SARS coronavirus (SARS-CoV). We therefore investigated eight disinfectants for their activity against SARS-CoV according to prEN 14476. Four hand rubs were tested at 30s (Sterillium, based on 45% iso-propanol, 30% n-propanol and 0.2% mecetronium etilsulphate; Sterillium Rub, based on 80% ethanol; Sterillium Gel, based on 85% ethanol; Sterillium Virugard, based on 95% ethanol). Three surface disinfectants were investigated at 0.5% for 30 min and 60 min (Mikrobac forte, based on benzalkonium chloride and laurylamine; Kohrsolin FF, based on benzalkonium chloride, glutaraldehyde and didecyldimonium chloride; Dismozon pur, based on magnesium monoperphthalate), and one instrument disinfectant was investigated at 4% for 15 min, 3% for 30 min and 2% for 60 min [Korsolex basic, based on glutaraldehyde and (ethylenedioxy)dimethanol]. Three types of organic load were used: 0.3% albumin, 10% fetal calf serum, and 0.3% albumin with 0.3% sheep erythrocytes. Virus titres were determined by a quantitative test (endpoint titration) in 96-well microtitre plates. With all tested preparations, SARS-CoV was inactivated to below the limit of detection (reduction factor mostly > or =4), regardless of the type of organic load. In summary, SARS-CoV can be inactivated quite easily with many commonly used disinfectants.

  10. Panoramic cone beam computed tomography

    SciTech Connect

    Chang Jenghwa; Zhou Lili; Wang Song; Clifford Chao, K. S.

    2012-05-15

    Purpose: Cone-beam computed tomography (CBCT) is the main imaging tool for image-guided radiotherapy but its functionality is limited by a small imaging volume and restricted image position (imaged at the central instead of the treatment position for peripheral lesions to avoid collisions). In this paper, the authors present the concept of ''panoramic CBCT,'' which can image patients at the treatment position with an imaging volume as large as practically needed. Methods: In this novel panoramic CBCT technique, the target is scanned sequentially from multiple view angles. For each view angle, a half scan (180 deg. + {theta}{sub cone} where {theta}{sub cone} is the cone angle) is performed with the imaging panel positioned in any location along the beam path. The panoramic projection images of all views for the same gantry angle are then stitched together with the direct image stitching method (i.e., according to the reported imaging position) and full-fan, half-scan CBCT reconstruction is performed using the stitched projection images. To validate this imaging technique, the authors simulated cone-beam projection images of the Mathematical Cardiac Torso (MCAT) thorax phantom for three panoramic views. Gaps, repeated/missing columns, and different exposure levels were introduced between adjacent views to simulate imperfect image stitching due to uncertainties in imaging position or output fluctuation. A modified simultaneous algebraic reconstruction technique (modified SART) was developed to reconstruct CBCT images directly from the stitched projection images. As a gold standard, full-fan, full-scan (360 deg. gantry rotation) CBCT reconstructions were also performed using projection images of one imaging panel large enough to encompass the target. Contrast-to-noise ratio (CNR) and geometric distortion were evaluated to quantify the quality of reconstructed images. Monte Carlo simulations were performed to evaluate the effect of scattering on the image quality and

  11. 40 CFR 141.543 - How is the disinfection benchmark calculated?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false How is the disinfection benchmark... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.543 How is the disinfection benchmark calculated? If your system is making a significant change to its disinfection practice, it...

  12. 40 CFR 141.543 - How is the disinfection benchmark calculated?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false How is the disinfection benchmark... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.543 How is the disinfection benchmark calculated? If your system is making a significant change to its disinfection practice, it...

  13. 40 CFR 141.543 - How is the disinfection benchmark calculated?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false How is the disinfection benchmark... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.543 How is the disinfection benchmark calculated? If your system is making a significant change to its disinfection practice, it...

  14. 40 CFR 141.543 - How is the disinfection benchmark calculated?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false How is the disinfection benchmark... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.543 How is the disinfection benchmark calculated? If your system is making a significant change to its disinfection practice, it...

  15. Cone penetrometer demonstration standard startup review checklist

    SciTech Connect

    KRIEG, S.A.

    1998-11-09

    Startup readiness for the Cone Penetrometer Demonstration in AX Tank Farm will be verified through the application of a Standard Startup Review Checklist. This is a listing of those items essential to demonstrating readiness to start the Cone Penetrometer Demonstration in AX Tank Farm.

  16. System design description cone penetrometer system

    SciTech Connect

    Seda, R.Y., Westinghouse Hanford

    1996-08-12

    The system design description documents in detail the design of the cone penetrometer system. The systems includes the cone penetrometer physical package, raman spectroscopy package and moisture sensor package. Information pertinent to the system design, development, fabrication and testing is provided.

  17. Recoverin depletion accelerates cone photoresponse recovery

    PubMed Central

    Zang, Jingjing; Keim, Jennifer; Kastenhuber, Edda; Gesemann, Matthias; Neuhauss, Stephan C. F.

    2015-01-01

    The neuronal Ca2+-binding protein Recoverin has been shown to regulate phototransduction termination in mammalian rods. Here we identify four recoverin genes in the zebrafish genome, rcv1a, rcv1b, rcv2a and rcv2b, and investigate their role in modulating the cone phototransduction cascade. While Recoverin-1b is only found in the adult retina, the other Recoverins are expressed throughout development in all four cone types, except Recoverin-1a, which is expressed only in rods and UV cones. Applying a double flash electroretinogram (ERG) paradigm, downregulation of Recoverin-2a or 2b accelerates cone photoresponse recovery, albeit at different light intensities. Exclusive recording from UV cones via spectral ERG reveals that knockdown of Recoverin-1a alone has no effect, but Recoverin-1a/2a double-knockdowns showed an even shorter recovery time than Recoverin-2a-deficient larvae. We also showed that UV cone photoresponse kinetics depend on Recoverin-2a function via cone-specific kinase Grk7a. This is the first in vivo study demonstrating that cone opsin deactivation kinetics determine overall photoresponse shut off kinetics. PMID:26246494

  18. Mechanochemical regulation of growth cone motility

    PubMed Central

    Kerstein, Patrick C.; Nichol IV, Robert H.; Gomez, Timothy M.

    2015-01-01

    Neuronal growth cones are exquisite sensory-motor machines capable of transducing features contacted in their local extracellular environment into guided process extension during development. Extensive research has shown that chemical ligands activate cell surface receptors on growth cones leading to intracellular signals that direct cytoskeletal changes. However, the environment also provides mechanical support for growth cone adhesion and traction forces that stabilize leading edge protrusions. Interestingly, recent work suggests that both the mechanical properties of the environment and mechanical forces generated within growth cones influence axon guidance. In this review we discuss novel molecular mechanisms involved in growth cone force production and detection, and speculate how these processes may be necessary for the development of proper neuronal morphogenesis. PMID:26217175

  19. Unique characteristics of cones in Central Elysium Planitia, Mars

    NASA Astrophysics Data System (ADS)

    Noguchi, Rina; Kurita, Kei

    2015-06-01

    Martian magmatism within recent several hundreds of millions years is still controversial. Central Elysium Planitia (CEP) is suspected as a site of the latest magmatism on Mars, but hot debates have been caused as for the origin of this flat plain. Cones in CEP are expected to be a key to resolve this controversy. In previous works, there are 2 models proposed for the origin of CEP cones: volcanic rootless cone (e.g. Jaeger et al., 2007) and periglacial pingo (e.g. Burr et al., 2002; Page et al., 2009). In this study, we described detail morphology, distribution and size of CEP cones by using high-resolution images and topographic data. CEP cones are classified into 3 morphological types: Single Cone (SC), Double Cone (DC), and Lotus Fruit Cone (LC). DC has an inner cone in the summit crater of the outer cone, and LC has several inner cones in the summit crater of the outer cone. Several cones have moat structure around the edifice with peripheral rise. DCs and LCs are located in very flat areas of Athabasca Valles in the vicinity of Cerberus Fossae, while SCs distribute in the entire region of CEP. We compared CEP cones with terrestrial rootless cones and pingos in aerial photos. In Lake Myvatn, Iceland, there exist rootless cones which resemble DCs and LCs in CEP. Based on the similarities with terrestrial analogies, we concluded that the most feasible origin of CEP cones is rootless cones.

  20. Primate Short-Wavelength Cones Share Molecular Markers with Rods

    PubMed Central

    Craft, Cheryl M.; Huang, Jing; Possin, Daniel E.; Hendrickson, Anita

    2015-01-01

    Macaca, Callithrix jacchus marmoset monkey, Pan troglodytes chim- panzee and human retinas were examined to define if short wavelength (S) cones share molecular markers with L&M cone or rod photoreceptors. S cones showed consistent differences in their immunohistochemical staining and expression levels compared to L&M cones for “rod” Arrestin1 (S-Antigen), “cone” Arrestin4, cone alpha transducin, and Calbindin. Our data verify a similar pattern of expression in these primate retinas and provide clues to the structural divergence of rods and S cones versus L&M cones, suggesting S cone retinal function is “intermediate” between them. PMID:24664680

  1. 21 CFR 874.4770 - Otoscope.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR... device intended to allow inspection of the external ear canal and tympanic membrane under magnification. The device provides illumination of the ear canal for observation by using an AC- or...

  2. 21 CFR 874.4770 - Otoscope.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR... device intended to allow inspection of the external ear canal and tympanic membrane under magnification. The device provides illumination of the ear canal for observation by using an AC- or...

  3. 21 CFR 874.4770 - Otoscope.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR... device intended to allow inspection of the external ear canal and tympanic membrane under magnification. The device provides illumination of the ear canal for observation by using an AC- or...

  4. Peracetic acid for secondary effluent disinfection: a comprehensive performance assessment.

    PubMed

    Antonelli, M; Turolla, A; Mezzanotte, V; Nurizzo, C

    2013-01-01

    The paper is a review of previous research on secondary effluent disinfection by peracetic acid (PAA) integrated with new data about the effect of a preliminary flash-mixing step. The process was studied at bench and pilot scale to assess its performance for discharge in surface water and agricultural reuse (target microorganisms: Escherichia coli and faecal coliform bacteria). The purposes of the research were: (1) determining PAA decay and disinfection kinetics as a function of operating parameters, (2) evaluating PAA suitability as a disinfectant, (3) assessing long-term disinfection efficiency, (4) investigating disinfected effluent biological toxicity on some aquatic indicator organisms (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum), (5) comparing PAA with conventional disinfectants (sodium hypochlorite, UV irradiation). PAA disinfection was capable of complying with Italian regulations on reuse (10 CFU/100 mL for E. coli) and was competitive with benchmarks. No regrowth phenomena were observed, as long as needed for agricultural reuse (29 h after disinfection), even at negligible concentrations of residual disinfectant. The toxic effect of PAA on the aquatic environment was due to the residual disinfectant in the water, rather than to chemical modification of the effluent. PMID:24355852

  5. Gravity duals of boundary cones

    NASA Astrophysics Data System (ADS)

    Camps, Joan

    2016-09-01

    The replica trick defines Rényi entropies as partition functions on conically singular geometries. We discuss their gravity duals: regular bulk solutions to the Einstein equations inducing conically singular metrics at the boundary. When the conical singularity is supported on a flat or spherical surface, these solutions are rewritings of the hyperbolic black hole. For more general shapes, these solutions are new. We construct them perturbatively in a double expansion in the distance and strength of the conical singularity, and extract the vacuum polarisation due to the cone. Recent results about the structure of logarithmic divergences of Rényi entropies are reproduced — in particular, f b ≠ f c . We discuss in detail the dynamical resolution of the singularity in the bulk. This resolution is in agreement with a previous proposal, and indicates a non-minimal settling to the `splitting problem': an apparent ambiguity in the holographic entropy formula of certain theories with higher derivatives.

  6. Elastic cone for Chinese calligraphy

    NASA Astrophysics Data System (ADS)

    Cai, Fenglei; Li, Haisheng

    2014-01-01

    The brush plays an important role in creating Chinese calligraphy. We regard a single bristle of a writing brush as an elastic rod and the brush tuft absorbing ink as an elastic cone, which naturally deforms according to the force exerted on it when painting on a paper, and the brush footprint is formed by the intersection region between the deformed tuft and the paper plane. To efficiently generate brush strokes, this paper introduces interpolation and texture mapping approach between two adjacent footprints, and automatically applies bristle-splitting texture to the stroke after long-time painting. Experimental results demonstrate that our method is effective and reliable. Users can create realistic calligraphy in real time.

  7. Reaction of silver nanoparticles in the disinfection process.

    PubMed

    Yuan, Zhihua; Chen, Yunbin; Li, Tingting; Yu, Chang-Ping

    2013-10-01

    This study investigated the dissolution, aggregation, and reaction kinetics of silver nanoparticles (AgNPs) with the three types of water disinfectants (ultraviolet, sodium hypochlorite, and ozone) under the different conditions of pH, ionic strength, or humic acid (HA). The physicochemical changes of AgNPs were measured by using UV-Vis spectroscopy, transmission electron microscopy, and inductively coupled plasma optical emission spectrometer. The results showed that when AgNPs contacted the disinfectants, oxidative dissolution was the primary reaction. In addition, the reaction kinetics studies revealed that the reaction rate of AgNPs with disinfectants was significantly influenced by different disinfectants along with different pH and the presence of sodium nitrate and HA. Our research demonstrated the potential effect of disinfectants on AgNPs, which will improve our understanding of the fate of AgNPs in the disinfection processes in the water and wastewater treatment plant. PMID:23830116

  8. Reaction of silver nanoparticles in the disinfection process.

    PubMed

    Yuan, Zhihua; Chen, Yunbin; Li, Tingting; Yu, Chang-Ping

    2013-10-01

    This study investigated the dissolution, aggregation, and reaction kinetics of silver nanoparticles (AgNPs) with the three types of water disinfectants (ultraviolet, sodium hypochlorite, and ozone) under the different conditions of pH, ionic strength, or humic acid (HA). The physicochemical changes of AgNPs were measured by using UV-Vis spectroscopy, transmission electron microscopy, and inductively coupled plasma optical emission spectrometer. The results showed that when AgNPs contacted the disinfectants, oxidative dissolution was the primary reaction. In addition, the reaction kinetics studies revealed that the reaction rate of AgNPs with disinfectants was significantly influenced by different disinfectants along with different pH and the presence of sodium nitrate and HA. Our research demonstrated the potential effect of disinfectants on AgNPs, which will improve our understanding of the fate of AgNPs in the disinfection processes in the water and wastewater treatment plant.

  9. 40 CFR 141.541 - What are significant changes to disinfection practice?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... point of disinfection; (b) Changes to the disinfectant(s) used in the treatment plant; (c) Changes to... (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration...

  10. 40 CFR 141.541 - What are significant changes to disinfection practice?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... point of disinfection; (b) Changes to the disinfectant(s) used in the treatment plant; (c) Changes to... (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration...

  11. 40 CFR 141.541 - What are significant changes to disinfection practice?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... point of disinfection; (b) Changes to the disinfectant(s) used in the treatment plant; (c) Changes to... (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration...

  12. 9 CFR 85.12 - Cleaning and disinfecting means of conveyance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... disinfected in accordance with § 71.7 of this chapter using one of the disinfectants registered under the... virucidal claims. These disinfectants shall be used in accordance with directions on their labels...

  13. 9 CFR 85.12 - Cleaning and disinfecting means of conveyance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... disinfected in accordance with § 71.7 of this chapter using one of the disinfectants registered under the... virucidal claims. These disinfectants shall be used in accordance with directions on their labels...

  14. Silver-based Antibacterial Surfaces for Drinking Water Disinfection - An overview

    EPA Science Inventory

    Risks associated with current disinfection techniques, including the formation of disinfection by-products and multi-drug resistant bacterial species, have prompted the exploration of advanced disinfection methods. One such technique employs silver nanoparticles incorporation on ...

  15. THE UPTAKE OF WATER DISINFECTION BY-PRODUCTS INTO FOODS DURING HOME PROCESSING

    EPA Science Inventory

    A variety of organic compounds in tap water are produced as a result of disinfection process. Use of chlorine-containing chemicals for disinfection produces many disinfection by-products (DBPs) including trihalomethanes, haloacetonitriles and haloacetic acid. Ozonation with secon...

  16. Research Issues Underlying the Four-Lab Study: Integrated Disinfection Byproducts Mixtures Research

    EPA Science Inventory

    Chemical disinfection of drinking water is a major public health triumph of the 20th century, resulting in significant decreases in morbidity and mortality from waterborne diseases. Disinfection byproducts (DBPs) are chemicals formed by the reaction of oxidizing disinfectants wi...

  17. Thyroid Hormone Signaling and Cone Photoreceptor Viability.

    PubMed

    Ma, Hongwei; Ding, Xi-Qin

    2016-01-01

    Thyroid hormone (TH) signaling regulates cell proliferation, differentiation, and apoptosis. In the retina, TH signaling plays a central role in cone opsin expression. TH signaling inhibits S opsin expression, stimulates M opsin expression, and promotes dorsal-ventral opsin patterning. TH signaling has also been associated with cone photoreceptor viability. Treatment with thyroid hormone triiodothyronine (T3) or induction of high T3 by deleting the hormone-inactivating enzyme type 3 iodothyronine deiodinase (DIO3) causes cone death in mice. This effect is reversed by deletion of the TH receptor (TR) gene. Consistent with the T3 treatment effect, suppressing TH signaling preserves cones in mouse models of retinal degeneration. The regulation of cone survival by TH signaling appears to be independent of its regulatory role in cone opsin expression. The mechanism by which TH signaling regulates cone viability remains to be identified. The current understanding of TH signaling regulation in photoreceptor viability suggests that suppressing TH signaling locally in the retina may represent a novel strategy for retinal degeneration management. PMID:26427466

  18. Disinfectants for spacecraft applications - An overview

    NASA Technical Reports Server (NTRS)

    Koenig, David W.; Mallary, Laura L.; Pierson, Duane L.

    1991-01-01

    The review of disinfectants for use on manned missions emphasizes the need for contamination control to prevent the detrimental effects of bacteria growth on crew health. Microbial control is possible by means of biocides, but the selected product has to meet stringent toxicity requirements for the small environments in spacecraft. The testing and evaluation is described of four biocide candidates: hydrogen peroxide, quaternary ammonium compounds, iodine, and glutaraldehyde. The effectiveness of the disinfectants are analyzed in terms of the ability to treat typical microbial counts from Skylab missions in a closed environment. It is shown that many biocide candidates are not compatible with the ECLSS, water-recovery management, and air-revitalization subsystems of the Space Station Freedom. The use of hydrogen peroxide is proposed with a secondary stronger agent for microbial spills from biological experiments.

  19. Suppression of Eimeria tenella sporulation by disinfectants.

    PubMed

    You, Myung-Jo

    2014-08-01

    The disinfectant effects (DEs) of 10 types of chemicals, defined by their ability to destroy or inhibit oocysts and consequently prevent sporulation of Eimeria tenella field isolate, were evaluated in vitro. Correct species assignments and sample purities were confirmed by the singular internal transcribed spacer (ITS)-PCR analysis. A total of 18 treatments were performed, and the disinfection suppression levels were 75.9% for 39% benzene + 22% xylene (1:10 dilution), 85.5% for 30% cresol soup (1:1 dilution), and 91.7% for 99.9% acetic acid (1:2 dilution) group. The results indicate that acetic acid, cresol soup, and benzene+xylene are good candidates for suppression of E. tenella oocyst sporulation.

  20. Lighting the way to improved disinfection

    SciTech Connect

    Valenti, M.

    1997-07-01

    Ultraviolet light has a proven track record of killing bacteria and viruses found in municipal wastewater. In addition, environmental concerns over the use of chemical disinfectants, coupled with improvements in ultraviolet-lighting technology, have led to the development of UV systems that treat spent metalworking fluids in the industrialized world; disinfect drinking water in developing countries; and clean aquaculture water, ballast water, and hospital air everywhere. A large-scale pilot plant capable of treating less than 1 million gallons per day was built on-site by Los Angeles-based Montgomery Watson and CCCSD in 1992. It demonstrated that UV was just as effective as chlorination in killing bacteria and slightly more effective in destroying viruses found in the Martinez plant`s wastewater. It also showed the lamps would need to be cleaned of fouling every two to four weeks. The paper discusses this plant and the use of UV light in the above-mentioned water treatment processes.

  1. [Sensitivity of Ps. aeruginosa to disinfectant agents].

    PubMed

    Korudzhiĭski, N; Tsankova, S; Karadzhov, S

    1986-01-01

    Pseudomonas aeruginosa strains, isolated from semen of bulls as well as from the surrounding milieu at Artificial Insemination Stations, were tested for susceptibility to disinfection agents, such as fesiasept, concentrate C4, and chloramine with 25% active chlorine and sodium hydroxide. The investigation was carried out in vitro under practical conditions too. The analysis of results led to the conclusion that in the case of environmental contamination with Ps. aeruginosa along with semen contamination most effective proved concentrate C4 in the form of 2.5 per cent water solution. The disinfection of lab glassware and equipment, instruments, towels, kerchiefs, cloths, and white overalls and aprons is to be carried out with 1.5 per cent water solution of chloramine. PMID:3101277

  2. Coated bedpans: their cleaning and disinfection.

    PubMed Central

    Mostafa, A. B.; Chackett, K. F.; Deverill, C. E.

    1976-01-01

    This paper reports on tests of cleaning and disinfection of stainless steel bedpans which have been coated with either a silicone grease or polytetrafluoroethylene (PTFE). The coatings were applied manually using an aerosol spray (silicone grease and PTFE), and by an industrial process (PTFE). Soils used comprised (i) British Standard Soil (B.S., 1966), (ii) human serum albumin labelled with technetium-99m (HSA-Tc), and (iii) a suspension of Streptococcus faecalis in broth. Tests of cleaning and disinfection were carried out in automatic washing and steam disinfector machines. Results show that aerosol spraying impairs the cleaning process but that bedpans coated by the industrial process with PTFE are superior to uncoated bedpans. Images Plate 3 Plate 2 Plate 1 PMID:1068198

  3. Influence of ultrasound enhancement on chlorine dioxide consumption and disinfection by-products formation for secondary effluents disinfection.

    PubMed

    Zhou, Xiaoqin; Zhao, Junyuan; Li, Zifu; Lan, Juanru; Li, Yajie; Yang, Xin; Wang, Dongling

    2016-01-01

    Chlorine dioxide (ClO2) has been promoted as an alternative disinfectant because of its high disinfection efficiency and less formation of organic disinfection by-products (DBPs). However, particle-associated microorganisms could be protected during the disinfection process, which decreases the disinfection efficiency or increases the required dosage. Besides, the formation of inorganic disinfection by-products is a significant concern in environment health. Ultrasound (US)-combined disinfection methods are becoming increasingly attractive because they are efficient and environmentally friendly. In this study, US was introduced as an enhancement method to identify its influence on ClO2 demand reduction and to minimize the production of potential DBPs for secondary effluents disinfection. Fecal coliform was used as an indicator, and DBPs, including trichloromethane (TCM), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), chlorite (ClO2(-)), and chlorate (ClO3(-)), were analyzed to observe the potential DBPs formation. Results show that US pretreatment could reduce half of ClO2 dosage compared with ClO2 disinfection alone for the same disinfection efficiency, and that an input power density of 2.64 kJ/L pretreatment with the 1.5mg/L ClO2 was enough to meet the discharge requirement in China (i.e., fecal coliform below 1000 CFU/L for Class 1A) for secondary effluent disinfection, and the ClO2(-) concentration in the disinfection effluent was only 1.37 mg/L at the same time. Furthermore, the different effects of US on the two processes (US as pretreatment and simultaneous US/ClO2 disinfection) were also analyzed, including deagglomerating, cell damage, and synergistic disinfection as well as degasing/sonolysis. It was proved that the production of TCM, DCAA, and TCAA was insignificantly influenced with the introduction of US, but US pretreatment did reduce the production of ClO2(-) and ClO3(-) effectually. In general, US pretreatment could be a better option for

  4. Influence of ultrasound enhancement on chlorine dioxide consumption and disinfection by-products formation for secondary effluents disinfection.

    PubMed

    Zhou, Xiaoqin; Zhao, Junyuan; Li, Zifu; Lan, Juanru; Li, Yajie; Yang, Xin; Wang, Dongling

    2016-01-01

    Chlorine dioxide (ClO2) has been promoted as an alternative disinfectant because of its high disinfection efficiency and less formation of organic disinfection by-products (DBPs). However, particle-associated microorganisms could be protected during the disinfection process, which decreases the disinfection efficiency or increases the required dosage. Besides, the formation of inorganic disinfection by-products is a significant concern in environment health. Ultrasound (US)-combined disinfection methods are becoming increasingly attractive because they are efficient and environmentally friendly. In this study, US was introduced as an enhancement method to identify its influence on ClO2 demand reduction and to minimize the production of potential DBPs for secondary effluents disinfection. Fecal coliform was used as an indicator, and DBPs, including trichloromethane (TCM), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), chlorite (ClO2(-)), and chlorate (ClO3(-)), were analyzed to observe the potential DBPs formation. Results show that US pretreatment could reduce half of ClO2 dosage compared with ClO2 disinfection alone for the same disinfection efficiency, and that an input power density of 2.64 kJ/L pretreatment with the 1.5mg/L ClO2 was enough to meet the discharge requirement in China (i.e., fecal coliform below 1000 CFU/L for Class 1A) for secondary effluent disinfection, and the ClO2(-) concentration in the disinfection effluent was only 1.37 mg/L at the same time. Furthermore, the different effects of US on the two processes (US as pretreatment and simultaneous US/ClO2 disinfection) were also analyzed, including deagglomerating, cell damage, and synergistic disinfection as well as degasing/sonolysis. It was proved that the production of TCM, DCAA, and TCAA was insignificantly influenced with the introduction of US, but US pretreatment did reduce the production of ClO2(-) and ClO3(-) effectually. In general, US pretreatment could be a better option for

  5. Modal content of living human cone photoreceptors

    PubMed Central

    Liu, Zhuolin; Kocaoglu, Omer P.; Turner, Timothy L.; Miller, Donald T.

    2015-01-01

    Decades of experimental and theoretical investigations have established that photoreceptors capture light based on the principles of optical waveguiding. Yet considerable uncertainty remains, even for the most basic prediction as to whether photoreceptors support more than a single waveguide mode. To test for modal behavior in human cone photoreceptors in the near infrared, we took advantage of adaptive-optics optical coherence tomography (AO-OCT, λc = 785 nm) to noninvasively image in three dimensions the reflectance profile of cones. Modal content of reflections generated at the cone inner segment and outer segment junction (IS/OS) and cone outer segment tip (COST) was examined over a range of cone diameters in 1,802 cones from 0.6° to 10° retinal eccentricity. Second moment analysis in conjunction with theoretical predictions indicate cone IS and OS have optical properties consistent of waveguides, which depend on segment diameter and refractive index. Cone IS was found to support a single mode near the fovea (≤3°) and multiple modes further away (>4°). In contrast, no evidence of multiple modes was found in the cone OSs. The IS/OS and COST reflections share a common optical aperture, are most circular near the fovea, show no orientation preference, and are temporally stable. We tested mode predictions of a conventional step-index fiber model and found that in order to fit our AO-OCT results required a lower estimate of the IS refractive index and introduction of an IS focusing/tapering effect. PMID:26417509

  6. The Cone-specific Visual Cycle

    PubMed Central

    Wang, Jin-Shan; Kefalov, Vladimir J

    2010-01-01

    Cone photoreceptors mediate our daytime vision and function under bright and rapidly-changing light conditions. As their visual pigment is destroyed in the process of photoactivation, the continuous function of cones imposes the need for rapid recycling of their chromophore and regeneration of their pigment. The canonical retinoid visual cycle through the retinal pigment epithelium cells recycles chromophore and supplies it to both rods and cones. However, shortcomings of this pathway, including its slow rate and competition with rods for chromophore, have led to the suggestion that cones might use a separate mechanism for recycling of chromophore. In the past four decades biochemical studies have identified enzymatic activities consistent with recycling chromophore in the retinas of cone-dominant animals, such as chicken and ground squirrel. These studies have led to the hypothesis of a cone-specific retina visual cycle. The physiological relevance of these studies was controversial for a long time and evidence for the function of this visual cycle emerged only in very recent studies and will be the focus of this review. The retina visual cycle supplies chromophore and promotes pigment regeneration only in cones but not in rods. This pathway is independent of the pigment epithelium and instead involves the Müller cells in the retina, where chromophore is recycled and supplied selectively to cones. The rapid supply of chromophore through the retina visual cycle is critical for extending the dynamic range of cones to bright light and for their rapid dark adaptation following exposure to light. The importance of the retina visual cycle is emphasized also by its preservation through evolution as its function has now been demonstrated in species ranging from salamander to zebrafish, mouse, primate, and human. PMID:21111842

  7. Regenerable Iodine Water-Disinfection System

    NASA Technical Reports Server (NTRS)

    Sauer, Richard L.; Colombo, Gerald V.; Jolly, Clifford D.

    1994-01-01

    Iodinated resin bed for disinfecting water regenerated to extend useful life. Water flows through regeneration bed of crystalline iodine during regeneration. At other times, flow diverted around regeneration bed. Although regeneration cycle manually controlled readily automated to start and stop according to signals from concentration sensors. Further benefit of regeneration is bed provides highly concentrated biocide source when needed. Concentrated biocide used to superiodinate system after contamination from routine maintenance or unexpected introduction of large concentration of microbes.

  8. Disinfection of secondary effluents by infiltration percolation.

    PubMed

    Makni, H

    2001-01-01

    Among the most attractive applications of reclaimed wastewater are: irrigation of public parks, sports fields, golf courses and market gardening. These uses require advanced wastewater treatment including disinfection. According to WHO guidelines (1989) and current rules and regulations in Tunisia, faecal coliform levels have to be reduced to < 10(3) or 10(2) CFU/100 mL. In Tunisia, most wastewater plants are only secondary treatment and, in order to meet health related regulations, the effluents need to be disinfected. However, it is usual for secondary effluents to need filtration prior to disinfection. Effectiveness of conventional disinfection processes, such as chlorination and UV radiation, are dependent upon the oxidation level and the levels of suspended solids of the treated water. Ozonation is relatively expensive and energy consuming. The consideration of the advantages and disadvantages of conventional techniques, their reliability, investment needs and operational costs will lead to the use of less sophisticated alternative techniques for certain facilities. Among alternative techniques, soil aquifer treatment and infiltration percolation through sand beds have been studied in Arizona, Israel, France, Spain and Morocco. Infiltration percolation plants have been intermittently fed with secondary or high quality primary effluents which percolated through 1.5-2 m unsaturated coarse sand and were recovered by under-drains. In such infiltration percolation facilities, microorganisms were eliminated through numerous physical, physicochemical and biological inter-related processes (mechanical filtration, adsorption and microbial degradation respectively). Efficiency of faecal coliform removal was dependent upon the water detention times in the filtering medium and on the oxidation of the filtered water. Effluents of Sfax town aerated ponds were infiltrated through 1.5 m deep sand columns in order to determine the performance of infiltration percolation in the

  9. Effects of disinfectants in renal dialysis patients

    SciTech Connect

    Klein, E.

    1986-11-01

    Patients receiving hemodialysis therapy risk exposure to both disinfectants and sterilants. Dialysis equipment is disinfected periodically with strong solutions of hypochlorite or formaldehyde. Gross hemolysis resulting from accidental hypochlorite infusion has led to cardiac arrest, probably as a result of hyperkalemia. Formaldehyde is commonly used in 4% solutions to sterilize the fluid paths of dialysis controllers and to sterilize dialyzers before reuse. It can react with red cell antigenic surfaces leading to the formation of anti-N antibodies. The major exposure risk is the low concentration of disinfectant found in municipal water used to prepare 450 L dialysate weekly. With thrice-weekly treatment schedules, the quality requirements for water used to make this solution must be met rigorously. Standards for water used in the preparation of dialysate have recently been proposed but not all patients are treated with dialysate meeting such standards. The introduction of sterilants via tap water is insidious and has let to more pervasive consequences. Both chlorine and chloramines, at concentrations found in potable water, are strong oxidants that cause extensive protein denaturation and hemolysis. Oxidation of the Fe/sup 2 +/ in hemoglobin to Fe/sup 3 +/ forms methemoglobin, which is incapable of carrying either O/sub 2/ or CO/sub 2/. Chloramine can form not only methemoglobin, but can also denature proteins within the red cell, thus forming aggregates (Heinz bodies). Chloramines also inhibit hexose monophosphate shunt activity, a mechanism that makes the red cell even more susceptible to oxidant damage.

  10. Evaluation of toothbrush disinfection via different methods.

    PubMed

    Basman, Adil; Peker, Ilkay; Akca, Gulcin; Alkurt, Meryem Toraman; Sarikir, Cigdem; Celik, Irem

    2016-01-01

    The aim of this study was to compare the efficacy of using a dishwasher or different chemical agents, including 0.12% chlorhexidine gluconate, 2% sodium hypochlorite (NaOCl), a mouthrinse containing essential oils and alcohol, and 50% white vinegar, for toothbrush disinfection. Sixty volunteers were divided into five experimental groups and one control group (n = 10). Participants brushed their teeth using toothbrushes with standard bristles, and they disinfected the toothbrushes according to instructed methods. Bacterial contamination of the toothbrushes was compared between the experimental groups and the control group. Data were analyzed by Kruskal-Wallis and Duncan's multiple range tests, with 95% confidence intervals for multiple comparisons. Bacterial contamination of toothbrushes from individuals in the experimental groups differed from those in the control group (p < 0.05). The most effective method for elimination of all tested bacterial species was 50% white vinegar, followed in order by 2% NaOCl, mouthrinse containing essential oils and alcohol, 0.12% chlorhexidine gluconate, dishwasher use, and tap water (control). The results of this study show that the most effective method for disinfecting toothbrushes was submersion in 50% white vinegar, which is cost-effective, easy to access, and appropriate for household use.

  11. Disinfecting action of a new multi-purpose disinfection solution for contact lenses.

    PubMed

    Rosenthal, R A; Bell, W M; Abshire, R

    1999-01-01

    The disinfection activity of a new multipurpose disinfection solution (OPTI-FREE Express with ALDOX) was compared to several other contact lens disinfecting solutions. The new solution is preserved with polyquaternium-1 and myristamidopropyl dimethylamine. The other solutions included 3% hydrogen peroxide systems and multipurpose solutions (MPS) preserved with polyhexamethylene biguanide. The products were tested for antimicrobial activity against Staphylococcus spp., Pseudomonas aeruginosa, Serratia marcescens, Candida albicans, Fusarium solani, and Aspergillus fumigatus. OPTI-FREE Express provided a broader range of antimicrobial activity than the MPS. It provided activity similar to that demonstrated by 3% hydrogen peroxide systems, but unlike the hydrogen peroxide system tested, it also prevented re growth of the organisms during extended storage. PMID:16303414

  12. Hydrogen peroxide as an effective disinfectant for Pasteurella multocida.

    PubMed

    Jung, In-Soo; Kim, Hyun-Jung; Jung, Won-Yong; Kim, Chan-Wha

    2014-07-01

    Pasteurella multocida (P. multocida) infections vary widely, from local infections resulting from animal bites and scratches to general infections. As of yet, no vaccine against P. multocida has been developed, and the most effective way to prevent pathogenic transmission is to clean the host environment using disinfectants. In this study, we identified which disinfectants most effectively inhibited environmental isolates of P. multocida. Three readily available disinfectants were compared: 3% hydrogen peroxide (HP), 70% isopropyl alcohol, and synthetic phenol. In suspension tests and zone inhibition tests, 3% HP was the most promising disinfectant against P. multocida.

  13. Efficiency of water disinfectants against Legionella pneumophila and Acanthamoeba.

    PubMed

    Dupuy, Mathieu; Mazoua, Stéphane; Berne, Florence; Bodet, Charles; Garrec, Nathalie; Herbelin, Pascaline; Ménard-Szczebara, Florence; Oberti, Sandrine; Rodier, Marie-Hélène; Soreau, Sylvie; Wallet, France; Héchard, Yann

    2011-01-01

    Free-living amoebae might be pathogenic by themselves and be a reservoir for bacterial pathogens, such as Legionella pneumophila. Not only could amoebae protect intra-cellular Legionella but Legionella grown within amoebae could undergo physiological modifications and become more resistant and more virulent. Therefore, it is important to study the efficiency of treatments on amoebae and Legionella grown within these amoebae to improve their application and to limit their impact on the environment. With this aim, we compared various water disinfectants against trophozoites of three Acanthamoeba strains and L. pneumophila alone or in co-culture. Three oxidizing disinfectants (chlorine, monochloramine, and chlorine dioxide) were assessed. All the samples were treated with disinfectants for 1 h and the disinfectant concentration was followed to calculate disinfectant exposure (Ct). We noticed that there were significant differences of susceptibility among the Acanthamoeba strains. However no difference was observed between infected and non-infected amoebae. Also, the comparison between the three disinfectants indicates that monochloramine was efficient at the same level towards free or co-cultured L. pneumophila while chlorine and chlorine dioxide were less efficient on co-cultured L. pneumophila. It suggests that these disinfectants should have different modes of action. Finally, our results provide for the first time disinfectant exposure values for Acanthamoeba treatments that might be used as references for disinfection of water systems.

  14. Additional disinfectants effective against the amphibian chytrid fungus Batrachochytrium dendrobatidis.

    PubMed

    Webb, R; Mendez, D; Berger, L; Speare, R

    2007-02-01

    Chytridiomycosis, a disease contributing to amphibian declines worldwide, is caused by the fungus Batrachochytrium dendrobatidis. Identifying efficient and practical disinfectants effective against B. dendrobatidis is important to reduce the spread of the disease both in the wild and captivity. Previous studies identified a range of suitable disinfectant strategies. We evaluated the suitability of 3 additional disinfectants: two of these (TriGene Virucidal Disinfectant Cleaner and F10 Super Concentrate Disinfectant) are mixtures of chemicals and one (Betadine Antiseptic Liquid) contains a single active ingredient, povidone iodine. The disinfectants were tested using a range of concentrations for 1,5 and 10 min to determine their ability to kill B. dendrobatidis in vitro. The measure of effectiveness was 100% kill of zoosporangia grown in multiwell plates. All disinfectants had a 100% efficacy at concentrations recommended by the manufacturers. The lowest concentrations capable of 100% kill after exposure for 1 min were 0.1 ml l(-1) for TriGene, 0.33 ml l(-1) for F10 and 100 ml l(-1) for Betadine. TriGene is the most effective disinfectant yet to be found, and both TriGene and F10 are more effective than various disinfectants tested in previous studies. TriGene and F10 are considered suitable for use in the field, as only small amounts of concentrate are needed. PMID:17425259

  15. The catheter hub disinfection cap as esophageal foreign body.

    PubMed

    Tawfik, Kareem O; Myer, Charles M; Shikary, Tasneem; Goldschneider, Kenneth R

    2015-12-01

    Disinfection caps are increasingly being used to prevent catheter-associated bloodstream infections. These devices, designed for continuous passive disinfection of catheter hubs, are typically small and often brightly colored. As such, they have the potential to become pediatric airway and esophageal foreign bodies. We report two patients who developed esophageal foreign body following ingestion of disinfection caps. Given the increasing use of these devices, it is imperative that health care providers be aware of this potential iatrogenic problem. We propose that the use of disinfection caps may not be appropriate in pediatric patients with risk factors for foreign body ingestion.

  16. Impact of food disinfection on beneficial biothiol contents in vegetables.

    PubMed

    Qiang, Zhimin; Demirkol, Omca; Ercal, Nuran; Adams, Craig

    2005-12-14

    In this work we investigated the impact of food disinfection on the beneficial biothiol contents in a suite of vegetables consumed daily, including spinach, green bean, asparagus, cucumber, and red pepper. Four disinfection technologies commonly studied and/or used in food processing and preservation, including hydrogen peroxide, free chlorine, and gaseous- and aqueous-phase ozone, were examined with common dosages and contact times. Results indicate that the common disinfection technologies may result in significant loss of beneficial biothiols in vegetables which are essentially important to human health. For example, as much as 70% of biothiols were lost when spinach was treated with hydrogen peroxide (5.0 wt %) for 30 min. Approximately 48-54% of biothiols were destroyed by free chlorine and gaseous- and aqueous-phase ozone under typical contacting conditions. In red pepper, about 60-71% of reduced glutathione was oxidized by the disinfectants. The potential decrease in biothiols during disinfection was dependent upon the biothiol type, the disinfectant, and the vegetable. The effectiveness of total bacterial inactivation by the four disinfection technologies was concurrently evaluated. Results show that free chlorine is most effective, achieving disinfection efficiencies of greater than 4 log for all study vegetables. This study may provide important information for the food industry to design optimum contacting methods for vegetables to simultaneously achieve sufficient bacterial disinfection while minimizing loss of beneficial biothiols.

  17. Resistance to chemical disinfection under conditions of microgravity

    NASA Astrophysics Data System (ADS)

    Marchin, George L.

    1998-01-01

    In unit gravity, bacteria and disinfecting resin beads co-sediment to the septum in a fluid processing apparatus (FPA) resulting in effective chemical disinfection. In microgravity bacteria in suspension have access to a larger volume of the FPA because of a lack of sedimentation. Further, when disinfecting resin beads are added to the FPA they also remain in suspension reducing their effective concentration. Typically, therefore, disinfection experiments in microgravity return larger numbers of viable bacteria than ground-based controls. Preliminary experiments aboard the MIR Space Station with Pseudomonas aeruginosa additionally suggest that the longer bacteria are retained in microgravity the more resistant they become to chemical disinfection. This phenomenon is probably due to additional time to develop resistant biofilms on the interior of the FPA. To partially solve these problems we have developed additional disinfecting materials to use in conjunction with polyiodide containing resin beads. One of these materials carbon beads coated with 3-trimethoxy silylpropyl dimethyloctadecyl ammonium chloride (Dow-Corning 5700®), acts synergistically with polyiodide resin disinfectants. Carbon beads so treated are still able to remove aqueous iodine from the water stream while providing an additional level of chemical disinfection. This additional capability prevents contamination of the carbon beads with heterotrophic bacteria and insures that bacteria surviving iodine disinfection are efficiently devitalized.

  18. Electrical coupling between cones in turtle retina.

    PubMed Central

    Detwiler, P B; Hodgkin, A L

    1979-01-01

    1. The electrical coupling between cones of known spectral sensitivity in the peripheral part of the turtle's retina was studied by passing current through a micro-electrode inserted into one cone and recording with a second micro-electrode inserted into a neighbouring cone. 2. Spatial sensitivity profiles were determined by recording flash responses to a long narrow strip of light which was moved across the impaled cones in orthogonal directions. These measurements gave both the length constant lambda of electrical spread in the cone network and the separation of the two cones. 3. The cone separation determined from the spatial profiles agreed closely with that measured directly by injecting a fluorescent dye into two cones. 4. The length constant lambda varied from 18 to 39 micron with a mean of 25 micron for red-sensitive cones and 26 micron for green-sensitive cones. 5. The majority of cone pairs studied were electrically coupled provided they had the same spectral sensitivity and were separated by less than 60 micron: thirty-two out of thirty-six red-red pairs, two out of two green-green pairs, none out of eight red-green pairs: no blue cones were observed. 6. The strength of electrical coupling was expressed as a mutual resistance defined as the voltage in one cell divided by the current flowing into the other. Mutual resistances decreased from a maximum value of about 30 M omega at separations close to zero to 0.2 M omega, the lower limit of detectable coupling at separations of about 60 micron. Mutual resistances were always positive and were independent of which cell was directly polarized. The coupling seemed to be ohmic and any rectification or non-linearity probably arose in the cone membranes rather than in the coupling resistances. 7. The results were analysed in terms of the Lamb & Simon (1977) theories of square and hexagonal lattices, which approximate to the continuous sheet model except in the case of the cone to which current is applied. 8. The

  19. Production of various disinfection byproducts in indoor swimming pool waters treated with different disinfection methods.

    PubMed

    Lee, Jin; Jun, Myung-Jin; Lee, Man-Ho; Lee, Min-Hwan; Eom, Seog-Won; Zoh, Kyung-Duk

    2010-11-01

    In this study, the concentrations of disinfection byproducts (DBPs), including trihalomethanes (THMs; chloroform, bromodichloromethane, dibromochloromethane, and bromoform), haloacetic acids (HAAs; dichloroacetic acid and trichloroacetic acid), haloacetonitriles (HANs; dichloroacetonitrile, trichloroacetonitrile, bromochloroacetonitrile, and dibromoacetonitrile), and chloral hydrate (CH) were measured in 86 indoor swimming pools in Seoul, Korea, treated using different disinfection methods, such as chlorine, ozone and chlorine, and a technique that uses electrochemically generated mixed oxidants (EGMOs). The correlations between DBPs and other environmental factors such as with total organic carbon (TOC), KMnO(4) consumption, free residual chlorine, pH, and nitrate (NO(3)(-)) in the pools were examined. The geometric mean concentrations of total DBPs in swimming pool waters were 183.1±2.5μg/L, 32.6±2.1μg/L, and 139.9±2.4μg/L in pools disinfected with chlorine, ozone/chlorine, and EGMO, respectively. The mean concentrations of total THMs (TTHMs), total HAAs (THAAs), total HANs (THANs), and CH differed significantly depending on the disinfection method used (P<0.01). Interestingly, THAAs concentrations were the highest, followed by TTHMs, CH, and THANs in all swimming pools regardless of disinfection method. TOC showed a good correlation with the concentrations of DBPs in all swimming pools (chlorine; r=0.82, P<0.01; ozone/chlorine; r=0.52, P<0.01, EGMO; r=0.39, P<0.05). In addition, nitrate was positively correlated with the concentrations of total DBPs in swimming pools disinfected with chlorine and ozone/chlorine (chlorine; r=0.58; ozone/chlorine; r=0.60, P<0.01), whereas was negative correlated with the concentrations of total DBPs (r=-0.53, P<0.01) in the EGMO-treated pools.

  20. Distribution and specificity of S-cone ("blue cone") signals in subcortical visual pathways.

    PubMed

    Martin, Paul R; Lee, Barry B

    2014-03-01

    We review here the distribution of S-cone signals and properties of S-cone recipient receptive fields in subcortical pathways. Nearly everything we know about S-cone signals in the subcortical visual system comes from the study of visual systems in cats and primates (monkeys); in this review, we concentrate on results from macaque and marmoset monkeys. We discuss segregation of S-cone recipient (blue-on and blue-off) receptive fields in the dorsal lateral geniculate nucleus and describe their receptive field properties. We treat in some detail the question of detecting weak S-cone signals as an introduction for newcomers to the field. Finally, we briefly consider the question on how S-cone signals are distributed among nongeniculate targets. PMID:24555883

  1. Distribution and specificity of S-cone ("blue cone") signals in subcortical visual pathways.

    PubMed

    Martin, Paul R; Lee, Barry B

    2014-03-01

    We review here the distribution of S-cone signals and properties of S-cone recipient receptive fields in subcortical pathways. Nearly everything we know about S-cone signals in the subcortical visual system comes from the study of visual systems in cats and primates (monkeys); in this review, we concentrate on results from macaque and marmoset monkeys. We discuss segregation of S-cone recipient (blue-on and blue-off) receptive fields in the dorsal lateral geniculate nucleus and describe their receptive field properties. We treat in some detail the question of detecting weak S-cone signals as an introduction for newcomers to the field. Finally, we briefly consider the question on how S-cone signals are distributed among nongeniculate targets.

  2. Amoebicidal activity of a preserved contact lens multipurpose disinfecting solution compared to a disinfection/neutralisation peroxide system.

    PubMed

    Buck, S L; Rosenthal, R A; Abshire, R L

    1998-01-01

    The amoebicidal activity of a contact lens multipurpose disinfecting solution (MPDS) containing polyquaternium-1 and myristamidopropyl dimethylamine was compared to a disinfection/neutralisation peroxide system against Acanthamoeba castellanii and Acanthamoeba polyphaga trophozoites and cysts. A quantitative microtitre method was used to evaluate the solutions. The MPDS showed similar amoebicidal activity to the disinfection/neutralisation peroxide system against the trophozoites of both species and equal or more rapid activity against the cysts of both species. PMID:16303382

  3. Nonlinear Resonance Cones and Converging Plasma Blobs

    NASA Astrophysics Data System (ADS)

    Agmon, Nathan; Pribyl, Patrick; Gekelman, Walter; Wise, Joe; Katz, Cami; Ha, Chis; Baker, Bob

    2013-10-01

    Electric field resonance cones have been shown to create density disturbances in cold, magnetized plasmas. Two circular antennas in the LAPTAG experimental plasma device were used to create converging, nonlinear resonance cones. The nonlinear electrostatic field is produced by large amplitude RF (ERF/nkTe >> 1). A movable probe, powered by a computerized motor and consisting of three mutually orthogonal electric dipoles, is used to measure the electric field of the cones which become distorted at large amplitudes. A 2D movable Langmuir probe was used to determine localized density perturbations after turn-off of the RF power. A density blob moving at 3-5 times the ion sound speed has been observed to propagate away (for at least 20 cm) from the focus of the cone. Two ring antennas produced colliding blobs. The physics of the collision will be described. Work performed at the Basic Plasma Science Facility supported by DOE and NSF.

  4. Some inversion formulas for the cone transform

    NASA Astrophysics Data System (ADS)

    Terzioglu, Fatma

    2015-11-01

    Several novel imaging applications have lead recently to a variety of Radon type transforms, where integration is made over a family of conical surfaces. We call them cone transforms (in 2D they are also called V-line or broken ray transforms). Most prominently, they are present in the so called Compton camera imaging that arises in medical diagnostics, astronomy, and lately in homeland security applications. Several specific incarnations of the cone transform have been considered separately. In this paper, we address the most general (and overdetermined) cone transform, obtain integral relations between cone and Radon transforms in {{{R}}}n, and a variety of inversion formulas. In many applications (e.g., in homeland security), the signal to noise ratio is very low. So, if overdetermined data is collected (as in the case of Compton imaging), attempts to reduce the dimensionality might lead to essential elimination of the signal. Thus, our main concentration is on obtaining formulas involving overdetermined data.

  5. Homologies among Coniferophyte cones: further observations

    NASA Astrophysics Data System (ADS)

    Grauvogel-Stamm, Léa; Galtier, Jean

    1998-04-01

    A reinvestigation of the Triassic conifer pollen cone of Darneya shows evidence that clusters of pollen sacs are attached (adnate), at regular intervals, to the upper side of the stalk and that the distribution of stomata is restricted to the apical part of the abaxial side of the peltate scale. These features and others, such as the commissure visible on the stalk and the scale, suggest a dual nature of the male scale complex of Darneya which therefore is interpreted as an abaxial bract fused with an adaxial fertile shoot bearing several clusters of pollen sacs. This conifer pollen cone is thus considered as a compound strobilus (inflorescence) homologous with the female cone of the conifers and therefore with the cones, both male and female, of the cordaites.

  6. The cytoskeletons of isolated, neuronal growth cones.

    PubMed

    Gordon-Weeks, P R

    1987-06-01

    We have examined by electron microscopy the cytoskeletons of growth cones isolated from neonatal rat forebrain by the method of Gordon-Weeks and Lockerbie [Gordon-Weeks and Lockerbie (1984) Neuroscience 13, 119-136]. When fixed in suspension with conventional fixatives, isolated growth cones contain a central region filled with a branching system of smooth endoplasmic reticulum and a cortical region immediately beneath the plasma membrane that is relatively free of organelles and is composed of an amorphous granular cytoplasm. The filopodia of isolated growth cones are also devoid of organelles and contain a cytoplasm that is similar in appearance to that in the cortical region. No microtubules or neurofilaments have been found in these growth cones. When isolated growth cones were prepared for electron microscopy by a method which preserves actin filaments [Boyles, Anderson and Hutcherson (1985) J. Histochem. Cytochem. 33, 1116-1128], microfilaments were found throughout the cortical cytoplasm. In the filopodia, the microfilaments were bundled together and oriented longitudinally. Filopodial microfilament bundles often extended into the body of the growth cone and could traverse it completely. Inclusion of Triton X-100 (1% v/v) in the fixative solubilized the membranes and soluble cytoplasmic proteins of growth cones, allowing an unobscured view of the microfilament cytoskeleton including the core bundle of microfilaments in filopodia. Suspended within the cytoskeleton were the coats of coated vesicles. These were particularly numerous at the broad bases of filopodia. Microfilaments bound heavy meromyosin and were cytochalasin B (2.0 X 10(-7) M) sensitive. Individual microfilaments branched and within filopodia they were extensively cross-linked by thin (7 nm) filaments. Microtubules and neurofilaments were not seen in these cytoskeletons despite the fact that the fixative contained a Ca2+ chelator. When growth cones were preincubated in taxol (14 microM) their

  7. DEFORMATION OF SCORIA CONE BY CONDUIT PRESSURIZATION

    SciTech Connect

    E.S. Gaffney; B. Damjanac; D. Krier; G. Valentine

    2005-08-26

    A simplified mechanical model is used to simulate the deformation of a scoria cone due to pressurization of magma in a feeder conduit. The scoria cone is modeled as consisting of a cone of stabilized scoria with an axial region of loose scoria (height h{sub 1}), all overlying a vertically oriented cylindrical conduit intruded into rhyolite tuff country rock. For our analyses, the conduit is filled with basalt magma, usually with the upper length (h{sub 2}) solidified. The style of deformation of the cone depends on both h{sub 1} and h{sub 2}. If magma is prevented from hydrofracturing out of the conduit (as, for example, might be the case if the magma is surrounded by a solidified, but plastically deformable layer acting as a gasket backed up by the brittle country rock) pressures in the magma can build to 10s of MPa. When h{sub 1} is 100 m, not unusual for a small isolated basaltic cinder cone, the magma pressure needed to destabilize the cone when molten magma extends all the way to the original ground surface (h{sub 2} = 0) is only about one-third of the pressure when the upper part of the conduit is solidified (h{sub 2} = 25m). In the former case, almost the entire upper third of the cone is at failure in tension when the configuration becomes unstable. In the latter case, small portions of the surface of the cone are failing in tension when instability occurs, but a large volume in the central core of the cone is failing in shear or compressions. These results may provide insight into the status of volcanic plumbing, either past or present, beneath scoria cones. Field observations at the Lathrop Wells volcano in southern Nevada identify structures at the outer edge just below the crater rim that appear to be inward-dipping listric normal faults. This may indicate that, near the end of its active stage, the cone was close to failing in this fashion. A companion paper suggests that such a failure could have been quite energetic had it occurred.

  8. Substrate Deformation Predicts Neuronal Growth Cone Advance

    PubMed Central

    Athamneh, Ahmad I.M.; Cartagena-Rivera, Alexander X.; Raman, Arvind; Suter, Daniel M.

    2015-01-01

    Although pulling forces have been observed in axonal growth for several decades, their underlying mechanisms, absolute magnitudes, and exact roles are not well understood. In this study, using two different experimental approaches, we quantified retrograde traction force in Aplysia californica neuronal growth cones as they develop over time in response to a new adhesion substrate. In the first approach, we developed a novel method, to our knowledge, for measuring traction forces using an atomic force microscope (AFM) with a cantilever that was modified with an Aplysia cell adhesion molecule (apCAM)-coated microbead. In the second approach, we used force-calibrated glass microneedles coated with apCAM ligands to guide growth cone advance. The traction force exerted by the growth cone was measured by monitoring the microneedle deflection using an optical microscope. Both approaches showed that Aplysia growth cones can develop traction forces in the 100–102 nN range during adhesion-mediated advance. Moreover, our results suggest that the level of traction force is directly correlated to the stiffness of the microneedle, which is consistent with a reinforcement mechanism previously observed in other cell types. Interestingly, the absolute level of traction force did not correlate with growth cone advance toward the adhesion site, but the amount of microneedle deflection did. In cases of adhesion-mediated growth cone advance, the mean needle deflection was 1.05 ± 0.07 μm. By contrast, the mean deflection was significantly lower (0.48 ± 0.06 μm) when the growth cones did not advance. Our data support a hypothesis that adhesion complexes, which can undergo micron-scale elastic deformation, regulate the coupling between the retrogradely flowing actin cytoskeleton and apCAM substrates, stimulating growth cone advance if sufficiently abundant. PMID:26445437

  9. An evaluation of drinking water samples treated with alternative disinfectants

    SciTech Connect

    Patterson, K.S.; Lykins, B.W. Jr.; Garner, L.M.

    1995-10-01

    Due to concern over potential human health risks associated with the use of chlorine (Cl{sub 2}) for disinfection of drinking water, many utilities are considering alternative disinfectants. An evaluation is thus needed of the potential risks associated with the use of alternative disinfectants relative to those posed by Cl{sub 2}. At a pilot-scale drinking water plant in Jefferson Parish, LA., two studies were conducted in which clarified and sand filtered Mississippi River water was treated with either ozone (O{sub 3}), monochloramine (NH{sub 2}Cl), Cl{sub 2} or was not disinfected. Ozonated water was also post-disinfected with either NH{sub 2}Cl or Cl{sub 2}, to provide a disinfectant residual. For each treatment stream total organic carbon (TOC), total organic halide (TOX) and microbiological contaminants were determined. XAD resin concentrates were also prepared for mutagenicity testing in the Ames Salmonella assay. Water samples disinfected with O{sub 3} alone had low levels of mutagenic activity, the same as the non-disinfected water. The level of mutagenicity observed following chlorination was approximately twice that observed following treatment with NH{sub 2}Cl. Disinfection with O{sub 3} prior to treatment with either Cl{sub 2} or NH{sub 2}Cl resulted in a significantly lower level of mutagenicity than when either disinfectant was used alone. The concentrations of TOX present in the water samples showed a pattern similar to that of the mutagenicity data. The levels of TOC, by contrast, were similar for all the treatment streams. No significant baterial contamination was observed in water samples treated with either Cl{sub 2} or NH{sub 2}Cl alone or in combination with O{sub 3}, as determined by heterotrophic plate counts. However, O{sub 3} alone did not insure an acceptable level of disinfection at the end of the treatment stream.

  10. Microspectrophotometric evidence for cone monochromacy in sharks

    NASA Astrophysics Data System (ADS)

    Hart, Nathan Scott; Theiss, Susan Michelle; Harahush, Blake Kristin; Collin, Shaun Patrick

    2011-03-01

    Sharks are apex predators, and their evolutionary success is in part due to an impressive array of sensory systems, including vision. The eyes of sharks are well developed and function over a wide range of light levels. However, whilst close relatives of the sharks—the rays and chimaeras—are known to have the potential for colour vision, an evolutionary trait thought to provide distinct survival advantages, evidence for colour vision in sharks remains equivocal. Using single-receptor microspectrophotometry, we measured the absorbance spectra of visual pigments located in the retinal photoreceptors of 17 species of shark. We show that, while the spectral tuning of the rod (wavelength of maximum absorbance, λmax 484-518 nm) and cone (λmax 532-561 nm) visual pigments varies between species, each shark has only a single long-wavelength-sensitive cone type. This suggests that sharks may be cone monochromats and, therefore, potentially colour blind. Whilst cone monochromacy on land is rare, it may be a common strategy in the marine environment: many aquatic mammals (whales, dolphins and seals) also possess only a single, green-sensitive cone type. It appears that both sharks and marine mammals may have arrived at the same visual design by convergent evolution. The spectral tuning of the rod and cone pigments of sharks is also discussed in relation to their visual ecology.

  11. Design of a trichromatic cone array.

    PubMed

    Garrigan, Patrick; Ratliff, Charles P; Klein, Jennifer M; Sterling, Peter; Brainard, David H; Balasubramanian, Vijay

    2010-02-01

    Cones with peak sensitivity to light at long (L), medium (M) and short (S) wavelengths are unequal in number on the human retina: S cones are rare (<10%) while increasing in fraction from center to periphery, and the L/M cone proportions are highly variable between individuals. What optical properties of the eye, and statistical properties of natural scenes, might drive this organization? We found that the spatial-chromatic structure of natural scenes was largely symmetric between the L, M and S sensitivity bands. Given this symmetry, short wavelength attenuation by ocular media gave L/M cones a modest signal-to-noise advantage, which was amplified, especially in the denser central retina, by long-wavelength accommodation of the lens. Meanwhile, total information represented by the cone mosaic remained relatively insensitive to L/M proportions. Thus, the observed cone array design along with a long-wavelength accommodated lens provides a selective advantage: it is maximally informative. PMID:20168996

  12. Cone Tracing for Furry Object Rendering.

    PubMed

    Qin, Hao; Chai, Menglei; Hou, Qiming; Ren, Zhong; Zhou, Kun

    2014-08-01

    We present a cone-based ray tracing algorithm for high-quality rendering of furry objects with reflection, refraction and defocus effects. By aggregating many sampling rays in a pixel as a single cone, we significantly reduce the high supersampling rate required by the thin geometry of fur fibers. To reduce the cost of intersecting fur fibers with cones, we construct a bounding volume hierarchy for the fiber geometry to find the fibers potentially intersecting with cones, and use a set of connected ribbons to approximate the projections of these fibers on the image plane. The computational cost of compositing and filtering transparent samples within each cone is effectively reduced by approximating away in-cone variations of shading, opacity and occlusion. The result is a highly efficient ray tracing algorithm for furry objects which is able to render images of quality comparable to those generated by alternative methods, while significantly reducing the rendering time. We demonstrate the rendering quality and performance of our algorithm using several examples and a user study. PMID:26357369

  13. Crowding in the S-cone pathway.

    PubMed

    Coates, Daniel R; Chung, Susana T L

    2016-05-01

    The spatial extent of interference from nearby object or contours (the critical spacing of "crowding") has been thoroughly characterized across the visual field, typically using high contrast achromatic stimuli. However, attempts to link this measure with known properties of physiological pathways have been inconclusive. The S-cone pathway, with its ease of psychophysical isolation and known anatomical characteristics, offers a unique tool to gain additional insights into crowding. In this study, we measured the spatial extent of crowding in the S-cone pathway at several retinal locations using a chromatic adaptation paradigm. S-cone crowding was evident and extensive, but its spatial extent changed less markedly as a function of retinal eccentricity than the extent found using traditional achromatic stimuli. However, the spatial extent agreed with that of low contrast achromatic stimuli matched for isolated resolvability. This suggests that common cortical mechanisms mediate the crowding effect in the S-cone and achromatic pathway, but contrast is an important factor. The low contrast of S-cone stimuli makes S-cone vision more acuity-limited than crowding-limited.

  14. Microspectrophotometric evidence for cone monochromacy in sharks.

    PubMed

    Hart, Nathan Scott; Theiss, Susan Michelle; Harahush, Blake Kristin; Collin, Shaun Patrick

    2011-03-01

    Sharks are apex predators, and their evolutionary success is in part due to an impressive array of sensory systems, including vision. The eyes of sharks are well developed and function over a wide range of light levels. However, whilst close relatives of the sharks-the rays and chimaeras-are known to have the potential for colour vision, an evolutionary trait thought to provide distinct survival advantages, evidence for colour vision in sharks remains equivocal. Using single-receptor microspectrophotometry, we measured the absorbance spectra of visual pigments located in the retinal photoreceptors of 17 species of shark. We show that, while the spectral tuning of the rod (wavelength of maximum absorbance, λ(max) 484-518 nm) and cone (λ(max) 532-561 nm) visual pigments varies between species, each shark has only a single long-wavelength-sensitive cone type. This suggests that sharks may be cone monochromats and, therefore, potentially colour blind. Whilst cone monochromacy on land is rare, it may be a common strategy in the marine environment: many aquatic mammals (whales, dolphins and seals) also possess only a single, green-sensitive cone type. It appears that both sharks and marine mammals may have arrived at the same visual design by convergent evolution. The spectral tuning of the rod and cone pigments of sharks is also discussed in relation to their visual ecology. PMID:21212930

  15. Microspectrophotometric evidence for cone monochromacy in sharks.

    PubMed

    Hart, Nathan Scott; Theiss, Susan Michelle; Harahush, Blake Kristin; Collin, Shaun Patrick

    2011-03-01

    Sharks are apex predators, and their evolutionary success is in part due to an impressive array of sensory systems, including vision. The eyes of sharks are well developed and function over a wide range of light levels. However, whilst close relatives of the sharks-the rays and chimaeras-are known to have the potential for colour vision, an evolutionary trait thought to provide distinct survival advantages, evidence for colour vision in sharks remains equivocal. Using single-receptor microspectrophotometry, we measured the absorbance spectra of visual pigments located in the retinal photoreceptors of 17 species of shark. We show that, while the spectral tuning of the rod (wavelength of maximum absorbance, λ(max) 484-518 nm) and cone (λ(max) 532-561 nm) visual pigments varies between species, each shark has only a single long-wavelength-sensitive cone type. This suggests that sharks may be cone monochromats and, therefore, potentially colour blind. Whilst cone monochromacy on land is rare, it may be a common strategy in the marine environment: many aquatic mammals (whales, dolphins and seals) also possess only a single, green-sensitive cone type. It appears that both sharks and marine mammals may have arrived at the same visual design by convergent evolution. The spectral tuning of the rod and cone pigments of sharks is also discussed in relation to their visual ecology.

  16. Photonic Landau levels on cones

    NASA Astrophysics Data System (ADS)

    Schine, Nathan; Ryou, Albert; Gromov, Andrey; Sommer, Ariel; Simon, Jonathan

    2016-05-01

    We present the first experimental realization of a bulk magnetic field for optical photons. By using a non-planar ring resonator, we induce an image rotation on each round trip through the resonator. This results in a Coriolis/Lorentz force and a centrifugal anticonfining force, the latter of which is cancelled by mirror curvature. Using a digital micromirror device to control both amplitude and phase, we inject arbitrary optical modes into our resonator. Spatial- and energy- resolved spectroscopy tracks photonic eigenstates as residual trapping is reduced, and we observe photonic Landau levels as the eigenstates become degenerate. We show that there is a conical geometry of the resulting manifold for photon dynamics and present a measurement of the local density of states that is consistent with Landau levels on a cone. While our work already demonstrates an integer quantum Hall material composed of photons, we have ensured compatibility with strong photon-photon interactions, which will allow quantum optical studies of entanglement and correlation in manybody systems including fractional quantum Hall fluids.

  17. Photonic Landau levels on cones

    NASA Astrophysics Data System (ADS)

    Schine, Nathan; Ryou, Albert; Gromov, Andrey; Sommer, Ariel; Simon, Jonathan

    2016-05-01

    Creating photonic materials with nontrivial topological characteristics has seen burgeoning interest in recent years; however, a major route to topology, a magnetic field for continuum photons, has remained elusive. We present the first experimental realization of a bulk magnetic field for optical photons. By using a non-planar ring resonator, we induce an image rotation on each round trip through the resonator. This results in a Coriolis/Lorentz force and a centrifugal anticonfining force, the latter of which is cancelled by mirror curvature. Spatial- and energy- resolved spectroscopy tracks photonic eigenstates as residual trapping is reduced, and we observe photonic Landau levels as the eigenstates become degenerate. We will discuss the conical geometry of the resulting manifold for photon dynamics and present a measurement of the local density of states that is consistent with Landau levels on a cone. While our work already demonstrates an integer quantum Hall material composed of photons, we have ensured compatibility with strong photon-photon interactions, which will allow quantum optical studies of entanglement and correlation in manybody systems including fractional quantum Hall fluids.

  18. [Genotoxicity of drinking water during chlorine and chloramine disinfection and the influence of disinfection conditions using the umu-test].

    PubMed

    Liu, Qing; Zhang, Li-Ping; Liu, Wen-Jun; Nie, Xue-Biao; Zhang, Su-Xia; Zhang, Shun

    2010-01-01

    In this study, the effects of disinfectant dosage, reaction time and the ratio of Cl2 to N of disinfectant on genotoxicity of effluent of ozone-biological activated carbon (O3-BAC) during chlorine or chloramine disinfection were investigated using umu-test. It was found that, the genotoxicity of effluent of O3-BAC before disinfection ranged from 20-70 ng/L, and it increased after disinfection by chlorine or chloramines. With the same reaction time(24 h), genotoxicity after chlorination (40-95 ng/L) was higher than that after chloramination (20-40 ng/L) under same initial dosage. For chlorination, with initial dosage increasing from 0 mg/L to 10 mg/L, genotoxicity increased firstly, and got the maximum value at about 0.5-1 mg/L dosage, then decreased and got the minimum value at about 3-5 mg/L dosage, and finally increased again. For chloramination, genotoxicity didn't change that much. With the dosage of 3 mg/L and reaction time increasing from 0 h to 72 h, no matter for chlorine or chloramines disinfection, genotoxicity of effluent of O3-BAC both increased firstly, and got the maximum value at about 2 h, then decreased and got the minimum value at about 18 h, and finally increased again, and genotoxicity after chlorine disinfection (83-120 ng/L) was higher than that after chloramines disinfection (20-62 ng/L) under same reaction time. Further more, effects of the different ratios of Cl2 to N of disinfectant on genotoxicity of effluent of O3-BAC were also studied. Results of this study demonstrate that under test conditions, chloramine disinfection is safer than chlorine disinfection in the aspect of genotoxicity for drinking water, and the changes of genotoxicity are different from those of total HAAs.

  19. Review of disinfectant susceptibility of bacteria isolated in hospital to commonly used disinfectants.

    PubMed

    Shiraishi, T; Nakagawa, Y

    1993-01-01

    The susceptibility of clinical isolates and indigenous bacteria to commonly used disinfectants was investigated during different time periods. Among the clinical isolates tested during Period I (August 1985-July 1986, 6 genera, 9 species, 353 strains) there were many resistant strains not killed within a short period of time by the recommended concentration of chlorhexidine gluconate (CHG) or benzalkonium chloride (BAC). During Period II (October 1987-May 1988, 6 genera, 9 species, 152 strains), however, a reduction in the number of strains resistant to these disinfectants was observed. The use of the broad spectrum disinfectant povidone-iodine (PVP-I) increased between those two time periods. With regard to the susceptibility of indigenous bacteria, tests were carried out on bacteria isolated from sinks and physicians' hands in the gastroenterology division of the Departments of Internal Medicine and Surgery at the hospital. During Phase I (April-June 1987), strains of Pseudomonas and Serratia resistant to CHG and BAC were isolated from sinks, while the same strains of Serratia were also isolated from physicians' hands. During Phase II (March-May 1988), however, no resistant strains were isolated. A comparison of the consumption of disinfectants during the two phases revealed that a greater amount of CHG was consumed during Phase I, while a greater amount of PVP-I was consumed during Phase II. There was a strong indication, therefore, that bacteria resistant to CHG and BAC decrease with the increased use of PVP-I.

  20. Drinking water and health: Disinfectants and disinfectant by-products. Volume 7

    SciTech Connect

    Not Available

    1987-01-01

    Studies of the toxicity of the by-products of disinfectants have focused on the trihalomethanes (THMs), which are formed during chlorination and for which considerable data on carcinogenicity have been developed. The level of total THMs in finished drinking water, currently regulated at 100 micrograms/L, should be reduced. Noting that chloroform is the principal THM produced by chlorination, the subcommittee found this level to be unsupportable on the basis of the risk values for chloroform developed in this review. Other, non-volatile by-products of chlorination may be important in contributing mutagenic properties to drinking water, especially when the natural water being treated contains high levels of organic matter. Short-term animal skin tests, although not conclusive, provide indications that organic concentrates from chlorinated water are tumorigenic under some experimental conditions. Unfortunately, many by-products of chlorination and other disinfection practices have not been identified. Consequently, the risks of ingesting cannot be quantified at present, but are potentially high enough to warrant continued efforts to analyze them. The use of alternative methods of drinking water disinfection is increasing, largely due to health and regulatory concerns about trihalomethanes. Thus, the nature and toxicity of the by-products of some other widely used water treatments (chloramination, ozonation, and chlorine dioxide) are also evaluated in the report to the extent allowed by available data. The subcommittee calculated quantitative risk assessment for disinfectants or their by-products when there was sufficient data.

  1. 9 CFR 71.11 - Cresylic disinfectant as permitted disinfectant; specifications.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... disinfectant; specifications. 71.11 Section 71.11 Animals and Animal Products ANIMAL AND PLANT HEALTH... than the equivalent of 0.5 percent of sodium hydroxide, and not less than 21 percent of soap exclusive... glyceride, fat acid, or resin acid may be used in preparing the soap, but not all are suitable nor are...

  2. 9 CFR 71.11 - Cresylic disinfectant as permitted disinfectant; specifications.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... disinfectant; specifications. 71.11 Section 71.11 Animals and Animal Products ANIMAL AND PLANT HEALTH... than the equivalent of 0.5 percent of sodium hydroxide, and not less than 21 percent of soap exclusive... glyceride, fat acid, or resin acid may be used in preparing the soap, but not all are suitable nor are...

  3. 9 CFR 71.11 - Cresylic disinfectant as permitted disinfectant; specifications.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... disinfectant; specifications. 71.11 Section 71.11 Animals and Animal Products ANIMAL AND PLANT HEALTH... than the equivalent of 0.5 percent of sodium hydroxide, and not less than 21 percent of soap exclusive... glyceride, fat acid, or resin acid may be used in preparing the soap, but not all are suitable nor are...

  4. Comparing irradiation parameters on disinfecting enterrecoccus faecalis in root canal disinfection

    NASA Astrophysics Data System (ADS)

    Sarp, Ayşe. S.; Gülsoy, Murat

    2016-02-01

    Although conventional method carries all the debris, studies on persisting infections in root canals show bacteria and their toxins spread from the root canal and contaminate the apical region. Thus developes apical periodontitis or symptoms, and loss of tooth. Even if the treatment has adequate success, anatomy of root canal system can be very complexwith accessory canals. The disinfecting effect of laser radiation has only recently been used in dentistry. Laser irradiation has a bactericidal effect. Each wavelength has its own advantages and limitations according to their different absorption characteristics, depending on their 'absorption coefficient'. The sterilizing efficiency of two types of wavelengths, a new fiber laser 1940- nm Thulium fiber Laser and an 2940 nm Er:YAG Laser were compared in this study. Irradiation with a power of 0.50 W with 1940- nm Thulium fiber Laser disinfected 95,15% of bacteria, however irradiation with same laser power with Er:YAG Laser caused a reduction of 96,48 %. But there was no significant difference in the disinfection effect of two different laser groups ( p < 0.05, Mann- U-Whitney Test). In addition to this, Er :YAG Laser caused three times more reduction from its own positive control group where 1940- nm Thulium fiber Laser caused 2,5 times effective disinfection.

  5. TRIBROMOPYRROLE, BROMINATED ACIDS, AND OTHER DISINFECTION BYPRODUCTS PRODUCED BY DISINFECTION OF DRINKING WATER RICH IN BROMIDE

    EPA Science Inventory

    Using gas chromatography/mass spectrometry (GC/MS), we investigated the formation of disinfection byproducts (DBPs) from high bromide waters (2 mg/L) treated with chlorine or chlorine dioxide used in combination with chlorine and chloramines. This study represents the first comp...

  6. MUTAGENICITY AND DISINFECTION BY-PRODUCTS IN SURFACE DRINKING WATER DISINFECTED WITH PERACETIC ACID

    EPA Science Inventory

    The aims of this research were to study the influence of peracetic acid (PAA) on the formation of mutagens in surface waters used for human consumption and to assess its potential application for the disinfection of drinking water. The results obtained using PAA were compared to ...

  7. Peracetic Acid as a Green Disinfectant for Combined Sewer Overflows

    EPA Science Inventory

    This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effect...

  8. CHALLENGES OF COMBINED SEWER OVERFLOW DISINFECTION BY ULTRAVIOLET LIGHT IRRADIATION

    EPA Science Inventory

    This article examines the performance and effectiveness of ultraviolet (UV) light irradiation for disinfection of combined sewer overflow (CSO). Due to the negative impact of conventional water disinfectants on aquatic life, new agents (e.g., UV light) are being investigated for ...

  9. 9 CFR 51.31 - Disinfecting premises, conveyances, and materials.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ANIMALS DESTROYED BECAUSE OF BRUCELLOSIS Indemnity for Sheep, Goats, and Horses § 51.31 Disinfecting... brucellosis, must be properly cleaned and disinfected in accordance with recommendations of the APHIS or State... the Veterinarian in Charge determines that an extension will not adversely affect the...

  10. [Scanning electron microscope study of chemically disinfected endodontic files].

    PubMed

    Navarro, G; Mateos, M; Navarro, J L; Canalda, C

    1991-01-01

    Forty stainless steel endodontic files were observed at scanning electron microscopy after being subjected to ten disinfection cycles of 10 minutes each one, immersed in different chemical disinfectants. Corrosion was not observed on the surface of the files in circumstances that this study was made.

  11. Zero-G Condensing Heat Exchanger with Integral Disinfection

    NASA Technical Reports Server (NTRS)

    Burke, Kenneth A. (Inventor)

    2012-01-01

    The system that operates in a zero gravity environment and has an integral ozone generating capability is disclosed. The system contributes to the control of metabolic water vapors in the air, and also provided disinfection of any resulting condensate within the system, as well as disinfection of the air stream that flows throughout the disclosed system.

  12. Disinfection By-Products: Formation and Occurrence in Drinking Water

    EPA Science Inventory

    The disinfection of drinking water has been rightly hailed as a public health triumph of the twentieth century. Millions of people worldwide receive quality drinking water every day from their public water systems. However, chemical disinfection has also produced an unintended he...

  13. The Next Generation of Disinfection By-Products

    EPA Science Inventory

    The disinfection of drinking water has been rightly hailed as a public health triumph of the 20th century. Millions of people worldwide receive quality drinking water every day from their public water systems. However, chemical disinfection has also produced an unintended health ...

  14. IDENTIFICATION OF DISINFECTION BY-PRODUCTS IN SWIMMING POOL WATER

    EPA Science Inventory

    In order to kill harmful pathogens, swimming pool water is treated with a disinfectant, such as chlorine or ozone. One of the most commonly used disinfectants is stabilized chlorine (typically trichloro-S-triazinetrione). Trichloro-S-triazinetrione reacts in water to form one m...

  15. Disinfection of water in recirculating aquaculture systems with peracetic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) has become a favoured alternative to chlorination in the disinfection of municipal waste water in recent years. It is also commonly used in the food industry as a disinfectant. Based on PAA concentration, the disulfide linkage in enzymes and proteins of microorganisms can be bro...

  16. Products identified at an alternative disinfection pilot plant.

    PubMed Central

    Lykins, B W; Koffskey, W

    1986-01-01

    Many drinking water utilities have recently changed or are seriously considering changing their disinfection practice from chlorine to some alternative treatment process. However, most of these utilities are changing their disinfectants without evaluating chemical impacts. Therefore, a research cooperative agreement was developed with Jefferson Parish, LA, to evaluate four parallel streams treated with four different disinfectants (chlorine, monochloramine, chlorine dioxide, and ozone.) These streams, along with a fifth parallel stream, which was not treated with a disinfectant (control), were passed through both sand and granular activated carbon (GAC). Ozonation reduced the total organic carbon (TOC) and total organic halide (TOX) concentration by 0.3 mg/L and 10 micrograms/L, respectively. The average concentration of TOC for the other disinfectants was comparable to that associated with the nondisinfected stream (3.3 mg/L). The average instantaneous TOX concentration for chlorine dioxide, chloramine, and chlorine disinfection after 30 min contact time increased by 60, 92, and 238 micrograms/L, respectively, from a nondisinfected concentration of 25 micrograms/L. The volatile organics most affected by disinfection (chlorination) were the trihalomethanes. No significant change in concentration was noted after disinfection for the other volatile organics evaluated, such as 1,2-dichlorethane, dichloromethane, trichloroethylene, 1,1,2-trichloroethane, and carbon tetrachloride. Ozonation produced an average concentration reduction of 11 to 84% for most of the nonvolatiles evaluated. Conversely, a concentration increase of 43 to 100% was noted, after chlorination, for some of the nonvolatile organics. PMID:3816717

  17. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Disinfection profiling and benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to...

  18. Design and bidding of UV disinfection equipment -- Case study

    SciTech Connect

    Akyurek, M.

    1998-07-01

    Ultraviolet (UV) disinfection systems are being widely considered for application to treated wastewaters, in lieu of conventional chlorination facilities. The number of UV systems operating in the US was approximately 50 in 1984. In 1990 there were over 500 systems, a ten-fold increase. The use of UV disinfection has increased since 1990, and will likely to increase in the future. It is anticipated that as many chlorine disinfection facilities reach their useful life, most of them will be replaced with UV disinfection systems. Several manufacturers offer different UV disinfection equipment. Each offers something different for the designer. There are also different approaches used in estimating the number of lamps needed for the disinfection system. The lack of standardization in determination of the number of lamps for a UV system poses problems for the designer. Such was the case during the design of the disinfection system for the Watertown, SD Wastewater Treatment Plant (WWRP). The purpose of this paper is to present a case study for the design and bidding of UV disinfection equipment.

  19. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Disinfection profiling and benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to...

  20. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Disinfection profiling and benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to...

  1. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Disinfection profiling and benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to...

  2. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Disinfection profiling and benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to...

  3. Products identified at an alternative disinfection pilot plant

    SciTech Connect

    Lykins, B.W. Jr.; Koffskey, W.

    1986-11-01

    Many drinking water utilities have recently changed or are seriously considering changing their disinfection practice from chlorine to some alternative treatment process. However, most of these utilities are changing their disinfectants without evaluating chemical impacts. Therefore, a research cooperative agreement was developed with Jefferson Parish, LA, to evaluate four parallel streams treated with four different disinfectants (chlorine, monochloramine, chlorine dioxide, and ozone.) These streams, along with a fifth parallel stream, which was not treated with a disinfectant (control), were passed through both sand and granular activated carbon (GAC). Ozonation reduced the total organic carbon (TOC) and total organic halide (TOX) concentration by 0.3 mg/L and 10 micrograms/L, respectively. The average concentration of TOC for the other disinfectants was comparable to that associated with the nondisinfected stream (3.3 mg/L). The average instantaneous TOX concentration for chlorine dioxide, chloramine, and chlorine disinfection after 30 min contact time increased by 60, 92, and 238 micrograms/L, respectively, from a nondisinfected concentration of 25 micrograms/L. The volatile organics most affected by disinfection (chlorination) were the trihalomethanes. No significant change in concentration was noted after disinfection for the other volatile organics evaluated, such as 1,2-dichlorethane, dichloromethane, trichloroethylene, 1,1,2-trichloroethane, and carbon tetrachloride. Ozonation produced an average concentration reduction of 11 to 84% for most of the nonvolatiles evaluated. Conversely, a concentration increase of 43 to 100% was noted, after chlorination, for some of the nonvolatile organics.

  4. The Next Generation of Drinking Water Disinfection By-Products

    EPA Science Inventory

    The disinfection of drinking water has been rightly hailed as a public health triumph of the 20th century. Millions of people worldwide receive quality drinking water every day from their public water systems. However, chemical disinfection has also produced an unintended healt...

  5. 9 CFR 147.24 - Cleaning and disinfecting.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Cleaning and disinfecting. 147.24 Section 147.24 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... solution. Rinse to remove soap. (4) Spray with a disinfectant which is registered by the...

  6. 9 CFR 147.24 - Cleaning and disinfecting.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Cleaning and disinfecting. 147.24 Section 147.24 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... solution. Rinse to remove soap. (4) Spray with a disinfectant which is registered by the...

  7. Genotoxicity of Disinfection By-products: Comparison to Carcinogenicity

    EPA Science Inventory

    Disinfection by-products (DBPs) can be formed when water is disinfected by various agents such as chlorine, ozone, or chloramines. Among the >600 DBPs identified in drinking water, 11 are regulated by the U.S. Environmental Protection Agency, and another ~70 DBPs that occur at s...

  8. Drowning in Disinfection Byproducts? Swimming Pool Water Quality

    EPA Science Inventory

    Disinfection is mandatory for swimming pools, because transmission of disease by bacteria, virus and protozoa is the most significant health issue. However another issue arises, and care should be taken to minimize the risks from disinfection by-products (DBPs). Public pools are ...

  9. HIGH-RATE DISINFECTION TECHNIQUES FOR COMBIND SEWER OVERFLOW

    EPA Science Inventory

    This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH )...

  10. PERFORMANCE OF OZONE AS A DISINFECTANT FOR COMBINED SEWER OVERFLOW

    EPA Science Inventory

    Disinfection of combined sewer overflow (CSO) minimizes the amount of disease-causing microorganisms (pathogens) released into receiving waters. Currently, the primary disinfecting agent used in the US for wastewater treatment is chlorine (Cl2); however, Cl2 produces problems in ...

  11. [Scanning electron microscope study of chemically disinfected endodontic files].

    PubMed

    Navarro, G; Mateos, M; Navarro, J L; Canalda, C

    1991-01-01

    Forty stainless steel endodontic files were observed at scanning electron microscopy after being subjected to ten disinfection cycles of 10 minutes each one, immersed in different chemical disinfectants. Corrosion was not observed on the surface of the files in circumstances that this study was made. PMID:1659857

  12. 9 CFR 51.31 - Disinfecting premises, conveyances, and materials.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... ANIMALS DESTROYED BECAUSE OF BRUCELLOSIS Indemnity for Sheep, Goats, and Horses § 51.31 Disinfecting... brucellosis, must be properly cleaned and disinfected in accordance with recommendations of the APHIS or State... the Veterinarian in Charge determines that an extension will not adversely affect the...

  13. 42 CFR 71.42 - Disinfection of imports.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Disinfection of imports. 71.42 Section 71.42 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES QUARANTINE, INSPECTION, LICENSING FOREIGN QUARANTINE Requirements Upon Arrival at U.S. Ports: Sanitary Inspection § 71.42 Disinfection...

  14. 42 CFR 71.42 - Disinfection of imports.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Disinfection of imports. 71.42 Section 71.42 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES QUARANTINE, INSPECTION, LICENSING FOREIGN QUARANTINE Requirements Upon Arrival at U.S. Ports: Sanitary Inspection § 71.42 Disinfection...

  15. ULTRAVIOLET LIGHT DISINFECTION OF COMBINED SEWER OVERFLOW (NEW ORLEANS)

    EPA Science Inventory

    The objective of this state-of-the-art review is to examine the performance and effectiveness of ultraviolet (UV) light disinfection for combined sewer overflow (CSO) applications. Topics presented include the use of UV light as a disinfecting agent, its practical applications, d...

  16. Guidelines for ultraviolet disinfection of drinking water: considerations for Ontario.

    PubMed

    Hofmann, Ron; Andrews, Bob; Lachmaniuk, Pat

    The Ontario Ministry of the Environment is actively investigating protocols for approving the installation of ultraviolet (UV) disinfection systems for drinking water disinfection. This paper discusses issues that may be considered for selecting the appropriate UV dose, validating UV reactor performance, and monitoring the performance of the reactor once installed.

  17. Peracetic Acid as a Green Disinfectant for Combined Sewer Overflows

    EPA Science Inventory

    This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effectiven...

  18. Biofilm and siderophore effects on secondary waste water disinfection.

    PubMed

    Saidi, N; Kouki, S; Mehri, I; Ben Rejeb, A; Belila, A; Hassen, A; Ouzari, H

    2011-10-01

    The efficiency of ultraviolet (UV) light disinfection of wastewater effluent using a large-scale pilot system was studied. The relationship between biofilm and siderophore production and UV doses received by Pseudomonas aeruginosa strain ATCC 15442 was determined. UV decreased pyoverdine production and enhanced biofilm production. Consequently external factors conditioned by both pyoverdine and biofilm may affect the UV effect on bacterial disinfection.

  19. The alternative methods for disinfection of E. coli

    NASA Astrophysics Data System (ADS)

    Yetim, Tuba; Görmez, Arzu; Gürkök, Sümeyra

    2016-04-01

    Recently, advanced oxidation processes have gained significant interest for bacterial inactivation. In the present study, the efficacy of sonolysis, photocatalysis and sonophotocatalysis was evaluated for disinfection of Escherichia coli O157:H7 strain. Sonophotocatalysis proved to be the most effective disinfection methods by generating greater amount of •OHradical.

  20. Effectiveness of Four Disinfectants against Ebola Virus on Different Materials.

    PubMed

    Smither, Sophie; Phelps, Amanda; Eastaugh, Lin; Ngugi, Sarah; O'Brien, Lyn; Dutch, Andrew; Lever, Mark Stephen

    2016-01-01

    The West Africa Ebola virus (EBOV) outbreak has highlighted the need for effective disinfectants capable of reducing viral load in a range of sample types, equipment and settings. Although chlorine-based products are widely used, they can also be damaging to equipment or apparatus that needs continuous use such as aircraft use for transportation of infected people. Two aircraft cleaning solutions were assessed alongside two common laboratory disinfectants in a contact kill assay with EBOV on two aircraft relevant materials representative of a porous and non-porous surface. A decimal log reduction of viral titre of 4 is required for a disinfectant to be deemed effective and two of the disinfectants fulfilled this criteria under the conditions tested. One product, Ardrox 6092, was found to perform similarly to sodium hypochlorite, but as it does not have the corrosive properties of sodium hypochlorite, it could be an alternative disinfectant solution to be used for decontamination of EBOV on sensitive apparatus.

  1. Impact of disinfection on drinking water biofilm bacterial community.

    PubMed

    Mi, Zilong; Dai, Yu; Xie, Shuguang; Chen, Chao; Zhang, Xiaojian

    2015-11-01

    Disinfectants are commonly applied to control the growth of microorganisms in drinking water distribution systems. However, the effect of disinfection on drinking water microbial community remains poorly understood. The present study investigated the impacts of different disinfectants (chlorine and chloramine) and dosages on biofilm bacterial community in bench-scale pipe section reactors. Illumina MiSeq sequencing illustrated that disinfection strategy could affect both bacterial diversity and community structure of drinking water biofilm. Proteobacteria tended to predominate in chloraminated drinking water biofilms, while Firmicutes in chlorinated and unchlorinated biofilms. The major proteobacterial groups were influenced by both disinfectant type and dosage. In addition, chloramination had a more profound impact on bacterial community than chlorination.

  2. Effectiveness of Four Disinfectants against Ebola Virus on Different Materials

    PubMed Central

    Smither, Sophie; Phelps, Amanda; Eastaugh, Lin; Ngugi, Sarah; O’Brien, Lyn; Dutch, Andrew; Lever, Mark Stephen

    2016-01-01

    The West Africa Ebola virus (EBOV) outbreak has highlighted the need for effective disinfectants capable of reducing viral load in a range of sample types, equipment and settings. Although chlorine-based products are widely used, they can also be damaging to equipment or apparatus that needs continuous use such as aircraft use for transportation of infected people. Two aircraft cleaning solutions were assessed alongside two common laboratory disinfectants in a contact kill assay with EBOV on two aircraft relevant materials representative of a porous and non-porous surface. A decimal log reduction of viral titre of 4 is required for a disinfectant to be deemed effective and two of the disinfectants fulfilled this criteria under the conditions tested. One product, Ardrox 6092, was found to perform similarly to sodium hypochlorite, but as it does not have the corrosive properties of sodium hypochlorite, it could be an alternative disinfectant solution to be used for decontamination of EBOV on sensitive apparatus. PMID:27399759

  3. Recent advances in drinking water disinfection: successes and challenges.

    PubMed

    Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

    2013-01-01

    Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality

  4. Effectiveness of Four Disinfectants against Ebola Virus on Different Materials.

    PubMed

    Smither, Sophie; Phelps, Amanda; Eastaugh, Lin; Ngugi, Sarah; O'Brien, Lyn; Dutch, Andrew; Lever, Mark Stephen

    2016-01-01

    The West Africa Ebola virus (EBOV) outbreak has highlighted the need for effective disinfectants capable of reducing viral load in a range of sample types, equipment and settings. Although chlorine-based products are widely used, they can also be damaging to equipment or apparatus that needs continuous use such as aircraft use for transportation of infected people. Two aircraft cleaning solutions were assessed alongside two common laboratory disinfectants in a contact kill assay with EBOV on two aircraft relevant materials representative of a porous and non-porous surface. A decimal log reduction of viral titre of 4 is required for a disinfectant to be deemed effective and two of the disinfectants fulfilled this criteria under the conditions tested. One product, Ardrox 6092, was found to perform similarly to sodium hypochlorite, but as it does not have the corrosive properties of sodium hypochlorite, it could be an alternative disinfectant solution to be used for decontamination of EBOV on sensitive apparatus. PMID:27399759

  5. Exposure to common quaternary ammonium disinfectants decreases fertility in mice.

    PubMed

    Melin, Vanessa E; Potineni, Haritha; Hunt, Patricia; Griswold, Jodi; Siems, Bill; Werre, Stephen R; Hrubec, Terry C

    2014-12-01

    Quaternary ammonium compounds (QACs) are antimicrobial disinfectants commonly used in commercial and household settings. Extensive use of QACs results in ubiquitous human exposure, yet reproductive toxicity has not been evaluated. Decreased reproductive performance in laboratory mice coincided with the introduction of a disinfectant containing both alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC). QACs were detected in caging material over a period of several months following cessation of disinfectant use. Breeding pairs exposed for six months to a QAC disinfectant exhibited decreases in fertility and fecundity: increased time to first litter, longer pregnancy intervals, fewer pups per litter and fewer pregnancies. Significant morbidity in near term dams was also observed. In summary, exposure to a common QAC disinfectant mixture significantly impaired reproductive health in mice. This study illustrates the importance of assessing mixture toxicity of commonly used products whose components have only been evaluated individually.

  6. UV disinfection pilot plant study at the Savannah River Site

    SciTech Connect

    Huffines, R.L.; Beavers, B.A.

    1993-01-01

    An ultraviolet light disinfection system pilot plant was operated at the Savannah River Site Central Shops sanitary wastewater treatment package plant July 14, 1992 through August 13, 1992. The purpose was to determine the effectiveness of ultraviolet light disinfection on the effluent from the small package-type wastewater treatment plants currently used on-site. This pilot plant consisted of a rack of UV lights suspended in a stainless steel channel through which a sidestream of effluent from the treatment plant clarifier was pumped. Fecal coliform analyses were performed on the influent to and effluent from the pilot unit to verify the disinfection process. UV disinfection was highly effective in reducing fecal coliform colonies within NPDES permit limitations even under process upset conditions. The average fecal coliform reduction exceeded 99.7% using ultraviolet light disinfection under normal operating conditions at the package treatment plants.

  7. Efficacy of Five Commonly Used Disinfectants Against Turkey Arthritis Reovirus.

    PubMed

    Mor, Sunil K; Bekele, Aschalew Z; Sharafeldin, Tamer A; Porter, Robert E; Goyal, Sagar M

    2015-03-01

    Since late 2009, an unusual problem of reovirus-related lameness has been seen in market-age tom turkeys in the upper Midwest area of the United States. In this study, we determined the efficacy of five commonly used disinfectants (Virocid, Keno X5, Synergize, One Stroke, and Tek Trol) against turkey arthritis reoviruses (TARVs). For comparison, turkey enteric reovirus (TERV) and chicken arthritis reovirus (CARV) were also included. At their recommended concentrations, all five disinfectants were found to be effective virucidals, inactivating 99.99% of all viruses within 10 min. However, oxidizing agents and quaternary ammonium compounds + aldehyde types of disinfectants were more effective, killing the viruses in a shorter time (2-5 min) than the other types of disinfectants. These results indicate that these disinfectants can be an effective tool in the control of these viruses.

  8. UV disinfection pilot plant study at the Savannah River Site

    SciTech Connect

    Huffines, R.L.; Beavers, B.A.

    1993-05-01

    An ultraviolet light disinfection system pilot plant was operated at the Savannah River Site Central Shops sanitary wastewater treatment package plant July 14, 1992 through August 13, 1992. The purpose was to determine the effectiveness of ultraviolet light disinfection on the effluent from the small package-type wastewater treatment plants currently used on-site. This pilot plant consisted of a rack of UV lights suspended in a stainless steel channel through which a sidestream of effluent from the treatment plant clarifier was pumped. Fecal coliform analyses were performed on the influent to and effluent from the pilot unit to verify the disinfection process. UV disinfection was highly effective in reducing fecal coliform colonies within NPDES permit limitations even under process upset conditions. The average fecal coliform reduction exceeded 99.7% using ultraviolet light disinfection under normal operating conditions at the package treatment plants.

  9. Exposure to common quaternary ammonium disinfectants decreases fertility in mice

    PubMed Central

    Melin, Vanessa E.; Potineni, Haritha; Hunt, Patricia; Griswold, Jodi; Siems, Bill; Werre, Stephen R.; Hrubec, Terry C.

    2014-01-01

    Quaternary ammonium compounds (QACs) are antimicrobial disinfectants commonly used in commercial and household settings. Extensive use of QACs results in ubiquitous human exposure, yet reproductive toxicity has not been evaluated. Decreased reproductive performance in laboratory mice coincided with the introduction of a disinfectant containing both alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC). QACs were detected in caging material over a period of several months following cessation of disinfectant use. Breeding pairs exposed for six months to a QAC disinfectant exhibited decreases in fertility and fecundity: increased time to first litter, longer pregnancy intervals, fewer pups per litter and fewer pregnancies. Significant morbidity in near term dams was also observed. In summary, exposure to a common QAC disinfectant mixture significantly impaired reproductive health in mice. This study illustrates the importance of assessing mixture toxicity of commonly used products whose components have only been evaluated individually. PMID:25483128

  10. Recent advances in drinking water disinfection: successes and challenges.

    PubMed

    Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

    2013-01-01

    Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality

  11. Impact of disinfection on drinking water biofilm bacterial community.

    PubMed

    Mi, Zilong; Dai, Yu; Xie, Shuguang; Chen, Chao; Zhang, Xiaojian

    2015-11-01

    Disinfectants are commonly applied to control the growth of microorganisms in drinking water distribution systems. However, the effect of disinfection on drinking water microbial community remains poorly understood. The present study investigated the impacts of different disinfectants (chlorine and chloramine) and dosages on biofilm bacterial community in bench-scale pipe section reactors. Illumina MiSeq sequencing illustrated that disinfection strategy could affect both bacterial diversity and community structure of drinking water biofilm. Proteobacteria tended to predominate in chloraminated drinking water biofilms, while Firmicutes in chlorinated and unchlorinated biofilms. The major proteobacterial groups were influenced by both disinfectant type and dosage. In addition, chloramination had a more profound impact on bacterial community than chlorination. PMID:26574105

  12. Disinfection of contaminated water by using solar irradiation.

    PubMed

    Caslake, Laurie F; Connolly, Daniel J; Menon, Vilas; Duncanson, Catriona M; Rojas, Ricardo; Tavakoli, Javad

    2004-02-01

    Contaminated water causes an estimated 6 to 60 billion cases of gastrointestinal illness annually. The majority of these cases occur in rural areas of developing nations where the water supply remains polluted and adequate sanitation is unavailable. A portable, low-cost, and low-maintenance solar unit to disinfect unpotable water has been designed and tested. The solar disinfection unit was tested with both river water and partially processed water from two wastewater treatment plants. In less than 30 min in midday sunlight, the unit eradicated more than 4 log10 U (99.99%) of bacteria contained in highly contaminated water samples. The solar disinfection unit has been field tested by Centro Panamericano de Ingenieria Sanitaria y Ciencias del Ambiente in Lima, Peru. At moderate light intensity, the solar disinfection unit was capable of reducing the bacterial load in a controlled contaminated water sample by 4 log10 U and disinfected approximately 1 liter of water in 30 min.

  13. Mutagenic activity of disinfection by-products.

    PubMed

    Cognet, L; Courtois, Y; Mallevialle, J

    1986-11-01

    Data on raw water quality, disinfection treatment practices, and the resulting mutagenic properties of the treated water were compiled from pilot- and full-scale treatment experiments to evaluate that parameter which might produce variability in the results of a mutagenic study. Analysis of the data and comparison of treatment practices indicated that the measured mutagenic activity is strongly related to the characteristics of the organic matter in the raw water, the methodology used to sample and detect mutagens, the scale of the study both in terms of treatment flow and period of study, and the point at which and the conditions under which oxidants are added during treatment. Conclusions regarding disinfection systems in full-scale water treatment plants include the following: When raw water is pretreated and high concentrations of organics are present in the raw water, both ozonation and chlorination increased mutagenic activity. However, no significant difference in mutagenicity was found between the two oxidants. Both in the case of a nitrified groundwater and a clarified surface water, the mutagenic activity of the water after ozonation was related to its mutagenic activity before ozonation. With ozonation, mutagenic activity decreased after granular activated carbon (GAC) filtration. Thus, when GAC filtration follows ozone disinfection, early addition of oxidants may not be deleterious to the finished water quality. When chlorine or chlorine dioxide is added after GAC filtration, chlorine dioxide was found to produce a less mutagenic water than chlorine. Although these conclusions suggest means of controlling mutagenic activity during treatment, it must be stressed that the measurement of mutagenicity is a presumptive index of contamination level.

  14. Regenerable Iodine Water-Disinfection System

    NASA Technical Reports Server (NTRS)

    Sauer, Richard L.; Colombo, Gerald V.; Jolly, Clifford D.

    1994-01-01

    Iodinated resin bed for disinfecting water regenerated to extend its useful life. Water flows through regeneration bed of crystalline iodine during regeneration. At other times, flow diverted around regeneration bed. Although regeneration cycle was manually controlled in demonstration, readily automated to start and stop according to signals and stop according to signals from concentration sensors. Further benefit of regeneration is that regeneration bed provides highly concentrated biocide source (200 mg/L) when needed. Concentrated biocide used to superiodinate system after contamination from routine maintenance or unexpected introduction of large concentration of microbes.

  15. Bioassay and dose measurement in UV disinfection.

    PubMed Central

    Qualls, R G; Johnson, J D

    1983-01-01

    A bioassay method was developed to measure the average intensity within a UV disinfection reactor. The survival of spores of Bacillus subtilis was determined as a function of UV dose to prepare a standard curve. Spores were added to unknown systems, and the survival rate was used to determine the average intensity. A modification was used for flow-through reactors by which spores were injected as a spike and collected at a known time after injection. A point source summation method for calculating intensity was verified by bioassay measurements in a simple cylinder. This calculation method was also applied to multiple-lamp reactors. PMID:6405690

  16. Light responses of primate and other mammalian cones

    PubMed Central

    Cao, Li-Hui; Luo, Dong-Gen; Yau, King-Wai

    2014-01-01

    Retinal cones are photoreceptors for daylight vision. For lower vertebrates, cones are known to give monophasic, hyperpolarizing responses to light flashes. For primate cones, however, they have been reported to give strongly biphasic flash responses, with an initial hyperpolarization followed by a depolarization beyond the dark level, now a textbook dogma. We have reexamined this primate-cone observation and, surprisingly, found predominantly monophasic cone responses. Correspondingly, we found that primate cones began to adapt to steady light at much lower intensities than previously reported, explainable by a larger steady response to background light for a monophasic than for a biphasic response. Similarly, we have found a monophasic cone response for several other mammalian species. Thus, a monophasic flash response may in fact be the norm for primate and other mammalian cones as for lower-vertebrate cones. This revised information is important for ultimately understanding human retinal signal processing and correlating with psychophysical data. PMID:24550304

  17. Origin and Impact of Phototransduction Noise in Primate Cone Photoreceptors

    PubMed Central

    Angueyra, Juan Manuel; Rieke, Fred

    2013-01-01

    Noise in the responses of cone photoreceptors sets a fundamental limit to visual sensitivity, yet the origin of noise in mammalian cones and its relation to behavioral sensitivity are poorly understood. Our work here on primate cones improves understanding of these issues in three ways. First, we find that cone noise is not dominated by spontaneous photopigment activation or by quantal fluctuations in photon absorption but instead by other sources, namely channel noise and fluctuations in cGMP. Second, we find that adaptation in cones, unlike that in rods, affects signals and noise differently. This difference helps explain why thresholds for rod- and cone-mediated signals have different dependencies on background light level. Third, past estimates of noise in mammalian cones are too high to explain behavioral sensitivity. Our measurements indicate a lower level of cone noise, and thus help reconcile physiological and behavioral estimates of cone noise and sensitivity. PMID:24097042

  18. Light responses of primate and other mammalian cones.

    PubMed

    Cao, Li-Hui; Luo, Dong-Gen; Yau, King-Wai

    2014-02-18

    Retinal cones are photoreceptors for daylight vision. For lower vertebrates, cones are known to give monophasic, hyperpolarizing responses to light flashes. For primate cones, however, they have been reported to give strongly biphasic flash responses, with an initial hyperpolarization followed by a depolarization beyond the dark level, now a textbook dogma. We have reexamined this primate-cone observation and, surprisingly, found predominantly monophasic cone responses. Correspondingly, we found that primate cones began to adapt to steady light at much lower intensities than previously reported, explainable by a larger steady response to background light for a monophasic than for a biphasic response. Similarly, we have found a monophasic cone response for several other mammalian species. Thus, a monophasic flash response may in fact be the norm for primate and other mammalian cones as for lower-vertebrate cones. This revised information is important for ultimately understanding human retinal signal processing and correlating with psychophysical data. PMID:24550304

  19. 40 CFR 141.708 - Requirements when making a significant change in disinfection practice.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Changes to the point of disinfection; (2) Changes to the disinfectant(s) used in the treatment plant; (3... PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Treatment for Cryptosporidium Disinfection Profiling and Benchmarking Requirements § 141.708...

  20. 40 CFR 141.708 - Requirements when making a significant change in disinfection practice.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) Changes to the point of disinfection; (2) Changes to the disinfectant(s) used in the treatment plant; (3... PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Treatment for Cryptosporidium Disinfection Profiling and Benchmarking Requirements § 141.708...

  1. 40 CFR 141.708 - Requirements when making a significant change in disinfection practice.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Requirements when making a significant change in disinfection practice. 141.708 Section 141.708 Protection of Environment ENVIRONMENTAL...) Changes to the point of disinfection; (2) Changes to the disinfectant(s) used in the treatment plant;...

  2. 40 CFR 141.708 - Requirements when making a significant change in disinfection practice.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Requirements when making a significant change in disinfection practice. 141.708 Section 141.708 Protection of Environment ENVIRONMENTAL...) Changes to the point of disinfection; (2) Changes to the disinfectant(s) used in the treatment plant;...

  3. 40 CFR 141.541 - What are significant changes to disinfection practice?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false What are significant changes to disinfection practice? 141.541 Section 141.541 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... point of disinfection; (b) Changes to the disinfectant(s) used in the treatment plant; (c) Changes...

  4. 40 CFR 141.708 - Requirements when making a significant change in disinfection practice.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Requirements when making a significant change in disinfection practice. 141.708 Section 141.708 Protection of Environment ENVIRONMENTAL...) Changes to the point of disinfection; (2) Changes to the disinfectant(s) used in the treatment plant;...

  5. 40 CFR 141.541 - What are significant changes to disinfection practice?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false What are significant changes to disinfection practice? 141.541 Section 141.541 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... point of disinfection; (b) Changes to the disinfectant(s) used in the treatment plant; (c) Changes...

  6. 40 CFR 141.540 - Who has to develop a disinfection benchmark?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... benchmark? 141.540 Section 141.540 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.540 Who has to develop a disinfection benchmark? If you are a subpart H system required to develop a disinfection profile under §§...

  7. Corrosion control and disinfection studies in spacecraft water systems. [considering Saturn 5 orbital workshop

    NASA Technical Reports Server (NTRS)

    Shea, T. G.

    1974-01-01

    Disinfection and corrosion control in the water systems of the Saturn 5 Orbital Workshop Program are considered. Within this framework, the problem areas of concern are classified into four general areas: disinfection; corrosion; membrane-associated problems of disinfectant uptake and diffusion; and taste and odor problems arising from membrane-disinfectant interaction.

  8. 40 CFR 141.540 - Who has to develop a disinfection benchmark?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... benchmark? 141.540 Section 141.540 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.540 Who has to develop a disinfection benchmark? If you are a subpart H system required to develop a disinfection profile under §§...

  9. 40 CFR 141.540 - Who has to develop a disinfection benchmark?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... benchmark? 141.540 Section 141.540 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.540 Who has to develop a disinfection benchmark? If you are a subpart H system required to develop a disinfection profile under §§...

  10. 40 CFR 141.540 - Who has to develop a disinfection benchmark?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... benchmark? 141.540 Section 141.540 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.540 Who has to develop a disinfection benchmark? If you are a subpart H system required to develop a disinfection profile under §§...

  11. Regulated plasmalemmal expansion in nerve growth cones.

    PubMed

    Lockerbie, R O; Miller, V E; Pfenninger, K H

    1991-03-01

    To study the mechanisms underlying plasmalemmal expansion in the nerve growth cone, a cell-free assay was developed to quantify membrane addition, using ligand binding and sealed growth cone particles isolated by subcellular fractionation from fetal rat brain. Exposed versus total binding sites of 125I-wheat germ agglutinin were measured in the absence or presence of saponin, respectively, after incubation with various agents. Ca2(+)-ionophore A23187 in the presence of Ca2+ increases the number of binding sites (Bmax) but does not change their affinity (KD), indicating that new receptors appear on the plasma membrane. Similarly, membrane depolarization by high K+ or veratridine significantly induces, in a Ca2(+)-dependent manner, the externalization of lectin binding sites from an internal pool. Morphometric analysis of isolated growth cones indicates that A23187 and high K+ treatment cause a significant reduction in a specific cytoplasmic membrane compartment, thus confirming the lectin labeling results and identifying the plasmalemmal precursor. The isolated growth cones take up gamma-amino-butyric acid and serotonin, but show no evidence for Ca2(+)-dependent transmitter release so that transmitter exocytosis is dissociated from plasmalemmal expansion. The data demonstrate that plasmalemmal expansion in the growth cone is a regulated process and identify an internal pool of precursor membrane.

  12. Regulated plasmalemmal expansion in nerve growth cones

    PubMed Central

    1991-01-01

    To study the mechanisms underlying plasmalemmal expansion in the nerve growth cone, a cell-free assay was developed to quantify membrane addition, using ligand binding and sealed growth cone particles isolated by subcellular fractionation from fetal rat brain. Exposed versus total binding sites of 125I-wheat germ agglutinin were measured in the absence or presence of saponin, respectively, after incubation with various agents. Ca2(+)-ionophore A23187 in the presence of Ca2+ increases the number of binding sites (Bmax) but does not change their affinity (KD), indicating that new receptors appear on the plasma membrane. Similarly, membrane depolarization by high K+ or veratridine significantly induces, in a Ca2(+)-dependent manner, the externalization of lectin binding sites from an internal pool. Morphometric analysis of isolated growth cones indicates that A23187 and high K+ treatment cause a significant reduction in a specific cytoplasmic membrane compartment, thus confirming the lectin labeling results and identifying the plasmalemmal precursor. The isolated growth cones take up gamma-amino-butyric acid and serotonin, but show no evidence for Ca2(+)-dependent transmitter release so that transmitter exocytosis is dissociated from plasmalemmal expansion. The data demonstrate that plasmalemmal expansion in the growth cone is a regulated process and identify an internal pool of precursor membrane. PMID:1999470

  13. Whiskers, cones and pyramids created in sputtering by ion bombardment

    NASA Technical Reports Server (NTRS)

    Wehner, G. K.

    1979-01-01

    A thorough study of the role which foreign atoms play in cone formation during sputtering of metals revealed many experimental facts. Two types of cone formation were distinquished, deposit cones and seed cones. Twenty-six combinations of metals for seed cone formation were tested. The sputtering yield variations with composition for combinations which form seed cones were measured. It was demonstrated that whisker growth becomes a common occurrence when low melting point material is sputter deposited on a hot nonsputtered high melting point electrode.

  14. Effects of disinfectants on Campylobacter jejuni.

    PubMed Central

    Wang, W L; Powers, B W; Leuchtefeld, N W; Blaser, M J

    1983-01-01

    Because of the increasing recognition that Campylobacter jejuni is an important enteric pathogen of humans, we studied the effects of widely used disinfectants on the viability of this organism. At an inoculum size of 10(3) to 10(4) CFU/ml, 1.25 mg of hypochlorite per liter killed three strains within 1 min. At an inoculum size of 10(6) to 10(7) CFU/ml, 5 mg of hypochlorite per liter killed three strains within 15 min. Killing of similar concentrations of C. jejuni and Escherichia coli by hypochlorite was approximately the same. At the high inoculum, 0.15% phenolic compound, 10 mg of iodophor per liter, 1:50,000 quaternary ammonium compound, 70% ethyl alcohol, and 0.125% glutaraldehyde killed all three strains within 1 min. These studies demonstrate that, under the conditions we tested (pH 7.0; 24 to 26 degrees C), the recommended standard concentrations of disinfecting agents are adequate to destroy C. jejuni. PMID:6305266

  15. Disinfection byproduct formation from lignin precursors.

    PubMed

    Hua, Guanghui; Kim, Junsung; Reckhow, David A

    2014-10-15

    Lignin is the most abundant aromatic plant component in terrestrial ecosystems. This study was conducted to determine the contribution of lignin residues in natural water to the formation of disinfection byproducts (DBPs) in drinking water. We investigated the formation of different classes of DBPs from lignin model compounds, lignin polymers, and humic substances using two common disinfection techniques, chlorination and chloramination. The contributions of lignin to the overall formation of DBPs from these organic products were determined based on the observed abundances of individual lignin phenols and their DBP yields. Model lignin phenols generally produced higher trichloroacetic acid (TCAA) yields than chloroform and dichloroacetic acid (DCAA) during chlorination. Lignin phenols generally produced higher DBP yields but lower percentages of unknown total organic halogen compared to bulk humic substances and lignin polymers. The relative significance of lignin phenols as chlorination DBP precursors generally follows the order of TCAA > DCAA&chloroform. The relative significance of lignin phenols to DBP formation by chloramination follows the order: TCAA > DCAA&DCAN > chloroform. Overall, lignin phenols are more important as TCAA precursors than as chloroform and DCAA precursors.

  16. Measuring the effectiveness of gaseous virus disinfectants.

    PubMed

    Knotzer, Simone; Kindermann, Johanna; Modrof, Jens; Kreil, Thomas R

    2015-11-01

    The efficacy of gaseous disinfection is critical for prevention and treatment of microbial contamination in biotechnological facilities. For an evaluation of gaseous disinfection efficacy, a down-scaled laboratory model was established, using currently available carrier tests and a custom-made dry fog box. A mixture of peroxyacetic acid and hydrogen peroxide (PAA/HP) was investigated as example, at concentrations between 0.4 and 2.9 mL/m(3) for up to 3 h for inactivation of a panel of lipid-enveloped and non-lipid-enveloped viruses. The influenza viruses were most sensitive to PAA/HP treatment and minute virus of mice was most resistant. Bovine viral diarrhea virus and reovirus III showed intermediate stability and similar inactivation kinetics. Use of the dry fog box circumvents dedicating an entire lab for the investigation, which renders the generation of data more cost-effective and allows for production of highly reproducible kinetic data.

  17. Efficacies of selected disinfectants against Mycobacterium tuberculosis.

    PubMed

    Best, M; Sattar, S A; Springthorpe, V S; Kennedy, M E

    1990-10-01

    The activities of 10 formulations as mycobactericidal agents in Mycobacterium tuberculosis-contaminated suspensions (suspension test) and stainless steel surfaces (carrier test) were investigated with sputum as the organic load. The quaternary ammonium compound, chlorhexidine gluconate, and an iodophor were ineffective in all tests. Ethanol (70%) was effective against M. tuberculosis only in suspension in the absence of sputum. Povidone-iodine was not as efficacious when the test organism was dried on a surface as it was in suspension, and its activity was further reduced in the presence of sputum. Sodium hypochlorite required a higher concentration of available chlorine to achieve an effective level of disinfection than did sodium dichloroisocyanurate. Phenol (5%) was effective under all test conditions, producing at least a 4-log10 reduction in CFU. The undiluted glutaraldehyde-phenate solution was effective against M. tuberculosis and a second test organism, Mycobacterium smegmatis, even in the presence of dried sputum, whereas the diluted solution (1:16) was only effective against M. smegmatis in the suspension test. A solution of 2% glutaraldehyde was effective against M. tuberculosis. This investigation presents tuberculocidal efficacy data generated by methods simulating actual practices of routine disinfection. PMID:2121783

  18. Anaerobic effluent disinfection using ozone: byproducts formation.

    PubMed

    Silva, G H R; Daniel, L A; Bruning, H; Rulkens, W H

    2010-09-01

    This research was aimed at studying oxidation processes, coliform inactivation effectiveness and disinfection byproducts (DBPs) associated with the disinfection of anaerobic sanitary wastewater effluent with ozone applied at doses of 5.0, 8.0 and 10.0mg O(3)L(-1) for contact times of 5, 10 and 15 min. The wastewater used in this research was generated by the wastewater treatment plant (WWTP), University of São Paulo - Brazil. The total coliform inactivation range was 2.00-4.06 log(10), and the inactivation range for Escherichia coli was 2.41-4.65 log(10). Mean chemical oxygen demand (COD) reductions were 37.6%, 48.8% and 42.4% for doses of 5.0, 8.0 and 10.0mg O(3)L(-1), respectively. Aldehyde formation varied with dosage only when the ozone dose was increased from 5.0 to 8.0mg O(3)L(-1) for acetaldehyde and from 5.0 to 8.0 and from 8.0 to 10.0mg O(3)L(-1) for glyoxal. PMID:20434908

  19. Measuring the effectiveness of gaseous virus disinfectants.

    PubMed

    Knotzer, Simone; Kindermann, Johanna; Modrof, Jens; Kreil, Thomas R

    2015-11-01

    The efficacy of gaseous disinfection is critical for prevention and treatment of microbial contamination in biotechnological facilities. For an evaluation of gaseous disinfection efficacy, a down-scaled laboratory model was established, using currently available carrier tests and a custom-made dry fog box. A mixture of peroxyacetic acid and hydrogen peroxide (PAA/HP) was investigated as example, at concentrations between 0.4 and 2.9 mL/m(3) for up to 3 h for inactivation of a panel of lipid-enveloped and non-lipid-enveloped viruses. The influenza viruses were most sensitive to PAA/HP treatment and minute virus of mice was most resistant. Bovine viral diarrhea virus and reovirus III showed intermediate stability and similar inactivation kinetics. Use of the dry fog box circumvents dedicating an entire lab for the investigation, which renders the generation of data more cost-effective and allows for production of highly reproducible kinetic data. PMID:26260690

  20. Moist heat intraluminal disinfection of CAPD connectors.

    PubMed

    Fessia, S L; Grabowy, R S; Bousquet, G G

    1990-01-01

    A moist heat technique for disinfecting the inner lumen of commercially available connectology used in the exchange process for Continuous Ambulatory Peritoneal Dialysis (CAPD) was evaluated. Moist heat was generated by a device (PDM-1) that directed microwave energy to heat a sample solution containing a concentration of 10(6) microorganisms inside a pair of mated plastic CAPD connectors. Microorganisms tested included those most prevalent and most problematic in causing peritonitis. Testing, performed according to F.D.A. approved standards, involved heating a sample solution and then placing the sample solution into vials which were then sealed and incubated. Absolute determination of growth versus no growth was measured by macroscopic observation. Positive control samples were performed in the same manner but were not exposed to heat. Negative controls were performed in the same manner in the absence of test organisms. At temperatures of approximately 100 degrees C a D-value of 6.6 seconds was determined using the organism found the most thermoresistant. A cycle time of 54 seconds appeared sufficient to achieve a 10(6) population reduction of all microorganisms tested. The moist heat technique offers a safe, effective method for disinfection of the inner lumen of CAPD connectors. PMID:1982800

  1. Virus Sensitivity Index of UV disinfection.

    PubMed

    Tang, Walter Z; Sillanpää, Mika

    2015-01-01

    A new concept of Virus Sensitivity Index (VSI) is defined as the ratio between the first-order inactivation rate constant of a virus, ki, and that of MS2-phage during UV disinfection, kr. MS2-phage is chosen as the reference virus because it is recommended as a virus indicator during UV reactor design and validation by the US Environmental Protection Agency. VSI has wide applications in research, design, and validation of UV disinfection systems. For example, it can be used to rank the UV disinfection sensitivity of viruses in reference to MS2-phage. There are four major steps in deriving the equation between Hi/Hr and 1/VSI. First, the first-order inactivation rate constants are determined by regression analysis between Log I and fluence required. Second, the inactivation rate constants of MS2-phage are statistically analysed at 3, 4, 5, and 6 Log I levels. Third, different VSI values are obtained from the ki of different viruses dividing by the kr of MS2-phage. Fourth, correlation between Hi/Hr and 1/VSI is analysed by using linear, quadratic, and cubic models. As expected from the theoretical analysis, a linear relationship adequately correlates Hi/Hr and 1/VSI without an intercept. VSI is used to quantitatively predict the UV fluence required for any virus at any log inactivation (Log I). Four equations were developed at 3, 4, 5, and 6 Log I. These equations have been validated using external data which are not used for the virus development. At Log I less than 3, the equation tends to under-predict the required fluence at both low Log I such as 1 and 2 Log I. At Log I greater than 3 Log I, the equation tends to over-predict the fluence required. The reasons for these may very likely be due to the shoulder at the beginning and the tailing at the end of the collimated beam test experiments. At 3 Log I, the error percentage is less than 6%. The VSI is also used to predict inactivation rate constants under two different UV disinfection

  2. UV Disinfection System for Cabin Air

    NASA Astrophysics Data System (ADS)

    Lim, Soojung

    Ultraviolet (UV) radiation is commonly used for disinfection of water. As a result of advancements made in the last 10-15 years, the analysis and design of UV disinfection systems for water is well developed. UV disinfection is also used for disinfection of air; however, despite the fact the UV-air systems have a longer record of application than UV-water systems, the methods used to analyze and design UV-air disinfection systems remain quite empirical. It is well-established that the effectiveness of UV-air systems is strongly affected by the type of microorganisms, the irradiation level/type (lamp power and wavelength), duration of irradiation (exposure time), air movement pattern (mixing degree), and relative humidity. This paper will describe ongoing efforts to evaluate, design and test a UV-air system based on first principles. Specific issues to be addressed in this work will include laboratory measurements of relevant kinetics (i.e., UV dose-response behavior) and numerical simulations designed to represent fluid mechanics and the radiation intensity field. UV dose-response behavior of test microorganism was measured using a laboratory (bench-scale) system. Target microorganisms (e.g., bacterial spores) were first applied to membrane filters at sub-monolayer coverage. The filters were then transferred to an environmental chamber at fixed relative humidity (RH) and allowed to equilibrate with their surroundings. Microorganisms were then subjected to UV exposure under a collimated beam. The experiment was repeated at RH values ranging from 20% to 100%. UV dose-response behavior was observed to vary with RH. For example, at 100% RH, a UV dose of 20 mJ/cm2 accomplished 90% (1 log10 units) of the B. subtilis spore inactivation, whereas 99 % (2 log10 units) inactivation was accomplished at this same UV dose under 20% RH conditions. However, at higher doses, the result was opposite of that in low dose. Reactor behavior is simulated using an integrated application

  3. Efficacy of a variety of disinfectants against Listeria spp.

    PubMed Central

    Best, M; Kennedy, M E; Coates, F

    1990-01-01

    The efficacy of 14 disinfectants against Listeria innocua and two strains of Listeria monocytogenes in the presence of organic matter was studied. Quantitative efficacy tests were used. Many of the disinfectants tested were not as effective on Listeria spp. when the test organisms were dried onto the surface of steel disks (carrier tests) as they were when the organisms were placed in suspension (suspension test). The presence of whole serum and milk (2% fat) further reduced the disinfectant capacities of most of the formulations studied. Only three disinfectants (povidone-iodine, chlorhexidine gluconate, and glutaraldehyde) were effective in the carrier test in the presence of serum; however, all three were ineffective when challenged with milk (2% fat). Only one solution, sodium dichloroisocyanurate, was effective in the presence of milk. All but four formulations (chloramine-T, phosphoric acid, an iodophor, and formaldehyde) were effective in the suspension tests, regardless of the organic load. L. monocytogenes was observed to be slightly more resistant to disinfection than L. innocua was. There was no difference in disinfectant susceptibility between the two strains of L. monocytogenes. These findings emphasize the need for caution in selecting an appropriate disinfectant for use on contaminated surfaces, particularly in the presence of organic material. PMID:2106285

  4. Cytotoxicity assessment of residual high-level disinfectants.

    PubMed

    Ryu, Mizuyuki; Kobayashi, Toshihiro; Kawamukai, Emiko; Quan, Glenlelyn; Furuta, Taro

    2013-01-01

    Some studies show the uptake of disinfectants on medical devices but no studies on their cytotoxicity have been reported. This study aimed to assess that cytotoxicity in a 3-dimensional culture system using HeLa cells grown in matrices composed of collagen. Plastic materials were soaked in the use solutions of the widely used high-level disinfectants, glutaraldehyde (GA), ortho-phthalaldehyde (OPA) and peracetic acid (PAA). After being rinsed, they were allowed to dry and were embedded into the cell medium to investigate the cytotoxicity of the residual disinfectants. Cytotoxicity was observed with the polyvinyl chloride, polyurethane and silicon tubes soaked in GA and OPA, indicating that both disinfectants were absorbed in the test pieces, whereas for PAA, none was observed. As for the polytetrafluoroethylene (PTFE) tubes, no disinfectant displayed cytotoxicity. GA and OPA are primary irritants, having a potential to cause anaphylaxis and other forms of allergic reactions. There should be consideration not only about the toxicity of the residual disinfectant from poor rinsing, but also about the toxicity that would result from the disinfectants that were absorbed and consequently released from the medical devices or materials.

  5. Efficacy of a variety of disinfectants against Listeria spp.

    PubMed

    Best, M; Kennedy, M E; Coates, F

    1990-02-01

    The efficacy of 14 disinfectants against Listeria innocua and two strains of Listeria monocytogenes in the presence of organic matter was studied. Quantitative efficacy tests were used. Many of the disinfectants tested were not as effective on Listeria spp. when the test organisms were dried onto the surface of steel disks (carrier tests) as they were when the organisms were placed in suspension (suspension test). The presence of whole serum and milk (2% fat) further reduced the disinfectant capacities of most of the formulations studied. Only three disinfectants (povidone-iodine, chlorhexidine gluconate, and glutaraldehyde) were effective in the carrier test in the presence of serum; however, all three were ineffective when challenged with milk (2% fat). Only one solution, sodium dichloroisocyanurate, was effective in the presence of milk. All but four formulations (chloramine-T, phosphoric acid, an iodophor, and formaldehyde) were effective in the suspension tests, regardless of the organic load. L. monocytogenes was observed to be slightly more resistant to disinfection than L. innocua was. There was no difference in disinfectant susceptibility between the two strains of L. monocytogenes. These findings emphasize the need for caution in selecting an appropriate disinfectant for use on contaminated surfaces, particularly in the presence of organic material. PMID:2106285

  6. A review of heterogeneous photocatalysis for water and surface disinfection.

    PubMed

    Byrne, John Anthony; Dunlop, Patrick Stuart Morris; Hamilton, Jeremy William John; Fernández-Ibáñez, Pilar; Polo-López, Inmaculada; Sharma, Preetam Kumar; Vennard, Ashlene Sarah Margaret

    2015-03-30

    Photo-excitation of certain semiconductors can lead to the production of reactive oxygen species that can inactivate microorganisms. The mechanisms involved are reviewed, along with two important applications. The first is the use of photocatalysis to enhance the solar disinfection of water. It is estimated that 750 million people do not have accessed to an improved source for drinking and many more rely on sources that are not safe. If one can utilize photocatalysis to enhance the solar disinfection of water and provide an inexpensive, simple method of water disinfection, then it could help reduce the risk of waterborne disease. The second application is the use of photocatalytic coatings to combat healthcare associated infections. Two challenges are considered, i.e., the use of photocatalytic coatings to give "self-disinfecting" surfaces to reduce the risk of transmission of infection via environmental surfaces, and the use of photocatalytic coatings for the decontamination and disinfection of medical devices. In the final section, the development of novel photocatalytic materials for use in disinfection applications is reviewed, taking account of materials, developed for other photocatalytic applications, but which may be transferable for disinfection purposes.

  7. Cytotoxicity assessment of residual high-level disinfectants.

    PubMed

    Ryu, Mizuyuki; Kobayashi, Toshihiro; Kawamukai, Emiko; Quan, Glenlelyn; Furuta, Taro

    2013-01-01

    Some studies show the uptake of disinfectants on medical devices but no studies on their cytotoxicity have been reported. This study aimed to assess that cytotoxicity in a 3-dimensional culture system using HeLa cells grown in matrices composed of collagen. Plastic materials were soaked in the use solutions of the widely used high-level disinfectants, glutaraldehyde (GA), ortho-phthalaldehyde (OPA) and peracetic acid (PAA). After being rinsed, they were allowed to dry and were embedded into the cell medium to investigate the cytotoxicity of the residual disinfectants. Cytotoxicity was observed with the polyvinyl chloride, polyurethane and silicon tubes soaked in GA and OPA, indicating that both disinfectants were absorbed in the test pieces, whereas for PAA, none was observed. As for the polytetrafluoroethylene (PTFE) tubes, no disinfectant displayed cytotoxicity. GA and OPA are primary irritants, having a potential to cause anaphylaxis and other forms of allergic reactions. There should be consideration not only about the toxicity of the residual disinfectant from poor rinsing, but also about the toxicity that would result from the disinfectants that were absorbed and consequently released from the medical devices or materials. PMID:24366628

  8. GABA release from mouse axonal growth cones

    PubMed Central

    Gao, Xiao-Bing; van den Pol, Anthony N

    2000-01-01

    Using developing hypothalamic neurons from transgenic mice that express high levels of green fluorescent protein in growing axons, and an outside-out patch from mature neuronal membranes that contain neurotransmitter receptors as a sensitive detector, we found that GABA is released by a vesicular mechanism from the growth cones of developing axons prior to synapse formation. A low level of GABA release occurs spontaneously from the growth cone, and this is substantially increased by evoked action potentials. Neurotransmitters such as acetylcholine can enhance protein kinase C (PKC) activity even prior to synapse formation; PKC activation caused a substantial increase in spontaneous GABA release from the growth cone, probably acting at the axon terminal. These data indicate that GABA is secreted from axons during a stage of neuronal development when GABA is excitatory, and that neuromodulators could alter GABA release from the growing axon, potentially enabling other developing neurons of different transmitter phenotype to modulate the early actions of GABA. PMID:10718743

  9. Hurricane track forecast cones from fluctuations

    NASA Astrophysics Data System (ADS)

    Meuel, T.; Prado, G.; Seychelles, F.; Bessafi, M.; Kellay, H.

    2012-06-01

    Trajectories of tropical cyclones may show large deviations from predicted tracks leading to uncertainty as to their landfall location for example. Prediction schemes usually render this uncertainty by showing track forecast cones representing the most probable region for the location of a cyclone during a period of time. By using the statistical properties of these deviations, we propose a simple method to predict possible corridors for the future trajectory of a cyclone. Examples of this scheme are implemented for hurricane Ike and hurricane Jimena. The corridors include the future trajectory up to at least 50 h before landfall. The cones proposed here shed new light on known track forecast cones as they link them directly to the statistics of these deviations.

  10. Hurricane track forecast cones from fluctuations.

    PubMed

    Meuel, T; Prado, G; Seychelles, F; Bessafi, M; Kellay, H

    2012-01-01

    Trajectories of tropical cyclones may show large deviations from predicted tracks leading to uncertainty as to their landfall location for example. Prediction schemes usually render this uncertainty by showing track forecast cones representing the most probable region for the location of a cyclone during a period of time. By using the statistical properties of these deviations, we propose a simple method to predict possible corridors for the future trajectory of a cyclone. Examples of this scheme are implemented for hurricane Ike and hurricane Jimena. The corridors include the future trajectory up to at least 50 h before landfall. The cones proposed here shed new light on known track forecast cones as they link them directly to the statistics of these deviations.

  11. Hurricane track forecast cones from fluctuations

    PubMed Central

    Meuel, T.; Prado, G.; Seychelles, F.; Bessafi, M.; Kellay, H.

    2012-01-01

    Trajectories of tropical cyclones may show large deviations from predicted tracks leading to uncertainty as to their landfall location for example. Prediction schemes usually render this uncertainty by showing track forecast cones representing the most probable region for the location of a cyclone during a period of time. By using the statistical properties of these deviations, we propose a simple method to predict possible corridors for the future trajectory of a cyclone. Examples of this scheme are implemented for hurricane Ike and hurricane Jimena. The corridors include the future trajectory up to at least 50 h before landfall. The cones proposed here shed new light on known track forecast cones as they link them directly to the statistics of these deviations. PMID:22701776

  12. Pure bending of a solid cone

    NASA Astrophysics Data System (ADS)

    Renton, J. D.

    1997-05-01

    The problems of torsion, axial loading and shear of a solid cone were solved around the turn of the century by Michell and Föppl. Surprisingly, no solution to the problem of the elastic response of a cone to the only other possible resultant applied to its apex seems to have been published until now. The method used here is based on certain theoretical considerations related to the author's work on generalizing the engineering theory of beams. This means that the result is derived rather than being the result of a trial-and-error process. A comparison is made with the usual engineering theory as modified for variable bending stiffness. The two analyses give the same results at the limit as the cone angle tends to zero.

  13. Evaluation of alternative methods for the disinfection of toothbrushes.

    PubMed

    Komiyama, Edson Yukio; Back-Brito, Graziella Nuernberg; Balducci, Ivan; Koga-Ito, Cristiane Yumi

    2010-01-01

    The aim of this study was to evaluate alternative methods for the disinfection of toothbrushes considering that most of the previously proposed methods are expensive and cannot be easily implemented. Two-hundred toothbrushes with standardized dimensions and bristles were included in the study. The toothbrushes were divided into 20 experimental groups (n = 10), according to microorganism considered and chemical agent used. The toothbrushes were contaminated in vitro by standardized suspensions of Streptococcus mutans, Streptococcus pyogenes, Staphylococcus aureus or Candida albicans. The following disinfectants were tested: 0.12% chlorhexidine digluconate, 50% white vinegar, a triclosan-containing dentifrice solution, and a perborate-based tablet solution. The disinfection method was immersion in the disinfectant for 10 min. After the disinfection procedure, the number of remaining microbial cells was evaluated. The values of cfu/toothbrush of each group of microorganism after disinfection were compared by Kruskal-Wallis ANOVA and Dunn's test for multiple comparisons (5%). The chlorhexidine digluconate solution was the most effective disinfectant. The triclosan-based dentifrice solution promoted a significant reduction of all microorganisms' counts in relation to the control group. As to the disinfection with 50% vinegar, a significant reduction was observed for all the microorganisms, except for C. albicans. The sodium perborate solution was the less effective against the tested microorganisms. Solutions based on triclosan-containing dentifrice may be considered effective, nontoxic, cost-effective, and an easily applicable alternative for the disinfection of toothbrushes. The vinegar solution reduced the presence of S. aureus, S. mutans and S. pyogenes on toothbrushes. PMID:20339710

  14. Wettability changes in polyether impression materials subjected to immersion disinfection

    PubMed Central

    Shetty, Shweta; Kamat, Giridhar; Shetty, Rajesh

    2013-01-01

    Background: Disinfection of impression materials prevents cross-contamination; however, the disinfectants may alter the wettability property. The purpose of this investigation was to evaluate the wettability changes of polyether impression material after immersing in four different chemical disinfectant solutions for a period of 10 min and 30 min, respectively. Materials and Methods: A total of 45 samples of polyether dental impression material (Impregum soft, 3MESPE, St. Paul, MN, USA) were randomly divided into nine groups with five specimens each. Each specimen was disc shaped, flat of 32 mm diameter and 3 mm thickness. The samples were immersed in four disinfectant solutions: 2% Glutaraldehyde, 5% sodium hypochlorite, 0.05% iodophor, and 5.25% phenol for 10 min and 30 min, respectively. The control was without disinfection. Wettability of the samples was assessed by measuring the contact angle by using the Telescopic Goniometer. Data were subjected to analysis of variance (Fisher's test) and Tukey's post hoc test for multiple comparisons at 5% level of significance. Results: The contact angle of 20.21° ± 0.22° were recorded in the control samples. After 10 min, the samples that were immersed in 5% sodium hypochlorite and 5.25% phenol showed significant statistical increase in the contact angle as compared to the control (P < 0.001). After 30 min of disinfection, only the samples immersed in 0.05% iodophor showed there were no significant changes in the contact angle, whereas the other disinfectants significantly increased the contact angle and decreased the wettability of the polyether material. Conclusion: Within the limitations of the study, 2% glutaraldehyde proved safe for 10 min of immersion disinfection while 0.05% iodophor holds promise as an effective disinfectant without affecting the wettability of the material. PMID:24130593

  15. South African survey on disinfection techniques for the flexible nasopharyngoscope.

    PubMed

    Lubbe, Darlene E; Fagan, Johannes J

    2003-10-01

    This random survey was to determine the flexible nasopharyngoscope disinfection practice employed by South African otolaryngologists and to establish whether a breach in the disinfection process exists. The study also aimed to identify organisms most likely to be transmitted via endoscopy and to propose a protocol for the disinfection of the flexible nasopharyngoscope. A questionnaire regarding disinfection techniques used for the flexible nasopharyngoscope was sent to 90 otolaryngologists in South Africa. All provinces were equally represented in the survey. Forty-five otolaryngologists out of a total of 90 participated in the study. Many of the otolaryngologists had no access to a flexible nasopharyngoscope and were therefore not included in the study. Fewer than 50 per cent of the 45 surgeons washed the instrument with soap/detergent and water after use. Only 42 per cent of surgeons used a FDA-approved disinfectant, 52 per cent of which immersed the scope for a shorter period than the recommended contact time. Of the 58 per cent using non-FDA-approved products, 33 per cent used only a 70 per cent Isopropyl alcohol wipe, without immersion of the scope in disinfectant solution. The remaining 25 per cent used non-FDA-approved disinfectants either by wiping or limited immersion of the scope. Of the 45 surgeons, 49 per cent used a different method of disinfection for high-risk patients. Strict guidelines have been proposed for the disinfection of this semi-critical device by the Association of Professionals for Infection Control (APIC) and the Centers for Disease Control (CDC). These guidelines are currently not being followed by many South African otolaryngologists. There is therefore a real risk of transmitting infectious diseases, especially tuberculosis, via endoscopy.

  16. Lightcone: Light-cone generating script

    NASA Astrophysics Data System (ADS)

    Bernyk, Max

    2014-03-01

    Lightcone works with simulated galaxy data stored in a relational database to rearrange the data in a shape of a light-cone; simulated galaxy data is expected to be in a box volume. The light-cone constructing script works with output from the SAGE semi-analytic model, but will work with any other model that has galaxy positions (and other properties) saved per snapshots of the simulation volume distributed in time. The database configuration file is set up for PostgreSQL RDBMS, but can be modified for use with any other SQL database.

  17. Understanding Cone Photoreceptor Cell Death in Achromatopsia.

    PubMed

    Carvalho, Livia S; Vandenberghe, Luk H

    2016-01-01

    Colour vision is only achieved in the presence of healthy and functional cone photoreceptors found in the retina. It is an essential component of human vision and usually the first complaint patients undergoing vision degeneration have is the loss of daylight colour vision. Therefore, an understanding of the biology and basic mechanisms behind cone death under the degenerative state of retinal dystrophies and how the activation of the apoptotic pathway is triggered will provide valuable knowledge. It will also have broader applications for a spectrum of visual disorders and will be critical for future advances in translational research. PMID:26427416

  18. Status report on development of regulations for disinfectants and disinfection by-products

    SciTech Connect

    Not Available

    1991-06-01

    The purpose of this document is to indicate the status of regulation development for the disinfectants (Ds) and disinfection by-products (DBPs) and to solicit feedback from the public. Previously, EPA made available to the public a strawman rule (October 1989) and a conceptual framework for developing these regulations (December 1990). This document reflects EPA's current thinking on how the criteria for the D/DBP regulations are evolving. The document consists of four sections: (1) overview of anticipated general requirements of the rule and major issues, (2) fact sheet on the status of pertinent analytical methods, (3) fact sheet on the status of health effects information, and (4) draft compliance monitoring requirements.

  19. Disinfection of dental impressions and occlusal records by ultraviolet radiation.

    PubMed

    Larsen, T; Fiehn, N E; Peutzfeldt, A; Owall, B

    2000-06-01

    As chemical disinfection of dental impressions may cause adverse effects on materials and the dental personnel this study examined disinfection by ultraviolet radiation. Alginate, addition silicone rubber and red wax contaminated by Streptococcus salivarius, Fusobacterium nucleatum and five other bacteria in different suspension media were radiated for up to 18 min, and the number of colony forming units was compared to non-radiated controls. The effect of ultraviolet radiation differed among bacterial species and depended on the organic content in the suspension. Generally, the bacterial reduction after ultraviolet radiation was below 4 log steps and thus insufficient for disinfection of dental impressions. PMID:11307403

  20. Disinfection of dental impressions and occlusal records by ultraviolet radiation.

    PubMed

    Larsen, T; Fiehn, N E; Peutzfeldt, A; Owall, B

    2000-06-01

    As chemical disinfection of dental impressions may cause adverse effects on materials and the dental personnel this study examined disinfection by ultraviolet radiation. Alginate, addition silicone rubber and red wax contaminated by Streptococcus salivarius, Fusobacterium nucleatum and five other bacteria in different suspension media were radiated for up to 18 min, and the number of colony forming units was compared to non-radiated controls. The effect of ultraviolet radiation differed among bacterial species and depended on the organic content in the suspension. Generally, the bacterial reduction after ultraviolet radiation was below 4 log steps and thus insufficient for disinfection of dental impressions.

  1. Basaltic Cone Suggests Constructional Origin of Some Guyots.

    PubMed

    Christensen, M N; Gilbert, C M

    1964-01-17

    A basaltic cinder cone was built beneath the waters of Mono Lake in Pleistocene time. This cone is now exposed. Its internal structure, external form, and petrography suggest that it was constructed with a flat top.

  2. Basaltic Cone Suggests Constructional Origin of Some Guyots.

    PubMed

    Christensen, M N; Gilbert, C M

    1964-01-17

    A basaltic cinder cone was built beneath the waters of Mono Lake in Pleistocene time. This cone is now exposed. Its internal structure, external form, and petrography suggest that it was constructed with a flat top. PMID:17753148

  3. Measurements of growth cone adhesion to culture surfaces by micromanipulation

    PubMed Central

    1994-01-01

    Neurons were grown on plastic surfaces that were untreated, or treated with polylysine, laminin, or L1 and their growth cones were detached from their culture surface by applying known forces with calibrated glass needles. This detachment force was taken as a measure of the force of adhesion of the growth cone. We find that on all surfaces, lamellipodial growth cones require significantly greater detachment force than filopodial growth cones, but this differences is, in general, due to the greater area of lamellipodial growth cones compared to filopodial growth cones. That is, the stress (force/unit area) required for detachment was similar for growth cones of lamellipodial and filopodial morphology on all surfaces, with the exception of lamellipodial growth cones on L1-treated surfaces, which had a significantly lower stress of detachment than on other surfaces. Surprisingly, the forces required for detachment (760-3,340 mudynes) were three to 15 times greater than the typical resting axonal tension, the force exerted by advancing growth cones, or the forces of retraction previously measured by essentially the same method. Nor did we observe significant differences in detachment force among growth cones of similar morphology on different culture surfaces, with the exception of lamellipodial growth cones on L1-treated surfaces. These data argue against the differential adhesion mechanism for growth cone guidance preferences in culture. Our micromanipulations revealed that the most mechanically resistant regions of growth cone attachment were confined to quite small regions typically located at the ends of filopodia and lamellipodia. Detached growth cones remained connected to the substratum at these regions by highly elastic retraction fibers. The closeness of contact of growth cones to the substratum as revealed by interference reflection microscopy (IRM) did not correlate with our mechanical measurements of adhesion, suggesting that IRM cannot be used as a

  4. Antimicrobial-Coated Granules for Disinfecting Water

    NASA Technical Reports Server (NTRS)

    Akse, James R.; Holtsnider, John T.; Kliestik, Helen

    2011-01-01

    Methods of preparing antimicrobialcoated granules for disinfecting flowing potable water have been developed. Like the methods reported in the immediately preceding article, these methods involve chemical preparation of substrate surfaces (in this case, the surfaces of granules) to enable attachment of antimicrobial molecules to the surfaces via covalent bonds. A variety of granular materials have been coated with a variety of antimicrobial agents that include antibiotics, bacteriocins, enzymes, bactericides, and fungicides. When employed in packed beds in flowing water, these antimicrobial-coated granules have been proven effective against gram-positive bacteria, gram-negative bacteria, fungi, and viruses. Composite beds, consisting of multiple layers containing different granular antimicrobial media, have proven particularly effective against a broad spectrum of microorganisms. These media have also proven effective in enhancing or potentiating the biocidal effects of in-line iodinated resins and of very low levels of dissolved elemental iodine.

  5. Chemical disinfection under conditions of microgravity

    NASA Astrophysics Data System (ADS)

    Marchin, George L.

    1997-01-01

    There is enormous potential for point-of-use water purifiers where central water treatment does not exist or distribution systems are faulty and allow incursion of pathogenic organisms after primary treatment. Manned space missions on the Space Shuttle and planned missions on the Space Station also employ point-of-use water purifiers termed microbial check valves (MCVs). Polyiodide resin materials in use on the Space Shuttle within the MCV and in terrestrial water purifiers, silver and copper chelex resins, zirconium peroxide chelex resin, and a quaternary ammonium compound-Dow Corning 5700-polymerized to carbon and polystyrene beads, were compared for disinfection ability. Experiments were conducted in fluid processing apparatus (FPAs) at unit gravity and in microgravity conditions aboard seven STS missions. These new materials may have applications in both space and terrestrial water treatment devices.

  6. Predictive capability of chlorination disinfection byproducts models.

    PubMed

    Ged, Evan C; Chadik, Paul A; Boyer, Treavor H

    2015-02-01

    There are over 100 models that have been developed for predicting trihalomethanes (THMs), haloacetic acids (HAAs), bromate, and unregulated disinfection byproducts (DBPs). Until now no publication has evaluated the variability of previous THM and HAA models using a common data set. In this article, the standard error (SE), Marquardt's percent standard deviation (MPSD), and linear coefficient of determination (R(2)) were used to analyze the variability of 87 models from 23 different publications. The most robust models were capable of predicting THM4 with an SE of 48 μg L(-1) and HAA6 with an SE of 15 μg L(-1), both achieving R(2) > 0.90. The majority of models were formulated for THM4. There is a lack of published models evaluating total HAAs, individual THM and HAA species, bromate, and unregulated DBPs.

  7. The role of collapsing and cone rafting on eruption style changes and final cone morphology: Los Morados scoria cone, Mendoza, Argentina

    NASA Astrophysics Data System (ADS)

    Németh, Karoly; Risso, Corina; Nullo, Francisco; Kereszturi, Gabor

    2011-06-01

    Payún Matru Volcanic Field is a Quaternary monogenetic volcanic field that hosts scoria cones with perfect to breached morphologies. Los Morados complex is a group of at least four closely spaced scoria cones (Los Morados main cone and the older Cones A, B, and C). Los Morados main cone was formed by a long lived eruption of months to years. After an initial Hawaiian-style stage, the eruption changed to a normal Strombolian, conebuilding style, forming a cone over 150 metres high on a northward dipping (˜4°) surface. An initial cone gradually grew until a lava flow breached the cone's base and rafted an estimated 10% of the total volume. A sudden sector collapse initiated a dramatic decompression in the upper part of the feeding conduit and triggered violent a Strombolian style eruptive stage. Subsequently, the eruption became more stable, and changed to a regular Strombolian style that partially rebuilt the cone. A likely increase in magma flux coupled with the gradual growth of a new cone caused another lava flow outbreak at the structurally weakened earlier breach site. For a second time, the unstable flank of the cone was rafted, triggering a second violent Strombolian eruptive stage which was followed by a Hawaiian style lava fountain stage. The lava fountaining was accompanied by a steady outpour of voluminous lava emission accompanied by constant rafting of the cone flank, preventing the healing of the cone. Santa Maria is another scoria cone built on a nearly flat pre-eruption surface. Despite this it went through similar stages as Los Morados main cone, but probably not in as dramatic a manner as Los Morados. In contrast to these examples of large breached cones, volumetrically smaller cones, associated to less extensive lava flows, were able to heal raft/collapse events, due to the smaller magma output and flux rates. Our evidence shows that scoria cone growth is a complex process, and is a consequence of the magma internal parameters (e.g. volatile

  8. Funnel cone for focusing intense ion beams on a target

    SciTech Connect

    Bieniosek, F.M.; Henestroza, E.; Ni, P.

    2009-10-05

    We describe a funnel cone for concentrating an ion beam on a target. The cone utilizes the reflection characteristic of ion beams on solid walls to focus the incident beam andincrease beam intensity on target. The cone has been modeled with the TRIM code. A prototype has been tested and installed for use in the 350-keV K+ NDCX target chamber.

  9. Vision. Realignment of cones after cataract removal.

    PubMed

    Smallman, H S; MacLeod, D I; Doyle, P

    2001-08-01

    Through unique observations of an adult case of bilateral congenital cataract removal, we have found evidence that retinal photoreceptors will swiftly realign towards the brightest regions in the pupils of the eye. Cones may be phototropic, actively orientating themselves towards light like sunflowers in a field.

  10. Performance analysis of cone detection algorithms.

    PubMed

    Mariotti, Letizia; Devaney, Nicholas

    2015-04-01

    Many algorithms have been proposed to help clinicians evaluate cone density and spacing, as these may be related to the onset of retinal diseases. However, there has been no rigorous comparison of the performance of these algorithms. In addition, the performance of such algorithms is typically determined by comparison with human observers. Here we propose a technique to simulate realistic images of the cone mosaic. We use the simulated images to test the performance of three popular cone detection algorithms, and we introduce an algorithm which is used by astronomers to detect stars in astronomical images. We use Free Response Operating Characteristic (FROC) curves to evaluate and compare the performance of the four algorithms. This allows us to optimize the performance of each algorithm. We observe that performance is significantly enhanced by up-sampling the images. We investigate the effect of noise and image quality on cone mosaic parameters estimated using the different algorithms, finding that the estimated regularity is the most sensitive parameter. PMID:26366758

  11. Final design report for cone penetrometer platform

    SciTech Connect

    Seda, R.Y., Westinghouse Hanford

    1996-08-13

    The final design report documents the completion of the design review meetings for acceptance of the cone penetrometer from the vendor. All design comments have been dispositioned and closed. Open items dealt with completion of the safety assessment,operational procedures, operational testing and readiness review.

  12. In-office microwave disinfection of soft contact lenses

    SciTech Connect

    Harris, M.G.; Rechberger, J.; Grant, T.; Holden, B.A. )

    1990-02-01

    We evaluated the effectiveness of an in-office microwave disinfection procedure which allowed for the disinfection of up to 40 soft contact lenses at one time. Ciba AOSept cases filled with sterile unpreserved saline were contaminated with one of six FDA test challenge microorganisms at a concentration of approximately 10(3) colony forming units per milliliter (CFU/ml). Twenty cases were placed on the rotating plate of a standard 2450 MHz 650 W microwave oven in a 10-cm diameter circle. The cases were exposed to high intensity microwave irradiation for periods of 0 to 15 min. None of the 6 microorganisms evaluated survived 2 min or longer of microwave exposure. Our findings indicated that microwave irradiation can be a convenient, rapid, and effective method of disinfecting a number of soft contact lenses at one time and thus adaptable as an in-office soft contact lens disinfection procedure.

  13. 9 CFR 147.24 - Cleaning and disinfecting.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... dirty smock/coveralls and place into plastic garbage bag before loading in the truck. Be sure to keep... disinfectant before leaving the main road and entering the farm driveway. (2) Put on sturdy, disposable...

  14. 9 CFR 147.24 - Cleaning and disinfecting.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... dirty smock/coveralls and place into plastic garbage bag before loading in the truck. Be sure to keep... disinfectant before leaving the main road and entering the farm driveway. (2) Put on sturdy, disposable...

  15. U.S. EPA's Ultraviolet Disinfection Technologies Demonstration Study

    EPA Science Inventory

    This presentation will give a background on USEPA's Disinfection Technologies Demonstration Study. This will include regulatory background, science background, goals of the project, and ultimate expected outcome of the project. This presentation will preceed a panel discussion ...

  16. IDENTIFICATION OF TI02/UV DISINFECTION BYPRODUCTS IN DRINKING WATER

    EPA Science Inventory

    Due to concern over the presence of trihalomethanes (THMs) and other chlorinated byproducts in chlorinated drinking water, alternative disinfection methods are being explored. One of the alternative treatment methods currently being evaluated for potential use with small systems ...

  17. DISINFECTION OF WATER: DRINKING WATER, RECREATIONAL WATER, AND WASTEWATER

    EPA Science Inventory

    This chapter describes and categorizes the methodology used for disinfection of drinking water, recreational water and wastewater including wastewater sludges. It largely is a literature summary and references articles covering the years of 1939 through 1999, with a few reference...

  18. Use of buffered hypochlorite solution for disinfecting fibrescopes.

    PubMed Central

    Coates, D; Death, J E

    1982-01-01

    The possible use of sodium hypochlorite solution buffered to pH 7.6 and containing 100 ppm available chlorine (avCl) for disinfecting fibrescopes was investigated. A flexible fibrescope experimentally contaminated with Pseudomonas putida, Mycobacterium fortuitum, or Bacillus subtilis spores was effectively disinfected within 10 m in repeatedly and without any observable adverse effect on the instrument. The corrosive nature of buffered hypochlorite was investigated by immersing various fibrescope components and metal wires in solutions of different strength for long periods and examining them for damage. Stainless steel, platinum, glass, Teflon, polythene and epoxy resin were apparently unaffected whereas polyurethane, rubber and other metals tested were damaged to different extents. Buffered hypochlorite solutions may have many applications pertaining to the disinfection of items which are either thermolabile or require rapid effective disinfection. PMID:6802880

  19. USEPA Research on Monochloramine Disinfection Kinetics of Nitrosomonas Europaea

    EPA Science Inventory

    Based on utility surveys, 30 to 63% of utilities practicing chloramination for secondary disinfection experience nitrification episodes (American Water Works Association 2006). Nitrification in drinking water distribution systems is undesirable and may result in water quality deg...

  20. US EPA Research on Monochloramine Disinfection Kinetics of Nitrosomonas europaea

    EPA Science Inventory

    Based on utility surveys, 30 to 63% of utilities practicing chloramination for secondary disinfection experience nitrification episodes (American Water Works Association 2006). Nitrification in drinking water distribution systems is undesirable and may result in water quality deg...

  1. 9 CFR 147.24 - Cleaning and disinfecting.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... disinfectant before leaving the main road and entering the farm driveway. (2) Put on sturdy, disposable plastic... dirty smock/coveralls and place into plastic garbage bag before loading in the truck. Be sure to...

  2. Effects of wastewater disinfection on waterborne bacteria and viruses

    USGS Publications Warehouse

    Blatchley, E. R.; Gong, W.-L.; Alleman, J.E.; Rose, J.B.; Huffman, D.E.; Otaki, M.; Lisle, J.T.

    2007-01-01

    Wastewater disinfection is practiced with the goal of reducing risks of human exposure to pathogenic microorganisms. In most circumstances, the efficacy of a wastewater disinfection process is regulated and monitored based on measurements of the responses of indicator bacteria. However, inactivation of indicator bacteria does not guarantee an acceptable degree of inactivation among other waterborne microorganisms (e.g., microbial pathogens). Undisinfected effluent samples from several municipal wastewater treatment facilities were collected for analysis. Facilities were selected to provide a broad spectrum of effluent quality, particularly as related to nitrogenous compounds. Samples were subjected to bench-scale chlorination and dechlorination and UV irradiation under conditions that allowed compliance with relevant discharge regulations and such that disinfectant exposures could be accurately quantified. Disinfected samples were subjected to a battery of assays to assess the immediate and long-term effects of wastewater disinfection on waterborne bacteria and viruses. In general, (viable) bacterial populations showed an immediate decline as a result of disinfectant exposure; however, incubation of disinfected samples under conditions that were designed to mimic the conditions in a receiving stream resulted in substantial recovery of the total bacterial community. The bacterial groups that are commonly used as indicators do not provide an accurate representation of the response of the bacterial community to disinfectant exposure and subsequent recovery in the environment. UV irradiation and chlorination/dechlorination both accomplished measurable inactivation of indigenous phage; however, the extent of inactivation was fairly modest under the conditions of disinfection used in this study. UV irradiation was consistently more effective as a virucide than chlorination/dechlorination under the conditions of application, based on measurements of virus (phage

  3. [Research development on disinfection technology for viruses in drinking water].

    PubMed

    Zhang, Yun; Zhang, Qiang; Liu, Yan; Dai, Ruihua; Liu, Xiang

    2010-09-01

    With the deterioration of water source pollution, the quality requirements for drinking water of countries will become stricter and stricter, and the microbe index has been one of the important aspects. The introduction of the virus index and the development of disinfection technology focusing on virus have significant importance for the improvement of the drinking water standards and for the protection of people health in every country. To be familiar with the domestic and abroad research development of the disinfection control technology focusing on virus provides certain theory guidance and technological support for continuously improving drinking water standard in our country and for establishing safer drinking water processing technologies. So, this article will comprehensively describes 4 aspects: resistance comparison of virus over every disinfection technology, influential factors of disinfection, research development of new technology, and the mechanisms.

  4. Visual Cone Arrestin 4 Contributes to Visual Function and Cone Health

    PubMed Central

    Deming, Janise D.; Pak, Joseph S.; Brown, Bruce M.; Kim, Moon K.; Aung, Moe H.; Eom, Yun Sung; Shin, Jung-a; Lee, Eun-Jin; Pardue, Machelle T.; Craft, Cheryl Mae

    2015-01-01

    Purpose Visual arrestins (ARR) play a critical role in shutoff of rod and cone phototransduction. When electrophysiological responses are measured for a single mouse cone photoreceptor, ARR1 expression can substitute for ARR4 in cone pigment desensitization; however, each arrestin may also contribute its own, unique role to modulate other cellular functions. Methods A combination of ERG, optokinetic tracking, immunohistochemistry, and immunoblot analysis was used to investigate the retinal phenotypes of Arr4 null mice (Arr4−/−) compared with age-matched control, wild-type mice. Results When 2-month-old Arr4−/− mice were compared with wild-type mice, they had diminished visual acuity and contrast sensitivity, yet enhanced ERG flicker response and higher photopic ERG b-wave amplitudes. In contrast, in older Arr4−/− mice, all ERG amplitudes were significantly reduced in magnitude compared with age-matched controls. Furthermore, in older Arr4−/− mice, the total cone numbers decreased and cone opsin protein immunoreactive expression levels were significantly reduced, while overall photoreceptor outer nuclear layer thickness was unchanged. Conclusions Our study demonstrates that Arr4−/− mice display distinct phenotypic differences when compared to controls, suggesting that ARR4 modulates essential functions in high acuity vision and downstream cellular signaling pathways that are not fulfilled or substituted by the coexpression of ARR1, despite its high expression levels in all mouse cones. Without normal ARR4 expression levels, cones slowly degenerate with increasing age, making this a new model to study age-related cone dystrophy. PMID:26284544

  5. [Current disinfecting and antiseptic agents in anesthesiology and resuscitation].

    PubMed

    Pkhakadze, T Ia; Bogomolova, N S; Eremenko, A A

    1999-01-01

    Prevention of nosocomial infection includes, along with other factors, measures aimed at maintenance of aseptic and antiseptic conditions by means of modern effective antiseptics and disinfectants. Efficacy of skin antiseptics (plivasept tincture, plivasept blue, plivasept foamy), disinfectants for instruments, surfaces, equipment (plivasept with and without PAV, aldesol, isosan G) manufactured by Pliva (Croatia) is assessed at Surgical Center. All these agents are recommended for improving the epidemiological situation in intensive care departments.

  6. Equivalency testing of ultraviolet disinfection for wastewater reclamation

    SciTech Connect

    Oppenheimer, J.A.; Jacangelo, J.G.; Laine, J.M.

    1996-11-01

    UV light disinfection was shown to continuously provide microbial inactivation equivalent to chlorine while reducing the formation of known carcinogenic disinfection by-products and the formation of chronic whole effluent toxicity. This was the first study to demonstrate UV`s performance relative to chlorination over an extended timeframe at a full-scale facility treating to meet the most stringent California reclamation standards.

  7. [The mode of detection of microorganisms' sensitivity to disinfectants].

    PubMed

    Shkarin, V V; Blagonravova, A S; Kovalishena, O V

    2012-06-01

    The article presents the technique to evaluate the sensitivity of microorganisms-causative agents of infections isolated from patients, carriers and environment to the disinfectants. The proposed technique gives a possibility to detect the condition of microorganism resistance to disinfectant and to evaluate the degree of its sensitivity. The evaluation of sensitivity specificity accuracy, positive and negative prognostic value, reproducibility of developed technique was made.

  8. The effectiveness of photocatalytic ionisation disinfection of filter materials.

    PubMed

    Pietrzak, Katarzyna; Gutarowska, Beata

    2013-01-01

    The purpose of this study was to determine the effectiveness of photocatalytic ionisation as a disinfection method for filter materials contaminated by microorganisms, and to assess how air relative humidity (RH), time and microbe type influence the effectiveness of this disinfection. In the quantitative analysis of a used car air filter, bacterial contamination equalled 1.2 x 10(5) cfu/cm2, fungal contamination was 3.8 x 10(6) cfu/cm2, and the isolated microorganisms were Aspergillus niger, Bacillus megaterium, Cladosporium herbarum, Cryptococcus laurenti, Micrococcus sp., Rhodotorula glutinis and Staphylococcus cohnii. In the model experiment, three isolates (C. herbarum, R. glutinis, S. cohnii) and 3 ATCC species (A. niger, E. coli, S. aureus) were used for photocatalytic ionisation disinfection. The conditions of effective photocatalytic ionisation disinfection (R > or = 99.9%) were established as 2-3 h at RH = 77% (bacteria) and 6-24 h at RH = 53% (fungi). RH has an influence on the effectiveness of the photocatalytic disinfection process; the highest effectiveness was obtained for bacteria at RH = 77%, with results 5% higher than for RH = 49%. The studies show that the sensitivity of microorganisms to photocatalytic ionisation disinfection is ordered as follows: Gram-positive bacteria (S. cohnii, S. aureus), Gram-negative bacteria (E. coli), yeasts (R. glutinis), and moulds (C. herbarum, A. niger). Of all the mathematical models used for the description of death dynamics after photocatalytic ionisation disinfection, the Chick-Watson model is the most useful, but for more resistant microorganisms, the delayed Chick-Watson model is highly recommended. It therefore seems, that the presented disinfection method of photocatalytic ionisation can be successfully used to clean filtration materials.

  9. Perturbation theory in light-cone quantization

    SciTech Connect

    Langnau, A.

    1992-01-01

    A thorough investigation of light-cone properties which are characteristic for higher dimensions is very important. The easiest way of addressing these issues is by analyzing the perturbative structure of light-cone field theories first. Perturbative studies cannot be substituted for an analysis of problems related to a nonperturbative approach. However, in order to lay down groundwork for upcoming nonperturbative studies, it is indispensable to validate the renormalization methods at the perturbative level, i.e., to gain control over the perturbative treatment first. A clear understanding of divergences in perturbation theory, as well as their numerical treatment, is a necessary first step towards formulating such a program. The first objective of this dissertation is to clarify this issue, at least in second and fourth-order in perturbation theory. The work in this dissertation can provide guidance for the choice of counterterms in Discrete Light-Cone Quantization or the Tamm-Dancoff approach. A second objective of this work is the study of light-cone perturbation theory as a competitive tool for conducting perturbative Feynman diagram calculations. Feynman perturbation theory has become the most practical tool for computing cross sections in high energy physics and other physical properties of field theory. Although this standard covariant method has been applied to a great range of problems, computations beyond one-loop corrections are very difficult. Because of the algebraic complexity of the Feynman calculations in higher-order perturbation theory, it is desirable to automatize Feynman diagram calculations so that algebraic manipulation programs can carry out almost the entire calculation. This thesis presents a step in this direction. The technique we are elaborating on here is known as light-cone perturbation theory.

  10. Stability and effectiveness of chlorine disinfectants in water distribution systems

    SciTech Connect

    Olivieri, V.P.; Snead, M.C.; Kruse, C.W.; Kawata, K.

    1986-11-01

    A test system for water distribution was used to evaluate the stability and effectiveness of three residual disinfectants - free chlorine, combined chlorine, and chlorine dioxide - when challenged with a sewage contaminant. The test distribution system consisted of the street main and internal plumbing for two barracks at Fort George G. Meade, MD. To the existing pipe network, 152 m (500 ft) of 13-mm (0.5 in.) copper pipe were added for sampling, and 60 m (200 ft) of 2.54-cm (1.0 in.) plastic pipe were added for circulation. The levels of residual disinfectants tested were 0.2 mg/L and 1.0 mg/L as available chlorine. In the absence of a disinfectant residual, microorganisms in the sewage contaminant were consistently recovered at high levels. The presence of any disinfectant residual reduced the microorganism level and frequency of occurrence at the consumer's tap. Free chlorine was the most effective residual disinfectant and may serve as a marker or flag in the distribution network. Free chlorine and chlorine dioxide were the least stable in the pipe network. The loss of disinfectant in the pipe network followed first-order kinetics. The half-life determined in static tests for free chlorine, chlorine dioxide, and combined chlorine was 140, 93, and 1680 min.

  11. Disinfectants in health care: finding an alternative to chlorine dioxide.

    PubMed

    Keward, Josephine

    Cleanliness of the clinical environment has a direct impact on healthcare-associated infection (HCAI) incidence and there is increasing evidence of its importance with regard to infection prevention and control. While traditional high-level disinfectants have excellent antimicrobial properties, these are typically offset against issues such as corrosiveness, toxicity, cost and user acceptance. Recent years have seen several user-friendly sporicidal disinfectants emerge onto the market. Antimicrobial profile and user acceptance determine the clinical success of any disinfectant. Therefore, product adoption is often a two-stage process with a tabletop evaluation of the appropriate technical data, including efficacy claims, followed by an in-use product evaluation. The first part of this article demonstrates the importance of the clinical environment with respect to HCAI and examines some of the issues around disinfectants used in health care and considerations when selecting a new disinfectant for use. The second part reports the experiences of the Infection Prevention and Control team at Alder Hey Children's Hospital in their assessment and subsequent adoption of a new user-friendly sporicidal disinfectant into clinical practice.

  12. Mechanisms of Escherichia coli inactivation by several disinfectants.

    PubMed

    Cho, Min; Kim, Jaeeun; Kim, Jee Yeon; Yoon, Jeyong; Kim, Jae-Hong

    2010-06-01

    The objective of this study was to elucidate dominant mechanisms of inactivation, i.e. surface attack versus intracellular attack, during application of common water disinfectants such as ozone, chlorine dioxide, free chlorine and UV irradiation. Escherichia coli was used as a representative microorganism. During cell inactivation, protein release, lipid peroxidation, cell permeability change, damage in intracellular enzyme and morphological change were comparatively examined. For the same level of cell inactivation by chemical disinfectants, cell surface damage was more pronounced with strong oxidant such as ozone while damage in inner cell components was more apparent with weaker oxidant such as free chlorine. Chlorine dioxide showed the inactivation mechanism between these two disinfectants. The results suggest that the mechanism of cell inactivation is primarily related to the reactivity of chemical disinfectant. In contrast to chemical disinfectants, cell inactivation by UV occurred without any changes measurable with the methods employed. Understanding the differences in inactivation mechanisms presented herein is critical to identify rate-limiting steps involved in the inactivation process as well as to develop more effective disinfection strategies.

  13. Disinfection of Needleless Connector Hubs: Clinical Evidence Systematic Review

    PubMed Central

    Moureau, Nancy L.

    2015-01-01

    Background. Needleless connectors (NC) are used on virtually all intravascular devices, providing an easy access point for infusion connection. Colonization of NC is considered the cause of 50% of postinsertion catheter-related infections. Breaks in aseptic technique, from failure to disinfect, result in contamination and subsequent biofilm formation within NC and catheters increasing the potential for infection of central and peripheral catheters. Methods. This systematic review evaluated 140 studies and 34 abstracts on NC disinfection practices, the impact of hub contamination on infection, and measures of education and compliance. Results. The greatest risk for contamination of the catheter after insertion is the NC with 33–45% contaminated, and compliance with disinfection as low as 10%. The optimal technique or disinfection time has not been identified, although scrubbing with 70% alcohol for 5–60 seconds is recommended. Studies have reported statistically significant results in infection reduction when passive alcohol disinfection caps are used (48–86% reduction). Clinical Implications. It is critical for healthcare facilities and clinicians to take responsibility for compliance with basic principles of asepsis compliance, to involve frontline staff in strategies, to facilitate education that promotes understanding of the consequences of failure, and to comply with the standard of care for hub disinfection. PMID:26075093

  14. Effects of Disinfectants on Larval Development of Ascaris suum Eggs

    PubMed Central

    Oh, Ki-Seok; Kim, Geon-Tae; Ahn, Kyu-Sung; Shin, Sung-Shik

    2016-01-01

    The objective of this study was to evaluate the effects of several different commercial disinfectants on the embryogenic development of Ascaris suum eggs. A 1-ml aliquot of each disinfectant was mixed with approximately 40,000 decorticated or intact A. suum eggs in sterile tubes. After each treatment time (at 0.5, 1, 5, 10, 30, and 60 min), disinfectants were washed away, and egg suspensions were incubated at 25˚C in distilled water for development of larvae inside. At 3 weeks of incubation after exposure, ethanol, methanol, and chlorohexidin treatments did not affect the larval development of A. suum eggs, regardless of their concentration and treatment time. Among disinfectants tested in this study, 3% cresol, 0.2% sodium hypochlorite and 0.02% sodium hypochlorite delayed but not inactivated the embryonation of decorticated eggs at 3 weeks of incubation, because at 6 weeks of incubation, undeveloped eggs completed embryonation regardless of exposure time, except for 10% povidone iodine. When the albumin layer of A. suum eggs remained intact, however, even the 10% povidone iodine solution took at least 5 min to reasonably inactivate most eggs, but never completely kill them with even 60 min of exposure. This study demonstrated that the treatment of A. suum eggs with many commercially available disinfectants does not affect the embryonation. Although some disinfectants may delay or stop the embryonation of A. suum eggs, they can hardly kill them completely. PMID:26951988

  15. Effect of well disinfection on arsenic in ground water

    USGS Publications Warehouse

    Gotkowitz, M.; Ellickson, K.; Clary, A.; Bowman, G.; Standridge, J.; Sonzogni, W.

    2008-01-01

    Domestic water wells are routinely subjected to in situ chemical disinfection treatments to control nuisance or pathogenic bacteria. Most treatments are chlorine based and presumably cause strongly oxidizing conditions in the wellbore. Water resource managers in Wisconsin were concerned that such treatments might facilitate release of arsenic from sulfide minerals disseminated within a confined sandstone aquifer. To test this hypothesis, a well was subjected to four disinfection treatments over 9 months time. The first treatment consisted of routine pumping of the well without chemical disinfection; three subsequent treatments included chlorine disinfection and pumping. Pretreatment arsenic concentrations in well water ranged from 7.4 to 18 ??g/L. Elevated arsenic concentrations up to 57 ??g/L in the chemical treatment solutions purged from the well are attributed to the disintegration or dissolution of biofilms or scale. Following each of the four treatments, arsenic concentrations decreased to less than 10 ??g/L during a period of pumping. Arsenic concentrations generally returned to pretreatment levels under stagnant, nonpumping conditions imposed following each treatment. Populations of iron-oxidizing, heterotrophic, and sulfate-reducing bacteria decreased following chemical treatments but were never fully eradicated from the well. Strongly oxidizing conditions were induced by the chlorine-based disinfections, but the treatments did not result in sustained increases in well water arsenic. Results suggest that disruption of biofilm and mineral deposits in the well and the water distribution system in tandem with chlorine disinfection can improve water quality in this setting. ?? 2008 The Author(s).

  16. SAFER STERILE COMPOUNDING: Choosing and Using Disinfectants for the Cleanroom.

    PubMed

    Kastango, Eric S; Douglass, Kate; Patel, Kedar; Givehchi, Babak; Brister, Paul; Postlewaite, Jay; Taraban, Laura

    2015-01-01

    Compounders worldwide are responsible for ensuring that the sterile preparations they dispense are pure, potent, and safe. To achieve that result, proper cleaning and disinfection of International Organization for Standardization controlled environments must occur. Because those tasks must be performed according to established standards, the compounding pharmacist must research regulatory requirements and appropriate products for use. In this report, we focus on U.S. regulations, guiding entities, and effective products that enable compliance with the increasingly stringent procedures required for pharmaceutical compounding. We also review cleaning and disinfecting processes, discuss the importance of correctly choosing and using disinfectants and/ or sporicidal disinfectants with surface claims in the cleanroom, and provide answers to questions frequently asked by staff who use those agents. In addition, we profile specific disinfectants that are compliant with UnitedStates Pharmacopeia Chapter <797> and current good manufacturing practice standards. Biological safety cabinets and compounding aseptic containment isolators must undergo an additional process that deactivates hazardous drug residues and removes them from the interior surfaces of those devices before they are cleaned and disinfected, but that discussion is beyond the scope of this article.

  17. Essential oils for the disinfection of grey water.

    PubMed

    Winward, Gideon P; Avery, Lisa M; Stephenson, Tom; Jefferson, Bruce

    2008-04-01

    Although the antimicrobial properties of many plant essential oils (EOs) are well known, their application for the disinfection of water has received little attention. In this study, their use as alternative 'natural' disinfectants for grey water reuse was assessed. Toxicity screening of eight EOs and their components highlighted origanum oil (Thymus capitatus) and carvacrol as exerting the most antimicrobial activity. Over a 30-min contact time, origanum EO concentrations of up to 94 mg L(-1) had minimal effect on total coliform concentrations in the grey water while a concentration of 468 mg L(-1) rendered total coliforms non-detectable in 100mL grey water. Coliform inactivation was found to increase with EO contact time. Organic concentration and particulate size in grey water were shown to reduce the efficacy of disinfection with origanum EO. Origanum EO prevented regrowth of coliform bacteria in reed bed-treated grey water for up to 14 days at a concentration of 468 mg L(-1), with or without prior disinfection by ultraviolet (UV) light. Based on the disinfection data reported here, the production of sufficient origanum EO for the disinfection of grey water for reuse with toilet flushing, would require approximately 35 times the average land area of a UK household.

  18. Microbial contamination of fruit and vegetables and their disinfection.

    PubMed

    Oie, Shigeharu; Kiyonaga, Hiroko; Matsuzaka, Yuuki; Maeda, Kumiko; Masuda, Yuki; Tasaka, Katsuko; Aritomi, Sanae; Yamashita, Akiko; Kamiya, Akira

    2008-10-01

    We evaluated the microbial contamination of 17 types of vegetable and 10 types of fruit after 30-s washing with tap water with and without subsequent disinfection by 10-min immersion in 0.01% (100 ppm) sodium hypochlorite. The mean microbial contamination level of 9 types of leafy vegetable was 2.8 x 10(5) colony-forming units (CFU)/g after washing with water and 3.4 x 10(4) CFU/g after washing followed by disinfection. The mean microbial contamination level of 8 types of nonleafy vegetable was 3.4 x 10(4) CFU/g after washing with water and 1.0 x 10(4) CFU/g after washing followed by disinfection. The mean microbial contamination level of 10 types of unpeeled fleshy fruit was 9.3 x 10(3) CFU/g after washing with water and 1.3 x 10(3) CFU/g after washing followed by disinfection. The contaminants in vegetables and unpeeled fruit were similar after washing and after washing followed by disinfection, including Pseudomonas fluorescens and Pseudomonas aeruginosa. The contamination did not markedly decrease even after disinfection with sodium hypochlorite. However, the flesh of each type of peeled fruit showed no or only low levels of contamination (

  19. SAFER STERILE COMPOUNDING: Choosing and Using Disinfectants for the Cleanroom.

    PubMed

    Kastango, Eric S; Douglass, Kate; Patel, Kedar; Givehchi, Babak; Brister, Paul; Postlewaite, Jay; Taraban, Laura

    2015-01-01

    Compounders worldwide are responsible for ensuring that the sterile preparations they dispense are pure, potent, and safe. To achieve that result, proper cleaning and disinfection of International Organization for Standardization controlled environments must occur. Because those tasks must be performed according to established standards, the compounding pharmacist must research regulatory requirements and appropriate products for use. In this report, we focus on U.S. regulations, guiding entities, and effective products that enable compliance with the increasingly stringent procedures required for pharmaceutical compounding. We also review cleaning and disinfecting processes, discuss the importance of correctly choosing and using disinfectants and/ or sporicidal disinfectants with surface claims in the cleanroom, and provide answers to questions frequently asked by staff who use those agents. In addition, we profile specific disinfectants that are compliant with UnitedStates Pharmacopeia Chapter <797> and current good manufacturing practice standards. Biological safety cabinets and compounding aseptic containment isolators must undergo an additional process that deactivates hazardous drug residues and removes them from the interior surfaces of those devices before they are cleaned and disinfected, but that discussion is beyond the scope of this article. PMID:26625562

  20. Simulated and empiric wind pollination patterns of conifer ovulate cones

    PubMed Central

    Niklas, Karl J.

    1982-01-01

    Wind tunnel analyses of conifer ovulate cones indicate that the total geometry of the cone enhances the probability of pollen entrapment. Aerodynamic characteristics of cone scale-bract complexes are such that suspended pollen is directed toward the micropyles of attached ovules. Within the taxa examined, there appears to be a preferential entrapment by ovulate cones of pollen of the same species. The data are interpreted as evidence for an aerodynamic reciprocity between wind-suspended pollen and the structure of ovulate cones which increases the frequency of pollination and the potential for fertilization. Images PMID:16593147

  1. A MULTIPLE-PURPOSE DESIGN APPROACH TO THE EVALUATION OF RISKS FROM COMPLEX MIXTURES OF DISINFECTION BY-PRODUCTS

    EPA Science Inventory

    Drinking water disinfection has effectively eliminated much of the morbidity and mortality associated with waterborne infectious diseases in the United States. Various disinfection processes, however, produce certain types and amounts of disinfection by-products (DBPs), including...

  2. Disinfection and Sterilization in Health Care Facilities: An Overview and Current Issues.

    PubMed

    Rutala, William A; Weber, David J

    2016-09-01

    When properly used, disinfection and sterilization can ensure the safe use of invasive and noninvasive medical devices. The method of disinfection and sterilization depends on the intended use of the medical device: critical items (contact sterile tissue) must be sterilized before use; semicritical items (contact mucous membranes or nonintact skin) must be high-level disinfected; and noncritical items (contact intact skin) should receive low-level disinfection. Cleaning should always precede high-level disinfection and sterilization. Current disinfection and sterilization guidelines must be strictly followed. PMID:27515140

  3. Characterizing the Human Cone Photoreceptor Mosaic via Dynamic Photopigment Densitometry

    PubMed Central

    Sabesan, Ramkumar; Hofer, Heidi; Roorda, Austin

    2015-01-01

    Densitometry is a powerful tool for the biophysical assessment of the retina. Until recently, this was restricted to bulk spatial scales in living humans. The application of adaptive optics (AO) to the conventional fundus camera and scanning laser ophthalmoscope (SLO) has begun to translate these studies to cellular scales. Here, we employ an AOSLO to perform dynamic photopigment densitometry in order to characterize the optical properties and spectral types of the human cone photoreceptor mosaic. Cone-resolved estimates of optical density and photosensitivity agree well with bulk estimates, although show smaller variability than previously reported. Photopigment kinetics of individual cones derived from their selective bleaching allowed efficient mapping of cone sub-types in human retina. Estimated uncertainty in identifying a cone as long vs middle wavelength was less than 5%, and the total time taken per subject ranged from 3–9 hours. Short wavelength cones were delineated in every subject with high fidelity. The lack of a third cone-type was confirmed in a protanopic subject. In one color normal subject, cone assignments showed 91% correspondence against a previously reported cone-typing method from more than a decade ago. Combined with cone-targeted stimulation, this brings us closer in studying the visual percept arising from a specific cone type and its implication for color vision circuitry. PMID:26660894

  4. Prospects for retinal cone-targeted gene therapy.

    PubMed

    Alexander, John J; Hauswirth, William W

    2008-06-01

    Gene therapy strategies that target therapeutic genes to retinal cones are a worthy goal both because cone photoreceptor diseases are severely vision limiting and because many retinal diseases that do not affect cones directly eventually lead to cone loss, the reason for eventual blindness. Human achromatopsia is a genetic disease of cones that renders them nonfunctional but otherwise intact. Thus, animal models of achromatopsia were used in conjunction with adeno-associated virus (AAV) vectors whose serotype efficiently transduces cones and with a promoter that limits transgene expression to cones. In the Gnat2(cpfl3) mouse model of one genetic form of human achromatopsia, we were able to demonstrate recovery of normal cone function and visual acuity after a single subretinal treatment of vector that supplied wild-type Gnat2 protein to cones. This validates the overall strategy of targeting cones using recombinant viral vectors and justifies a more complete examination of animal models of cone disease as a prelude to considering a clinical gene therapy trial. PMID:18596991

  5. Micro focusing of fast electrons with opened cone targets

    SciTech Connect

    Liu Feng; Liu Xiaoxuan; Ding Wenjun; Du Fei; Li Yutong; Ma Jinglong; Liu Xiaolong; Chen Liming; Lu Xin; Dong Quanli; Wang Weimin; Wang Zhaohua; Wei Zhiyi; Liu Bicheng; Sheng Zhengming; Zhang Jie

    2012-01-15

    Using opened reentrant cone silicon targets, we have demonstrated the effect of micro focusing of fast electrons generated in intense laser-plasma interactions. When an intense femtosecond laser pulse is focused tightly onto one of the side walls of the cone, fast electron beam emitted along the side wall is observed. When a line focus spot, which is long enough to irradiate both of the side walls of the cone simultaneously, is used, two electron beams emitted along each side wall, respectively, are observed. The two beams should cross each other near the open tip of the cone, resulting in micro focusing. We use a two-dimensional Particle-In-Cell code to simulate the electron emission both in opened and closed cone targets. The simulation results of the opened cone targets are in agreement with the experimental observation while the results of the closed cone targets do not show the micro focusing effect.

  6. In vitro study on the disinfectability of two split-septum needle-free connection devices using different disinfection procedures

    PubMed Central

    Engelhart, Steffen; Exner, Martin; Simon, Arne

    2015-01-01

    This in vitro study investigated the external disinfection of two needle-free connection devices (NFC) using Octeniderm® (spraying and wiping technique) vs. Descoderm® pads (wiping technique). The split-septum membrane of the NFC was contaminated with >105 CFU K. pneumoniae or S. epidermidis. The efficacy of the disinfection at 30 sec. exposure time was controlled by taking a swab sample and by flushing the NFC with sterile 0.9% sodium chloride solution. Disinfection with octenidine dihydrochloride 0.1 g, 1-Propanol 30.0 g, and 2-Propanol 45.0 g in 100 g solution was highly effective (CFU reduction ≥4 log) against both microorganisms, whereas the use of 63.1 g 2-Propanol in 100 ml solution led to residual contamination with S. epidermidis. Our investigation underlines that (i) in clinical practice disinfection of NFCs before use is mandatory, and that (ii) details of disinfection technique are of utmost importance regarding their efficacy. Our investigation revealed no significant differences between both split-septum NFC types. Clinical studies are needed to confirm a possible superiority of disinfectants with long-lasting residual antimicrobial activity. PMID:26693394

  7. WE-G-18A-03: Cone Artifacts Correction in Iterative Cone Beam CT Reconstruction

    SciTech Connect

    Yan, H; Folkerts, M; Jiang, S; Jia, X; Wang, X; Bai, T; Lu, W

    2014-06-15

    Purpose: For iterative reconstruction (IR) in cone-beam CT (CBCT) imaging, data truncation along the superior-inferior (SI) direction causes severe cone artifacts in the reconstructed CBCT volume images. Not only does it reduce the effective SI coverage of the reconstructed volume, it also hinders the IR algorithm convergence. This is particular a problem for regularization based IR, where smoothing type regularization operations tend to propagate the artifacts to a large area. It is our purpose to develop a practical cone artifacts correction solution. Methods: We found it is the missing data residing in the truncated cone area that leads to inconsistency between the calculated forward projections and measured projections. We overcome this problem by using FDK type reconstruction to estimate the missing data and design weighting factors to compensate the inconsistency caused by the missing data. We validate the proposed methods in our multi-GPU low-dose CBCT reconstruction system on multiple patients' datasets. Results: Compared to the FDK reconstruction with full datasets, while IR is able to reconstruct CBCT images using a subset of projection data, the severe cone artifacts degrade overall image quality. For head-neck case under a full-fan mode, 13 out of 80 slices are contaminated. It is even more severe in pelvis case under half-fan mode, where 36 out of 80 slices are affected, leading to inferior soft-tissue delineation. By applying the proposed method, the cone artifacts are effectively corrected, with a mean intensity difference decreased from ∼497 HU to ∼39HU for those contaminated slices. Conclusion: A practical and effective solution for cone artifacts correction is proposed and validated in CBCT IR algorithm. This study is supported in part by NIH (1R01CA154747-01)

  8. X-linked cone dystrophy caused by mutation of the red and green cone opsins.

    PubMed

    Gardner, Jessica C; Webb, Tom R; Kanuga, Naheed; Robson, Anthony G; Holder, Graham E; Stockman, Andrew; Ripamonti, Caterina; Ebenezer, Neil D; Ogun, Olufunmilola; Devery, Sophie; Wright, Genevieve A; Maher, Eamonn R; Cheetham, Michael E; Moore, Anthony T; Michaelides, Michel; Hardcastle, Alison J

    2010-07-01

    X-linked cone and cone-rod dystrophies (XLCOD and XLCORD) are a heterogeneous group of progressive disorders that solely or primarily affect cone photoreceptors. Mutations in exon ORF15 of the RPGR gene are the most common underlying cause. In a previous study, we excluded RPGR exon ORF15 in some families with XLCOD. Here, we report genetic mapping of XLCOD to Xq26.1-qter. A significant LOD score was detected with marker DXS8045 (Z(max) = 2.41 [theta = 0.0]). The disease locus encompasses the cone opsin gene array on Xq28. Analysis of the array revealed a missense mutation (c. 529T>C [p. W177R]) in exon 3 of both the long-wavelength-sensitive (LW, red) and medium-wavelength-sensitive (MW, green) cone opsin genes that segregated with disease. Both exon 3 sequences were identical and were derived from the MW gene as a result of gene conversion. The amino acid W177 is highly conserved in visual and nonvisual opsins across species. We show that W177R in MW opsin and the equivalent W161R mutation in rod opsin result in protein misfolding and retention in the endoplasmic reticulum. We also demonstrate that W177R misfolding, unlike the P23H mutation in rod opsin that causes retinitis pigmentosa, is not rescued by treatment with the pharmacological chaperone 9-cis-retinal. Mutations in the LW/MW cone opsin gene array can, therefore, lead to a spectrum of disease, ranging from color blindness to progressive cone dystrophy (XLCOD5). PMID:20579627

  9. Establishment of a cone photoreceptor transplantation platform based on a novel cone-GFP reporter mouse line

    PubMed Central

    Smiley, Sheila; Nickerson, Philip E.; Comanita, Lacrimioara; Daftarian, Narsis; El-Sehemy, Ahmed; Tsai, En Leh Samuel; Matan-Lithwick, Stuart; Yan, Keqin; Thurig, Sherry; Touahri, Yacine; Dixit, Rajiv; Aavani, Tooka; De Repentingy, Yves; Baker, Adam; Tsilfidis, Catherine; Biernaskie, Jeff; Sauvé, Yves; Schuurmans, Carol; Kothary, Rashmi; Mears, Alan J.; Wallace, Valerie A.

    2016-01-01

    We report successful retinal cone enrichment and transplantation using a novel cone-GFP reporter mouse line. Using the putative cone photoreceptor-enriched transcript Coiled-Coil Domain Containing 136 (Ccdc136) GFP-trapped allele, we monitored developmental reporter expression, facilitated the enrichment of cones, and evaluated transplanted GFP-labeled cones in wildtype and retinal degeneration mutant retinas. GFP reporter and endogenous Ccdc136 transcripts exhibit overlapping temporal and spatial expression patterns, both initiated in cone precursors of the embryonic retina and persisting to the adult stage in S and S/M opsin+ cones as well as rod bipolar cells. The trapped allele does not affect cone function or survival in the adult mutant retina. When comparing the integration of GFP+ embryonic cones and postnatal Nrl−/− ‘cods’ into retinas of adult wildtype and blind mice, both cell types integrated and exhibited a degree of morphological maturation that was dependent on donor age. These results demonstrate the amenability of the adult retina to cone transplantation using a novel transgenic resource that can advance therapeutic cone transplantation in models of age-related macular degeneration. PMID:26965927

  10. The S-cone contribution to luminance depends on the M- and L-cone adaptation levels: silent surrounds?

    PubMed

    Ripamonti, Caterina; Woo, Wen Ling; Crowther, Elizabeth; Stockman, Andrew

    2009-01-01

    Under dim background conditions, the S-cones make little or no contribution to luminance (A. Eisner & D. I. MacLeod, 1980; W. Verdon & A. J. Adams, 1987), yet under conditions of intense long-wavelength adaptation, a small but robust contribution to luminance--as defined by heterochromatic flicker photometry (A. Stockman, D. I. MacLeod, & D. D. DePriest, 1987, 1991) or motion (J. Lee & C. F. Stromeyer, 1989)--can be found. Here, by using selective adaptation and/or tritanopic metamers to isolate the S-cone response, we investigate the dependence of the S-cone luminance input on changes in background wavelength and radiance. Interestingly, the S-cone luminance input disappears completely when no adapting background is present, even though the same S-cone stimulus makes a clear contribution to luminance when a background is present. The dependence of the S-cone luminance input on the wavelength and radiance of the adapting background is surprising. We find that the S-cone signal can be measured on fields of 491 nm and longer wavelengths that exceed a criterion background radiance. These criterion radiances roughly follow an L + M spectral sensitivity, which suggests that the S-cone luminance input is silent unless the L- and M-cones are excited above a certain level. We hypothesize that the L + M cone signals produced by the steady adapting backgrounds somehow "gate" the S-cone luminance signals, perhaps by being modulated by them.

  11. Efficacy of dental unit waterlines disinfectants on a polymicrobial biofilm.

    PubMed

    Costa, Damien; Girardot, Marion; Bertaux, Joanne; Verdon, Julien; Imbert, Christine

    2016-03-15

    Due to their high surface-volume ratio, their laminar flow and frequent stagnation periods, dental unit waterlines (DUWL) foster the attachment of microorganisms and the development of biofilm, resulting in the continuous contamination of the outlet water from dental units; this contamination may be responsible for a potential risk of infection due to the exposure of patients and medical staff to droplet inhalation or splashed water. In this study, the anti-biofilm activity of three disinfectants recommended by dental unit manufacturers -Calbenium(©), Oxygenal 6(©) and Sterispray(©) - was evaluated. A dynamic model simulating DUWL conditions was developed and polymicrobial biofilms containing bacteria (Pseudomonas aeruginosa), fungi (Candida albicans) and Free Living Amoeba (FLA: Vermamoeba vermiformis) were allowed to form. The ability of disinfectants to reduce biofilm formation or to eradicate an already formed biofilm was evaluated. Results showed the various effects of the tested disinfectants according to their composition, concentration and the targeted species. V. vermiformis was resistant to disinfectants, regardless of the tested concentrations and the concentrations recommended by manufacturers were not the most appropriate. Results also showed that Calbenium(©) was the most effective disinfectant to reduce already formed biofilms; its maximum efficiency was observed from 0.5% on both P. aeruginosa and C. albicans compared to 2 and 3% respectively for Sterispray(©). The maximum efficiency of Oxygenal(©) was observed from 3% on P. aeruginosa but Oxygenal(©) was unable to totally eliminate C. albicans in the tested conditions, contrary to other disinfectants. Calbenium(©) was able to prevent biofilm formation efficiently even if it displayed no prophylactic activity against V. vermiformis. Overall, the FLA survival may contribute to maintaining other species. Finally the tested disinfectants were partially active against sessile microorganisms

  12. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell.

    PubMed

    Huang, Xiao; Qu, Yan; Cid, Clément A; Finke, Cody; Hoffmann, Michael R; Lim, Keahying; Jiang, Sunny C

    2016-04-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source.

  13. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell

    PubMed Central

    Huang, Xiao; Qu, Yan; Cid, Clément A.; Finke, Cody; Hoffmann, Michael R.; Lim, Keahying; Jiang, Sunny C.

    2016-01-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [•OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source. PMID:26854604

  14. Enterobacter cloacae outbreak in the NICU related to disinfected thermometers.

    PubMed

    van den Berg, R W; Claahsen, H L; Niessen, M; Muytjens, H L; Liem, K; Voss, A

    2000-05-01

    In the first week ot December 1997, an increasing incidence of neonates colonized with multi-drug resistant Enterobacter cloacae (MR-E. cloacae) was observed in the neonatal Intensive care unit of our 950-bed university hospital. Initially, re-enforcement of infection control practices including hand disinfection and cohort isolation seemed to be sufficient to control the outbreak. Nevertheless, an increasing number of newly admitted patients was paralleled by another rise in the incidence of colonized neonates. Since E. cloacae was initially found in urine specimens of the patients, surveillance and environmental cultures were aimed at procedures and instruments that might colonize the gastro-intestinal and/or urinary tract. E, cloacae was isolated from a single cap of an electronic digital thermometer. Despite banning of this possible source, newly admitted neonates still became colonized. The unit was closed for further admissions and a second round of extensive screening was started; this time including all available thermometers and continuous rectal temperature probes. Ready-to-use 'disinfected thermometers and probes were found to be colonized with MR-E. cloacae. Observation of disinfection procedures and a laboratory investigation revealed that 'rushed disinfection with alcohol 80% led to a 1 in 10 chance of thermometers still being contaminated. Furthermore, alcoholic hand rub used for convenience disinfection failed to disinfect thermometers in 40% and 20% of the cases when done in a 'rushed' or 'careful' fashion, respectively. Adequate disinfection of the thermometers led to the control of the outbreak, with no new occurrence of MR-E. cloacae in the following months.

  15. Local Protein Synthesis in Axonal Growth Cones

    PubMed Central

    Šatkauskas, Saulius

    2007-01-01

    While initially thought to be essentially a developmental characteristic observed in artificial in vitro models, local protein synthesis in growth cones has been described in the adult, and more interestingly, during nerve regeneration. This emerging field is under intense investigation, revealing new functions of localized protein synthesis that include axon guidance, growth cone adaptation and sensitivity modulation at intermediate targets or axon regeneration. Here, we will review these functions and provide a short survey of the current knowledge on mechanisms of mRNA transport and regulation of localized protein synthesis. In addition, we will consider what lessons can be learned from localized protein synthesis in dendrites and what developments can be expected next in the field. This latter question relates to the crucial point of which technical strategy to adopt for an ideal and pertinent analysis of the phenomenon. PMID:19262143

  16. k-cones and kirigami metamaterials

    NASA Astrophysics Data System (ADS)

    Seffen, Keith A.

    2016-09-01

    We are inspired by the tensile buckling of a thin sheet with a slit to create a foldable planar metamaterial. The buckled shape comprises two pairs of identical e-cones connected to the slit, which we refer to as a k-cone. We approximate this shape as discrete vertices that can be folded out of plane as the slit is pulled apart. We determine their kinematics and we calculate generic shape properties using a simple elastic model of the folded shape. We then show how the folded sheet may be tessellated as a unit cell within a larger sheet, which may be constructed a priori by cutting and folding the latter in a regular way, in order to form a planar kirigami structure with a single degree of freedom.

  17. Instantons on Calabi-Yau cones

    NASA Astrophysics Data System (ADS)

    Sperling, Marcus

    2015-12-01

    The Hermitian Yang-Mills equations on certain vector bundles over Calabi-Yau cones can be reduced to a set of matrix equations; in fact, these are Nahm-type equations. The latter can be analysed further by generalising arguments of Donaldson and Kronheimer used in the study of the original Nahm equations. Starting from certain equivariant connections, we show that the full set of instanton equations reduce, with a unique gauge transformation, to the holomorphicity condition alone.

  18. Hadronic wavefunctions in light-cone quantization

    SciTech Connect

    Hyer, T.

    1994-05-01

    The analysis of light-cone wavefunctions seems the most promising theoretical approach to a detailed understanding of the structure of relativistic bound states, particularly hadrons. However, there are numerous complications in this approach. Most importantly, the light-cone approach sacrifices manifest rotational invariance in exchange for the elimination of negative-energy states. The requirement of rotational invariance of the full theory places important constraints on proposed light-cone wavefunctions, whether they are modelled or extracted from some numerical procedure. A formulation of the consequences of the hidden rotational symmetry has been sought for some time; it is presented in Chapter 2. In lattice gauge theory or heavy-quark effective theory, much of the focus is on the extraction of numerical values of operators which are related to the hadronic wavefunction. These operators are to some extent interdependent, with relations induced by fundamental constraints on the underlying wavefunction. The consequences of the requirement of unitarity are explored in Chapter 3, and are found to have startling phenomenological relevance. To test model light-cone wavefunctions, experimental predictions must be made. The reliability of perturbative QCD as a tool for making such predictions has been questioned. In Chapter 4, the author presents a computation of the rates for nucleon-antinucleon annihilation, improving the reliability of the perturbative computation by taking into account the Sudakov suppression of exclusive processes at large transverse impact parameter. In Chapter 5, he develops the analysis of semiexclusive production. This work focuses on processes in which a single isolated meson is produced perturbatively and recoils against a wide hadronizing system. At energies above about 10 GeV, semiexclusive processes are shown to be the most sensitive experimental probes of hadronic structure.

  19. Internal Reflection Sensor for the Cone Penetrometer

    SciTech Connect

    Job Bello

    1998-05-29

    The objectives of this project are to design, assemble, test, and demonstrate a prototype Internal Reflection Sensor (IRS) for the cone penetrometer. The sensor will ultimately be deployed during site characterization with the goal of providing real-time, in situ detection of NonAqueous Phase Liquids (NAPLs) in the subsurface. In the first phase of this program, we have designed and assembled an IRS module that interfaces directly to a standard cone penetrometer system. Laboratory tests demonstrated that the sensor responds in real-time to a wide variety of free phase NAPLs without interference from natural materials such as water and soil of various types or dissolved contaminants. In a preliminary field test, the sensor was able to locate NAPLs at thin, discrete depths in a soil test pit when deployed with a cone penetrometer. Ruggedness of the device was tested with a series of penetrometer pushes to the depth of refusal at a clean location. There was no visible damage to the sensor and its performance did not change in the course of these experiments. Based on the successes of the Phase I program, it is recommended that the project proceed to full-scale demonstration in Phase II.

  20. Long polymers near wedges and cones

    NASA Astrophysics Data System (ADS)

    Hammer, Yosi; Kantor, Yacov

    2015-12-01

    We perform a Monte Carlo study of N -step self-avoiding walks, attached to the corner of an impenetrable wedge in two dimensions (d =2 ), or the tip of an impenetrable cone in d =3 , of sizes ranging up to N =106 steps. We find that the critical exponent γα, which determines the dependence of the number of available conformations on N for a cone or wedge with opening angle α , is in good agreement with the theory for d =2 . We study the end-point distribution of the walks in the allowed space and find similarities to the known behavior of random walks (ideal polymers) in the same geometry. For example, the ratio between the mean square end-to-end distances of a polymer near the cone or wedge and a polymer in free space depends linearly on γα, as is known for ideal polymers. We show that the end-point distribution of polymers attached to a wedge does not separate into a product of angular and radial functions, as it does for ideal polymers in the same geometry. The angular dependence of the end position of polymers near the wedge differs from theoretical predictions.

  1. Long polymers near wedges and cones.

    PubMed

    Hammer, Yosi; Kantor, Yacov

    2015-12-01

    We perform a Monte Carlo study of N-step self-avoiding walks, attached to the corner of an impenetrable wedge in two dimensions (d=2), or the tip of an impenetrable cone in d=3, of sizes ranging up to N=10(6) steps. We find that the critical exponent γ(α), which determines the dependence of the number of available conformations on N for a cone or wedge with opening angle α, is in good agreement with the theory for d=2. We study the end-point distribution of the walks in the allowed space and find similarities to the known behavior of random walks (ideal polymers) in the same geometry. For example, the ratio between the mean square end-to-end distances of a polymer near the cone or wedge and a polymer in free space depends linearly on γ(α), as is known for ideal polymers. We show that the end-point distribution of polymers attached to a wedge does not separate into a product of angular and radial functions, as it does for ideal polymers in the same geometry. The angular dependence of the end position of polymers near the wedge differs from theoretical predictions. PMID:26764719

  2. Numerical Simulation of Taylor Cone-Jet

    NASA Astrophysics Data System (ADS)

    Toledo, Ronne

    The Taylor cone-jet is a particular type of electrohydrodynamic phenomenon where electrostatic stresses and surface tension effects shape the interface of the jet in a peculiar conical shape. A thin jet is issued from the cone apex that further breaks up into a fine aerosol. Due to its monodispersive properties, this fine aerosol has found a number of applications, ranging from mass spectrometry, colloidal space propulsion, combustion, nano-fabrication, coating/painting, and many others. In this study, a general non-dimensional analysis is performed to derive the governing equations and boundary conditions. In accordance with the observations of Gamero-Castano (2010), noting that droplet electric potential is insensitive to the flow rate conditions, a particular set of characteristic parameters is proposed, based on the terminal jet diameter. In order to solve the non-dimensional set of governing equations and boundary conditions, a numerical method combining the Boundary Element Method and the Finite Volume Method is developed. Results of electric current have shown good agreement with numerical and experimental data available in the literature. The main feature of the algorithm developed is related to the decoupling of the electrostatic from the hydrodynamic problem, allowing us to accurately prescribe the far field electric potential boundary conditions away from the hydrodynamic computational domain used to solve the hydrodynamics of the transition region near the cone apex.

  3. Cusp formation in drops inside Taylor cones

    NASA Astrophysics Data System (ADS)

    Marin, Alvaro G.; Loscertales, Ignacio G.; Barrero, Antonio

    2005-11-01

    Here, we report the formation of cusp in insulating drops inside compound Taylor cones. The action of the electrical shear stress acting on the outer interface, which is transmitted by viscous forces inside the Taylor cone, tends to deform the drop of insulating liquid placed inside. For appropriate values of the capillary number, the insulating drop develops a steady cusp angle which depends on both the capillary number and the conducting to insulating viscosity ratio. A self-similar analysis has been developed to qualitatively describe the flow inside these compounds Taylor cones. Any perturbation of the cusp gives rise to an intermittent emission of tiny droplets; this effect may recall the tip-streaming observed by G.I. Taylor in his four-roll mill device. This emission can be stabilized by an appropriate control of the injected flow rate of the insulating liquid. When the capillary number increases, the cusped interface turns into a spout which flows coated by the conducting liquid forming the electrified coaxial jet which has been successfully employed for the production of nanocapsules, coaxial nanofibers and nanotubes (Science 295, n. 5560, 1695, 2002; JACS 126, 5376, 2004).

  4. Reconfiguration of broad leaves into cones

    NASA Astrophysics Data System (ADS)

    Miller, Laura

    2013-11-01

    Flexible plants, fungi, and sessile animals are thought to reconfigure in the wind and water to reduce the drag forces that act upon them. Simple mathematical models of a flexible beam immersed in a two-dimensional flow will also exhibit this behavior. What is less understood is how the mechanical properties of a leaf in a three-dimensional flow will passively allow roll up and reduce drag. This presentation will begin by examining how leaves roll up into drag reducing shapes in strong flow. The dynamics of the flow around the leaf of the wild ginger Hexastylis arifolia are described using particle image velocimetry. The flows around the leaves are compared with those of simplified sheets using 3D numerical simulations and physical models. For some reconfiguration shapes, large forces and oscillations due to strong vortex shedding are produced. In the actual leaf, a stable recirculation zone is formed within the wake of the reconfigured cone. In physical and numerical models that reconfigure into cones, a similar recirculation zone is observed with both rigid and flexible tethers. These results suggest that the three-dimensional cone structure in addition to flexibility is significant to both the reduction of vortex-induced vibrations and the forces experienced by the leaf.

  5. Water disinfection through photoactive modified titania.

    PubMed

    Sethi, Diptipriya; Pal, Ajoy; Sakthivel, Ramasamy; Pandey, Sony; Dash, Tapan; Das, Trupti; Kumar, Rohit

    2014-01-01

    TiO(2), N-TiO(2) and S-TiO(2) samples have been prepared by various chemical methods. These samples were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), Laser Raman spectrometer, UV-Visible spectrophotometer, field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). X-ray powder diffraction study reveals that all three samples are single anatase phase of titania and the crystallinity of titania decreases with sulphur doping whereas nitrogen doping does not affect it. UV-Visible (diffuse) reflectance spectra shows that doping of titania with nitrogen and sulphur shift the absorption edge of titania from ultraviolet to visible region. XPS study confirms that both nitrogen and sulphur are well doped in the titania lattice. It is observed that nitrogen occupies at both substitutional and interstitial position in the lattice of titania. FE-SEM and TEM studies demonstrate that the particles are below 50nm range. It is found that S and N doping of titania increased its water disinfection property in the order TiO(2)

  6. CRALBP supports the mammalian retinal visual cycle and cone vision

    PubMed Central

    Xue, Yunlu; Shen, Susan Q.; Jui, Jonathan; Rupp, Alan C.; Byrne, Leah C.; Hattar, Samer; Flannery, John G.; Corbo, Joseph C.; Kefalov, Vladimir J.

    2015-01-01

    Mutations in the cellular retinaldehyde–binding protein (CRALBP, encoded by RLBP1) can lead to severe cone photoreceptor–mediated vision loss in patients. It is not known how CRALBP supports cone function or how altered CRALBP leads to cone dysfunction. Here, we determined that deletion of Rlbp1 in mice impairs the retinal visual cycle. Mice lacking CRALBP exhibited M-opsin mislocalization, M-cone loss, and impaired cone-driven visual behavior and light responses. Additionally, M-cone dark adaptation was largely suppressed in CRALBP-deficient animals. While rearing CRALBP-deficient mice in the dark prevented the deterioration of cone function, it did not rescue cone dark adaptation. Adeno-associated virus–mediated restoration of CRALBP expression specifically in Müller cells, but not retinal pigment epithelial (RPE) cells, rescued the retinal visual cycle and M-cone sensitivity in knockout mice. Our results identify Müller cell CRALBP as a key component of the retinal visual cycle and demonstrate that this pathway is important for maintaining normal cone–driven vision and accelerating cone dark adaptation. PMID:25607845

  7. Growth cone behavior and production of traction force

    PubMed Central

    1990-01-01

    The growth cone must push its substrate rearward via some traction force in order to propel itself forward. To determine which growth cone behaviors produce traction force, we observed chick sensory growth cones under conditions in which force production was accommodated by movement of obstacles in the environment, namely, neurites of other sensory neurons or glass fibers. The movements of these obstacles occurred via three, different, stereotyped growth cone behaviors: (a) filopodial contractions, (b) smooth rearward movement on the dorsal surface of the growth cone, and (c) interactions with ruffling lamellipodia. More than 70% of the obstacle movements were caused by filopodial contractions in which the obstacle attached at the extreme distal end of a filopodium and moved only as the filopodium changed its extension. Filopodial contractions were characterized by frequent changes of obstacle velocity and direction. Contraction of a single filopodium is estimated to exert 50-90 microdyn of force, which can account for the pull exerted by chick sensory growth cones. Importantly, all five cases of growth cones growing over the top of obstacle neurites (i.e., geometry that mimics the usual growth cone/substrate interaction), were of the filopodial contraction type. Some 25% of obstacle movements occurred by a smooth backward movement along the top surface of growth cones. Both the appearance and rate of movements were similar to that reported for retrograde flow of cortical actin near the dorsal growth cone surface. Although these retrograde flow movements also exerted enough force to account for growth cone pulling, we did not observe such movements on ventral growth cone surfaces. Occasionally obstacles were moved by interaction with ruffling lamellipodia. However, we obtained no evidence for attachment of the obstacles to ruffling lamellipodia or for directed obstacle movements by this mechanism. These data suggest that chick sensory growth cones move forward by

  8. Biochemical pharmacology of isolated neuronal growth cones: implications for synaptogenesis.

    PubMed

    Lockerbie, R O

    1990-01-01

    The neuronal growth cone is critical to the establishment of neuronal polarity through its motile, pathfinding and target recognition properties exhibited during synaptogenesis. Subcellular fractionation procedures yielding milligram quantities of isolated growth cones has allowed for biochemical and pharmacological investigation of intrinsic growth cone components that are likely to be involved in regulation of growth cone function in neuronal development. These 'mapping' studies of growth cone components are prerequisites to elucidating the mechanisms by which extracellular factors influence the motility, adhesion and directed growth of the growth cone. For example, neurotransmitters and polypeptide growth factors which have been shown in other systems to modulate growth cone behavior are presumed to act through receptors on the growth cone, inducing second-messenger molecule formation and consequent modification and regulation of proteins effecting the response(s) of the growth cone (i.e. proteins involved in motility, adhesion and membrane turnover). In a relatively short period of time, work with the isolated growth cone preparation has identified, in independent studies, many of the elements involved in this proposed scheme of events, including transmitter receptors, second-messenger cascades, and second-messenger post-translational modifications. An obvious future goal will be to analyze in more detail the intracellular events, and the relationships between them, in the growth cone and how they transmit extracellular signals into responses such as motility and adhesivity which underly the growth cone's synaptogenic properties. It is to be expected that much of this information will come forth from experimentation with the isolated growth cone preparation.

  9. 9 CFR 85.13 - Cleaning and disinfecting livestock markets and other facilities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... using one of the disinfectants registered under the Federal Insecticide, Fungicide and Rodenticide Act, as amended (7 U.S.C. 135 et seq.) with herpes virucidal claims. These disinfectants shall be used...

  10. 9 CFR 85.13 - Cleaning and disinfecting livestock markets and other facilities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... using one of the disinfectants registered under the Federal Insecticide, Fungicide and Rodenticide Act, as amended (7 U.S.C. 135 et seq.) with herpes virucidal claims. These disinfectants shall be used...

  11. The Occurrence and Comparative Toxicity of Haloacetaldehyde Disinfection Byproducts in Drinking Water

    EPA Science Inventory

    The introduction of drinking water disinfection greatly reduced the incidence of waterborne diseases. However, the reaction between disinfectants and natural organic matter in the source water can lead to an unintended consequence, which is the formation of drinking water disinfe...

  12. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE DISINFECTION BY-PRODUCTS IN DRINKING WATER

    EPA Science Inventory

    This paper discusses the identification of organic disinfection by-products (DBPs) at a pilot plant in Evansville, Indiana, that uses chlorine dioxide as a primary disinfectant. nconventional multispectral identification techniques (gas chromatography combined with high and low r...

  13. RESEARCH PLAN FOR MICROBIAL PATHOGENS AND DISINFECTION BY-PRODUCTS IN DRINKING WATER

    EPA Science Inventory

    This research plan was developed to describe research needed to support EPA's development of drinking water regulations concerning disinfectants, disinfection by-products (DBPs) and microbial pathogens, focusing on key scientific and technical information needed. The research pl...

  14. NEW DISINFECTION BY-PRODUCT ISSUES: EMERGING DBP'S AND ALTERNATIVE ROUTES OF EXPOSURE

    EPA Science Inventory

    This paper discusses current issues with drinking water disinfection by-products (DBPs), which include emerging (unregulated) DBPs that can be formed at greater levels with alternative disinfectants (as compared to chlorine) and routes of human exposure (which include inhalation ...

  15. Roadmap for Interdisciplinary Research on Drinking Water Disinfection By-Products

    EPA Science Inventory

    Slide presentation on interdisciplinary research on drinking water disinfection by-products which summarized important issues with drinking water disinfection by-products and focused on emerging, unregulated DBPs.

  16. QUENCHING OF CHLORINATION DISINFECTION BY-PRODUCT FORMATION IN DRINKING WATER BY HYDROGEN PEROXIDE. (R825362)

    EPA Science Inventory

    Reactions between chlorine disinfectants, dissolved organic matter, and other chemicals in water form a series of disinfection by-products (DBPs), including trihalomethanes (THMs) and haloacetic acids (HAAs), that are toxic and subject to increasingly stringent regulations. Th...

  17. CHEMICAL AND BIOLOGICAL CHARACTERIZATION OF NEWLY DISCOVERED IODOACID DRINKING WATER DISINFECTION BYPRODUCTS

    EPA Science Inventory

    Iodoacid drinking water disinfection byproducts (DBPs) were recently uncovered in drinking water samples from source water with a high bromide/iodide concentration that was disinfected with chloramines. The purpose of this paper is to report the analytical chemical identification...

  18. Integrated Disinfection By-Products Mixtures Research: Concentration by Reverse Osmosis Membrane Techniques of Disinfection By-Products from Water Disinfected by Chlorination and Ozonation/Postchlorination

    EPA Science Inventory

    To conduct the health-effect studies described in subsequent articles in this series, concentrated aqueous mixtures of disinfection by-products were required for the two water treatment trains described in the preceding article (Miltner et al., 2008). To accomplish this, the fini...

  19. Disinfection by-product formation during seawater desalination: A review.

    PubMed

    Kim, Daekyun; Amy, Gary L; Karanfil, Tanju

    2015-09-15

    Due to increased freshwater demand across the globe, seawater desalination has become the technology of choice in augmenting water supplies in many parts of the world. The use of chemical disinfection is necessary in desalination plants for pre-treatment to control both biofouling as well as the post-disinfection of desalinated water. Although chlorine is the most commonly used disinfectant in desalination plants, its reaction with organic matter produces various disinfection by-products (DBPs) (e.g., trihalomethanes [THMs], haloacetic acids [HAAs], and haloacetonitriles [HANs]), and some DBPs are regulated in many countries due to their potential risks to public health. To reduce the formation of chlorinated DBPs, alternative oxidants (disinfectants) such as chloramines, chlorine dioxide, and ozone can be considered, but they also produce other types of DBPs. In addition, due to high levels of bromide and iodide concentrations in seawater, highly cytotoxic and genotoxic DBP species (i.e., brominated and iodinated DBPs) may form in distribution systems, especially when desalinated water is blended with other source waters having higher levels of organic matter. This article reviews the knowledge accumulated in the last few decades on DBP formation during seawater desalination, and summarizes in detail, the occurrence of DBPs in various thermal and membrane plants involving different desalination processes. The review also identifies the current challenges and future research needs for controlling DBP formation in seawater desalination plants and to reduce the potential toxicity of desalinated water.

  20. Kennel Disinfectants for Microsporum canis and Trichophyton sp.

    PubMed

    Moriello, Karen A

    2015-01-01

    The antifungal efficacy of commonly used kennel disinfectants for large surfaces was tested using naturally infective material from untreated animals (M. canis and Trichophyton sp.) soaked and macerated but unfiltered leaving visible fluorescing hairs and/or scales in the test inoculum to create a robust challenge. Disinfectants included sodium hypochlorite (1 : 32 and 1 : 100), enilconazole (1 : 100), accelerated hydrogen peroxide (1 : 16), potassium peroxymonosulfate (1% and 2%), and calcium hypochlorite "dry bleach." Disinfectants were tested at a 1 : 10, 1 : 5, and 1 : 1 dilution of test inoculum to disinfectant with a 10 min contact time. Good efficacy was defined as a disinfectant resulting in no growth. Control plates grew >300 colonies of each pathogen per plate. Enilconazole, sodium hypochlorite (all dilutions), accelerated hydrogen peroxide, and 2% potassium peroxymonosulfate (but not 1%) inhibited all growth of both pathogens at 1 : 10, 1 : 5, and 1 : 1 dilutions. Calcium hypochlorite showed no antifungal efficacy (>300 colonies per plate). Enilconazole (1 : 100), sodium hypochlorite (1 : 32 or 1 : 100), accelerated hydrogen peroxide (1 : 16), and 2% potassium peroxymonosulfate are recommended for decontamination of kennels exposed to dermatophyte pathogens.

  1. Electrochemical disinfection using the gas diffusion electrode system.

    PubMed

    Xu, Wenying; Li, Ping; Dong, Bin

    2010-01-01

    A study on the electrochemical disinfection with H2O2 generated at the gas diffusion electrode (GDE) from active carbon/polytetrafluoroethylene was performed in a non-membrane cell. The effects of Pt load and the pore-forming agent content in GDE, and operating conditions were investigated. The experimental results showed that nearly all bacterial cultures inoculated in the secondary effluent from wastewater treatment plant could be inactivated within 30 min at a current density of 10 mA/cm2. The disinfection improved with increasing Pt load. Addition of the pore-forming agent NH4HCO3 improved the disinfection, while a drop in the pH value resulted in a rapid rise of germicidal efficacy and the disinfection time was shortened with increasing oxygen flow rate. Adsorption was proved to be ineffective in destroying bacteria, while germicidal efficacy increased with current density. The acceleration rate was different, it initially increased with current density. Then decreased, and finally reached a maximum at a current density of 6.7 mA/cm2. The disinfection also improved with decreasing total bacterial count. The germicidal efficacy in the cathode compartment was approximately the same as in the anode compartment, indicating that the contribution of direct oxidation and the indirect treatment of bacterial cultures by hydroxyl radical was similar to the oxidative indirect effect of the generated H2O2.

  2. Indicators for photoreactivation and dark repair studies following ultraviolet disinfection.

    PubMed

    Quek, Puay Hoon; Hu, Jiangyong

    2008-06-01

    Repair of DNA in bacteria following ultraviolet (UV) disinfection can cause reactivation of inactivated bacteria and negatively impact the efficiency of the UV disinfection process. In this study, various strains of E. coli (wild-type, UV-resistant and antibiotic-resistant strains) were investigated for their ability to perform dark repair and photoreactivation, and compared based on final repair levels after 4 h of incubation, as well as repair rates. Analysis of the results revealed that the repair abilities of different E. coli strains can differ quite significantly. In photoreactivation, the log repair ranged from 10 to 85%, with slightly lower log repair percentages when medium-pressure (MP) UV disinfection was employed. In dark repair, log repair ranged from 13 to 28% following low-pressure (LP) UV disinfection. E. coli strains ATCC 15597 and ATCC 11229 were found to repair the fastest and to the highest levels for photoreactivation and dark repair, respectively. These strains were also confirmed to repair to higher levels when compared to a pathogenic E. coli O157:H7 strain. Hence, these strains could possibly serve as conservative indicators for future repair studies following UV disinfection. In addition, dimer repair by photoreactivation and dark repair was also confirmed on a molecular level using the endonuclease sensitive site (ESS) assay.

  3. Disinfection of water by adsorption combined with electrochemical treatment.

    PubMed

    Hussain, S N; de Las Heras, N; Asghar, H M A; Brown, N W; Roberts, E P L

    2014-05-01

    The disinfection performance of a unique process of adsorption combined with electrochemical treatment is evaluated. A flake graphite intercalation compound adsorbent was used, which is effective for the removal of organic contaminants and is amenable to anodic electrochemical regeneration. Adsorption of Escherichia coli on the graphite flake was followed by electrochemical treatment under a range of experimental conditions in a sequential batch reactor. The adsorption of E. coli cells was found to be a fast process and was capable of removing >99.98% of cells from solution after 5 min with a ca. 6.5-log10 reduction in E. coli concentration after 10 min. With electrochemical treatment the adsorbent could be reused, with no decrease in E. coli adsorption observed over five cycles. In the presence of chloride, >8.5-log10 reduction of E. coli concentration was achieved. Disinfection was found to be less effective in the absence of chloride. However, selection of appropriate operating conditions enabled effective disinfection in a chloride free system, reducing the potential for formation of disinfection by-products. The energy consumption required to achieve >8.5-log10 disinfection was 2-7 kWh m(-3).

  4. Disinfection by-product formation during seawater desalination: A review.

    PubMed

    Kim, Daekyun; Amy, Gary L; Karanfil, Tanju

    2015-09-15

    Due to increased freshwater demand across the globe, seawater desalination has become the technology of choice in augmenting water supplies in many parts of the world. The use of chemical disinfection is necessary in desalination plants for pre-treatment to control both biofouling as well as the post-disinfection of desalinated water. Although chlorine is the most commonly used disinfectant in desalination plants, its reaction with organic matter produces various disinfection by-products (DBPs) (e.g., trihalomethanes [THMs], haloacetic acids [HAAs], and haloacetonitriles [HANs]), and some DBPs are regulated in many countries due to their potential risks to public health. To reduce the formation of chlorinated DBPs, alternative oxidants (disinfectants) such as chloramines, chlorine dioxide, and ozone can be considered, but they also produce other types of DBPs. In addition, due to high levels of bromide and iodide concentrations in seawater, highly cytotoxic and genotoxic DBP species (i.e., brominated and iodinated DBPs) may form in distribution systems, especially when desalinated water is blended with other source waters having higher levels of organic matter. This article reviews the knowledge accumulated in the last few decades on DBP formation during seawater desalination, and summarizes in detail, the occurrence of DBPs in various thermal and membrane plants involving different desalination processes. The review also identifies the current challenges and future research needs for controlling DBP formation in seawater desalination plants and to reduce the potential toxicity of desalinated water. PMID:26099832

  5. M-cone opsin gene number does not correlate with variation in L/M-cone sensitivity.

    PubMed

    Knau, H; Kremers, J; Schmidt, H-J; Wolf, S; Wissinger, B; Sharpe, L T

    2002-07-01

    Molecular genetic studies demonstrate that the human cone opsin gene array on the q-arm of the X-chromosome typically consists of one long-wave-sensitive (L) cone opsin gene and from one to several middle-wave-sensitive (M) cone opsin genes. Although the presence of the single L-cone opsin gene and at least one M-cone opsin gene is essential for normal red-green colour discrimination, the function of the additional M-cone opsin genes is still unclear. To investigate whether any variations in phenotype correlate with differences in the number of M-cone opsin genes, we selected 13 normal trichromat males, for whom four independent molecular techniques have exactly determined their number of M-cone opsin genes, ranging from one to four. Their phenotype was characterized by estimating their foveal L- to M-cone ratio from heterochromatic flicker photometric (HFP) thresholds, by measuring the wavelength corresponding to their 'unique yellow', and by determining their L- and M-cone modulation thresholds (CMTs). No correlation was found between these psychophysical measures and the number of M-cone opsin genes. Although, we found a reasonably good correlation between the L/M-cone ratios based on HFP and on CMT, we did not find any correlation between the estimated L/M-cone ratios and the settings of 'unique yellow'. Our results accord with previous molecular genetic studies that suggest that only the first two genes in the X-linked opsin gene array are expressed.

  6. Comparison of cone and cone shell configuration for depth sensitive fluorescence measurements in turbid media

    NASA Astrophysics Data System (ADS)

    Ong, Yi Hong; Liu, Quan

    2014-03-01

    We have developed a novel cone shell illumination and detection configurations using combination of axicon lenses for depth sensitive fluorescence spectroscopy. The probe was demonstrated experimentally to be able to selectively detecting fluorescence from different depths from a two-layered turbid agar phantom. In addition to enhanced contrast of subsurface fluorescence measurement as compared to a conventional cone configuration implemented by a microscope objective lens, the axicon lenses based setup eliminated the need of moving the objective lens up or down to achieve depth sensitive measurements, which effectively improves the consistency of optical coupling thus would be preferred in a clinical setting.

  7. Evaluation of disinfectants to prevent mechanical transmission of viruses and a viroid in greenhouse tomato production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an effort to select disinfectant(s) with capability to deactivate infectivity from a broad range of viruses and viroids that are commonly observed in greenhouse tomato production systems, a total of 16 disinfectants were evaluated against Pepino mosaic virus (PepMV), Tomato mosaic virus (ToMV), T...

  8. Evaluation of effectiveness of chemical disinfectants in reducing bacterial growth on orthodontic instruments.

    PubMed

    Reddy, R Vamshidhar; Tanveer, K; Sharma, K Dinesh; Kokkula, Naveen; Suresh, P L; Sudhakar, Meher

    2013-11-01

    Infection control requires serious effort in all fields of dentistry including orthodontics. Though there are various means of sterilization and disinfection in dental office, chemical disinfection is the most preferred method among orthodontists. The purpose of this study is to evaluate different chemical sterilization and disinfection methods used in orthodontic offices, which would guide the orthodontists in infection control.

  9. USING MEMBRANES TO CONCENTRATE DISINFECTION BYPRODUCTS FOR SUBSEQUENT HEALTH EFFECTS STUDIES

    EPA Science Inventory

    Chemical disinfection of water is a major public health advance that has decreased dramatically water-borne disease. Disinfecting agents react with naturally occurring organic and inorganic matter in water to produce a wide variety of disinfection byproducts (DBPs). Although mo...

  10. Reducing transmission risk through high-level disinfection of transvaginal ultrasound transducer handles.

    PubMed

    Ngu, Andrew; McNally, Glenn; Patel, Dipika; Gorgis, Vivian; Leroy, Sandrine; Burdach, Jon

    2015-05-01

    Intracavity ultrasound transducer handles are not routinely immersed in liquid high-level disinfectants. We show that residual bacteria, including pathogens, persist on more than 80% of handles that are not disinfected, whereas use of an automated device reduces contamination to background levels. Clinical staff should consider the need for handle disinfection.

  11. Testing the Carcinogenic Potential of Water Disinfectant Byproducts in a Human Colon Mucosal Culture System

    EPA Science Inventory

    Epidemiological studies have linked the consumption of disinfected surface waters to an increased risk of colorectal cancer. Approximately 600 disinfection byproducts (DBPs) have been identified for a number of disinfectants currently in use. An in-depth mechanism-based structure...

  12. Tantalum cones and bone defects in revision total knee arthroplasty.

    PubMed

    Boureau, F; Putman, S; Arnould, A; Dereudre, G; Migaud, H; Pasquier, G

    2015-04-01

    Management of bone loss is a major challenge in revision total knee arthroplasty (TKA). The development of preformed porous tantalum cones offers new possibilities, because they seem to have biological and mechanical qualities that facilitate osseointegration. Compared to the original procedure, when metaphyseal bone defects are too severe, a single tantalum cone may not be enough and we have developed a technique that could extend the indications for this cone in these cases. We used 2 cones to fill femoral bone defects in 7 patients. There were no complications due to wear of the tantalum cones. Radiological follow-up did show any migration or loosening. The short-term results confirm the interest of porous tantalum cones and suggest that they can be an alternative to allografts or megaprostheses in case of massive bone defects.

  13. Pulsar average waveforms and hollow cone beam models

    NASA Technical Reports Server (NTRS)

    Backer, D. C.

    1975-01-01

    An analysis of pulsar average waveforms at radio frequencies from 40 MHz to 15 GHz is presented. The analysis is based on the hypothesis that the observer sees one cut of a hollow-cone beam pattern and that stationary properties of the emission vary over the cone. The distributions of apparent cone widths for different observed forms of the average pulse profiles (single, double/unresolved, double/resolved, triple and multiple) are in modest agreement with a model of a circular hollow-cone beam with random observer-spin axis orientation, a random cone axis-spin axis alignment, and a small range of physical hollow-cone parameters for all objects.

  14. Heating distribution comparison between asymmetric and symmetric blunt cones

    NASA Technical Reports Server (NTRS)

    Stewart, D. A.; Kolodziej, P.

    1986-01-01

    An experiment was performed to compare the heating distribution between symmetric and asymmetric large-angle blunt cones, with cone angles of 100, 120, and 140 deg. These hot-wall data were obtained from models made from typical thermal protection insulation for proposed aeroassisted orbital transfer vehicles. Experimental data are compared with predictions using a boundary-layer integral matrix procedure with kinetics to determine how well the heating distribution over an asymmetric cone could be approximated using axisymmetric solutions for a cone and spherical segment. In addition, a relationship between the stagnation-point heat-transfer rate and the bow-shock standoff distance for these cones is discussed. The heat-distribution data from the symmetric and asymmetric cones were very similar. Numerical results compared well with the measured wall temperatures at the stagnation point but slightly underpredicted them over the conical portion of the models.

  15. Rod-cone interactions and analysis of retinal disease.

    PubMed Central

    Arden, G B; Hogg, C R

    1985-01-01

    Cone flicker threshold rises as the rods dark adapt, though the cone threshold to continuous light remains constant. The rise is normally about 1 log unit, but in certain patients who complain of night blindness it may be as great as 2.5 log units. In these persons the kinetics of the rod-cone interaction are those of the recovery of rod sensitivity. The rods impose a low-pass filter on the cones. This effect is absent in congenital nyctalopia and X-linked retinoschisis. We suggest that cone flicker is maintained through a feedback system involving horizontal cells, and when the rod dark current returns in dark adaptation this feedback is altered. Rod cone interaction thus tests rod dark current, and cases of abnormal interaction in patients with retinitis pigmentosa occur, which indicate that the transduction mechanism and the membrane dark current may be differentially affected. Images PMID:3873959

  16. Partial cone calix[4]arene-crown-6-ethers

    SciTech Connect

    Das, G.; Sachleben, R.A.; Descazeaud, T.; Bryan, J.C.; Moyer, B.A.

    1997-12-31

    Partial cone calix[4] arene crown ethers represents a new category of lariat ethers. In general, calix arene crown ethers have been previously shown to be efficient extractants for metal cations. Appropriately substituted cone and 1, 3-alt conformers of calix crowns exhibit selectivities for Na{sup +} and Cs{sup +}, respectively. The partial cone conformers have not been as throughly studied. We have developed an efficient method of synthesis of partial cone calix[4]arene-crown ethers and have synthesized a variety of partial cone calix[4]arene crowns. Solution and solid-state structures of representative examples have been determined by {sup 1}H NMR spectroscopy and X-ray crystallography. Relative affinities of these partial cone calix[4]arene crowns for alkali metal ions have been investigated by solvent extraction techniques.

  17. Disinfection of animal manures, food safety and policy.

    PubMed

    Cliver, Dean O

    2009-11-01

    Manure is a resource, but sometimes also a nuisance. Manure management strategies have traditionally focused on soil nutrients (N, P, K), COD, and more recently biological substances (antibiotics, hormones, etc.), with disinfection being a relative afterthought. Zoonotic pathogens (Salmonella and other bacteria, protozoa, etc.) may be present in manure, but only occasionally cause foodborne disease. In countries where food is relatively safe, requiring heroic manure disinfection measures may be a net detriment to public health. Decisions that a new, elegant disinfection technology can, should, or must be done may result from invoking the "precautionary principle." Additional capital and operating costs must be passed to the consumer. Since such measures are likely to prevent very few human illnesses, policymakers should also consider the effect of increased prices on human nutrition and hunger. In most situations, not eating is more dangerous than eating. PMID:19447609

  18. Water disinfection: microbes versus molecules - an introduction of issues

    SciTech Connect

    Fowle, J.R. III, Kopfler, F.C.

    1986-11-01

    If the chemicals used to rid drinking water of disease-causing microbes are themselves potentially harmful, is drinking water safe. What trade-offs are acceptable with respect to microbial versus chemical water quality. This conference deals with current thinking about these topics. The subjects discussed reflect the evolution of thinking, both scientifically and socially, about how best to supply the public with safe, pure potable water. The goal of this paper is to introduce the issues associated with disinfectants and disinfectant by-products in water. This will be done by presenting a historical overview of the use of chemical disinfectants to purify drinking water and the subsequent awareness of potential health concerns. Historically, the major health issue associated with water has been the demonstrated role that water has played in spreading infectious disease. Waterborne infectious agents remain in the environment, and new ones emerge through evolution of humans and microorganisms and because of changing exposure patterns.

  19. Effect of iodine disinfection products on higher plants

    NASA Technical Reports Server (NTRS)

    Janik, D.; Macler, B.; Macelroy, R. D.; Thorstenson, Y.; Sauer, R.

    1989-01-01

    Iodine is used to disinfect potable water on United States spacecraft. Iodinated potable water will likely be used to grow plants in space. Little is known about the effects of iodine disinfection products on plants. Seeds of select higher plants were germinated in water iodinated using the Shuttle Microbial Check Valve, and water to which measured amounts of iodine was added. Percent germination was decreased in seeds of most species germinated in iodinated water. Beans were most affected. Germination rates, determined from germination half-times, were decreased for beans germinated in iodinated water, and water to which iodide was added. Development was retarded and rootlets were conspicuously absent in bean and several other plant species germinated in iodinated water. Iodide alone did not elicit these responses. Clearly iodine disinfection products can affect higher plants. These effects must be carefully considered for plant experimentation and cultivation in space, and in design and testing of closed environmental life support systems.

  20. [Disinfection of wood in mushroom growing cellars with Mycetox].

    PubMed

    Szymański, J; Wazny, J

    1995-01-01

    Since the use od phenolic disinfectants for impregnating and disinfecting of wood in mushroom--growing cellars was banned in Poland for ecologic and hygienic reasons, the new product, namely Mycetox, containing quaternary ammonium compound and boric acid has been registered for this purpose. Mycetox belongs to new generation products and is non toxic for man and the environment. It is first Polish product developed for the general disinfection as well as for impregnating purposes in mushroom farms. The efficacy of Mycetox in mushroom-growing cellars has been evaluated basing on its fungicidal properties in the different substrates used for the cultivation of mushrooms. Also its influence on mushroom spawn growth, crop yield, and the penetration of spawn into wooden cages impregnated with Mycetox as well as its influence on blanching of mushrooms has been investigated.

  1. Tests of disinfection by heat in a bedpan washing machine.

    PubMed

    Ayliffe, G A; Collins, B J; Deverill, C E

    1974-09-01

    Tests of effectiveness of disinfection of metal and polypropylene bedpans were made in a washer fitted with a steam generator. Broth cultures of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, or Streptococcus faecalis (approximately 4 x 10(8) organisms) were sealed in lengths of capillary tubing and attached to the surface of the pans. In other tests, pans were contaminated with an artificial soil containing Str. faecalis (10(8) organisms/ml). In both series of tests, counts of surviving organisms were made at the end of the washing and disinfection cycle. The tests using capillary tubes showed that the Gram-negative bacilli were effectively killed, but not necessarily Gram-positive cocci. However, when incorporated in standard soil, Str. faecalis was killed or removed during the cycle. The results indicate that the disinfection process was effective for metal bedpans, but less so for polypropylene. Possible disadvantages and modification of the machine are suggested. PMID:4214841

  2. Drinking water and biofilm disinfection by Fenton-like reaction.

    PubMed

    Gosselin, F; Madeira, L M; Juhna, T; Block, J C

    2013-10-01

    A Fenton-like disinfection process was conducted with Fenton's reagent (H2O2) at pH 3 or 5 on autochthonous drinking water biofilms grown on corroded or non-corroded pipe material. The biofilm disinfection by Fenton-like oxidation was limited by the low content of iron and copper in the biomass grown on non-corroded plumbing. It was slightly improved by spiking the distribution system with some additional iron source (soluble iron II or ferrihydrite particles appeared as interesting candidates). However successful in situ disinfection of biofilms was only achieved in fully corroded cast iron pipes using H2O2 and adjusting the pH to 5. These new results provide additional support for the use of Fenton's processes for cleaning drinking water distribution systems contaminated with biological agents or organics.

  3. Photovoltage of Rods and Cones in the Macaque Retina

    NASA Astrophysics Data System (ADS)

    Schneeweis, David M.; Schnapf, Julie L.

    1995-05-01

    The kinetics, gain, and reliability of light responses of rod and cone photoreceptors are important determinants of overall visual sensitivity. In voltage recordings from photoreceptors in an intact primate retina, rods were found to be functionally isolated from each other, unlike the tightly coupled rods of cold-blooded vertebrates. Cones were observed to receive excitatory input from rods, which indicates that the cone pathway also processes rod signals. This input might be expected to degrade the spatial resolution of mesopic vision.

  4. Generation of ozone foam and its application for disinfection

    NASA Astrophysics Data System (ADS)

    Hiragaki, Keisuke; Ishimaru, Tomiya; Nakanishi, Masaru; Muraki, Ryouji; Nieda, Masanori; Yamabe, Chobei

    2015-07-01

    Generated ozone foam was applied to the disinfection of Pseudomonas fluorescens. The effect of disinfection has been confirmed experimentally and new equipment for the disinfection of hands using this ozone foam has been put on the market for the practical use. The ozone foam was produced in the foam generator after mixing the water including surfactant (30 mL/min) and air including ozone (1000 ppm = 2.14 g/m3 ~ 1600 ppm = 3.4 g/m3, 300 mL/min). The liquid-to-gas ratio is 100 L/m3. The concentration of dissolved ozone in the thin liquid films of the bubbles was about 3 mg/L which was measured by the chemical method of the KI absorption and titration of sodium thiosulfate solution. The disinfection test samples were prepared using the PET disk on which Pseudomonas fluorescens of its number of more than 108 were attached. Test sample was inserted into ozone foam set on the glass plate for one to 6 min. The survival rate log (N/N0 decreased with time and its value of about-2.6 (i.e., ~1/400) was obtained at 6 min (2 min × 3 times repeated). It was also confirmed that the ozone foam was useful for the disinfection of hands. For more effective disinfection (in case of taking a long time for foam melting), the ozone foam was broken by force and changed into ozone water by which the survival rate decreased ×4 (i.e., N/N0 = 1/10 000) at 4 ~ 6 min. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  5. Eliminating Medical Waste Liabilities Through Mobile Maceration and Disinfection

    SciTech Connect

    R. A. Rankin; N. R. Soelberg; K. M. Klingler; C. W. Lagle; L. L. Byers

    2006-02-01

    Commercial medical waste treatment technologies include incineration, melting, autoclaving, and chemical disinfection. Incineration disinfects, destroys the original nature of medical waste, and reduces the waste volume by converting organic waste content to carbon dioxide and water, leaving only residual inorganic ash. However, medical waste incinerator numbers have plummeted from almost 2,400 in 1995 to 115 in 2003 and to about 62 in 2005, due to negative public perception and escalating compliance costs associated with increasingly strict regulations. High-temperature electric melters have been designed and marketed as incinerator alternatives, but they are also costly and generally must comply with the same incinerator emissions regulations and permitting requirements. Autoclave processes disinfect medical waste at much lower operating temperatures than incinerators operate at, but are sometimes subject to limitations such as waste segregration requirements to be effective. Med-Shred, Inc. has developed a patented mobile shredding and chemical disinfecting process for on-site medical waste treatment. Medical waste is treated on-site at customer facilities by shredding and disinfecting the waste. The treated waste can then be transported in compliance with Health Insurance Portability and Accountability Act of 1996 (HIPAA) requirements to a landfill for disposal as solid municipal waste. A team of Idaho National Laboratory engineers evaluated the treatment process design. The process effectiveness has been demonstrated in mycobacterium tests performed by Analytical Services Incorporated. A process description and the technical and performance evaluation results are presented in the paper. A treatment demonstration and microbiological disinfecting tests show that the processor functions as it was intended.

  6. The trip of the tip: understanding the growth cone machinery.

    PubMed

    Lowery, Laura Anne; Van Vactor, David

    2009-05-01

    The central component in the road trip of axon guidance is the growth cone, a dynamic structure that is located at the tip of the growing axon. During its journey, the growth cone comprises both 'vehicle' and 'navigator'. Whereas the 'vehicle' maintains growth cone movement and contains the cytoskeletal structural elements of its framework, a motor to move forward and a mechanism to provide traction on the 'road', the 'navigator' aspect guides this system with spatial bias to translate environmental signals into directional movement. The understanding of the functions and regulation of the vehicle and navigator provides new insights into the cell biology of growth cone guidance.

  7. Dynamics on the cone: Closed orbits and superintegrability

    SciTech Connect

    Brihaye, Y.; Kosiński, P.

    2014-05-15

    The generalization of Bertrand’s theorem to the case of the motion of point particle on the surface of a cone is presented. The superintegrability of such models is discussed. The additional integrals of motion are analysed for the case of Kepler and harmonic oscillator potentials. -- Highlights: •Bertrand’s theorem is generalized to the case of the motion on a cone. •The superintegrability of the dynamics on a cone is discussed. •The W-algebra of integrals of motion for Kepler and harmonic oscillator problems on a cone is derived.

  8. Associating color appearance with the cone chromaticity space.

    PubMed

    Cao, Dingcai; Pokorny, Joel; Smith, Vivianne C

    2005-07-01

    A cone chromaticity space, a transform of a colorimetric specification system into coordinates that represent cone excitations, does not provide color appearance information. Boynton and Olson (Color Research and Application 12, 94-105, 1987) gathered color naming for the 424 Optical Society of America Uniform Color Scales (OSA-UCS) color samples. Here, a computational algorithm was developed that converts OSA-UCS sample values into L, M, S cone excitations based on the 1964 CIE 10 degrees Standard Observer. This makes it possible to plot the cone chromaticities associated with the eight color names used by Boynton and Olsen's observers to describe the non-dark appearing colors.

  9. Psychophysical definition of S-cone stimuli in the macaque

    PubMed Central

    Hall, Nathan; Colby, Carol

    2013-01-01

    We used the perceptual reports of nonhuman primates to perform psychophysical calibrations of S-cone isolating stimuli. S-cone stimuli were calibrated separately at several spatial locations for each monkey. To do this we exploited the effect of transient tritanopia, which causes a selective decrease of sensitivity in the observer's S-cone channel. At the start of each transient tritanopia trial monkeys were visually adapted to a bright yellow background. This type of adaptation is known to induce transient tritanopia. Calibrated S-cone isolating stimuli were determined by finding a near S-cone stimulus whose detection threshold was maximally elevated during transient tritanopia. At the start of each control trial, monkeys were adapted to a bright white background. In these trials, monkeys' detection thresholds for near S-cone stimuli were unchanged. We found that S-cone isolating stimuli could be determined at most locations tested in each monkey. Calibrated S-cone stimuli were particular to both spatial location and animal. To understand the visual system as a whole in vivo requires physiological methods not possible in human subjects. The present results open the door to novel behavioral and physiological experiments by showing that S-cone isolating stimuli can be calibrated in monkeys. PMID:23412341

  10. [Control of disinfection in the buildings of pig farms].

    PubMed

    Maris, P

    1990-01-01

    A survey carried out in pig farms was undertaken in order to compare 4 disinfectants used in 13 disinfecting operations, during the vacation period. It was immediately noticeable that after swabbing and counting the staphylococci, the chloramine T-based preparation was more effective than the quaternary ammonium-aldehyde association, phenolic acid derivatives or the quaternary ammonium preparations. We then observed that although the number of organisms decreased by 99.8%, their number on slatted floors still ranged between 0.02 x 10(4) and 3 x 10(4) per cm2. PMID:2344140

  11. The effectiveness of "Protex" for disinfection of the ultrasound probe.

    PubMed

    Koibuchi, Harumi; Tsuda, Kyoko; Taniguchi, Nobuyuki; Shimada, Isamu; Miyazawa, Tadashi; Sawada, Takeo

    2013-04-01

    The aim of this study was to evaluate the effectiveness of "Protex" (Parker; Fairfield, NJ, USA) for disinfection of ultrasound probes. We examined bacterial contamination on ultrasound probes that were wiped with a plain paper towel, with a plain and an ethanol-soaked paper towel, or with a plain and Protex-soaked paper towel. The plain paper towel was used to remove the gel, and was contaminated by large numbers of bacteria, but the use of ethanol-soaked paper towels and that of paper towels soaked in Protex™ broad-spectrum disinfectant (Parker: Fairfield, NJ, USA) reduced those numbers markedly. PMID:27277109

  12. Use of Hydrogen Peroxide to Disinfect Hydroponic Plant Growth Systems

    NASA Technical Reports Server (NTRS)

    Barta, Daniel J.; Henderson, Keith

    2000-01-01

    Hydrogen peroxide was studied as an alternative to conventional bleach and rinsing methods to disinfect hydroponic plant growth systems. A concentration of 0.5% hydrogen peroxide was found to be effective. Residual hydrogen peroxide can be removed from the system by repeated rinsing or by flowing the solution through a platinum on aluminum catalyst. Microbial populations were reduced to near zero immediately after treatment but returned to pre-disinfection levels 2 days after treatment. Treating nutrient solution with hydrogen peroxide and planting directly into trays being watered with the nutrient solution without replenishment, was found to be detrimental to lettuce germination and growth.

  13. Light-cone quantization and QCD phenomenology

    SciTech Connect

    Brodsky, S.J.; Robertson, D.G.

    1995-12-31

    In principle, quantum chromodynamics provides a fundamental description of hadronic and nuclear structure and dynamics in terms of their elementary quark and gluon degrees of freedom. In practice, the direct application of QCD to reactions involving the structure of hadrons is extremely complex because of the interplay of nonperturbative effects such as color confinement and multi-quark coherence. A crucial tool in analyzing such phenomena is the use of relativistic light-cone quantum mechanics and Fock state methods to provide tractable and consistent treatments of relativistic many-body systems. In this article we present an overview of this formalism applied to QCD, focusing in particular on applications to the final states in deep inelastic lepton scattering that will be relevant for the proposed European Laboratory for Electrons (ELFE), HERMES, HERA, SLAC, and CEBAF. We begin with a brief introduction to light-cone field theory, stressing how it many allow the derivation of a constituent picture, analogous to the constituent quark model, from QCD. We then discuss several applications of the light-cone Fock state formalism to QCD phenomenology. The Fock state representation includes all quantum fluctuations of the hadron wavefunction, including far off-shell configurations such as intrinsic charm and, in the case of nuclei, hidden color. In some applications, such as exclusive processes at large momentum transfer, one can make first-principle predictions using factorization theorems which separate the hard perturbative dynamics from the nonpertubative physics associated with hadron binding. The Fock state components of the hadron with small transverse size, which dominate hard exclusive reactions, have small color dipole moments and thus diminished hadronic interactions. Thus QCD predicts minimal absorptive corrections, i.e., color transparency for quasi-elastic exclusive reactions in nuclear targets at large momentum transfer.

  14. Cone Beam Computed Tomography - Know its Secrets

    PubMed Central

    Kumar, Mohan; Shanavas, Muhammad; Sidappa, Ashwin; Kiran, Madhu

    2015-01-01

    Cone-beam computed tomography (CBCT) is an advanced imaging modality that has high clinical applications in the field of dentistry. CBCT proved to be a successful investigative modality that has been used for dental and maxillofacial imaging. Radiation exposure dose from CBCT is 10 times less than from conventional CT scans during maxillofacial exposure. Furthermore, CBCT is highly accurate and can provide a three-dimensional volumetric data in axial, sagittal and coronal planes. This article describes the basic technique, difference in CBCT from CT and main clinical applications of CBCT. PMID:25859112

  15. Bistatic scattering from a cone frustum

    NASA Technical Reports Server (NTRS)

    Ebihara, W.; Marhefka, R. J.

    1986-01-01

    The bistatic scattering from a perfectly conducting cone frustum is investigated using the Geometrical Theory of Diffraction (GTD). The first-order GTD edge-diffraction solution has been extended by correcting for its failure in the specular region off the curved surface and in the rim-caustic regions of the endcaps. The corrections are accomplished by the use of transition functions which are developed and introduced into the diffraction coefficients. Theoretical results are verified in the principal plane by comparison with the moment method solution and experimental measurements. The resulting solution for the scattered fields is accurate, easy to apply, and fast to compute.

  16. Control of disinfection and halogenated disinfection byproducts by the electrochemical process.

    PubMed

    Jung, Y J; Oh, B S; Kang, J W; Page, M A; Phillips, M J; Mariñas, B J

    2007-01-01

    The aim of this study was to investigate some aspects of the performance of electrochemical process as an alternative disinfection strategy, while minimising DBPs, for water purification. The study of electrochemical processes has shown free chlorine to be produced, but smaller amounts of stronger oxidants, such as ozone, hydrogen peroxide and OH radicals (*OH), were also generated. The formation of mixed oxidants increased with increasing electric conductivity, but was limited at conductivities greater than 0.6 mS/cm. Using several microorganisms, such as E. coli and MS2 bacteriophage, inactivation kinetic studies were performed. With the exception of free chlorine, the role of mixed oxidants, especially OH radicals, was investigated for enhancement of the inactivation rate. Additionally, the formation and reduction of DBPs was studied by monitoring the concentration of haloacetic acids (HAAs) during the process. PMID:17674851

  17. [Formation of Disinfection By-Products During Chlor(am)ination of Danjiangkou Reservoir Water and Comparison of Disinfection Processes].

    PubMed

    Zhang, Min-sheng; Xu, Bin; Zhang, Tian-yang; Cheng, Tuo; Xia, Sheng-ji; Chu, Wen-hai

    2015-09-01

    This study discussed the formation of volatile carbonaceous disinfection by-products (DBPs) and nitrogenous DBPs during chlor(am) ination of Danjingkou Reservoir water which was the source of the Middle Route Project of South-to-North Water Diversion Project. The effects of disinfection methods, disinfectant dosage, reaction time, pH values and bromide ion concentration were investigated. And the disinfection parameters were optimized. Four DBPs, including chloroform (CF), bromodichloromethane (BDCM), dichloroacetonitrile(DCAN) and trichloronitromethane(TCNM), were observed during the chlorination. But only CF and TCNM were detected during the chloramination of water. The disinfection by-product (DBP) concentration from chlorination is 7. 5 times higher than that from chloramination, and the yield of DBPs from short time chlorination then chloramination is in between the first two methods. All kinds of DBPs detected increased with the dosage of increasing chlorine, but the increases slowed down when the dosage was higher than 2 mg . L -1. The formation of CF varied a little as the dosage of chloramine increasing. TCNM was detected when the chloramine dosage was greater than 2 mg . L -1. As reaction time going on, chlorine decayed much faster than chloramine, while DBP formation under chlorination was faster than that of chloramination. THM produced by chlorine increased with the increasing pH, while chloramination showed no obvious changes. As the bromide ion increasing, the species of DBPs transformed from chlorinated DBPs to brominated ones, and the total yield of DBPs increased during both chlorination and chloramination, but the former one was obviously more than that of the latter one. In order to reduce the risk of DBP formation, the chloramination is suggested in the treatment of water from Danjiangkou Reservoir. And if chlorination is applied, the disinfectant dosage should be controlled seriously.

  18. Emerging nitrogenous disinfection byproducts: Transformation of the antidiabetic drug metformin during chlorine disinfection of water.

    PubMed

    Armbruster, Dominic; Happel, Oliver; Scheurer, Marco; Harms, Klaus; Schmidt, Torsten C; Brauch, Heinz-Jürgen

    2015-08-01

    As an environmental contaminant of anthropogenic origin metformin is present in the high ng/L- up to the low μg/L-range in most surface waters. Residues of metformin may lead to the formation of disinfection by-products during chlorine disinfection, when these waters are used for drinking water production. Investigations on the underlying chemical processes occurring during treatment of metformin with sodium hypochlorite in aqueous medium led to the discovery of two hitherto unknown transformation products. Both substances were isolated and characterized by HPLC-DAD, GC-MS, HPLC-ESI-TOF, (1)H-NMR and single-crystal X-ray structure determination. The immediate major chlorination product is a cyclic dehydro-1,2,4-triazole-derivate of intense yellow color (Y; C4H6ClN5). It is a solid chlorimine of limited stability. Rapid formation was observed between 10 °C and 30 °C, as well as between pH 3 and pH 11, in both ultrapure and tap water, even at trace quantities of reactants (ng/L-range for metformin, mg/L-range for free chlorine). While Y is degraded within a few hours to days in the presence of light, elevated temperature, organic solvents and matrix constituents within tap water, a secondary degradation product was discovered, which is stable and colorless (C; C4H6ClN3). This chloroorganic nitrile has a low photolysis rate in ambient day light, while being resistant to heat and not readily degraded in the presence of organic solvents or in the tap water matrix. In addition, the formation of ammonia, dimethylamine and N,N-dimethylguanidine was verified by cation exchange chromatography.

  19. Precautionary practices of healthcare workers who disinfect medical and dental devices using high-level disinfectants.

    PubMed

    Henn, Scott A; Boiano, James M; Steege, Andrea L

    2015-02-01

    BACKGROUND High-level disinfectants (HLDs) are used throughout the healthcare industry to chemically disinfect reusable, semicritical medical and dental devices to control and prevent healthcare-associated infections among patient populations. Workers who use HLDs are at risk of exposure to these chemicals, some of which are respiratory and skin irritants and sensitizers. OBJECTIVE To evaluate exposure controls used and to better understand impediments to healthcare workers using personal protective equipment while handling HLDs. DESIGN Web-based survey. PARTICIPANTS A targeted sample of members of professional practice organizations representing nurses, technologists/technicians, dental professionals, respiratory therapists, and others who reported handling HLDs in the previous 7 calendar days. Participating organizations invited either all or a random sample of members via email, which included a hyperlink to the survey. METHODS Descriptive analyses were conducted including simple frequencies and prevalences. RESULTS A total of 4,657 respondents completed the survey. The HLDs used most often were glutaraldehyde (59%), peracetic acid (16%), and ortho-phthalaldehyde (15%). Examples of work practices or events that could increase exposure risk included failure to wear water-resistant gowns (44%); absence of standard procedures for minimizing exposure (19%); lack of safe handling training (17%); failure to wear protective gloves (9%); and a spill/leak of HLD during handling (5%). Among all respondents, 12% reported skin contact with HLDs, and 33% of these respondents reported that they did not always wear gloves. CONCLUSION Findings indicated that precautionary practices were not always used, underscoring the importance of improved employer and worker training and education regarding HLD hazards.

  20. Precautionary practices of healthcare workers who disinfect medical and dental devices using high-level disinfectants.

    PubMed

    Henn, Scott A; Boiano, James M; Steege, Andrea L

    2015-02-01

    BACKGROUND High-level disinfectants (HLDs) are used throughout the healthcare industry to chemically disinfect reusable, semicritical medical and dental devices to control and prevent healthcare-associated infections among patient populations. Workers who use HLDs are at risk of exposure to these chemicals, some of which are respiratory and skin irritants and sensitizers. OBJECTIVE To evaluate exposure controls used and to better understand impediments to healthcare workers using personal protective equipment while handling HLDs. DESIGN Web-based survey. PARTICIPANTS A targeted sample of members of professional practice organizations representing nurses, technologists/technicians, dental professionals, respiratory therapists, and others who reported handling HLDs in the previous 7 calendar days. Participating organizations invited either all or a random sample of members via email, which included a hyperlink to the survey. METHODS Descriptive analyses were conducted including simple frequencies and prevalences. RESULTS A total of 4,657 respondents completed the survey. The HLDs used most often were glutaraldehyde (59%), peracetic acid (16%), and ortho-phthalaldehyde (15%). Examples of work practices or events that could increase exposure risk included failure to wear water-resistant gowns (44%); absence of standard procedures for minimizing exposure (19%); lack of safe handling training (17%); failure to wear protective gloves (9%); and a spill/leak of HLD during handling (5%). Among all respondents, 12% reported skin contact with HLDs, and 33% of these respondents reported that they did not always wear gloves. CONCLUSION Findings indicated that precautionary practices were not always used, underscoring the importance of improved employer and worker training and education regarding HLD hazards. PMID:25633000

  1. Occurrence assessment for disinfectants and disinfection by-products (phase 6A) in public drinking water. Final report

    SciTech Connect

    Not Available

    1992-08-03

    The EPA Office of Ground Water and Drinking Water is developing national primary drinking water regulations for disinfectant and disinfection by-product contaminants. Thirteen contaminants are being considered to be regulated under Phase 6. These contaminants, referred to as Phase 6a, are the subject of the report. The information is important for setting the Maximum Contaminant Level Goal for a contaminant. The exposure information also is used to estimate the baseline health impact assessment of current levels and for evaluation of the health benefits of the regulatory alternatives.

  2. Microcomputed tomography and shock microdeformation studies on shatter cones

    NASA Astrophysics Data System (ADS)

    Zaag, Patrice Tristan; Reimold, Wolf Uwe; Hipsley, Christy Anna

    2016-08-01

    One of the aspects of impact cratering that are still not fully understood is the formation of shatter cones and related fracturing phenomena. Yet, shatter cones have been applied as an impact-diagnostic criterion for decades without the role of shock waves and target rock defects in their formation having been elucidated ever. We have tested the application of the nondestructive microcomputed tomography (μCT) method to visualize the interior of shatter cones in order to possibly resolve links between fracture patterns and shatter cone surface features (striations and intervening "valleys"). Shatter-coned samples from different impact sites and in different lithologies were investigated for their μCT suitability, with a shatter cone in sandstone from the Serra da Cangalha impact structure (Brazil) remaining as the most promising candidate because of the fracture resolution achieved. To validate the obtained CT data, the scanned specimen was cut into three orthogonal sets of thin sections. Scans with 13 μm resolution were obtained. μCT scans and microscopic analysis unraveled an orientation of subplanar fractures and related fluid inclusion trails, and planar fracture (PF) orientations in the interior of shatter cones. Planar deformation features (PDF) were observed predominantly near the shatter cone surface. Previously undescribed varieties of feather features (FF), in the form of lamellae emanating from curviplanar and curved fractures, as well as an "arrowhead"-like FF development with microlamellae originating from both sides of a PF, were observed. The timing of shatter cone formation was investigated by establishing temporal relations to the generation of various shock microscopic effects. Shatter cones are, thus, generated post- or syn-formation of PF, FF, subplanar fractures, and PDF. The earliest possible time for shatter cone formation is during the late stage of the compressional phase, that is, shock wave passage, of an impact event.

  3. Controlling Legionella in hospital drinking water: an evidence-based review of disinfection methods.

    PubMed

    Lin, Yusen E; Stout, Janet E; Yu, Victor L

    2011-02-01

    Hospital-acquired Legionnaires' disease is directly linked to the presence of Legionella in hospital drinking water. Disinfecting the drinking water system is an effective preventive measure. The efficacy of any disinfection measures should be validated in a stepwise fashion from laboratory assessment to a controlled multiple-hospital evaluation over a prolonged period of time. In this review, we evaluate systemic disinfection methods (copper-silver ionization, chlorine dioxide, monochloramine, ultraviolet light, and hyperchlorination), a focal disinfection method (point-of-use filtration), and short-term disinfection methods in outbreak situations (superheat-and-flush with or without hyperchlorination). The infection control practitioner should take the lead in selection of the disinfection system and the vendor. Formal appraisals by other hospitals with experience of the system under consideration is indicated. Routine performance of surveillance cultures of drinking water to detect Legionella and monitoring of disinfectant concentrations are necessary to ensure long-term efficacy.

  4. Conductive diamond sono-electrochemical disinfection (CDSED) for municipal wastewater reclamation.

    PubMed

    Llanos, Javier; Cotillas, Salvador; Cañizares, Pablo; Rodrigo, Manuel A

    2015-01-01

    In the present work, the disinfection of actual effluents from a municipal wastewater treatment plant (WWTP) by a conductive diamond sono-electrochemical process was assessed. First, efficiency of single electrodisinfection process with diamond anodes (without the contribution of ultrasounds) was studied, finding that the total disinfection can be attained at current charges applied below 0.02kAhm(-3). It was also found that the main disinfection mechanism is the attack of Escherichia coli (E. coli) by the disinfectants produced in the electrochemical cell and that the production of chlorates is avoided when working at current densities not higher than 1.27Am(-2). Next, a marked synergistic effect was found when coupling ultrasound (US) irradiation to the electrochemical system (sono-electrochemical disinfection). This increase in the disinfection rate was found to be related to the suppression of the agglomeration of E. coli cells and the enhancement in the production of disinfectant species.

  5. UV disinfection system for cabin air

    NASA Astrophysics Data System (ADS)

    Lim, Soojung; Blatchley, Ernest R.

    2009-10-01

    The air of indoor cabin environments is susceptible to contamination by airborne microbial pathogens. A number of air treatment processes are available for inactivation or removal of airborne pathogens; included among these processes is ultraviolet (UV) irradiation. The effectiveness of UV-based processes is known to be determined by the combined effects of UV dose delivery by the reactor and the UV dose-response behavior of the target microbe(s). To date, most UV system designs for air treatment have been based on empirical approaches, often involving crude representations of dose delivery and dose-response behavior. The objective of this research was to illustrate the development of a UV system for disinfection of cabin air based on well-defined methods of reactor and reaction characterization. UV dose-response behavior of a test microorganism was measured using a laboratory (bench-scale) system. Target microorganisms (bacterial spores) were first applied to membrane filters at sub-monolayer coverage. The filters were then transferred to a humidity chamber at fixed relative humidity (RH) and allowed to equilibrate with their surroundings. Microorganisms were then subjected to UV exposure under a collimated beam. The experiment was repeated at RH values ranging from 20% to 100%. UV dose-response behavior was observed to vary with RH. For example, at 100% RH, a UV dose of 20 mJ/cm 2 accomplished 99.7% (2.5 log10 U) of the Bacillus subtilis spore inactivation, whereas 99.94% (3.2 log10 U) inactivation was accomplished at this same UV dose under 20% RH conditions. To determine reactor behavior, UV dose-response behavior was combined with simulated results of computational fluid dynamics (CFD) and radiation intensity field models. This modeling approach allowed estimating the UV dose distribution delivered by the reactor. The advantage of this approach is that simulation of many reactor configurations can be done in a relatively short period of time. Moreover, by

  6. Real Gas/Blunt Cone. Phase 2

    NASA Technical Reports Server (NTRS)

    Deiwert, George S.; Eitelberg, Georg

    1998-01-01

    In this chapter recent activity in real-gas database definition and code validation will be summarized. In the Phase I report of the Working Group (WG) 181, aerothermodynamic problems were classified, for purpose of discussion, into seven types: aerodynamic parameters, viscous/shock interaction, boundary-layer transition, forebody-heating/heat-transfer, radiation and ablation, lee and base-region flow, and low-density flow. Several of these problem types were the subject of various chapters of the Phase 1 report describing real-gas effects and ground test facility issues. In this chapter some background and objectives outlined in the real-Gas effects Chapter V of the Phase 1 report will be reviewed. The results of the blunt cone test campaign developed under the auspices of the WG18 activity to study real-gas phenomena will be summarized, including the experimental and computational programs, issues and questions, and recommendations. Further, recent progress in other real-gas areas beyond the blunt cone test campaign will be discussed. Finally, a summary in which the present status of our understanding of real-gas issues will be presented.

  7. Light-cone quantization and hadron structure

    SciTech Connect

    Brodsky, S.J.

    1996-04-01

    Quantum chromodynamics provides a fundamental description of hadronic and nuclear structure and dynamics in terms of elementary quark and gluon degrees of freedom. In practice, the direct application of QCD to reactions involving the structure of hadrons is extremely complex because of the interplay of nonperturbative effects such as color confinement and multi-quark coherence. In this talk, the author will discuss light-cone quantization and the light-cone Fock expansion as a tractable and consistent representation of relativistic many-body systems and bound states in quantum field theory. The Fock state representation in QCD includes all quantum fluctuations of the hadron wavefunction, including fax off-shell configurations such as intrinsic strangeness and charm and, in the case of nuclei, hidden color. The Fock state components of the hadron with small transverse size, which dominate hard exclusive reactions, have small color dipole moments and thus diminished hadronic interactions. Thus QCD predicts minimal absorptive corrections, i.e., color transparency for quasi-elastic exclusive reactions in nuclear targets at large momentum transfer. In other applications, such as the calculation of the axial, magnetic, and quadrupole moments of light nuclei, the QCD relativistic Fock state description provides new insights which go well beyond the usual assumptions of traditional hadronic and nuclear physics.

  8. Scatter corrections for cone beam optical CT

    NASA Astrophysics Data System (ADS)

    Olding, Tim; Holmes, Oliver; Schreiner, L. John

    2009-05-01

    Cone beam optical computed tomography (OptCT) employing the VISTA scanner (Modus Medical, London, ON) has been shown to have significant promise for fast, three dimensional imaging of polymer gel dosimeters. One distinct challenge with this approach arises from the combination of the cone beam geometry, a diffuse light source, and the scattering polymer gel media, which all contribute scatter signal that perturbs the accuracy of the scanner. Beam stop array (BSA), beam pass array (BPA) and anti-scatter polarizer correction methodologies have been employed to remove scatter signal from OptCT data. These approaches are investigated through the use of well-characterized phantom scattering solutions and irradiated polymer gel dosimeters. BSA corrected scatter solutions show good agreement in attenuation coefficient with the optically absorbing dye solutions, with considerable reduction of scatter-induced cupping artifact at high scattering concentrations. The application of BSA scatter corrections to a polymer gel dosimeter lead to an overall improvement in the number of pixel satisfying the (3%, 3mm) gamma value criteria from 7.8% to 0.15%.

  9. UV-laser-based longitudinal illuminated diffuser (LID) incorporating diffractive and Lambertian reflectance for the disinfection of beverages

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd

    2010-08-01

    A novel laser beam shaping system was designed to demonstrate the potential of using high power UV laser sources for large scale disinfection of liquids used in the production of food products, such as juices, beer, milk and other beverage types. The design incorporates a patented assembly of optical components including a diffractive beam splitting/shaping element and a faceted pyramidal or conically shaped Lambertian diffuser made from a compression molded PTFE compounds. When properly sintered to an appropriate density, as an example between 1.10 and 1.40 grams per cubic centimeter, the compressed PTFE compounds show a ~99% reflectance at wavelengths ranging from 300 nm to 1500 nm, and a ~98.5% refection of wavelengths from 250 nm to 2000 nm [1]. The unique diffuser configuration also benefits from the fact that the PTFE compounds do not degrade when exposed to ultraviolet radiation as do barium sulfate materials and silver or aluminized mirror coatings [2]. These components are contained within a hermetically sealed quartz tube. Once assembled a laser beam is directed through one end of the tube. This window takes the form of a computer generated diffractive splitter or other diffractive shaper element to split the laser beam into a series of spot beamlets, circular rings or other geometric shapes. As each of the split beamlets or rings cascade downward, they illuminate various points along the tapered PTFE cone or faceted pyramidal form. As they strike the surface they each diffuse in a Lambertian reflectance pattern creating a pseudo-uniform circumferential illuminator along the length of the quartz tube enclosing the assembly. The compact tubular structure termed Longitudinal Illuminated Diffuser (LID) provides a unique UV disinfection source that can be placed within a centrifugal reactor or a pipe based reactor chamber. This paper will review the overall design principle, key component design parameters, preliminary analytic and bench operational testing

  10. 7 CFR 301.89-12 - Cleaning, disinfection, and disposal.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Cleaning, disinfection, and disposal. 301.89-12 Section 301.89-12 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT... animal consumption must be disposed of by means of burial under a minimum of 24 inches of soil in...

  11. ANALYTICAL METHODS FOR WATER DISINFECTION BYPRODUCTS IN FOODS AND BEVERAGES

    EPA Science Inventory

    The determination of exposure to drinking water disinfection byproducts (DBPs) requires an understanding of how drinking water comes into contact with human through multiple pathways. In order to facilitate the investigation of human exposure to DBPs via foods and beverages, anal...

  12. 9 CFR 53.6 - Disinfection of animals.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Disinfection of animals. 53.6 Section 53.6 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... of animals. Animals of species not susceptible to the disease for which a quarantine has...

  13. 9 CFR 53.6 - Disinfection of animals.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Disinfection of animals. 53.6 Section 53.6 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... of animals. Animals of species not susceptible to the disease for which a quarantine has...

  14. 9 CFR 53.6 - Disinfection of animals.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Disinfection of animals. 53.6 Section 53.6 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... of animals. Animals of species not susceptible to the disease for which a quarantine has...

  15. 9 CFR 53.6 - Disinfection of animals.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Disinfection of animals. 53.6 Section 53.6 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... of animals. Animals of species not susceptible to the disease for which a quarantine has...

  16. Disinfection By-Products and Drinking Water Treatment

    EPA Science Inventory

    The disinfection of drinking water has been rightly hailed as a public health triumph of the 20th century. Before its widespread use, millions of people died from waterborne diseases. Now, people in developed nations receive quality drinking water every day from their public wa...

  17. COMPARATIVE RISK DILEMNAS IN DRINKING WATER DISINFECTION [EDITORIAL

    EPA Science Inventory

    Disinfection of drinking water supplies has been one of the most succesful public health interventions of the twentieth century. It has virtually eliminated outbreaks of serious waterborne infectious diseases, such as cholera and typhoid. there are still, however, an average of...

  18. 9 CFR 82.22 - Cleaning and disinfecting premises.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfecting premises. 82.22 Section 82.22 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE INTERSTATE TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS...

  19. 9 CFR 82.22 - Cleaning and disinfecting premises.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Cleaning and disinfecting premises. 82.22 Section 82.22 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE INTERSTATE TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS...

  20. Improved method of using paraformaldehyde as a disinfectant

    NASA Technical Reports Server (NTRS)

    Milner, J. F.

    1971-01-01

    Paraformaldehyde decreases required enclosed compartment disinfectant time and temperature by vaporizing powdered material from water slurry. Fire and explosion hazard at lower temperature is reduced. Total mixture evaporation occurs at plate temperature of approximately 167 deg K below that required to vaporize powdered material.