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Sample records for control e-csf osmolarity

  1. Variability of tear osmolarity in dry eye patients and controls

    PubMed Central

    Bunya, Vatinee Y.; Fuerst, Nicole M.; Pistilli, Maxwell; McCabe, Bridgette E.; Salvo, Rebecca; Macchi, Ilaria; Ying, Gui-Shuang; Massaro-Giordano, Mina

    2015-01-01

    Importance Knowledge about the variability of measurements using the TearLab™ osmolarity system is necessary when evaluating the clinical utility of readings. Objective To examine the variability of tear osmolarity, as measured by the TearLab™ system, in subjects with Sjogren's syndrome (SS), blepharitis and controls. Design Cross-sectional study. Setting Tertiary care, academic center. Participants Seventy-four eyes of thirty-seven subjects from a volunteer sample (18 SS, 11 blepharitis, 8 controls) were evaluated using the TearLab™ osmolarity system with three consecutive osmolarity measurements taken at one-minute intervals in a session, and fifteen of these subjects had the same measurements taken by the same examiner in two additional sessions on the same day (9–10am, 12-1pm, or 3–4pm). The majority of SS and blepharitis subjects were on systemic or topical dry eye medications at the time of enrollment. Main Outcome Measures Mean osmolarity and its variability calculated from a linear mixed model for each disease group that accounts for the variations attributable to different subjects, eyes, and sessions, and measurement error specific to each disease group. Results Mean tear osmolarity was 307, 304, and 301 mOsm/L within the SS, blepharitis, and control groups, respectively (p=0.46). The error associated with repeated measurements within a session in the non-dry eye subjects (10.5 [95% CI 9.0, 12.4] mOsm/L) was significantly lower than in the blepharitis (14.6 [12.5, 17.5] mOsm/L, p=0.006) or SS (15.8 [14.2, 17.8] mOsm/L, p<0.0001) subjects, but a difference in the error of repeated measurements between blepharitis and SS subjects was not identified (p=0.46). Conclusions and Relevance There was increased variability attributable to error in repeated measurements among SS and blepharitis subjects compared to controls. The high variability of TearLab™ osmolarity readings in all groups makes clinical interpretation of measurements unclear. PMID

  2. Diagnostic Accuracy, Image Quality, and Patient Comfort for Coronary CT Angiography Performed Using Iso-Osmolar versus Low-Osmolar Iodinated Contrast: A Prospective International Multicenter Randomized Controlled Trial.

    PubMed

    Nakazato, Ryo; Arsanjani, Reza; Shalev, Aryeh; Leipsic, Jonathon A; Gransar, Heidi; Lin, Fay Y; Gomez, Millie; Berman, Daniel S; Min, James K

    2016-06-01

    The impact of iso-osmolar versus low-osmolar iodinated contrast on diagnostic accuracy for coronary computed tomography angiography (CCTA), against the reference standard of invasive coronary angiography (ICA), has not been determined. We sought to compare in an international multicenter randomized controlled trial the impact of iso-osmolar iodixanol versus low-osmolar iopamidol on diagnostic accuracy, image quality, patient symptoms, and heart rate variability. Adult patients who were clinically referred for ICA were randomly assigned to receive either iodixanol (n = 133) or iopamidol (n = 133) with an investigational CCTA. CCTA stenosis and image quality were scored by consensus of independent blinded core laboratory readers. Degree of stenosis by ICA was evaluated using quantitative coronary angiography and used to calculate diagnostic accuracy. Heart rate variability and patient-reported symptom questionnaires were compared between the two groups. A total of 266 subjects underwent both CCTA and ICA (57 ± 11 years, 58% male). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for detecting coronary artery disease were 86.8%, 93.7%, 84.6%, 94.7%, and 91.7% for iodixanol and 94.7%, 88.4%, 76.6%, 97.7%, and 90.2% for iopamidol, respectively, on a per-patient level. These values were not significantly different between the two groups. There was no significant difference in image quality and heart rate increase or variability. The majority of patients reported symptoms (59.4%), with no differences in the overall or individual rate of any or moderate to severe symptoms between the two groups. Patients receiving iodixanol reported lower incidence of moderate to severe flushing (3.0% vs. 12.8%, P = .005). Lower rates of moderate to severe symptoms were particularly evident for patients with ≥55 years receiving iodixanol versus iopamidol (8.5% vs. 24.6%, P = .01). Diagnostic performance and image

  3. A dual-core double emulsion platform for osmolarity-controlled microreactor triggered by coalescence of encapsulated droplets

    PubMed Central

    Guan, Xuewei; Hou, Likai; Ren, Yukun; Deng, Xiaokang; Lang, Qi; Jia, Yankai; Hu, Qingming; Tao, Ye; Liu, Jiangwei; Jiang, Hongyuan

    2016-01-01

    Droplet-based microfluidics has provided a means to generate multi-core double emulsions, which are versatile platforms for microreactors in materials science, synthetic biology, and chemical engineering. To provide new opportunities for double emulsion platforms, here, we report a glass capillary microfluidic approach to first fabricate osmolarity-responsive Water-in-Oil-in-Water (W/O/W) double emulsion containing two different inner droplets/cores and to then trigger the coalescence between the encapsulated droplets precisely. To achieve this, we independently control the swelling speed and size of each droplet in the dual-core double emulsion by controlling the osmotic pressure between the inner droplets and the collection solutions. When the inner two droplets in one W/O/W double emulsion swell to the same size and reach the instability of the oil film interface between the inner droplets, core-coalescence happens and this coalescence process can be controlled precisely. This microfluidic methodology enables the generation of highly monodisperse dual-core double emulsions and the osmolarity-controlled swelling behavior provides new stimuli to trigger the coalescence between the encapsulated droplets. Such swelling-caused core-coalescence behavior in dual-core double emulsion establishes a novel microreactor for nanoliter-scale reactions, which can protect reaction materials and products from being contaminated or released. PMID:27279935

  4. A dual-core double emulsion platform for osmolarity-controlled microreactor triggered by coalescence of encapsulated droplets.

    PubMed

    Guan, Xuewei; Hou, Likai; Ren, Yukun; Deng, Xiaokang; Lang, Qi; Jia, Yankai; Hu, Qingming; Tao, Ye; Liu, Jiangwei; Jiang, Hongyuan

    2016-05-01

    Droplet-based microfluidics has provided a means to generate multi-core double emulsions, which are versatile platforms for microreactors in materials science, synthetic biology, and chemical engineering. To provide new opportunities for double emulsion platforms, here, we report a glass capillary microfluidic approach to first fabricate osmolarity-responsive Water-in-Oil-in-Water (W/O/W) double emulsion containing two different inner droplets/cores and to then trigger the coalescence between the encapsulated droplets precisely. To achieve this, we independently control the swelling speed and size of each droplet in the dual-core double emulsion by controlling the osmotic pressure between the inner droplets and the collection solutions. When the inner two droplets in one W/O/W double emulsion swell to the same size and reach the instability of the oil film interface between the inner droplets, core-coalescence happens and this coalescence process can be controlled precisely. This microfluidic methodology enables the generation of highly monodisperse dual-core double emulsions and the osmolarity-controlled swelling behavior provides new stimuli to trigger the coalescence between the encapsulated droplets. Such swelling-caused core-coalescence behavior in dual-core double emulsion establishes a novel microreactor for nanoliter-scale reactions, which can protect reaction materials and products from being contaminated or released.

  5. [Plasma osmolarity and cerebral volume].

    PubMed

    Boulard, G

    2001-02-01

    Under normal physiological conditions, the osmolarity of extracellular fluids (ECFs) and natremia are controlled by two regulatory mechanisms modulating the water balance and sodium outflow from information collected by the osmoreceptors and baroreceptors, respectively. As well, under normal physiological conditions, water and electrolytes of brain ECFs are secreted by the endothelial cells of brain capillaries. Furthermore, isotonicity is present on both sides of the blood-brain barrier. In the event of systemic osmolarity disorders, water transport subject to osmosis laws occurs at the level of the blood-brain barrier. In the case of plasmatic hyperosmolarity cerebral dehydration is observed, while cerebral edema occurs in the contrary case. However, plasmatic osmolarity disorders have less effect on the cerebral volume when their introduction is slow. Experimentation in acute conditions shows that measured variations of the cerebral water content are lower than calculated variations, thus suggesting the existence of an adaptive mechanism, that is, the cerebral osmoregulation which limits the variation of the volume of brain cells by modulating their osmoactive molecule content. These osmoactive molecules are, on the one hand, the electrolytes, which are early and rapidly mobilized, and, on the other hand, the organic osmoles (amino acids, etc.), whose secretion is slower and delayed. This phenomenon should be taken into account in the treatment of osmolarity disorders. Thus, the related-risk of treatment for natremia disorders is therapeutic reversal of the osmotic gradient at the level of the blood-brain barrier. This reversal, which corresponds to a second osmotic stress, requires the implementation of a new procedure of cerebral osmoregulation in the opposite direction of the preceding one. As successive osmotic stresses decrease the effectiveness of brain osmoregulation, the risk for cerebral dehydration and pontine myelinolysis increases when the treatment

  6. [Tear osmolarity and dry eye].

    PubMed

    Pan, Shi-yin; Xiao, Xiang-hua; Wang, Yang-zheng; Liu, Xian-ning; Zhu, Xiu-ping

    2011-05-01

    Dry eye is a common eye disease, and its incidence rate has been escalating. The increased tear osmolarity is one of the main reasons for complaint, damage and inflammation of dry eye patients. With the breakthrough of testing technology for tear osmolarity, more research and application of tear osmolarity was reported, and papers on tear osmolarity of normal eye and dry eye in different regions were also published. In this article, the progress of the tear osmolarity research, the range of tear osmolarity and its application in diagnosis and therapy of dry eye was introduced, and the prospect for the clinical application of hypotonic artificial tears was also discussed.

  7. A randomized controlled trial of glucose versus amylase resistant starch hypo-osmolar oral rehydration solution for adult acute dehydrating diarrhea.

    PubMed

    Ramakrishna, Balakrishnan S; Subramanian, Venkataraman; Mohan, Vivek; Sebastian, Bendon K; Young, Graeme P; Farthing, Michael J; Binder, Henry J

    2008-02-13

    Reduction of gross diarrhea rate in excess of that seen over time with intravenous therapy and appropriate antibiotics is not usually achieved by oral glucose-electrolyte rehydration therapy for cholera and cholera-like diarrheas. This prospective randomized clinical trial at a tertiary referral hospital in southern India was undertaken to determine whether amylase resistant starch, substituting for glucose in hypo-osmolar oral rehydration solution, would reduce diarrhea duration and weight in adults with acute severe dehydrating diarrhea. 50 adult males with severe watery diarrhea of less than three days' duration and moderate to severe dehydration were randomized to receive hypo-osmolar ORS (HO-ORS) or HO-ORS in which amylase resistant high amylose maize starch 50g/L substituted for glucose (HAMS-ORS). All remaining therapy followed standard protocol. Duration of diarrhea (ORS commencement to first formed stool) in hours was significantly shorter with HAMS-ORS (median 19, IQR 10-28) compared to HO-ORS (median 42, IQR 24-50) (Bonferroni adjusted P, P(adj)<0.001). Survival analysis (Kaplan-Meier) showed faster recovery from diarrhea in the HAMS-ORS group (P<0.001, log rank test). Total diarrhea fecal weight in grams (median, IQR) was not significantly lower in the HAMS-ORS group (2190, 1160-5635) compared to HO-ORS (5210, 2095-12190) (P(adj) = 0.08). However, stool weight at 13-24 hours (280, 0-965 vs. 1360, 405-2985) and 25-48 hours (0, 0-360 vs. 1080, 55-3485) were significantly lower in HAMS-ORS compared to HO-ORS group (P(adj) = 0.048 and P = 0.012, respectively). ORS intake after first 24 hours was lower in the HAMS-ORS group. Subgroup analysis of patients with culture isolates of Vibrio cholerae indicated similar significant differences between the treatment groups. Compared to HO-ORS, HAMS-ORS reduced diarrhea duration by 55% and significantly reduced fecal weight after the first 12 hours of ORS therapy in adults with cholera-like diarrhea. Current

  8. Osmolarity and root canal antiseptics.

    PubMed

    Rossi-Fedele, G; Guastalli, A R

    2014-04-01

    Antiseptics used in endodontics for disinfection purposes include root canal dressings and irrigants. Osmotic shock is known to cause the alteration of microbial cell viability and might have a role in the mechanism of action of root canal antiseptics. The aim of this review was to determine the role of osmolarity on the performance of antiseptics in root canal treatment. A literature search using the Medline electronic database was conducted up to 30 May 2013 using the following search terms and combinations: 'osmolarity AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmolality AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmotic AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmosis AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; sodium chloride AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm'. Publications were included if the effects of osmolarity on the clinical performance of antiseptics in root canal treatment were stated, if preparations with different osmolarities values were compared and if they were published in English. A hand search of articles published online, 'in press' and 'early view', and in the reference list of the included papers was carried out following the same criteria. A total of 3274 publications were identified using the database, and three were included in the review. The evidence available in endodontics suggests a possible role for hyperosmotic root canal medicaments as disinfectants, and that there is no influence of osmolarity on the tissue dissolution capacity of sodium hypochlorite. There are insufficient data to obtain a sound conclusion regarding the role of hypo-osmosis in root canal disinfection, or osmosis in any further desirable

  9. [The Tear Osmolarity of PATIENTS with Lagophthalmos].

    PubMed

    Píšová, A; Chovanec, M; Betka, J; Ferrová, K; Česká Burdová, M; Odehnal, M; Dotřelová, D; Mahelková, G

    Lagophthalmos can be characterized as the dysfunction of the eye aperture and in some cases even by the disruption of tear production. Dry eye syndrome can consequently develop. Instability of the tear film, hyperosmolarity and inflammatory reaction are considered as the key mechanisms of dry eye syndrome. In our report we monitored the tear osmolarity of patients with postsurgical unilateral lagophthalmos. Results were compared with tear osmolarity of the non-lagophthalmic eyes. We examined 10 patients (6 women, 4 men) with postsurgical facial nerve palsy and lagophthalmos complicating management of either cerebellopontine (8 patients) or salivary gland tumors (2 patients). Only patients without severe corneal defects enrolled the study. The tear osmolarity was measured in lower tear meniscus by TearLab Osmolarity System device. The lagophthalmic eye was always examined first. The results are presented as mean plus/minus the standard deviation. The paired t-test was used for statistical data processing. The p-value 0,05 was considered as statistically significant. The mean tear osmolarity of the lagophthalmic eyes was 296 ± 15,0 mosmol/l (275-315 mosmol/l). In case of healthy eyes the mean osmolarity was 310 ± 12 mosmol/l (292-336 mosmol/l). The tear osmolarity in case of lagophthalmos was significantly lower than in the healthy eyes (p = 0,05). In contrary to the studies demonstrating higher tear osmolarity under the scenario of dry eye syndrome, we found lower tear osmolarity in the lagophthalmic eyes than in the healthy eyes. The possible reason could be the changes in tear dynamics of the lagophthalmic eye due to disturbance of eye lid function. Our results also stress the need of evaluation of the actual tear osmolarity in the view of complex clinical eye findings. The place of tear collection should also be considered.Key words: lagophthalmos, dry eye syndrom, tear osmolarity.

  10. The Effects of Hemodialysis on Tear Osmolarity

    PubMed Central

    Taskapili, Muhittin; Serefoglu Cabuk, Kubra; Aydin, Rukiye; Atalay, Kursat; Kirgiz, Ahmet; Sit, Dede; Kayabasi, Hasan

    2015-01-01

    Aim. To determine the effects of hemodialysis (HD) on tear osmolarity and to define the blood biochemical tests correlating with tear osmolarity among patients with end stage renal disease (ESRD). Material-Method. Tear osmolarity of ESRD patients before and after the hemodialysis program was determined as well as the blood biochemical data including glucose, sodium, potassium, calcium, urea, and creatinine levels. Results. Totally 43 eyes of 43 patients (20 females and 23 males) with a mean age of 53.98 ± 18.06 years were included in the study. Tear osmolarity of patients was statistically significantly decreased after hemodialysis (314.06 ± 17.77 versus 301.88 ± 15.22 mOsm/L, p = 0.0001). In correlation analysis, pre-HD tear osmolarity was negatively correlated with pre-HD blood creatinine level (r = −0.366,  p = 0.016). Post-HD tear osmolarity was statistically significantly correlated with the post-HD glucose levels (r = 0.305  p = 0.047). Tear osmolarity alteration by HD was negatively correlated with creatinine alteration, body weight alteration, and ultrafiltration (r = −0.426,  p = 0.004; r = −0.365,  p = 0.016; and r = −0.320, p = 0.036, resp.). There was no correlation between tear osmolarity and Kt/V and URR values. Conclusion. HD effectively decreases tear osmolarity to normal values and corrects the volume and composition of the ocular fluid transiently. Tear osmolarity alteration induced by HD is correlated with body weight changes, creatinine alterations, and ultrafiltration. PMID:26640702

  11. Reduced osmolarity oral rehydration solution for treating cholera.

    PubMed

    Murphy, C; Hahn, S; Volmink, J

    2004-10-18

    Oral rehydration solution (ORS) is used to treat dehydration caused by diarrheal diseases including cholera. Reduced osmolarity formulations are safe and more effective than standard ORS for treating non-cholera diarrhea. As cholera causes rapid electrolyte loss, it is important to know if these benefits are similar for people with cholera. To compare the safety and efficacy of reduced osmolarity oral rehydration solution (ORS) with standard ORS for treating diarrhea due to cholera. We searched the Cochrane Infectious Disease Group Specialized Register (January 2004), CENTRAL (The Cochrane Library Issue 1, 2004), MEDLINE (1966 to January 2004), EMBASE (1974 to January 2004), and LILACS (1982 to January 2004). We also contacted organizations and searched reference lists. Randomized controlled trials comparing reduced osmolarity ORS with standard ORS for treating adults and children with acute diarrhea due to cholera. Two reviewers independently applied eligibility criteria, assessed trial quality, and extracted data. We pooled binary data using relative risks (RR), continuous data using weighted mean difference (WMD) or the standardized mean difference (SMD), and presented the results with 95% confidence intervals (CI). For glucose-based reduced osmolarity ORS, seven trials (718 participants) met the inclusion criteria. Biochemical hyponatremia (serum sodium < 130 mmol/L) was more common with reduced osmolarity ORS (RR 1.67, CI 1.09 to 2.57; 465 participants, 4 trials); for severe biochemical hyponatremia (serum sodium < 125 mmol/L) this was not significant (RR 1.58, CI 0.62 to 4.04; 465 participants, 4 trials). No trials reported symptomatic hyponatremia or death. We found no statistically significant difference in the need for unscheduled intravenous infusion. Analyses separating children and adults showed no obvious trends. Two trials also examined rice-based ORS. In the reduced osmolarity group, duration of diarrhea was shorter (WMD -16.85 hours, CI -21.22 to

  12. Relationship between extracellular osmolarity, NaCl concentration and cell volume in rat glioma cells.

    PubMed

    Rouzaire-Dubois, Béatrice; Ouanounou, Gilles; Dubois, Jean Marc

    2011-06-01

    The cell volume, which controls numerous cellular functions, is theoretically linearly related with the inverse osmolarity. However, deviations from this law have often been observed. In order to clarify the origin of these deviations we electronically measured the mean cell volume of rat glioma cells under three different experimental conditions, namely: at different osmolarities and constant NaCl concentration; at different NaCl concentrations and constant osmolarity and at different osmolarities caused by changes in NaCl concentration. In each condition, the osmolarity was maintained constant or changed with NaCl or mannitol. We showed that the cell volume was dependent on both the extracellular osmolarity and the NaCl concentration. The relationship between cell volume, osmolarity and NaCl concentration could be described by a new equation that is the product of the Boyle-van't Hoff law and the Michaelis-Menten equation at a power of 4. Together, these results suggest that in hyponatriemia, the cell volume deviates from the Boyle-van't Hoff law because either the activity of aquaporin 1, expressed in glioma cells, is decreased or the reduced NaCl influx decreases the osmotically obliged influx of water.

  13. Tear Osmolarity in Sjogren’s Syndrome

    PubMed Central

    Bunya, Vatinee Y.; Langelier, Nicole; Chen, Sarah; Pistilli, Maxwell; Vivino, Frederick B.; Massaro-Giordano, Giacomina

    2013-01-01

    Purpose The Schirmer test is one of two ocular surface tests included in the current classification criteria for Sjögren’s Syndrome (SS). Tear osmolarity may also be a useful test for the diagnosis of dry eye disease. The purpose of this study was to examine the relationship between tear osmolarity, the Schirmer test I, and dry eye symptoms in SS. Methods Patients with a diagnosis of SS were assessed for tear osmolarity with the TearLab™ Osmolarity System, tear production with Schirmer testing, symptoms with the Ocular Surface Disease Index (OSDI), and discomfort associated with each test. Results Forty-nine patients with a mean age of 53.7 years and a female (92%) predominance were enrolled. The majority of patients (86%) were receiving systemic therapy for severe SS. Higher tear osmolarity was moderately associated with lower scores on the Schirmer test I (ρ = −0.39, P < 0.01) and with lower scores on the OSDI (ρ = −0.45, P < 0.01). Schirmer test I results and lower OSDI scores were not correlated significantly (ρ = 0.20, P = 0.17). Tear osmolarity testing was significantly less painful than Schirmer testing (P < 0.01). Conclusions Signs and symptoms of dry eye in SS patients were not strongly correlated. An unexpected finding was that higher tear osmolarity was associated with lower symptom severity. Tear osmolarity testing in the clinical setting was feasible and was associated with significantly less discomfort than Schirmer testing in patients with severe SS. PMID:23407318

  14. Safety and Efficacy of Low-osmolarity ORS vs. Modified Rehydration Solution for Malnourished Children for Treatment of Children with Severe Acute Malnutrition and Diarrhea: A Randomized Controlled Trial.

    PubMed

    Kumar, Ruchika; Kumar, Praveen; Aneja, S; Kumar, Virendra; Rehan, Harmeet S

    2015-12-01

    World Health Organization-recommended rehydration solution for malnourished children (ReSoMal) for rehydrating severe acute malnourished children is not available in India. In present study, 110 consecutive children aged 6-59 months with severely acute malnourishment and acute diarrhea were randomized to low-osmolarity oral rehydration solution (ORS) (osmolarity: 245, sodium: 75) with added potassium (20 mmol/l) or modified ReSoMal (osmolarity: 300, sodium: 45). In all, 15.4% of modified ReSoMal group developed hyponatremia as compared with 1.9% in low-osmolarity ORS, but none developed severe hyponatremia or hypernatremia. Both groups had equal number of successful rehydration (52 each). Both types of ORS were effective in correcting hypokalemia and dehydration, but rehydration was achieved in shorter duration with modified ReSoMal.

  15. Osmolarity: A hidden factor in Nanotoxicology.

    PubMed

    Moayyedi, Saeid; Mashinchian, Omid; Dinarvand, Rassoul

    2016-03-22

    In the field of drug delivery, long circulating nanocarriers in the blood have many advantages such as targeted drug delivery and sustained release. Based on our current knowledge, evaluation of the effect of long circulating nanocarriers in the blood stream on osmolarity of plasma has not been reported before. In this study, osmotic pressure developed by some commercially available nanocarriers was estimated based on Van't Hoff equation. It is noteworthy that theoretically, nanocarriers do not have any significant effect on osmolarity of plasma. However, it is worth being evaluated experimentally in order to be taken into account in future studies.

  16. Tear film dynamics with evaporation and osmolarity

    NASA Astrophysics Data System (ADS)

    Siddique, Javed; Braun, Richard

    2011-11-01

    We consider a model problem for the evaporation and breakup up of tear film. The model includes the effects of surface tension, Marangoni stresses, insoluble surfactant transport, evaporation, osmolarity transport, osmosis and wetting of corneal surface. Evaporation is made dependent on surface concentration in order to mimic the lipid layer of the tear film when there is a single fluid layer in the model. In many cases for a single layer, the Marangoni effect seems to eliminate a localized area of increased evaporation due to reduced surfactant concentration. In this model the osmolarity in the tear film increases because of average evaporation rate rather than by a locally increased evaporation rate. If time permits, the effect of having a second fluid layer, representing the lipid layer, will be explored as well.

  17. Tear film osmolarity measurements in dry eye disease using electrical impedance technology.

    PubMed

    Jacobi, Christina; Jacobi, Arnd; Kruse, Friedrich E; Cursiefen, Claus

    2011-12-01

    Tear film hyperosmolarity is recognized as an important pathogenetic factor in dry eye syndrome, but difficulties in its measurement have limited its utility in the recent past. This prospective, nonrandomized, clinical single-center study investigates the osmolarity in tear samples of patients with keratoconjunctivitis sicca compared with healthy controls. One hundred thirty-three patients [aged 58 years (51-64 years), 86 women and 47 men] with moderate to severe keratoconjunctivitis sicca and 95 controls [aged 52 years (48-61 years), 55 women and 40 men] were enrolled in the trial. Tear samples were collected directly from the inferior lateral tear meniscus. Inclusion criteria were a tear breakup time of less than 5 seconds, a Schirmer test with anesthesia less than 5 mm, and positive symptoms (Ocular Surface Disease Index score > 83). Tear film osmolarity was analyzed by the TearLab osmometer. In our study, patients with moderate to severe keratoconjunctivitis sicca showed a tear film osmolarity of 320 mOsmol/L (301-324 mOsmol/L). The results of the control group were 301 mOsmol/L (298-304 mOsmol/L). Our results revealed a significantly higher tear film osmolarity in patients with moderate to severe keratoconjunctivitis sicca compared with the control group. The sensitivity was 87%, and the specificity was 81%. Our results approved the referent value in moderate to severe dry eye of approximately 316 mOsmol/L, as described in the literature. The results showed a significantly higher tear film osmolarity in patients with severe keratoconjunctivitis sicca compared with the healthy controls. Testing tear film osmolarity can be a very effective objective diagnostic tool in the diagnosis of dry eye disease.

  18. Osmolar therapy in pediatric traumatic brain injury.

    PubMed

    Bennett, Tellen D; Statler, Kimberly D; Korgenski, E Kent; Bratton, Susan L

    2012-01-01

    To describe patterns of use for mannitol and hypertonic saline in children with traumatic brain injury, to evaluate any potential associations between hypertonic saline and mannitol use and patient demographic, injury, and treatment hospital characteristics, and to determine whether the 2003 guidelines for severe pediatric traumatic brain injury impacted clinical practice regarding osmolar therapy. Retrospective cohort study. Pediatric Health Information System database, January, 2001 to December, 2008. Children (age <18 yrs) with traumatic brain injury and head/neck Abbreviated Injury Scale score ≥ 3 who received mechanical ventilation and intensive care. : None. The primary outcome was hospital billing for parenteral hypertonic saline and mannitol use, by day of service. Overall, 33% (2,069 of 6,238) of the patients received hypertonic saline, and 40% (2,500 of 6,238) received mannitol. Of the 1,854 patients who received hypertonic saline or mannitol for ≥ 2 days in the first week of therapy, 29% did not have intracranial pressure monitoring. After adjustment for hospital-level variation, primary insurance payer, and overall injury severity, use of both drugs was independently associated with older patient age, intracranial hemorrhage (other than epidural), skull fracture, and higher head/neck injury severity. Hypertonic saline use increased and mannitol use decreased with publication of the 2003 guidelines, and these trends continued through 2008. Hypertonic saline and mannitol are used less in infants than in older children. The patient-level and hospital-level variation in osmolar therapy use and the substantial amount of sustained osmolar therapy without intracranial pressure monitoring suggest opportunities to improve the quality of pediatric traumatic brain injury care. With limited high-quality evidence available, published expert guidelines appear to significantly impact clinical practice in this area.

  19. Effect of low-osmolar contrast medium iopromide and iso-osmolar iodixanol on DNA fragmentation in renal tubular cell culture.

    PubMed

    Ludwig, Ulla; Connemann, Julia; Keller, Frieder

    2013-12-01

    Intravascular administration of iodinated contrast media continues to be a common cause of hospital-acquired acute kidney injury. Accumulating evidence suggests that radiocontrast agent-induced nephrotoxicity is associated with increased oxidative stress, which leads to renal tissue damage with DNA fragmentation. We therefore tested whether an iso-osmolar contrast medium (iodixanol) causes less oxidative DNA damage to renal tubular cells than a low-osmolar contrast medium (iopromide). HK-2 cells (human proximal renal tubular cell line) were incubated at different time points (10 min-2 h) with increasing concentrations (20-120 mg/ml iodine) of iodixanol or of iopromide. Oxidative DNA damage to renal tubular cells was measured by alkaline comet assay (single-cell gel electrophoresis). Both iso- and low-osmolar contrast agents induced time- and concentration-dependent DNA fragmentation. DNA fragmentation was maximal at 2 h with 120 mg/ml iodine for iopromide (32 ± 27 tail moments) and iodixanol (46 ± 41 tail moments); both were significantly different from the control value with 3.15 ± 1.6 tail moments (Student's t test; p < 0.001). After 1 and 2 h and for all concentrations, iodixanol produced significantly higher DNA fragmentation than iopromide (ANOVA for 1 h p = 0.039 and 2 h p = 0.025, respectively). We were able to demonstrate for the first time that an iso-osmolar contrast medium induced even greater oxidative stress and DNA damage than a low-osmolar agent in HK-2 cells. This could provide an explanation for the nephrotoxicity that also is observed with iodixanol in clinical practice.

  20. Prediction of parenteral nutrition osmolarity by digital refractometry.

    PubMed

    Chang, Wei-Kuo; Yeh, Ming-Kung

    2011-05-01

    Infusion of high-osmolarity parenteral nutrition (PN) formulations into a peripheral vein will damage the vessel. In this study, the authors developed a refractometric method to predict PN formulation osmolarity for patients receiving PN. Nutrients in PN formulations were prepared for Brix value and osmolality measurement. Brix value and osmolality measurement of the dextrose, amino acids, and electrolytes were used to evaluate the limiting factor of PN osmolarity prediction. A best-fit equation was generated to predict PN osmolarity (mOsm/L): 81.05 × Brix value--116.33 (R(2) > 0.99). To validate the PN osmolarity prediction by these 4 equations, a total of 500 PN admixtures were tested. The authors found strong linear relationships between the Brix values and the osmolality measurement of dextrose (R(2) = 0.97), amino acids (R(2) = 0.99), and electrolytes (R(2) > 0.96). When PN-measured osmolality was between 600 and 900 mOsm/kg, approximately 43%, 29%, 43%, and 0% of the predicted osmolarity obtained by equations 1, 2, 3, and 4 were outside the acceptable 90% to 110% confidence interval range, respectively. When measured osmolality was between 900 and 1,500 mOsm/kg, 31%, 100%, 85%, and 15% of the predicted osmolarity by equations 1, 2, 3, and 4 were outside the acceptable 90% to 110% confidence interval range, respectively. The refractive method permits accurate PN osmolarity prediction and reasonable quality assurance before PN formulation administration.

  1. Influence of osmolarity on the optical properties of human erythrocytes.

    PubMed

    Friebel, Moritz; Helfmann, Jürgen; Meinke, Martina C

    2010-01-01

    Plasma osmolarity influences the volume and shape of red blood cells (RBCs). The volume change is inversely related to the hemoglobin concentration and as a consequence to the complex refractive index within the cell. These morphological changes can be linked to changes in the optical behavior of the cells. The optical parameters, absorption coefficient μa, scattering coefficient μs, and effective scattering phase function of red blood cells are investigated in dependence on osmolarity in the spectral range from 250 to 1100 nm. Integrating sphere measurements of light transmittance and reflectance in combination with inverse Monte-Carlo simulations are carried out for osmolarities from 225 to 400 mosmol/L. Osmolarity changes have a significant influence on the optical parameters, which can in part be explained by changes in the complex refractive index, cell shape, and cell volume. Spherical forms of RBCs induced by low osmolarity show reduced scattering effects compared to the normal RBC biconcave disk shape. Spinocytes, which are crenated erythrocytes induced by high osmolarity, show the highest scattering effects. Even only a 10% change in osmolarity has a drastic influence on the optical parameters, which appears to be of the same order as for 10% hematocrit and oxygen saturation changes.

  2. Influence of osmolarity on the optical properties of human erythrocytes

    NASA Astrophysics Data System (ADS)

    Friebel, Moritz; Helfmann, Jürgen; Meinke, Martina C.

    2010-09-01

    Plasma osmolarity influences the volume and shape of red blood cells (RBCs). The volume change is inversely related to the hemoglobin concentration and as a consequence to the complex refractive index within the cell. These morphological changes can be linked to changes in the optical behavior of the cells. The optical parameters, absorption coefficient μa, scattering coefficient μs, and effective scattering phase function of red blood cells are investigated in dependence on osmolarity in the spectral range from 250 to 1100 nm. Integrating sphere measurements of light transmittance and reflectance in combination with inverse Monte-Carlo simulations are carried out for osmolarities from 225 to 400 mosmol/L. Osmolarity changes have a significant influence on the optical parameters, which can in part be explained by changes in the complex refractive index, cell shape, and cell volume. Spherical forms of RBCs induced by low osmolarity show reduced scattering effects compared to the normal RBC biconcave disk shape. Spinocytes, which are crenated erythrocytes induced by high osmolarity, show the highest scattering effects. Even only a 10% change in osmolarity has a drastic influence on the optical parameters, which appears to be of the same order as for 10% hematocrit and oxygen saturation changes.

  3. Tear osmolarity and dry eye symptoms in diabetics.

    PubMed

    Fuerst, Nicole; Langelier, Nicole; Massaro-Giordano, Mina; Pistilli, Maxwell; Stasi, Kalliopi; Burns, Carrie; Cardillo, Serena; Bunya, Vatinee Y

    2014-01-01

    To assess the relationship between tear osmolarity and dry eye symptoms in patients with diabetes. Fifty patients with diabetes were enrolled. Demographic information and past medical history were recorded. Symptoms were assessed using the ocular surface disease index (OSDI). Tear osmolarity of each eye was measured with the TearLab® Osmolarity System. The majority of the subjects were female (76%), African American (56%), and/or had a diagnosis of type 2 diabetes (82%). The mean ± standard deviation (SD) for age was 54.6±13.4, and maximum tear osmolarity was 304.6±12.7 mOsm/L. Men had higher osmolarity than women (mean ± standard error (SE) 311.8±4.0 mOsm/L versus 302.3±1.9 mOsm/L, P=0.02). Age, race, use of artificial tears, years of diabetes, and hemoglobin A1c did not have a statistically significant association with tear osmolarity. Longer duration of diabetes was associated with lower (less severe) OSDI scores (r=-0.35, P=0.01). Higher tear osmolarity was associated with lower (less severe) OSDI scores (r=-0.29, P=0.04). Approximately half of the diabetic subjects in our study had elevated tear osmolarity, and half of our population also reported symptoms consistent with dry eye disease. However, the two were slightly inversely related in that those with higher osmolarity reported fewer symptoms. Subjects with a longer duration of diabetes also reported fewer dry eye symptoms. Therefore, health care providers should be aware that patients who are most likely to have ocular surface disease, including those with long-standing diabetes, may not experience symptoms and seek care in a timely manner.

  4. Tear osmolarity and dry eye symptoms in diabetics

    PubMed Central

    Fuerst, Nicole; Langelier, Nicole; Massaro-Giordano, Mina; Pistilli, Maxwell; Stasi, Kalliopi; Burns, Carrie; Cardillo, Serena; Bunya, Vatinee Y

    2014-01-01

    Purpose To assess the relationship between tear osmolarity and dry eye symptoms in patients with diabetes. Patients and methods Fifty patients with diabetes were enrolled. Demographic information and past medical history were recorded. Symptoms were assessed using the ocular surface disease index (OSDI). Tear osmolarity of each eye was measured with the TearLab® Osmolarity System. Results The majority of the subjects were female (76%), African American (56%), and/or had a diagnosis of type 2 diabetes (82%). The mean ± standard deviation (SD) for age was 54.6±13.4, and maximum tear osmolarity was 304.6±12.7 mOsm/L. Men had higher osmolarity than women (mean ± standard error (SE) 311.8±4.0 mOsm/L versus 302.3±1.9 mOsm/L, P=0.02). Age, race, use of artificial tears, years of diabetes, and hemoglobin A1c did not have a statistically significant association with tear osmolarity. Longer duration of diabetes was associated with lower (less severe) OSDI scores (r=−0.35, P=0.01). Higher tear osmolarity was associated with lower (less severe) OSDI scores (r=−0.29, P=0.04). Conclusion Approximately half of the diabetic subjects in our study had elevated tear osmolarity, and half of our population also reported symptoms consistent with dry eye disease. However, the two were slightly inversely related in that those with higher osmolarity reported fewer symptoms. Subjects with a longer duration of diabetes also reported fewer dry eye symptoms. Therefore, health care providers should be aware that patients who are most likely to have ocular surface disease, including those with long-standing diabetes, may not experience symptoms and seek care in a timely manner. PMID:24648714

  5. Tear Osmolarity, Break-up Time and Schirmer’s Scores in Parkinson’s Disease

    PubMed Central

    Söğütlü Sarı, Esin; Koç, Rabia; Yazıcı, Alper; Şahin, Gözde; Çakmak, Harun; Kocatürk, Tolga; Ermiş, Sıtkı Samet

    2015-01-01

    Objectives: Dry eye is an important problem in Parkinson’s disease (PD) with a potential to affect life quality. Tear osmolarity, accepted as the gold standard in dry eye diagnosis, has not been studied in this subset of patients so far. Therefore, in this study we aimed to evaluate tear osmolarity, Schirmer’s test scores and tear film break-up time (TBUT) in PD patients. Ma­te­ri­als and Met­hods: PD patients with a minimum follow-up of 1 year and healthy controls who admitted for refractive abnormalities were enrolled to the study. Subjects using any systemic medication with a possibility to affect tear tests were not included in the study. The presence of any ocular surface disorder, previous ocular surgery, previous dry eye diagnosis, any topical ophthalmic medication or contact lens use were other exclusion criteria. Age, gender, disease duration, and Hoehn and Yahr (H&Y) score for disease severity were noted, and blink rate (BR), Schirmer’s test score, TBUT and tear osmolarity of the right eye were measured in both groups. Re­sults: Thirty-seven PD patients and 37 controls were enrolled to the study. The groups were age and gender matched. The mean disease duration and H&Y score were 5.70±2.64 years and 1.70±0.93, respectively. H&Y staging and disease duration were not correlated to BR, Schirmer’s scores, TBUT, or tear osmolarity (p>0.05). The mean BR was 8.54±4.99 blinks/minute in PD patients and 11.97±6.36 blinks/minute in the control group. Mean Schirmer’s scores, TBUT and osmolarity values were 9.08±4.46 mm, 11.38±4.05 seconds and 306.43±12.63 mOsm/L in the PD group and 17.16±9.57 mm, 12.81±3.66 seconds and 303.81±16.13 mOsm/L in the control group. The differences were significant only in BR and Schirmer’s scores. Conclusion: BR and Schirmer’s scores decreased significantly in PD patients. Although not significant, the demonstrated tear osmolarity increment might be important to document the dry eye and inflammatory process of

  6. Transcriptional profiling of dendritic cells matured in different osmolarities.

    PubMed

    Chessa, Federica; Hielscher, Thomas; Mathow, Daniel; Gröne, Hermann-Josef; Popovic, Zoran V

    2016-03-01

    Tissue-specific microenvironments shape the fate of mononuclear phagocytes [1-3]. Interstitial osmolarity is a tissue biophysical parameter which considerably modulates the phenotype and function of dendritic cells [4]. In the present report we provide a detailed description of our experimental workflow and bioinformatic analysis applied to our gene expression dataset (GSE72174), aiming to investigate the influence of different osmolarity conditions on the gene expression signature of bone marrow-derived dendritic cells. We established a cell culture system involving murine bone marrow cells, cultured under different NaCl-induced osmolarity conditions in the presence of the dendritic cell growth factor GM-CSF. Gene expression analysis was applied to mature dendritic cells (day 7) developed in different osmolarities, with and without prior stimulation with the TLR2/4 ligand LPS.

  7. [Osmolarity of solutions used in nebulization].

    PubMed

    Portel, L; Tunon de Lara, J M; Vernejoux, J M; Weiss, I; Taytard, A

    1998-04-01

    Inhaled medications are widely used in patients suffering from bronchial diseases. Beside their pharmacological properties, nebulised solutions have physico-chemical characteristics that can alter bronchial reactivity. Non-isotonic solutions can induce a bronchial hyperresponsiveness and/or a severe bronchonconstriction. Nevertheless, multiple drugs are used for nebulisation despite their unknown osmolarity. The aim of this study was to measure the tonicity of drug solutions commonly used for nebulisation in patients suffering from bronchial disease. Drug solutions were prepared either according to manufacturer recommendations or by diluting the stock in 5 ml of NaCl (0.9%) or H2CO3 (0.14%). Although bronchodilatator solutions (i.e. salbutamol, terbulatine, ipratropium bromide) were nearly isotonic, some drugs prepared for nebulisation had either a very high (e.g. mesna, netilmicine) or a very low (e.g. gomenol, sodium cromoglycate) tonicity. These values may be responsible for bronchoconstriction. Some hypertonic solutions, prepared with drugs such as acetylcytein or netilmycin, are not commercialised for nebulisation but are commonly used for aerosol therapy. In addition, solutions initially isotonic could become significantly hypertonic towards the end of nebulisation. Taken together, these results suggest that non-isotonic solutions should be used with caution specially in patients with bronchial hyperresponsiveness, even when aerosol therapy is prescribed for upper airways.

  8. Effects of sinusoidal magnetic field observed on cell proliferation, ion concentration, and osmolarity in two human cancer cell lines.

    PubMed

    Huang, Lingzhen; Dong, Liang; Chen, Yantian; Qi, Hanshi; Xiao, Dengming

    2006-01-01

    Low frequency magnetic fields have previously been shown to affect cell functions. In this article, the effects of 20 mT, 50 Hz sinusoidal magnetic field on cell proliferation, ion concentration, and osmolarity in two human cancer cell lines (HL-60 and SK-Hep-1) were investigated. Inhibition of cell growth was observed. On the other hand, the exposure also increased the Na+, K+ ion concentration and osmolarity in cell supernatant compared to the control group. To our knowledge, this is the first study on cancer cells where magnetic fields affect osmolarity in cell supernatant. In addition, a model of cells exposed to the oscillating magnetic field is described as well as the characteristics of ions in and out of cells. The experimental data appears to be consistent with the theoretical analysis. The results are also discussed in terms of the relationships among cell growth, ion concentration, and osmolarity. Magnetic field inhibitions of cell growth in vitro may relate to changes in cell ion concentration and osmolarity.

  9. Multicentre evaluation of reduced-osmolarity oral rehydration salts solution. International Study Group on Reduced-osmolarity ORS solutions.

    PubMed

    1995-02-04

    In developed countries, use of oral rehydration salts (ORS) solution with osmolarity lower than that of plasma has been recommended because of the risk of hypernatraemia. We compared the clinical efficacy of reduced-osmolarity ORS and standard ORS solutions in children with acute diarrhoea in four developing countries. 447 boys aged 1-24 months, admitted to hospitals in four countries with acute diarrhoea and signs of dehydration, were randomly assigned either standard ORS (311 mmol/L) or reduced-osmolarity ORS (224 mmol/L) solution. Total stool output was 39% greater (95% CI 11-75), total ORS intake 18% greater (3-33), and duration of diarrhoea 22% longer (2-45) in the standard ORS group than in the reduced-osmolarity ORS group. The risk of requiring intravenous infusion after completion of the initial oral rehydration was greater in children given standard ORS solution than in those given reduced-osmolarity ORS solution in three of the four countries (all-country relative risk 1.4 [0.9-2.4]). This relative risk was significantly increased only in non-breastfed children (2.0 [1.0-3.8], p < 0.05). In breastfed children, the relative risk of requiring intravenous infusion was not affected by the ORS solution (0.9 [0.4-2.0]). The mean sodium concentration 24 h after admission was significantly lower in the reduced-osmolarity ORS group than in the standard ORS group (135 [134-136] vs 138 [136-139] mmol/L, p < 0.01). Reduced-osmolarity ORS solution has beneficial effects on the clinical course of acute diarrhoea. Our findings support the use of reduced-osmolarity ORS solution in children with acute non-cholera diarrhoea in developing countries. Further studies are needed to find the best formulation and whether such a solution would be satisfactory for the treatment of cholera.

  10. Piezo1-dependent regulation of urinary osmolarity.

    PubMed

    Martins, Joana Raquel; Penton, David; Peyronnet, Rémi; Arhatte, Malika; Moro, Céline; Picard, Nicolas; Kurt, Birgül; Patel, Amanda; Honoré, Eric; Demolombe, Sophie

    2016-07-01

    The collecting duct (CD) is the final segment of the kidney involved in the fine regulation of osmotic and ionic balance. During dehydration, arginine vasopressin (AVP) stimulates the expression and trafficking of aquaporin 2 (AQP2) to the apical membrane of CD principal cells, thereby allowing water reabsorption from the primary urine. Conversely, when the secretion of AVP is lowered, as for instance upon water ingestion or as a consequence of diabetes insipidus, the CD remains water impermeable leading to enhanced diuresis and urine dilution. In addition, an AVP-independent mechanism of urine dilution is also at play when fasting. Piezo1/2 are recently discovered essential components of the non-selective mechanically activated cationic channels. Using quantitative PCR analysis and taking advantage of a β-galactosidase reporter mouse, we demonstrate that Piezo1 is preferentially expressed in CD principal cells of the inner medulla at the adult stage, unlike Piezo2. Remarkably, siRNAs knock-down or conditional genetic deletion of Piezo1 specifically in renal cells fully suppresses activity of the stretch-activated non-selective cationic channels (SACs). Piezo1 in CD cells is dispensable for urine concentration upon dehydration. However, urinary dilution and decrease in urea concentration following rehydration are both significantly delayed in the absence of Piezo1. Moreover, decreases in urine osmolarity and urea concentration associated with fasting are fully impaired upon Piezo1 deletion in CD cells. Altogether, these findings indicate that Piezo1 is critically required for SAC activity in CD principal cells and is implicated in urinary osmoregulation.

  11. Measurement variability of the TearLab Osmolarity System.

    PubMed

    Szczesna-Iskander, Dorota H

    2016-10-01

    To independently assess the measurement variability of TearLab System in a clinical setting of one visit and to estimate the minimum number of measurements required for reliable readings of tear osmolarity. Ten consecutive osmolarity measurements were taken from both eyes by the same examiner at one visit for fourteen subjects. The ocular surface disease index symptoms questionnaire and tear film break up time were also performed. Group average cumulative mean and cumulative coefficient of variation were calculated to assess the TearLab measurement variation. Repeated application of Thompson's tau method was performed to identify the outliers in tear osmolarity readings for each eye. Results from both eyes were analysed separately. Up to two randomly occurring outlying values in 10 consecutive measurements were found in 19 out of 28 measured eyes. No statistically significant differences between the left and right eye were found for the group mean and group standard deviation (paired t-test, p=0.099 and p=0.068, respectively), however the cumulative coefficient of variation indicated higher measurement group variability on one eye. Estimated cumulative coefficient of variation indicated the minimum of three consecutive acquisitions required for the measurement to be reliable. TearLab Osmolarity System required at least three consecutive measurements to be taken in order to provide clinically reliable tear osmolarity readings. Also, taking the maximum osmolarity value for detecting dry eye disease should be viewed with caution since outlying readings of tear osmolarity frequently occur. Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  12. Relationships among Tear Film Stability, Osmolarity, and Dryness Symptoms

    PubMed Central

    Yeh, Thao N.; Graham, Andrew D.; Lin, Meng C.

    2016-01-01

    Purpose To examine the relationships among tear osmolarity, tear film stability, and several measures of dry eye (DE) symptoms in a multivariable analysis. Methods A cross-sectional study was conducted with 137 subjects (68 non–contact lens [CL] wearers and 69 soft CL wearers) recruited from a university campus. Tear breakup time (TBUT) was measured noninvasively (NITBUT) and with fluorescein (FTBUT). Tear osmolarity was measured by an osmometer. Dry eye symptoms were assessed using the Dry Eye Flow Chart and several different questionnaires. Results Subjects ranged in age from 18 to 67 years, with a mean of 28 years. Subjects had a mean (SD) osmolarity of 293 (10) mOsm/L, NITBUT of 14.1 (10.9) seconds, and FTBUT of 14.8 (12.6) seconds. Shorter NITBUT and FTBUT were significantly associated with female sex (p = 0.001 and p = 0.027, respectively) and Asian ethnicity (p = 0.030 and p = 0.004, respectively). There were no clinically significant relationships between tear osmolarity and FTBUT, NITBUT, or DE symptoms. Higher Dry Eye Flow Chart score (i.e., worse symptoms) was associated with older age (p < 0.001), female sex (p = 0.014), CL wear (p < 0.001), shorter NITBUT (p < 0.001), and shorter FTBUT (p = 0.028). The sensitivities and specificities for using clinical measurements to diagnose moderate to severe DE were as follows: osmolarity, 0.67 and 0.46, respectively; NITBUT, 0.72 and 0.52, respectively; and FTBUT, 0.68 and 0.57, respectively. Conclusions In a population of asymptomatic, mild and moderate DE patients, increased tear osmolarity was not significantly associated with reported symptom severity and frequency. Tear osmolarity, NITBUT, and FTBUT exhibited similar sensitivities and specificities when used to diagnose moderate to severe DE. PMID:26154693

  13. Culturing bovine nucleus pulposus explants by balancing medium osmolarity.

    PubMed

    van Dijk, Bart; Potier, Esther; Ito, Keita

    2011-11-01

    Regenerative therapies are promising treatments for early intervertebral disc degeneration. To test their efficacy, an in vitro tissue-level model would be valuable. Nucleus pulposus (NP) explant culture may constitute such a model, as the earliest signs of degeneration are in the NP. However, in NP explant cultures, balancing tissue osmolarity is crucial to preventing swelling, proteoglycan (PG) loss and, therefore, maintaining a native cell environment. In this study, we investigated the effect of medium osmolarity on NP explants. We hypothesized that balancing the inherent tissue osmolarity would prevent swelling and thus maintain NP tissue in a native state. Bovine NP explants were cultured for 21 days in hypo-, iso-, and hyper-tonic conditions using either sucrose or polyethylene glycol (PEG) to raise medium osmolarity. Explants were analyzed for water and biochemical content, cell viability, gene expression, and tissue histology, and compared to day 0 samples. In hypo-tonic and both sucrose cultures, swelling was not prevented, resulting in PG loss and changes in cell behavior. Only PEG cultures maintained water and biochemical content and a histological aspect similar to those of native tissue, with better results for hyper- than for iso-tonic conditions. Using PEG to raise culture medium osmolarity, we were able to maintain the NP tissue specific matrix composition, important for disc cell behavior. This approach, thus, constitutes a promising model to test regenerative therapies for early intervertebral disc degeneration.

  14. A Model for Tear Film Thinning With Osmolarity and Fluorescein

    PubMed Central

    Braun, Richard J.; Gewecke, Nicholas R.; Begley, Carolyn G.; King-Smith, P. Ewen; Siddique, Javed I.

    2014-01-01

    Purpose. We developed a mathematical model predicting dynamic changes in fluorescent intensity during tear film thinning in either dilute or quenching regimes and we model concomitant changes in tear film osmolarity. Methods. We solved a mathematical model for the thickness, osmolarity, fluorescein concentration, and fluorescent intensity as a function of time, assuming a flat and spatially uniform tear film. Results. The tear film thins to a steady-state value that depends on the relative importance of the rates of evaporation and osmotic supply, and the resulting increase of osmolarity and fluorescein concentrations are calculated. Depending on the initial thickness, the rate of osmotic supply and the tear film thinning rate, the osmolarity increase may be modest or it may increase by as much as a factor of eight or more from isosmotic levels. Regarding fluorescent intensity, the quenching regime occurs for initial concentrations at or above the critical fluorescein concentration where efficiency dominates, while lower concentrations show little change in fluorescence with tear film thinning. Conclusions. Our model underscores the importance of using fluorescein concentrations at or near the critical concentration clinically so that quenching reflects tear film thinning and breakup. In addition, the model predicts that, depending on tear film and osmotic factors, the osmolarity within the corneal compartment of the tear film may increase markedly during tear film thinning, well above levels that cause marked discomfort. PMID:24458153

  15. Effect of osmolarity on shape retention following laser-mediated cartilage reshaping

    NASA Astrophysics Data System (ADS)

    Karamzadeh, Amir M.; Gray, Darren S.; Kimball, Joey A.; Wong, Brian J.

    2001-07-01

    Laser reshaping of mechanically deformed cartilage specimens accelerates stress relaxation and results in permanent shape change. The mechanism of laser-mediated cartilage reshaping is still unknown, but clearly depends upon the complex molecular interactions between the physio-chemical environment and matrix proteins (collagen, and proteoglycans). It is well known in articular tissues that the mechanical properties of cartilage are sensitive to changes in tissue pH and osmolarity. The objective of this study was to determine the effect of osmolarity on shape change during laser reshaping in morphologic cartilage tissues. Porcine nasal septal cartilage specimens were cut (20 x 5 x 1.5 mm) and immersed in osmotically graded NaCl (0.2NS, 0.8NS, 1.0NS, 1.2 NS and 5 NS) or Phosphate buffered (0.2NS, 0.9NS, 1.0NS, 1.1NS, and 5NS) solutions for 12 hours to establish equilibrium. Then, specimens were bent into semicircular shapes, secured with clamps, and irradiated with an Nd:YAG laser (λ= 1320nm, 5W, 15 secs, 5 mm spot size) along the region of maximum curvature. Resultant bend angle was measured. Shape retention was calculated by comparing resultant curvature with pre-irradiation measurements. Non-irradiated, untreated (negative controls) cartilage retained less than 46% of the original bend. There was no difference in shape retention with respect to varying osmolarity (changed tissue water content) in either group. Resultant bend angles varied from 84 degree(s) to 194 degree(s) corresponding to shape retention varying from 42% to 72% in specimens which were immersed in either NaCl of Phosphate buffered solutions. While laser heating of deformed specimens does result in significant reshaping, the alterations in osmolarity do not seem to effect this process significantly over the range of values evaluated in this study.

  16. Contrast-induced nephropathy: are there differences between low osmolar and iso-osmolar iodinated contrast media?

    PubMed

    Morcos, S K

    2009-05-01

    It is acknowledged that high osmolar contrast media are more nephrotoxic than low (LOCM) or iso-osmolar contrast media (IOCM). However, it remains contentious whether the IOCM are less nephrotoxic in comparison with LOCM. This article reviews published clinical studies that investigated this issue and demonstrates there are no conclusive data to indicate that there is a definite difference in renal tolerance between LOCM and IOCM. All these agents are potentially nephrotoxic in patients with advanced renal impairment. In these patients the smallest possible dose of IOCM or LOCM should be used in addition to adequate hydration to minimize the risk of contrast nephropathy.

  17. Effects of different osmolarities on bacterial biofilm formation

    PubMed Central

    Kavamura, Vanessa Nessner; de Melo, Itamar Soares

    2014-01-01

    Biofilm formation depends on several factors. The influence of different osmolarities on bacterial biofilm formation was studied. Two strains (Enterobacter sp. and Stenotrophomonas sp.) exhibited the most remarkable alterations. Biofilm formation is an important trait and its use has been associated to the protection of organisms against environmental stresses. PMID:25242950

  18. Coupling fluid and solute dynamics within the ocular surface tear film: a modelling study of black line osmolarity.

    PubMed

    Zubkov, V S; Breward, C J W; Gaffney, E A

    2012-09-01

    We present a mathematical model describing the spatial distribution of tear film osmolarity across the ocular surface of a human eye during one blink cycle, incorporating detailed fluid and solute dynamics. Based on the lubrication approximation, our model comprises three coupled equations tracking the depth of the aqueous layer of the tear film, the concentration of the polar lipid, and the concentration of physiological salts contained in the aqueous layer. Diffusive boundary layers in the salt concentration occur at the thinnest regions of the tear film, the black lines. Thus, despite large Peclet numbers, diffusion ameliorates osmolarity around the black lines, but nonetheless is insufficient to eliminate the build-up of solute in these regions. More generally, a heterogeneous distribution of solute concentration is predicted across the ocular surface, indicating that measurements of lower meniscus osmolarity are not globally representative, especially in the presence of dry eye. Vertical saccadic eyelid motion can reduce osmolarity at the lower black line, raising the prospect that select eyeball motions more generally can assist in alleviating tear film hyperosmolarity. Finally, our results indicate that measured evaporative rates will induce excessive hyperosmolarity at the black lines, even for the healthy eye. This suggests that further evaporative retardation at the black lines, for instance due to the cellular glycocalyx at the ocular surface or increasing concentrations of mucus, will be important for controlling hyperosmolarity as the black line thins.

  19. Two-Component Response Regulators Ssk1p and Skn7p Additively Regulate High-Osmolarity Adaptation and Fungicide Sensitivity in Cochliobolus heterostrophus▿ ‡

    PubMed Central

    Izumitsu, Kosuke; Yoshimi, Akira; Tanaka, Chihiro

    2007-01-01

    Filamentous ascomycetous fungi possess many histidine kinases and two conserved response regulators, Ssk1p and Skn7p, in their two-component signaling systems. We previously reported that the fungus unique group III histidine kinase regulates high-osmolarity adaptation and iprodione/fludioxonil fungicide sensitivity by controlling the phosphorylation of Hog1-type mitogen-activated protein kinase (MAPK) in filamentous ascomycetes. Here, we have characterized the response regulator genes ChSsk1 and ChSkn7 in the southern corn leaf blight fungus Cochliobolus heterostrophus. Both ChSsk1- and ChSkn7-disrupted mutants showed little sensitivity to high-osmolarity stress and moderate resistance to the iprodione/fludioxonil fungicides. The phosphorylation of Hog1-type MAPK BmHog1p induced by high-osmolarity stress and fungicide treatments was only regulated by ChSsk1p, indicating that ChSkn7p has roles in high-osmolarity adaptation and fungicide sensitivity that are independent from the activation of BmHog1p. The Chssk1 Chskn7 double mutants clearly showed higher sensitivity to osmolar stress and higher resistance to fungicides than the single mutants. The dose responses of the double mutants fit well with those of the group III histidine kinase-deficient strain. These results suggest that in filamentous ascomycetes, the Ssk1- and Skn7-type response regulators control high-osmolarity adaptation and fungicide sensitivity additively with differential mechanisms under the regulation of the group III histidine kinase. This study provides evidence that filamentous fungi have a unique two-component signaling system that is different from that of yeast and is responsible for high-osmolarity adaptation and fungicide sensitivity. PMID:17158737

  20. Renal failure in 57 925 patients undergoing coronary procedures using iso-osmolar or low-osmolar contrast media.

    PubMed

    Liss, P; Persson, P B; Hansell, P; Lagerqvist, B

    2006-11-01

    We compared the Swedish Coronary Angiography and Angioplasty Registry with the Swedish 'Hospital Discharge Register' to assess contrast media (CM)-induced renal failure. Hospitals used only one type CM. From 2000 to 2003, iodixanol (iso-osmolar) was used in 45 485 patients, ioxaglate (low osmolar) in 12 440 subjects. To include the earlier used CM iohexol (low osmolar), analysis extended back to 1990 (86 334 patients). Incidence of clinically significant renal failure was greatest for patients receiving the iso-osmolar CM iodixanol (1.7%). Ioxaglate-treated patients had a significantly lower renal failure incidence (0.8%, P<0.001). The odds ratio for iodixanol-treated patients was significantly higher than for ioxaglate (1 vs 0.48, P<0.001). In subsets of either diabetic patients or patients with previous renal failure, odds ratios for renal failure remained greater in the iodixanol groups (P<0.01). Hospitals switching CM to iodixanol experienced a doubling in clinically significant renal failure after cardiac procedures. Dialysis was required in 0.2% of patients receiving iodixanol, which was significantly higher (P<0.01) than for ioxaglate-treated patients (0.1%). Iohexol-treated patients had a similar low risk for developing clinically significant renal failure (0.9%) as ioxaglate. In conclusion, risk of developing renal failure and required dialysis after coronary procedures is higher when patients received iodixanol than ioxaglate or iohexol.

  1. Comparison of human tear film osmolarity measured by electrical impedance and freezing point depression techniques.

    PubMed

    Tomlinson, Alan; McCann, Louise C; Pearce, Edward I

    2010-09-01

    Tear hyperosmolarity is diagnostic of dry eye disease (DED), yet difficulty in measurement has limited its utility; development of new instruments could facilitate its clinical application. This study compares the new OcuSense TearLab osmometer (OcuSense, Inc, San Diego, CA), based on electrical impedance "lab-on-a-chip" nanoliter technology, with the freezing point depression Clifton Osmometer (Clifton Technical Physics, Hartford, NY). Thirty-six subjects were recruited: 15 DED (9 women, 6 men age: 41 +/- 16 years) and 21 controls (12 women, 9 men age: 35 +/- 12 years); criteria for DED were noninvasive tear breakup time <10 seconds, Schirmer I test <5 mm, and positive symptoms. Samples were collected from the inferior tear meniscus for testing with both osmometers. Osmolarity values measured with OcuSense TearLab were 308 +/- 6 and 321 +/- 16 mOsm/L for controls and dry eye, respectively, and those measured with Clifton were 310 +/- 7 and 323 +/- 14 mOsm/L for controls and dry eye, respectively; these values were significantly different. Significant correlation was found between OcuSense and Clifton measurements (r = 0.904; P = 0.006). Bland-Altman analysis revealed agreement between techniques; the majority of points fell within the 95% confidence limits, and actual values differed by less than 1%. A cutoff value of >316 mOsm/L, derived from the distribution of osmolarity values, was used to diagnose DED with an effectiveness of 73% sensitivity, 90% specificity, and 85% positive predictive value for the OcuSense and 73% sensitivity, 71% specificity, and 65% positive predictive value for the Clifton in the study samples. Tear film osmolarity measured with the OcuSense TearLab system correlates well with the Clifton Osmometer. The new instrument has the potential to provide clinicians with a readily available clinically applicable measure, which could become the gold standard in DED.

  2. Effect of osmolarity on potassium transport in isolated cerebral microvessels

    SciTech Connect

    Lin, J.D.

    1988-01-01

    Potassium transport in microvessels isolated from rat brain by a technique involving density gradient centrifugation was studied in HEPES buffer solutions of varying osmolarity from 200 to 420 mosmols, containing different concentration of sodium chloride, choline chloride, or sodium nitrate. The flux of /sup 86/Rb into and out of the endothelial cells was estimated. Potassium influx was very sensitive to the osmolarity of the medium. Ouabain-insensitive K-component was reduced in hypotonic medium and was increased in medium made hypertonic with sodium chloride or mannitol. Choline chloride replacement caused a large reduction in K influx. Potassium influx was significant decrease when nitrate is substituted for chloride ion in isotonic and hypertonic media, whereas a slight decrease was found in hypotonic medium. The decrease of K influx in the ion-replacement medium is due to a decrement of the ouabain-insensitive component. Potassium efflux was unchanged in hypotonic medium but was somewhat reduced in hypertonic medium. The marked effect of medium osmolarity of K fluxes suggests that these fluxes may be responsible for the volume regulatory K movements. The possible mechanism of changes of K flux under anisotonic media is also discussed.

  3. Effects of changes in osmolarity on isolated human airways.

    PubMed

    Jongejan, R C; De Jongste, J C; Raatgeep, R C; Bonta, I L; Kerrebijn, K F

    1990-04-01

    The effects of hypo- and hyperosmolarity on the function of isolated human airways were studied. Changes in osmolarity induced an increasing bronchoconstriction that was proportional to the magnitude of the change in osmolarity. Hypertonicity-induced airway narrowing resulted when buffer was made hypertonic with sodium chloride or mannitol but not with urea. The airways showed no tachyphylaxis to repetitive exposure to hypo- and hypertonic buffer of 200 and 600 mosM, respectively. The bronchoconstriction was not secondary to stimulation of H1 or leukotriene C4/D4 receptors or the release of prostaglandins in the preparation. The bronchoconstriction in hypotonic buffer was totally dependent on extracellular calcium, whereas in hypertonic buffer the bronchoconstriction seemed partially dependent on intracellular calcium release. Isoprenaline prevented the bronchoconstriction in hyper- or hypotonic buffer of 450 and 250 mosM but not in buffer of 600 and 150 mosM. It is concluded that hypo- and hypertonic buffers lead to bronchoconstriction via different mechanisms, which relate to influx of extracellular calcium in hyposmolar buffer and probably to release of calcium from intracellular stores in hypertonic buffer. In strongly hypertonic buffer, part of the bronchoconstriction may be due to osmotic shrinkage. The relevance of our data for the mechanism of bronchoconstriction after inhalation of hypo- or hypertonic saline depends on whether changes in osmolarity around the airway smooth muscle occur in asthmatics but not in normal subjects, and this has not yet been established.

  4. Reduced osmolarity oral rehydration salt in Cholera.

    PubMed

    Faruque, A S; Mahalanabis, D; Hamadani, J D; Zetterstrom, R

    1996-01-01

    In a controlled clinical trial conducted in 34 adults with severe cholera diarrhoea, the use of a relatively dilute oral rehydration salt (ORS) solution (sodium 67, potassium 20, chloride 66, citrate 7, glucose 89 mmol/l, osmolality 249 mOsmol/kg) caused a 29% (p=0.003) reduction in stool output over the first 24 h and a 37% (p=0.001) reduction over the first 48 h compared with 29 controls who received the hyperosmolar WHO/UNICEF ORS. No controls but 3 study-group patients had marked but asymptomatic hyponatraemia (sodium <125 mmol/l) at 24 h. Twenty-four % of controls and 12% of patients receiving the dilute ORS needed unscheduled intravenous therapy for recurrence of dehydration. The ORS intake was twice the 48 h stool volume in controls and 3 times in the study group. The test ORS with a reduced glucose and sodium concentration is more efficient than the WHO/UNICEF ORS in preserving net intestinal fluid balance in severe cholera.

  5. Correlation between Osmolarity and Luminescence of Symbiotic Vibrio fischeri Strain ES114

    PubMed Central

    Stabb, Eric V.; Butler, Melissa S.; Adin, Dawn M.

    2004-01-01

    Vibrio fischeri isolates from Euprymna scolopes are dim in culture but bright in the host. We found the luminescence of V. fischeri to be correlated with external osmolarity both in culture and in this symbiosis. Luminescence enhancement by osmolarity was independent of the lux promoter and unaffected by autoinducers or the level of lux expression, but the addition of an aldehyde substrate for luciferase raised the luminescence of cells grown at high and low osmolarities to the same high level. V. fischeri culture media have lower osmolarities than are typical in seawater or in cephalopods, partially accounting for the bacterium's low light output in culture. PMID:15090534

  6. Long-Term Adverse Effects of Low-Osmolar Compared With Iso-Osmolar Contrast Media After Coronary Angiography.

    PubMed

    Wang, Yuan-Cheng; Tang, Adrian; Chang, Di; Lu, Chun-Qiang; Zhang, Shi-Jun; Ju, Shenghong

    2016-10-01

    The relative incidence of long-term adverse effects between low-osmolar contrast media (LOCM) and iso-osmolar contrast media (IOCM) after coronary angiography is still unclear. We analyzed cardiology patients undergoing coronary angiography from January 2006 to July 2013 using either LOCM (iohexol, iopromide) or IOCM (iodixanol) at a single institution. For each contrast medium, primary (all-cause mortality, n = 6,992) and secondary outcomes (long-term renal injury and cardiovascular events beyond 90 days, n = 2,792) were recorded. Inverse probability weighing (IPW) was applied to minimize the selection bias between groups. Unadjusted all-cause mortality was significantly lower for LOCM versus IOCM (hazard ratio [HR] 0.28, 95% CI 0.23 to 0.34). After multivariate Cox regression or IPW, all-cause mortality became comparable and lost statistical significance. Chronic kidney disease subgroup had higher mortality risk when receiving LOCM compared with IOCM (regression adjusted HR 1.80, 95% CI 0.95 to 3.42; IPW-adjusted HR 1.57, 95% CI 0.99 to 2.48). In conclusion, after coronary angiography, patients receiving LOCM had comparable overall long-term mortality compared with IOCM after adjustment. LOCM tended to induce higher long-term mortality than IOCM in chronic kidney disease cohorts. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Coupling Osmolarity Dynamics within Human Tear Film on an Eye-Shaped Domain

    NASA Astrophysics Data System (ADS)

    Li, Longfei; Braun, R. J.; Driscoll, T. A.; Henshaw, W. D.; Banks, J. W.; King-Smith, P. E.

    2013-11-01

    The concentration of ions in the tear film (osmolarity) is a key variable in understanding dry eye symptoms and disease. We derived a mathematical model that couples osmolarity (treated as a single solute) and fluid dynamics within the tear film on a 2D eye-shaped domain. The model concerns the physical effects of evaporation, surface tension, viscosity, ocular surface wettability, osmolarity, osmosis and tear fluid supply and drainage. We solved the governing system of coupled nonlinear PDEs using the Overture computational framework developed at LLNL, together with a new hybrid time stepping scheme (using variable step BDF and RKC) that was added to the framework. Results of our numerical simulations show good agreement with existing 1D models (for both tear film and osmolarity dynamics) and provide new insight about the osmolarity distribution over the ocular surface during the interblink.

  8. Response of Leptospira interrogans to physiologic osmolarity: relevance in signaling the environment-to-host transition.

    PubMed

    Matsunaga, James; Lo, Miranda; Bulach, Dieter M; Zuerner, Richard L; Adler, Ben; Haake, David A

    2007-06-01

    Transmission of pathogenic Leptospira between mammalian hosts usually involves dissemination via soil or water contaminated by the urine of carrier animals. The ability of Leptospira to adapt to the diverse conditions found inside and outside the host is reflected in its relatively large genome size and high percentage of signal transduction genes. An exception is Leptospira borgpetersenii serovar Hardjo, which is transmitted by direct contact and appears to have lost genes necessary for survival outside the mammalian host. Invasion of host tissues by Leptospira interrogans involves a transition from a low osmolar environment outside the host to a higher physiologic osmolar environment within the host. Expression of the lipoprotein LigA and LigB adhesins is strongly induced by an upshift in osmolarity to the level found in mammalian host tissues. These data suggest that Leptospira utilizes changes in osmolarity to regulate virulence characteristics. To better understand how L. interrogans serovar Copenhageni adapts to osmolar conditions that correspond with invasion of a mammalian host, we quantified alterations in transcript levels using whole-genome microarrays. Overnight exposure in leptospiral culture medium supplemented with sodium chloride to physiologic osmolarity significantly altered the transcript levels of 6% of L. interrogans genes. Repressed genes were significantly more likely to be absent or pseudogenes in L. borgpetersenii, suggesting that osmolarity is relevant in studying the adaptation of L. interrogans to host conditions. Genes induced by physiologic osmolarity encoded a higher than expected number of proteins involved in signal transduction. Further, genes predicted to encode lipoproteins and those coregulated by temperature were overrepresented among both salt-induced and salt-repressed genes. In contrast, leptospiral homologues of hyperosmotic or general stress genes were not induced at physiologic osmolarity. These findings suggest that

  9. Correlation between Tear Osmolarity and Other Ocular Surface Parameters in Primary Sjögren's Syndrome

    PubMed Central

    Kim, Mirinae; Kim, Hyun Seung

    2017-01-01

    Purpose To investigate the relationships between tear osmolarity and other ocular surface parameters and to determine the diagnostic value of tear osmolarity in primary Sjögren's syndrome (SS) using tear film break-up time, Schirmer I test, and cornea/conjunctiva staining. Methods We included 310 eyes of 155 patients diagnosed with dry eye disease (39 primary SS and 116 non-Sjögren dry eye disease) at Seoul St. Mary's Hospital from August 2010 to January 2015. All subjects completed the Ocular Surface Disease Index (OSDI) questionnaire and underwent ocular examinations including tear osmolarity (TearLab Osmolarity System), Schirmer I test, slit lamp examination for tear film break-up time, and corneal and conjunctival fluorescein staining. We used the mean value of both eyes for all parameters. Fluorescein staining was assessed using the Sjögren's International Collaborative Clinical Alliance ocular staining score (OSS). Results In primary SS patients (n = 39), the mean subject age was 52.5 ± 11.9 years, and 94.9% of the subjects were women. Mean tear osmolarity in SS was 311.1 ± 16.4 mOsm/L, with 16 (41.0%) subjects having values ≥316 mOsm/L. In SS, there was a positive correlation between mean tear osmolarity and OSDI score (ρ = 0.405, p = 0.011) and OSS (ρ = 0.592, p < 0.001). There was a negative correlation between mean tear osmolarity and the Schirmer I test (ρ = −0.625, p < 0.001). There was no significant correlation between mean tear osmolarity and tear film break-up time in SS (ρ = 0.110, p = 0.505). Conclusions Tear osmolarity measurements using the TearLab Osmolarity System can reflect both symptom severity (OSDI) and objective signs (Schirmer test and OSS) in SS. PMID:28243020

  10. Paradoxically enhanced heart tolerance to ischaemia in type 1 diabetes and role of increased osmolarity.

    PubMed

    Chen, Hong; Shen, Wei-Li; Wang, Xu-Hui; Chen, Hong-Zhuan; Gu, Jian-Zhong; Fu, Jie; Ni, Ya-Feng; Gao, Ping-Jin; Zhu, Ding-Liang; Higashino, Hideaki

    2006-10-01

    There is considerable controversy regarding the tolerance of diabetic hearts to ischaemia and the underlying mechanisms responsible for the increased heart tolerance to ischamia remain uncertain. In the present study, we observed, in vitro, type 1 diabetic heart responses to ischaemia and reperfusion at different degrees of hyperglycaemia. In addition, the possible role of increased osmolarity in cardioprotection due to hyperglycaemia was evaluated. Hearts from 3 week streptozocin-induced diabetic rats were isolated and perfused in a Langendorff apparatus and subjected to 30 min ischaemia and 30 min reperfusion. Cardiac function and the electrocardiogram were recorded. Myocardial content of osmolarity associated heat shock protein (hsp) 90, heme oxygenase (HO)-1 and anti-oxidant enzymes were determined in diabetic or hyperosmotic solution-perfused hearts using western blot. The hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG; 2 x 10(-7) mol/L) or the nitric oxide synthase (NOS) inhibitor Nomega-nitro-L-arginine methyl ester (1 x 10(-5) mol/L) was added to the perfusate to observe the effects of hsp90 inhibition and hsp90-associated endothelial NOS on ischaemic responses of diabetic hearts. Compared with normal control rats, diabetic hearts with severe hyperglycaemia (blood glucose > 20 mmol/L) showed markedly improved postischaemic heart function with fewer reperfusion arrhythmias. Mild hyperglycaemia (< 12 mmol/L) exhibited no significant cardioprotection. Elevated expression of hsp90 accompanied the enhanced resistance to ischaemia in diabetic hearts, which was abrogated by 17-AAG. In the presence of the NOS inhibitor, heart function was preserved, whereas reperfusion arrhythmias were increased in diabetes. Diabetic hearts also had markedly elevated HO-1 and catalase, with no significant change in superoxide dismutase. Hyperosmotic perfusion with glucose or mannitol also increased myocardial hsp90 and catalase. The present findings reveal that

  11. Efficacy and safety of oral rehydration solution with reduced osmolarity in adults with cholera: a randomised double-blind clinical trial. CHOICE study group.

    PubMed

    Alam, N H; Majumder, R N; Fuchs, G J

    1999-07-24

    The effects of oral rehydration solution (ORS) with reduced osmolarity on children with acute watery diarrhoea are known, but little is known about the effects of such ORS on adults with cholera. We aimed to compare the efficacy and safety of an ORS with reduced osmolarity with that of standard WHO ORS in adults with cholera. We undertook a double-blind, controlled clinical trial in adults with severe cholera at the International Centre for Diarrhoeal Disease Research, Bangladesh. Our primary outcomes were mean stool output in the 24 h after randomisation, proportion of patients who needed unscheduled intravenous therapy, and proportion of patients with biochemical hyponatraemia 24 h after randomisation. 147 patients received ORS with reduced osmolarity and 153 received standard WHO ORS. There was no significant difference between the two groups in terms of main outcome variables: mean initial 24 h and total stool output (reduced osmolarity vs standard WHO ORS 212 [SE 8] vs 207 [8] and 284 [13] vs 273 [13] g/kg respectively), duration of diarrhoea (46 [1.5] vs 43 [1.5]). The proportion of patients vomiting during the first 24 h and the proportion who received unscheduled intravenous infusion during the first 24 h was similar between groups. More patients on reduced osmolarity ORS than on standard WHO ORS developed hyponatraemia during the first 24 h, defined as serum sodium concentration below 130 mmol/L (29 of 142 vs 16 of 150; odds ratio 2.1 [95% CI 1.1-4.1]). However, all hyponatraemic patients in both groups were symptom-free and the proportion of patients with serum sodium concentration below 125 mmol/L was similar between groups. There was no difference in clinical outcome between cholera patients treated with reduced osmolarity ORS solution and those treated with standard WHO ORS. The risk of increased incidence of symptom-free hyponatraemia in patients with cholera treated with an ORS with reduced osmolarity should be further assessed by meta-analysis. The

  12. Differential activation of signaling pathways by low-osmolar and iso-osmolar radiocontrast agents in human renal tubular cells.

    PubMed

    Andreucci, Michele; Faga, Teresa; Russo, Domenico; Bertucci, Bernardo; Tamburrini, Oscar; Pisani, Antonio; Sabbatini, Massimo; Fuiano, Giorgio; Michael, Ashour

    2014-02-01

    Radiocontrast media (RCM)-induced nephrotoxicity (CIN) is a major clinical problem accounting for 12% of all hospital-acquired cases of acute kidney injury (AKI). The pathophysiology of AKI due to RCM is not well understood, but direct toxic effects on renal cells have been postulated as contributing to CIN. It is believed that iso-osmolar RCM (IOCM) are less nephrotoxic than low-osmolar RCM (LOCM) but clinical data have been controversial. We have investigated the intracellular signaling pathways that may be affected by the LOCM iomeprol (IOM) and the IOCM iodixanol (IOD). Both IOM and IOD caused a dramatic decrease in phosphorylation of the kinase Akt at Ser473 and Thr308 in human renal tubular (HK-2) cells, with IOM having a greater effect; IOM also caused a greater decrease in cell viability. IOM also had a greater effect on phosphorylation of p38 MAP kinases, JNKs, and NF-kB (Ser276), and caused a marked decrease in the phosphorylation of forkhead box O3a (FOXO3a) and signal transducer and activator of transcription 3 (STAT3). However, IOD caused a greater decrease in the phosphorylation of mTOR (Ser2448) and phospho-ERK 1/2 while both RCM caused a similar decrease in the phosphorylation of phospho-p70S6 kinase (Ser371). In vivo studies showed that both IOM and IOD caused a significant decrease in both pAkt (Ser473) and pERK 1/2 in rat kidneys. Our study gives an insight into the possible mechanism of toxicity of RCM via their action on intracellular signaling pathways and may help in developing pharmacological interventions for their side-effects. © 2013 Wiley Periodicals, Inc.

  13. Heart rate variability and heat sensation during CT coronary angiography: Low-osmolar versus iso-osmolar contrast media.

    PubMed

    Svensson, Anders; Ripsweden, Jonaz; Rück, Andreas; Aspelin, Peter; Cederlund, Kerstin; Brismar, B Torkel

    2010-09-01

    During computed tomography coronary angiography (CTCA) unexpected changes in heart rate while scanning may affect image quality. To evaluate whether an iso-osmolar contrast medium (IOCM, iodixanol) and a low-osmolar contrast medium (LOCM, iomeprol) affect heart rate and experienced heat sensation differently. One hundred patients scheduled for CTCA were randomized to receive either iodixanol 320 mgI/ml or iomeprol 400 mgI/ml. Depending on their heart rate, the patients were assigned to one of five scanning protocols, each optimized for different heart rate ranges. During scanning the time between each heart beat (hb) was recorded, and the corresponding heart rate was calculated. For each contrast medium (CM) the average heart rate, the variation in heart rate from individual mean heart rate, and the mean deviation from the predefined scanning protocol were calculated. Experience of heat was obtained immediately after scanning by using a visual analog scale (VAS). Examination quality was rated by two radiologists on a three-point scale. The mean variation in heart rate after IOCM was 1.4 hb/min and after LOCM it was 4.4 hb/min (NS). The mean deviations in heart rate from that in the predefined scanning protocol were 2.0 hb/min and 4.7 hb/min, respectively (NS). A greater number of arrhythmic hb were observed after LOCM compared with IOCM (P<0.001). There was no statistically significant difference in image quality. The LOCM group reported a stronger heat sensation after CM injection than the IOCM group (VAS =36 mm and 18 mm, P<0.05). At clinically used concentrations the IOCM, iodixanol 320 mgI/ml, does not increase the heart rate during CTCA and causes less heart arrhythmia and less heat sensation than the LOCM, iomeprol 400 mgI/ml.

  14. [Rethinking clinical significance of tear osmolarity measurement for dry eye diagnosis and therapeutic efficacy evaluation].

    PubMed

    Liang, Lingyi; Ke, Hongming; Liu, Zuguo

    2014-09-01

    Increased tear osmolarity is one of the core mechanisms of dry eye and has been considered as an important diagnostic criterion, if not"gold standard", of dry eye. However, recent studies showed the limitations of tear osmolarity measurement not only in the diagnosis, but also in the therapeutic efficacy evaluation of dry eye. The clinical significance of tear osmolarity measurement has become a hot topic of argument. Herein, we review the publications on this topic and try to find the underlying causes of such argument.

  15. Computed tear film and osmolarity dynamics on an eye-shaped domain.

    PubMed

    Li, Longfei; Braun, Richard J; Driscoll, Tobin A; Henshaw, William D; Banks, Jeffrey W; King-Smith, P Ewen

    2016-06-01

    The concentration of ions, or osmolarity, in the tear film is a key variable in understanding dry eye symptoms and disease. In this manuscript, we derive a mathematical model that couples osmolarity (treated as a single solute) and fluid dynamics within the tear film on a 2D eye-shaped domain. The model includes the physical effects of evaporation, surface tension, viscosity, ocular surface wettability, osmolarity, osmosis and tear fluid supply and drainage. The governing system of coupled non-linear partial differential equations is solved using the Overture computational framework, together with a hybrid time-stepping scheme, using a variable step backward differentiation formula and a Runge-Kutta-Chebyshev method that were added to the framework. The results of our numerical simulations provide new insight into the osmolarity distribution over the ocular surface during the interblink.

  16. Red cell volume with changes in plasma osmolarity during maximal exercise.

    NASA Technical Reports Server (NTRS)

    Van Beaumont, W.

    1973-01-01

    The volume of the red cell in vivo was measured during acute changes in plasma osmolarity evoked through short (6 to 8 min) maximal exercise in six male volunteer subjects. Simultaneous measurements of mean corpuscular red cell volume (MCV), hematocrit, blood hemoglobin, mean corpuscular hemoglobin concentration (MCHC), and plasma osmolarity showed that there was no change in the MCV or MCHC with a concomitant rise of nearly 6% in plasma osmolarity. Apparently, in vivo, the volume of the red cell in exercising healthy human subjects does not change measurably, in spite of significant changes in osmotic pressure of the surrounding medium. Consequently, it is not justified to correct postexercise hematocrit measurements for changes in plasma osmolarity.

  17. The potential role of NFAT5 and osmolarity in peritoneal injury.

    PubMed

    Seeger, Harald; Kitterer, Daniel; Latus, Joerg; Alscher, Mark Dominik; Braun, Niko; Segerer, Stephan

    2015-01-01

    A rise in osmotic concentration (osmolarity) activates the transcription factor Nuclear Factor of Activated T Cells 5 (NFAT5, also known as Tonicity-responsive Enhancer Binding Protein, TonEBP). This is part of a regulatory mechanism of cells adjusting to environments of high osmolarity. Under physiological conditions these are particularly important in the kidney. Activation of NFAT5 results in the modulation of various genes including some which promote inflammation. The osmolarity increases in patients with renal failure. Additionally, in peritoneal dialysis the cells of the peritoneal cavity are repeatedly exposed to a rise and fall in osmotic concentrations. Here we review the current information about NFAT5 activation in uremic patients and patients on peritoneal dialysis. We suggest that high osmolarity promotes injury in the "uremic" milieu, which results in inflammation locally in the peritoneal membrane, but most likely also in the systemic circulation.

  18. Computed tear film and osmolarity dynamics on an eye-shaped domain

    PubMed Central

    Li, Longfei; Braun, Richard J.; Driscoll, Tobin A.; Henshaw, William D.; Banks, Jeffrey W.; King-Smith, P. Ewen

    2016-01-01

    The concentration of ions, or osmolarity, in the tear film is a key variable in understanding dry eye symptoms and disease. In this manuscript, we derive a mathematical model that couples osmolarity (treated as a single solute) and fluid dynamics within the tear film on a 2D eye-shaped domain. The model includes the physical effects of evaporation, surface tension, viscosity, ocular surface wettability, osmolarity, osmosis and tear fluid supply and drainage. The governing system of coupled non-linear partial differential equations is solved using the Overture computational framework, together with a hybrid time-stepping scheme, using a variable step backward differentiation formula and a Runge–Kutta–Chebyshev method that were added to the framework. The results of our numerical simulations provide new insight into the osmolarity distribution over the ocular surface during the interblink. PMID:25883248

  19. Red cell volume with changes in plasma osmolarity during maximal exercise.

    NASA Technical Reports Server (NTRS)

    Van Beaumont, W.

    1973-01-01

    The volume of the red cell in vivo was measured during acute changes in plasma osmolarity evoked through short (6 to 8 min) maximal exercise in six male volunteer subjects. Simultaneous measurements of mean corpuscular red cell volume (MCV), hematocrit, blood hemoglobin, mean corpuscular hemoglobin concentration (MCHC), and plasma osmolarity showed that there was no change in the MCV or MCHC with a concomitant rise of nearly 6% in plasma osmolarity. Apparently, in vivo, the volume of the red cell in exercising healthy human subjects does not change measurably, in spite of significant changes in osmotic pressure of the surrounding medium. Consequently, it is not justified to correct postexercise hematocrit measurements for changes in plasma osmolarity.

  20. Osmolarity regulates chondrogenic differentiation potential of synovial fluid derived mesenchymal progenitor cells.

    PubMed

    Bertram, Karri L; Krawetz, Roman J

    2012-06-08

    Cartilage is one of few tissues where adult stem/progenitor cells have not been putatively identified. Recent studies have provided strong evidence that a sub-population of mesenchymal progenitor cells (MPCs) derived from the synovial fluid may be able to affect some degree of cartilage repair both in vivo and in vitro/ex vivo, however this does not appear to be the case in patients with arthritis. Previously, it has been found that synovial fluid osmolarity is decreased in patients with osteoarthritis (OA) or Rheumatoid arthritis (RA) and these changes in osmolarity have been linked to changes in chondrocyte gene regulation. However, it is yet unknown if changes in osmolarity regulate the gene expression in synovial fluid MPCs (sfMPCs), and by extension, chondrogenesis of this cell population. In the present study we have collected synovial fluid samples from normal, OA and RA knee joints, quantified the osmolarity of the fluid and modified the culture/differentiation media to span a range of osmolarities (264-375 mOsm). Chondrogenesis was measured with Alcian blue staining of cultures in addition to quantitative PCR (qPCR) using probes to Sox9, ACAN and Col2A1. Overall, sfMPCs from arthritic joints demonstrated decreased chondrogenic potential compared to sfMPCs isolated from normal synovial fluid. Furthermore, the sfMPCs retained increased chondrogenic potential if differentiated under the same osmolarity conditions for which they were initially derived within. In conclusion, it does appear the synovial fluid osmolarity regulates the chondrogenic potential of sfMPCs, however, further study is required to elucidate the mechanism by which the changes in osmolarity are sensed by the cells and regulate chondrogenic gene expression.

  1. Exploring the links between contact lens comfort, osmolarity and lid wiper staining.

    PubMed

    Stahl, Ulrike; Jalbert, Isabelle

    2017-09-19

    Contact lens discomfort remains poorly understood, not least due to lack of associations between clinical signs and symptoms. This study aimed to explore the relationships between osmolarity, comfort and lid wiper epitheliopathy in contact lens wear. Twenty subjects participated in a randomized, cross-over study where comfilcon A and lotrafilcon A lenses were each worn for 10days separated by a 7days washout period. Tear and contact lens osmolarity, ocular symptoms including comfort, tear stability and production, and lid wiper epitheliopathy were measured. Comfort and tear stability decreased and upper lid wiper staining and foreign body sensation increased with lens wear. These were not affected by lens type. A reduction in tear production was seen after 10days of comfilcon A lens wear. High proportions of lid wiper epitheliopathy were observed at the upper (range 65%-85%) and lower (range 90%-100%) lid margins. Tear and contact lens osmolarity were unaffected by lens wear or type. Contact lens osmolarity was associated with comfort (r=0.45, p=0.009). Tear osmolarity moderately correlated with tear stability (r=-0.53, p=0.014) and tear production (r=-0.44, p=0.012) but not with lid wiper staining. A relationship between comfort and contact lens osmolarity and between tear osmolarity and tear stability and production were found, however, this study was unable to demonstrate an association between comfort and tear osmolarity or lid wiper epitheliopathy. Further studies using contact lenses with a wider range of comfort responses are warranted to investigate these associations further. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  2. Precision and accuracy of TearLab osmometer in measuring osmolarity of salt solutions.

    PubMed

    Yoon, Dan; Gadaria-Rathod, Neha; Oh, Cheongeun; Asbell, Penny A

    2014-12-01

    The purpose of this study was to examine the inherent precision and accuracy of TearLab Osmolarity System using salt solutions, including solutions of very high osmolarity (>360 mOsm/L). Ten salt solutions with osmolarity between 286 mOsm/L and 394 mOsm/L (increments of 12 mOsm/L) plus an additional solution of 400 mOsm/L were tested twice on both the TearLab osmometer and a freezing point depression osmometer. For precision, we compared the two repeated osmolarity measurements of 11 solutions obtained from TearLab. For accuracy, we compared the averaged osmolarity measurements obtained from TearLab to those from the freezing point depression osmometer. For both precision and accuracy, Bland-Altman test of agreement was used. For precision, the upper 95% limit of agreement was 4.7 mOsm/L, and the lower 95% limit of agreement was -7.1 mOsm/L. The repeatability coefficient was 5.9 mOsm/L. For accuracy, the upper 95% limit of agreement was 4.8 mOsm/L and the lower 95% limit of agreement was -5.3 mOsm/L. The present study is the first study to demonstrate that the TearLab in situ osmometer can precisely and accurately measure osmolarity of salt solutions, including those with very high osmolarity. Future studies to evaluate the precision and the accuracy of the machine in measuring complex fluids, such as tears, need to be done, and the clinical significance of measuring tear osmolarity in patients needs to be further determined.

  3. Tear-film osmolarity in normal cats and cats with conjunctivitis.

    PubMed

    Davis, Kyshia; Townsend, Wendy

    2011-09-01

    To compare the tear-film osmolarity of normal cats and cats with conjunctivitis. The population consisted of shelter, research, and privately owned cats. Cats were classified as normal or having conjunctivitis. An ophthalmic examination including Schirmer tear test (STT), fluorescein staining, tear-film break-up time (TFBUT), intraocular pressure (IOP), and slit-lamp biomicroscopy of the anterior segment was performed. The severity of conjunctivitis was graded and assigned a numerical score. The Tear Lab(TM) Osmolarity System was utilized to determine the tear-film osmolarity. Unpaired t-tests were used to compare tear-film osmolarity, TFBUT, IOP, and STT of the two groups. A total of 93 cats (186 eyes) were examined. There were 37 normal cats (74 eyes) and 39 conjunctivitis cats (78 eyes). The mean age was 2.34 years. There was no statistical difference (P = 0.2065) between the median tear-film osmolarity of normal cats (328.5 ± 17.94 mOsms/L) and conjunctivitis cats (325.0 ± 24.84 mOsms/L). Cats with conjunctivitis had an accelerated TFBUT (P < 0.0001) and lower IOPs (P < 0.0001) as compared to normal cats. No statistical difference was found between STT values (P = 0.1304). The median tear-film osmolarity of normal cats was 328.5 mOsms/L. Despite the accelerated TFBUT, conjunctivitis did not cause a statistically significant change in tear-film osmolarity. The Tear Lab(TM) Osmolarity System was easily used and well tolerated by the cats in the study. © 2011 American College of Veterinary Ophthalmologists.

  4. Changes in central sodium and not osmolarity or lactate induce panic-like responses in a model of panic disorder.

    PubMed

    Molosh, Andre I; Johnson, Philip L; Fitz, Stephanie D; Dimicco, Joseph A; Herman, James P; Shekhar, Anantha

    2010-05-01

    Panic disorder is a severe anxiety disorder characterized by recurrent panic attacks that can be consistently provoked with intravenous (i.v.) infusions of hypertonic (0.5 M) sodium lactate (NaLac), yet the mechanism/CNS site by which this stimulus triggers panic attacks is unclear. Chronic inhibition of GABAergic synthesis in the dorsomedial hypothalamus/perifornical region (DMH/PeF) of rats induces a vulnerability to panic-like responses after i.v. infusion of 0.5 M NaLac, providing an animal model of panic disorder. Using this panic model, we previously showed that inhibiting the anterior third ventricle region (A3Vr; containing the organum vasculosum lamina terminalis, the median preoptic nucleus, and anteroventral periventricular nucleus) attenuates cardiorespiratory and behavioral responses elicited by i.v. infusions of NaLac. In this study, we show that i.v. infusions of 0.5 M NaLac or sodium chloride, but not iso-osmolar D-mannitol, increased 'anxiety' (decreased social interaction) behaviors, heart rate, and blood pressure responses. Using whole-cell patch-clamp preparations, we also show that bath applications of NaLac (positive control), but not lactic acid (lactate stimulus) or D-mannitol (osmolar stimulus), increases the firing rates of neurons in the A3Vr, which are retrogradely labeled from the DMH/PeF and which are most likely glutamatergic based on a separate study using retrograde tracing from the DMH/PeF in combination with in situ hybridization for vesicular glutamate transporter 2. These data show that hypertonic sodium, but not hyper-osmolarity or changes in lactate, is the key stimulus that provokes panic attacks in panic disorder, and is consistent with human studies.

  5. Effects of light exposure, pH, osmolarity, and solvent on the retinal pigment epithelial toxicity of vital dyes.

    PubMed

    Costa, Elaine F; Barros, Nilana M T; Coppini, Larissa P; Neves, Raquel L; Carmona, Adriana K; Penha, Fernando M; Rodrigues, Eduardo B; Dib, Eduardo; Magalhães, Octaviano; Moraes-Filho, Milton N; Lima Filho, Acácio A S; Maia, Mauricio; Farah, Michel E

    2013-04-01

    To investigate the in vitro effect of pH, osmolarity, solvent, and light interaction on currently used and novel dyes to minimize dye-related retinal toxicity. Laboratory investigation. Retinal pigment epithelium (RPE) human cells (ARPE-19) were exposed for 10 minutes to different pH solutions (4, 5, 6, 7, 7.5, 8, and 9) and glucose solutions (2.5%, 5.0%, 10%, 20%, 40%, and 50%) with osmolarity from 142 to 2530 mOsm, with and without 0.5 mg/mL trypan blue. R28 cells were also incubated with glucose (150, 310, and 1000 mOsm) and mannitol used as an osmotic control agent in both experiments. Dye-light interaction was assessed by incubating ARPE-19 for 10 minutes with trypan blue, brilliant blue, bromophenol blue, fast green, light green, or indigo carmine (0.05 mg/mL diluted in balanced saline solution) in the presence of high-brightness xenon and mercury vapor light sources. Solutions with nonphysiologic pH, below 7 and above 7.5, proved to be remarkably toxic to RPE cells with or without trypan blue. Also, all glucose solutions were deleterious to RPE (P < .001) even in iso-osmolar range. No harmful effect was found with mannitol solutions. Among the dyes tested, only light green and fast green were toxic to ARPE-19 (P < .001). Light exposure did not increase RPE toxicity either with xenon light or mercury vapor lamp. Solutions containing glucose as a dye solvent or nonphysiologic pH should be used with care in surgical situations where the RPE is exposed. Light exposure under present assay conditions did not increase the RPE toxicity. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Changes in Central Sodium and not Osmolarity or Lactate Induce Panic-Like Responses in a Model of Panic Disorder

    PubMed Central

    Molosh, Andre I; Johnson, Philip L; Fitz, Stephanie D; DiMicco, Joseph A; Herman, James P; Shekhar, Anantha

    2010-01-01

    Panic disorder is a severe anxiety disorder characterized by recurrent panic attacks that can be consistently provoked with intravenous (i.v.) infusions of hypertonic (0.5 M) sodium lactate (NaLac), yet the mechanism/CNS site by which this stimulus triggers panic attacks is unclear. Chronic inhibition of GABAergic synthesis in the dorsomedial hypothalamus/perifornical region (DMH/PeF) of rats induces a vulnerability to panic-like responses after i.v. infusion of 0.5 M NaLac, providing an animal model of panic disorder. Using this panic model, we previously showed that inhibiting the anterior third ventricle region (A3Vr; containing the organum vasculosum lamina terminalis, the median preoptic nucleus, and anteroventral periventricular nucleus) attenuates cardiorespiratory and behavioral responses elicited by i.v. infusions of NaLac. In this study, we show that i.v. infusions of 0.5 M NaLac or sodium chloride, but not iso-osmolar -mannitol, increased ‘anxiety' (decreased social interaction) behaviors, heart rate, and blood pressure responses. Using whole-cell patch-clamp preparations, we also show that bath applications of NaLac (positive control), but not lactic acid (lactate stimulus) or -mannitol (osmolar stimulus), increases the firing rates of neurons in the A3Vr, which are retrogradely labeled from the DMH/PeF and which are most likely glutamatergic based on a separate study using retrograde tracing from the DMH/PeF in combination with in situ hybridization for vesicular glutamate transporter 2. These data show that hypertonic sodium, but not hyper-osmolarity or changes in lactate, is the key stimulus that provokes panic attacks in panic disorder, and is consistent with human studies. PMID:20130534

  7. The effect of reductive ventricular osmotherapy on the osmolarity of artificial cerebrospinal fluid and the water content of cerebral tissue ex vivo.

    PubMed

    Odland, Rick M; Panter, S Scott; Rockswold, Gaylan L

    2011-01-01

    The purpose of this study was to explore a novel treatment involving removal of free water from ventricular cerebrospinal fluid (CSF) for the reduction of cerebra]l edema. The hypothesis is that removal of free water from the CSF will increase the osmolarity of the CSF, which will favor movement of tissue-bound water into the ventricles, where the water can be removed. Reductive ventricular osmotherapy (RVOT) was tested in a flowing solution of artificial CSF (aCSF) with two end-points: (1) the effect of RVOT on osmolarity of the CSF, and (2) the effect of RVOT on water content of ex vivo cerebral tissue. RVOT catheters are made up of membranes permeable only to water vapor. When a sweep gas is drawn through the catheter, free water in the form of water vapor is removed from the solution. With RVOT treatment, aCSF osmolarity increased from a baseline osmolarity of 318.8 ± 0.8 mOsm/L to 339.0 ± 3.3 mOsm/L (mean ± standard deviation) within 2 h. After 10 h of treatment, aCSF osmolarity approached an asymptote at 344.0 ± 4.2 mOsm/L, which was significantly greater than control aCSF osmolarity (p <0.001 by t-test, n = 8). Water content at the end of 6 h of circulating aCSF exposure was 6.4 ± 0.9 g H₂O (g dry wt)⁻¹ in controls, compared to 6.1 ± 0.7 g H₂O (g dry wt)⁻ after 6 h of RVOT treatment of aCSF (p = 0.02, n = 24). The results support the potential of RVOT as a treatment for cerebral edema and intracranial hypertension.

  8. Growth and buoyant density of Escherichia coli at very low osmolarities.

    PubMed

    Baldwin, W W; Myer, R; Kung, T; Anderson, E; Koch, A L

    1995-01-01

    The growth and buoyant densities of two closely related strains of Escherichia coli in M9-glucose medium that was diluted to produce osmolarities that varied from as low as 5 to 500 mosM were monitored. At 15 mosM, the lowest osmolarity at which buoyant density could be measured reproducibly in Percoll gradients, both ML3 and ML308 had a buoyant density of about 1.079 g/ml. As the osmolarity of the medium was increased, the buoyant density also increased linearly up to about 125 mosM, at which the buoyant density was 1.089 g/ml. From 150 up to 500 mosM, the buoyant density again increased linearly but with a different slope from that seen at the lower osmolarities. The buoyant density at 150 mosM was about 1.091 g/ml, and at 500 mosM it was 1.101 g/ml. Both strains of E. coli could be grown in M9 medium diluted 1:1 with water, with an osmolarity of 120 mosM, but neither strain grew in 1:2-diluted M9 if the cells were pregrown in undiluted M9. (Note: undiluted M9 as prepared here has an osmolarity of about 250 mosM.) However, if the cells were pregrown in 30% M9, about 75 mosM, they would then grow in M9 at 45 mosM and above but not below 40 mosM. To determine which constituent of M9 medium was being diluted to such a low level that it inhibited growth, diluted M9 was prepared with each constituent added back singly. From this study, it was determined that both Ca2+ and Mg2+ could stimulate growth below 40 mosM. With Ca2+ - and Mg2+ -supplemented diluted M9 and cells pregrown in 75 mosM M9, it was possible to grow ML308 in 15 mosM M9. Strain ML3 would only haltingly grow at 15 mosM. Four attempts were made to grow both ML3 and ML308 at 5 mosM. In three of the experiments, ML308 grew, while strain ML3 grew in one experiment. While our experiments were designed to effect variations in medium osmolarity by using NaCl as an osmotic agent, osmolarity and salinity were changed concurrently. Therefore, from this study, we believe that E. coli might be defined as an

  9. An examination of the relationship between ocular surface tear osmolarity compartments and epitheliopathy.

    PubMed

    McMonnies, Charles W

    2015-04-01

    A 2014 PubMed search for tear hyperosmolarity and corneal stain yielded 2960 results. Selections from those providing evidence of variations in osmolarity were used to refine the compartmentalization model of tear osmolarity over the ocular surface. This new model includes the low point of freshly produced isotonic tears in the upper conjunctival sac, with osmolarity increasing successively in the upper meniscus, the upper area of exposed ocular surface, the lower area of over-exposed ocular surface, the lower meniscus, and the lower conjunctival sac. Compartmentalization is used to explain epitheliopathy over the ocular surface as resulting from variable degrees of exposure to hyperosmolarity-induced insult and/or friction-related mechanical damage. Also recognized is the role of localized increases in osmolarity, which appear likely to occur in the black lines and tear breakup areas of the exposed ocular surface. Variables such as the influence of ambient conditions of air humidity, temperature and movement have been considered, as well as rates of complete and incomplete blinks and associated potential for over-exposure of the inferior area of the normally exposed ocular surface. The exacerbating contribution from contact lens wear has been included. Friction-related damage may be the primary basis for lid wiper epitheliopathy, but tear hyperosmolarity could have an important contributory role. Subcompartmental consideration of variation in osmolarity may improve understanding of different presentations of epitheliopathy.

  10. Changes in the osmolarity of the embryonic microenvironment induce neural tube defects.

    PubMed

    Jin, Yi-Mei; Wang, Guang; Zhang, Nuan; Wei, Yi-Fan; Li, Shuai; Chen, You-Peng; Chuai, Manli; Lee, Henry Siu Sum; Hocher, Berthold; Yang, Xuesong

    2015-05-01

    Many maternal disorders that modify the embryonic microenvironment, such as a change in osmolarity, can affect development, but how these changes influence the early embryo remains obscure. Neural tube defects, for example, are common congenital disorders found in fetus and neonates. In this study, we investigated the impact of anisotonic osmolarity (unequal osmotic pressures) on neural tube development in the early chick embryo, finding that neuronal cell differentiation was impaired in the neural tube due to enhanced apoptosis and repressed cell proliferation. Anisotonic osmolarity also affected normal development of the neural crest, which in turn influenced abnormal development of the neural tube. As neural tube development is highly dependent on the proper expression of bone morphogenetic protein 4 (BMP4), paired box 7 (PAX7), and sonic hedgehog (SHH) genes in the dorsal and ventral regions along the tube, we investigated the impact of anisotonic osmolarity on their expression. Indeed, small changes in osmolarity could positively and negatively impact the expression of these regulatory genes, which profoundly affected neural tube development. Thus, both the central and peripheral nervous systems were perturbed by anisotonic consitions as a consequence of the abnormal expression of key genes within the developing neural tube.

  11. High osmolarity glycerol response PtcB phosphatase is important for Aspergillus fumigatus virulence.

    PubMed

    Winkelströter, Lizziane K; Bom, Vinícius Leite Pedro; de Castro, Patrícia Alves; Ramalho, Leandra Naira Zambelli; Goldman, Maria Helena S; Brown, Neil Andrew; Rajendran, Ranjith; Ramage, Gordon; Bovier, Elodie; Dos Reis, Thaila Fernanda; Savoldi, Marcela; Hagiwara, Daisuke; Goldman, Gustavo H

    2015-04-01

    Aspergillus fumigatus is a fungal pathogen that is capable of adapting to different host niches and to avoid host defenses. An enhanced understanding of how, and which, A. fumigatus signal transduction pathways are engaged in the regulation of these processes is essential for the development of improved disease control strategies. Protein phosphatases are central to numerous signal transduction pathways. To comprehend the functions of protein phosphatases in A. fumigatus, 32 phosphatase catalytic subunit encoding genes were identified. We have recognized PtcB as one of the phosphatases involved in the high osmolarity glycerol response (HOG) pathway. The ΔptcB mutant has both increased phosphorylation of the p38 MAPK (SakA) and expression of osmo-dependent genes. The ΔptcB strain was more sensitive to cell wall damaging agents, had increased chitin and β-1,3-glucan, and impaired biofilm formation. The ΔptcB strain was avirulent in a murine model of invasive pulmonary aspergillosis. These results stress the importance of the HOG pathway in the regulation of pathogenicity determinants and virulence in A. fumigatus.

  12. Bovine serum albumin: survival and osmolarity effect in bovine spermatozoa stored above freezing point.

    PubMed

    Nang, C F; Osman, K; Budin, S B; Ismail, M I; Jaffar, F H F; Mohamad, S F S; Ibrahim, S F

    2012-05-01

    Liquid nitrogen preservation in remote farms is a limitation. The goal of this study was to determine optimum temperature above freezing point for bovine spermatozoa preservation using bovine serum albumin (BSA) as a supplementation. Pooled semen sample from three ejaculates was subjected to various BSA concentration (1, 4, 8 and 12 mg ml(-1)), before incubation in different above freezing point temperatures (4, 25 and 37 °C). Viability assessment was carried out against time from day 0 (fresh sample) until all spermatozoa become nonviable. Optimal condition for bovine spermatozoa storage was at 4 °C with 1 mg ml(-1) BSA for almost 7 days. BSA improved bovine spermatozoa viability declining rate to 44.28% at day 4 and 57.59% at day 7 compared to control, with 80.54% and 98.57% at day 4 and 7 respectively. Increase in BSA concentration did not improve sperm viability. Our results also confirmed that there was a strong negative correlation between media osmolarity and bovine spermatozoa survival rate with r = 0.885, P < 0.0001. Bovine serum albumin helps to improve survival rate of bovine spermatozoa stored above freezing point. © 2011 Blackwell Verlag GmbH.

  13. Tear film osmolarity and dry eye disease: a review of the literature

    PubMed Central

    Potvin, Richard; Makari, Sarah; Rapuano, Christopher J

    2015-01-01

    Objective To evaluate the evidence in the peer-reviewed literature regarding the use of tear osmolarity as a physiological marker to diagnose, grade severity, and track therapeutic response in dry eye disease (DED). In addition, to review the evidence for the role of tear osmolarity in the pathophysiology of DED and ocular surface disease. Methods A literature review of all publications after the year 2000, which included the keywords “tear osmolarity”, was conducted. Relevant articles were graded according to quality of evidence and research, using the University of Michigan Practice Guideline and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) rating systems. Articles were further categorized by the nature of any reported financial support and by the overall impression they provided related to tear osmolarity. Results A total of 164 articles were identified as relevant to the search criteria, although some were editorials, and some were written in a foreign language. Of the total, it was possible to grade 159, and an overall impression was generated for 163. A positive impression of tear osmolarity in DED diagnosis was evident in 72% (117/163) of all articles, with a neutral impression in a further 21% (35/163); 7% had a negative impression. The percentage of positive impressions appeared independent of the quality of research; 73% (38/52) of articles graded high/moderate quality supported the use of tear film osmolarity measurement in DED diagnosis. Impressions were also independent of the source of financial support, with 72% (75/104) of independent studies positive. Conclusion The literature broadly supports the use of tear film osmolarity as an objective numerical measure for diagnosing, grading severity, and managing treatment of DED. PMID:26586933

  14. Renal Safety of Iodinated Contrast Media Depending on Their Osmolarity – Current Outlooks

    PubMed Central

    Mruk, Bartosz

    2016-01-01

    Summary Iodinated contrast media (ICM) are commonly administered pharmaceutical agents. Most often they are used intravenously and intraarterially. Although iodinated contrast agents are relatively safe and widely used, adverse events occur and questions remain about their use, safety, and interactions. The most important adverse effects of contrast media include hypersensitivity reactions, thyroid dysfunction, and contrast-induced nephropathy. Radiologists must be aware of the risk factors for reactions to contrast media. Nonionic iodinated contrast agents can be divided into monomeric, low-osmolar, and dimeric, iso-osmolar classes. The osmotic characteristics of contrast media have been a significant focus in many investigations of contrast-induced nephropathy. PMID:27141236

  15. What is the value of incorporating tear osmolarity measurement in assessing patient response to therapy in dry eye disease?

    PubMed

    Amparo, Francisco; Jin, Yiping; Hamrah, Pedram; Schaumberg, Debra A; Dana, Reza

    2014-01-01

    To evaluate the correlation between changes in tear osmolarity, symptoms, and corneal fluorescein staining in patients with dry eye disease (DED). Retrospective, clinic-based cohort study. In this single-institution study, we reviewed the charts of 186 patients with DED from whom we had data on tear osmolarity, symptoms, and corneal fluorescein staining from 2 separate visits. Main outcomes included the correlation of the changes between the 2 visits for tear osmolarity (TearLab system), symptoms (Ocular Surface Disease Index), and corneal fluorescein staining (modified Oxford scheme). For tear osmolarity and corneal fluorescein staining the scores from the eye with highest readings were analyzed. The correlations were repeated on subgroups based on proposed cutoffs for DED severity and on patients' treatment. We found a modest, though statistically significant, correlation between changes in corneal fluorescein staining and symptoms of DED (R = 0.31; P < .001). However, there was no correlation between the recorded change in tear osmolarity and symptoms (R = -0.091; P = .38) or between changes in tear osmolarity and corneal fluorescein staining (R = -0.02; P = .80). This lack of correlation was consistent in all the subgroups studied. A multivariate analysis revealed that changes in corneal fluorescein staining had predictive value on symptom changes, whereas tear osmolarity changes did not. Changes in tear osmolarity do not correlate significantly with changes in patient symptoms or corneal fluorescein staining in dry eye disease. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. What is the value of incorporating tear osmolarity measurement in assessing patient response to therapy in dry eye disease?

    PubMed Central

    Amparo, Francisco; Jin, Yiping; Hamrah, Pedram; Schaumberg, Debra A.; Dana, Reza

    2013-01-01

    Purpose To evaluate the correlation between changes in tear osmolarity, symptoms, and corneal fluorescein staining in patients with dry eye disease (DED). Design Retrospective, clinic-based cohort study. Methods In this single-institution study, we reviewed the charts of 186 patients with DED from whom we had data on tear osmolarity, symptoms, and corneal fluorescein staining from two separate visits. Main outcomes included the correlation of the changes between the two visits for tear osmolarity (TearLab® system), symptoms (Ocular Surface Disease Index© [OSDI]), and corneal fluorescein staining (modified Oxford scheme). For tear osmolarity and corneal fluorescein staining the scores from the eye with highest readings were analyzed. The correlations were repeated on subgroups based on proposed cutoffs for DED severity and on patients’ treatment. Results We found a modest, though statistically significant, correlation between changes in corneal fluorescein staining and symptoms of DED (R = .31; P < .001). However, there was no correlation between the recorded change in tear osmolarity and symptoms (R = −.091; P = .38) or between changes in tear osmolarity and corneal fluorescein staining (R = −.02; P = .80). This lack of correlation was consistent in all the subgroups studied. A multivariate analysis revealed that changes in corneal fluorescein staining had predictive value on symptom changes, while tear osmolarity changes did not. Conclusions Changes in tear osmolarity do not correlate significantly with changes in patient symptoms or corneal fluorescein staining in dry eye disease. PMID:24060433

  17. A Model for the Precorneal Tear Film with Osmolarity and Corneal Supply

    NASA Astrophysics Data System (ADS)

    Braun, R. J.; King-Smith, P. E.

    2010-11-01

    In the human tear film, a thin liquid layer is spread with a blink; it subsequently levels due to surface tension and evaporates more slowly than pure water due to the floating lipid layer. While eventually the tear film almost always ruptures, recent evidence suggests that in some cases supply of fluid from the cornea or conjunctiva may prolong the life of the tear film and prevent the osmolarity (combined concentration of certain salts and sugars) from reaching very large values that can cause irritation and damage. We incorporate osmolarity into a lubrication model for the tear film and study the dynamics of the tear film with osmotic supply from the corneal surface by numerically solving equations for the film thickness and osmolarity. It is treated as a classical osmotic semi-permeable barrier with parameters appropriate to the cornea. The tear film thinning may be slowed by these effects, and in some cases rupture prevented. The value of the osmolarity in regions thinned by evaporation is reduced by osmosis from the underlying surface.

  18. Tear Osmolarity and Tear Film Parameters in Patients With Ocular Rosacea.

    PubMed

    Karaman Erdur, Sevil; Eliacik, Mustafa; Kocabora, Mehmet Selim; Balevi, Ali; Demirci, Goktug; Ozsutcu, Mustafa; Gulkilik, Gokhan; Aras, Cengiz

    2016-11-01

    The aim of this study was to evaluate tear osmolarity and tear film parameters in patients with ocular rosacea. In a single center, 25 eyes of 25 patients with ocular rosacea (group 1), 25 eyes of 25 patients with rosacea without ocular involvement (group 2), and 20 eyes of 20 healthy individuals (group 3) were evaluated using the Ocular Surface Disease Index (OSDI) questionnaire, Schirmer I test, tear film break-up time (TBUT), scoring of ocular surface fluorescein staining using modified Oxford scale, and tear osmolarity. Tear osmolarity values, OSDI and Oxford scale scores were significantly higher in group 1 than in groups 2 and 3 (P<0.001 for all). Schirmer I test and TBUT in group 1 were significantly lower than in groups 2 and 3 (P<0.001 for all). There were no significant differences in OSDI, Schirmer I test, TBUT, Oxford scores, or tear osmolarity between groups 2 and 3 (P=0.629, P=0.175, P=0.713, P=865, and P=0.388, respectively). This study showed that ocular rosacea is associated with tear hyperosmolarity and tear film dysfunction.

  19. Tear Osmolarity and Dry Eye Symptoms in Women Using Oral Contraception and Contact Lenses

    PubMed Central

    Chen, Sarah P.; Massaro-Giordano, Giacomina; Pistilli, Maxwell; Schreiber, Courtney A.; Bunya, Vatinee Y.

    2013-01-01

    Purpose To examine the relationship between oral contraceptive pill (OCP) use, contact lens wear, and dry eye signs and symptoms in healthy young females. Methods Fifty-two women using OCPs and forty-five women not using any form of hormonal contraception were enrolled. Medical, menstrual, and contact lens histories were obtained and dry eye symptoms were assessed using the Ocular Surface Disease Index (OSDI) and Symptom Assessment iN Dry Eye (SANDE) questionnaires. Tear osmolarity testing was performed using the TearLab™ Osmolarity System. Results Mean age of all subjects was 26.0 ± 3.7 years. There were no significant differences in any of the measurements between the follicular and luteal phases. While SANDE scores were significantly higher in subjects with OCP and recent contact lens use (p<0.01), there were no significant differences in OSDI and tear osmolarity amongst the same subject groups. Subjects who reported both OCP and recent contact lens use had significantly higher OSDI and SANDE scores (p=0.015 and p<0.001, respectively). Conclusions There were no differences between the phases of the menstrual cycle. Tear osmolarity was not affected by OCP or contact lens use in young females. However, the combination of OCP use and contact lens wear may increase the severity of dry eye symptoms. PMID:23086364

  20. Characterization of the hypo-osmolarity-induced Ca2+ response in cultured rat astrocytes.

    PubMed

    Fischer, R; Schliess, F; Häussinger, D

    1997-05-01

    The influence of astrocyte swelling on the cytosolic free calcium concentration [Ca2+]i was studied at the single cell level. Sudden exposure of normo-osmotically (305 mosmol/l) cultured astrocytes to hypo-osmotic medium induced a biphasic increase in cytosolic calcium with an initial peak followed by a sustained plateau. The response was osmolarity dependent and was maximal at 205 mosmol/l with respect to [Ca2+]i and the percentage of responding cells. Other modes of astrocyte swelling [gradual adjustment of hypo-osmolarity, normo-osmotic exposure of hyper-osmotic (405 mosmol/l) maintained cells] produced a much weaker [Ca2+]i response. Change from 405 to 205 mosmol/l, however, resulted in the entire peak and an increased plateau. Experiments with Ca(2+)-free medium and after pretreatment with BAPTA-AM, thapsigargin, phorbol myristate acetate, or nimodipine revealed that the peak mainly resulted from depletion of intracellular Ca2+ stores, whereas the plateau was probably due to capacitative Ca2+ entry and Ca2+ influx independent of store depletion including a nimodipin-sensitive component. Prior depletion of ryanodine-, bradykinin- or ATP-sensitive stores revealed that the initial hypo-osmolarity-induced Ca(2+)-release was from a Ca2+ pool also affected by ATP and bradykinin, but not by ryanodine. The recent finding, that the hypo-osmolarity-induced [Ca2+]i response was completely maintained if phospholipase C-mediated phosphatidylinositol hydrolysis was blocked, suggests that hypo-osmolarity may exert an inositol (1,4,5) triphosphate-independent access to these stores.

  1. Comparison of the effects of first and second generation silicone hydrogel contact lens wear on tear film osmolarity

    PubMed Central

    Iskeleli, Guzin; Karakoc, Yunus; Ozkok, Ahmet; Arici, Ceyhun; Ozcan, Omer; Ipcioglu, Osman

    2013-01-01

    AIM To compare the effects of first and second generation silicone hydrogel (SiH) contact lens wear on tear film osmolarity. METHODS The healthy subjects who have never used contact lenses before were enrolled in the study. Tear film osmolarity values of 16 eyes (group 1) who wore first generation SiH contact lenses were compared with those of 18 eyes (group 2) who wore second generation SiH contact lenses after three months follow-up. RESULTS Before contact lens wear, tear film osmolarity of groups 1 and 2 were 305.02±49.08 milliosmole (mOsm) and 284.66±30.18mOsm, respectively. After three months of contact lens wear, osmolarity values were found 317.74±60.23mOsm in group 1 and 298.40±37.77mOsm in group 2. Although osmolarity values for both groups of SiH contact lens wear after three months periods were slightly higher than before the contact lens wear, the difference was not statistically significant. CONCLUSION Contact lens wear may cause evaporation from the tear film and can increase tear film osmolarity leading to symptoms of dry eye disease. In the current study, there is a tendency to increase tear film osmolarity for both groups of SiH contact lens wear, but the difference is not statistically significant. PMID:24195046

  2. Ethanol Metabolism and Osmolarity Modify Behavioral Responses to Ethanol in C. elegans

    PubMed Central

    Alaimo, Joseph T.; Davis, Scott J.; Song, Sam S.; Burnette, Christopher R.; Grotewiel, Mike; Shelton, Keith L.; Pierce-Shimomura, Jonathan T.; Davies, Andrew G.; Bettinger, Jill C.

    2012-01-01

    Background Ethanol is metabolized by a two-step process in which alcohol dehydrogenase (ADH) oxidizes ethanol to acetaldehyde, which is further oxidized to acetate by aldehyde dehydrogenase (ALDH). Although variation in ethanol metabolism in humans strongly influences the propensity to chronically abuse alcohol, few data exist on the behavioral effects of altered ethanol metabolism. Here, we used the nematode C. elegans to directly examine how changes in ethanol metabolism alter behavioral responses to alcohol during an acute exposure. Additionally, we investigated ethanol solution osmolarity as a potential explanation for contrasting published data on C. elegans ethanol sensitivity. Methods We developed a gas chromatography assay and validated a spectrophotometric method to measure internal ethanol in ethanol-exposed worms. Further, we tested the effects of mutations in ADH and ALDH genes on ethanol tissue accumulation and behavioral sensitivity to the drug. Finally, we tested the effects of ethanol solution osmolarity on behavioral responses and tissue ethanol accumulation. Results Only a small amount of exogenously applied ethanol accumulated in the tissues of C. elegans and consequently their tissue concentrations were similar to those that intoxicate humans. Independent inactivation of an ADH-encoding gene (sodh-1) or an ALDH-encoding gene (alh-6 or alh-13) increased the ethanol concentration in worms and caused hypersensitivity to the acute sedative effects of ethanol on locomotion. We also found that the sensitivity to the depressive effects of ethanol on locomotion is strongly influenced by the osmolarity of the exogenous ethanol solution. Conclusions Our results indicate that ethanol metabolism via ADH and ALDH has a statistically discernable but surprisingly minor influence on ethanol sedation and internal ethanol accumulation in worms. In contrast, the osmolarity of the medium in which ethanol is delivered to the animals has a more substantial effect on

  3. Osmolarity and composition of cell culture media affect further development and survival in zebrafish embryos.

    PubMed

    Perez-Camps, M; Garcia-Ximenez, F

    2008-04-01

    With the aim of carrying out chimaerism and somatic cell-midblastula transition (MBT) embryos co-culture experiments in freshwater fish species, we evaluated the effect of osmolarity and composition of two media commonly used in cell fish culture on MBT zebrafish embryos and their further development and survival. To this end, wild zebrafish dechorionated embryos in midblastula stage were cultured for 6 days (Experiment 1: 189 embryos) or 1 h (Experiment 2: 150 embryos) in three different media: Hanks' 10% (H-10), 35 mOsm; Hanks' 100% (CH), 315 mOsm; and L-15 with serum (L-15: 315 mOsm). High osmolarity affected the survival rate (6 days: L-15: 45.1% v. CH: 72.34% v. H-10: 100%, P < 0.05; after 6 days: 0% both in L-15 and CH) and slowed their developmental timing. Embryos showed tail deformation (curly) as well as body paralysis at 48 h when they showed tail movements at 28 h. Differences in tail deformation were observed between high-osmolarity groups (CH: 85.10% v. L-15: 98.04%; P < 0.05). In Experiment 2, no effects on survival rate were observed. Teratogenic effects were only observed in L-15 (L-15: 12.98% v. CH: 0%; P< 0.05). Loss of motility was not detected in any group at 48 h. Optimum osmolar condition for cultured cells and also embryonic cells is around 315 mOsm and so, during chimaerism experiments (usually practised at MBT stage), present results indicate that midblastula embryos can acceptably bear the effects caused by 315 mOsm (CH) for 1 h, even though this involves a certain delay in developmental timing.

  4. Differentiation of osmotic and secretory diarrhoea by stool carbohydrate and osmolar gap measurements

    PubMed Central

    Castro-Rodriguez, J. A.; Salazar-Lindo, E.; Leon-Barua, R.

    1997-01-01

    

 Clinical features and laboratory tests that determine carbohydrate in faeces were evaluated to determine which was best able to distinguish between osmotic and secretory diarrhoea in infants and children. For this purpose 80 boys aged 3 to 24 months, with acute watery diarrhoea, were studied prospectively. The faecal osmolar gap (FOG) was calculated as: serum osmolarity − [2 × (faecal sodium + potassium concentration)]. Fifty eight patients were classified as having predominantly osmotic diarrhoea (FOG >100 mosmol/l), and 22 as having predominantly secretory diarrhoea (FOG ⩽100 mosmol/l). The two groups were comparable in their clinical features on admission, in the results of blood and urine tests, and in the evolution of their diarrhoeal illness. Evidence of steatorrhoea (by positive Sudan III test) and of acid faecal pH on admission were significantly more frequent in patients with osmotic diarrhoea. Mean (SD) faecal osmolarity was not significantly different between the two groups (319 (80) mosmol/l in secretory diarrhoea v 361 (123) mosmol/l in osmotic diarrhoea). Tests for reducing substances in faeces such as Benedict's test—with and without hydrolysis—and glucose strip, all showed a positive and significant association with osmotic diarrhoea (p <0.05, <0.025, <0.05, respectively). The presence of excess reducing substances (Benedict's test with hydrolysis >++) on admission was the most sensitive and specific test with the best predictive value for differentiating between the two types of watery diarrhoea.

 PMID:9370895

  5. Dependence of tissue optical properties on solute-induced changes in refractive index and osmolarity

    NASA Astrophysics Data System (ADS)

    Liu, Hanli; Beauvoit, Bertrand; Kimura, Mika; Chance, Britton

    1996-04-01

    Additions of a solute/carbohydrate in tissue affect the size of tissue cells and the refractive indexes of the extra- and intracellular fluids, and thus the overall tissue scattering properties. We use both the Rayleigh-Gans and Mie theory approximation in calculating effects of the osmolarity and refractive indexes on the reduced scattering coefficient of tissue, and employ photon diffusion theory to associate the reduced scattering coefficient to the mean optical path length. The calculations show that changes of scattering in tissue depend not only on the change in extracellular refractive index but also on the change in osmolarity, and thus on the change in cell size and volume fraction. Experimentally, we have utilized time-domain and frequency- domain NIR techniques to measure the changes of optical properties caused by an addition of a solute in tissue models and in perfused rat livers. The temperature-dependent path length measurement of the perfused liver confirms the dependence of tissue scattering on the tissue cell size. The results obtained from the liver with three kinds of carbohydrate perfusion display different scattering aspects and can be well explained by changes in cell size and in extracellular as well as intracellular refractive indexes. The consistency between the theoretical and experimental results confirms the dependence of optical properties in (liver) tissue on both tissue osmolarity and relative refractive indexes between the extracellular and intracellular compartments. This study suggests that the NIR technique is a novel and useful tool for noninvasive, physiological monitoring.

  6. Effects of salinity fluctuation frequency on the osmolarity, Na+-K+-ATPase activity and HSP70 expression in juvenile chinese shrimp, Fenneropenaeus chinensis

    NASA Astrophysics Data System (ADS)

    Ding, Sen; Wang, Fang; Sun, Hao; Guo, Biao; Dong, Shuanglin

    2009-03-01

    Experiments were conducted to examine the effects of salinity fluctuation frequency on the osmolarity, Na+-K+-ATPase activity and HSP70 of Chinese shrimp Fenneropenaeus chinensis with initial wet body weight of 1.460 g ± 0.091 g. The salinity in the control group (D0) was 28 throughout the experiment, whereas treatments D2, D4, D6 and D8 were subjected to different salinity fluctuation frequencies of 2, 4, 6 and 8 d, respectively. The salinity in treatments D2, D4, D6 and D8 was kept at 28 for 2, 4, 6 and 8 d, respectively, decreased abruptly to salinity 24, lasted for another 2 d, and then was raised to its initial value 28. This was a complete salinity fluctuation cycle that afterwards repeated itself. After 32 days, the osmolarity in treatments D2, D4, D6 and D8 was significantly lower than that in treatment D0 ( P<0.05). There were significant differences in both muscle and eyestalks HSP70 expression among groups. The HSP70 expressions in muscle and eyestalks in group D4 were 61.4% and 57.0% higher, respectively, than that in the control group D0 ( P<0.05). There were, however, no significant differences in gill or hepatopancreas Na+-K+-ATPase activity between the treatments and the control.

  7. Light-absorbing properties and osmolarity of indocyanine-green depending on concentration and solvent medium.

    PubMed

    Haritoglou, Christos; Gandorfer, Arnd; Schaumberger, Markus; Tadayoni, Ramin; Gandorfer, Achim; Kampik, Anselm

    2003-06-01

    To evaluate the absorption spectrum and osmolarity of three currently used indocyanine green (ICG) products at different concentrations and with different solvent media. The absorption spectrum and osmolarity of three different ICG products (Pulsion, Munich, Germany; Akorn, Buffalo Grove, IL; and Laboratoires SERB, Paris, France) were analyzed. Each ICG was further diluted with balanced salt solution or glucose 5%. Four different concentrations were evaluated: 0.005%, 0.0025%, 0.001%, and 0.00025%. ICG (Pulsion) diluted in viscoelastic material (Healon; Pharmacia, Stockholm, Sweden) was analyzed at a concentration of 0.0025%. The following parameters were measured: absorption spectrum between 400 and 1000 nm, osmolarity, and the emission spectrum of the light source of a commonly used vitrectomy machine (Megatron; Geuder, Heidelberg, Germany). Independent from the manufacturer, concentrations of 0.005%, 0.0025%, and 0.001% ICG diluted in balanced salt solutions (BSS and BSS Plus; Alcon Pharmaceuticals, Fort Worth, TX) and glucose 5% showed two maxima, one at approximately 700 nm and a second one at 780 nm. There was an increase from zero to maximum absorption between 600 and 700 nm and a return to zero between 800 and 900 nm. The absorption band of ICG diluted in the viscoelastic material was similar to the saline solution (BSS or BSS Plus)-diluted ICG. At lower concentrations of 0.001% or 0.00025%, the peak at 700 nm decreased, forming a shoulder in the curve, whereas the peak at 780 nm remained stable. Osmolarity was in the range of 302 to 313 mOsM for BSS Plus-diluted ICG. When glucose 5% was used for ICG dilution, absorption between 600 and 700 nm decreased, and osmolarity was lower (between 292 and 298 mOsM). The light source emission was between 380 and 760 nm. Dilution of ICG using the balanced salt solutions BSS or BSS Plus resulted in a steep increase of absorption starting at 600 nm. In clinical practice, there is an overlap between the absorption band of

  8. Efficacy of standard glucose-based and reduced-osmolarity maltodextrin-based oral rehydration solutions: effect of sugar malabsorption.

    PubMed

    el-Mougi, M; Hendawi, A; Koura, H; Hegazi, E; Fontaine, O; Pierce, N F

    1996-01-01

    Previously we reported that standard oral rehydration salts (ORS) solution is not as effective as a reduced-osmolarity glucose-based ORS for the treatment of children with acute noncholera diarrhoea: with standard ORS the diarrhoea lasts longer, stool output is greater, serum sodium is higher, and there is more need for supplemental intravenous infusion. We studied a reduced-osmolarity maltodextrin (MD)-based ORS to determine whether it had similar benefits, and also the effect of sugar malabsorption on the efficacy of standard and MD-based ORS. A total of 90 boys aged 3-24 months with acute noncholera diarrhoea and moderate dehydration were randomly assigned to either standard ORS (glucose 20 g/l, osmolarity 311 mmol/l) or MD-ORS (MD 50 g/l, osmolarity 227 mmol/l). There were no differences in treatment results. Some 46% of subjects had a high total stool output (> 300 g/kg), which was unrelated to the type of ORS given. High stool output was significantly associated with a longer duration of diarrhoea (33 vs. 15 hours; P < 0.001), a persistently elevated serum sodium (149 vs. 144 mmol/l at 24 h; P < 0.02), the need for intravenous infusion (11/41 vs. 0/48; P < 0.002), and an increase in faecal reducing substances (10.8 vs. 3.4 g/l at 24 h; P < 0.001). We conclude that some children given standard ORS develop osmotic diarrhoea owing to the combined effect of transient sugar malabsorption and slight hypertonicity of the ORS. Earlier studies show that this adverse outcome can largely be avoided when extra water is given in reduced-osmolarity glucose-based ORS. Reduced osmolarity has no benefit, however, when glucose is replaced by maltodextrin, probably because the sugars released by hydrolysis of MD, when malabsorbed, raise the intraluminal osmolarity to equal or exceed that of standard ORS. Thus, reduced-osmolarity glucose-based ORS is superior to both standard ORS and reduced-osmolarity solutions based on maltodextrin and probably other complex carbohydrates

  9. Efficacy of standard glucose-based and reduced-osmolarity maltodextrin-based oral rehydration solutions: effect of sugar malabsorption.

    PubMed Central

    el-Mougi, M.; Hendawi, A.; Koura, H.; Hegazi, E.; Fontaine, O.; Pierce, N. F.

    1996-01-01

    Previously we reported that standard oral rehydration salts (ORS) solution is not as effective as a reduced-osmolarity glucose-based ORS for the treatment of children with acute noncholera diarrhoea: with standard ORS the diarrhoea lasts longer, stool output is greater, serum sodium is higher, and there is more need for supplemental intravenous infusion. We studied a reduced-osmolarity maltodextrin (MD)-based ORS to determine whether it had similar benefits, and also the effect of sugar malabsorption on the efficacy of standard and MD-based ORS. A total of 90 boys aged 3-24 months with acute noncholera diarrhoea and moderate dehydration were randomly assigned to either standard ORS (glucose 20 g/l, osmolarity 311 mmol/l) or MD-ORS (MD 50 g/l, osmolarity 227 mmol/l). There were no differences in treatment results. Some 46% of subjects had a high total stool output (> 300 g/kg), which was unrelated to the type of ORS given. High stool output was significantly associated with a longer duration of diarrhoea (33 vs. 15 hours; P < 0.001), a persistently elevated serum sodium (149 vs. 144 mmol/l at 24 h; P < 0.02), the need for intravenous infusion (11/41 vs. 0/48; P < 0.002), and an increase in faecal reducing substances (10.8 vs. 3.4 g/l at 24 h; P < 0.001). We conclude that some children given standard ORS develop osmotic diarrhoea owing to the combined effect of transient sugar malabsorption and slight hypertonicity of the ORS. Earlier studies show that this adverse outcome can largely be avoided when extra water is given in reduced-osmolarity glucose-based ORS. Reduced osmolarity has no benefit, however, when glucose is replaced by maltodextrin, probably because the sugars released by hydrolysis of MD, when malabsorbed, raise the intraluminal osmolarity to equal or exceed that of standard ORS. Thus, reduced-osmolarity glucose-based ORS is superior to both standard ORS and reduced-osmolarity solutions based on maltodextrin and probably other complex carbohydrates

  10. Cerebrospinal fluid control of neurogenesis induced by retinoic acid during early brain development.

    PubMed

    Alonso, M I; Martín, C; Carnicero, E; Bueno, D; Gato, A

    2011-07-01

    Embryonic-cerebrospinal fluid (E-CSF) plays crucial roles in early brain development including the control of neurogenesis. Although FGF2 and lipoproteins present in the E-CSF have previously been shown to be involved in neurogenesis, the main factor triggering this process remains unknown. E-CSF contains all-trans-retinol and retinol-binding protein involved in the synthesis of retinoic acid (RA), a neurogenesis inducer. In early chick embryo brain, only the mesencephalic-rombencephalic isthmus (IsO) is able to synthesize RA. Here we show that in chick embryo brain development: (1) E-CSF helps to control RA synthesis in the IsO by means of the RBP and all-trans-retinol it contains; (2) E-CSF has retinoic acid activity, which suggests it may act as a diffusion pathway for RA; and (3) the influence of E-CSF on embryonic brain neurogenesis is to a large extent due to its involvement in RA synthesis. These data help to understand neurogenesis from neural progenitor cells.

  11. High incidence of nephropathy in neurosurgical patients after intra-arterial administration of low-osmolar and iso-osmolar contrast media.

    PubMed

    Serafin, Zbigniew; Karolkiewicz, Maciej; Gruszka, Marzena; Strózecki, Pawel; Lasek, Wladyslaw; Odrowaz-Sypniewska, Grazyna; Manitius, Jacek; Beuth, Wojciech

    2011-05-01

    Percutaneous endovascular examinations and interventions require significant amounts of iodinated contrast media (CM) and have been reported to be complicated by an increased incidence of post-contrast nephropathy. To evaluate renal function, the incidence of post-contrast nephropathy, and risk factors after interventional procedures in neurosurgical patients after intra-arterial administration of a low-osmolar contrast medium (LOCM) versus an iso-osmolar contrast medium (IOCM). This single-center, prospective, randomized, double-blinded study included 92 patients in its final analysis (mean age 49.6 ± 12.6 years, 29.3% men, mean eGFR 97.8 ± 26.3 mL/min/1.73 m(2)). LOCM was used in 48 patients (52.2%) and IOCM in 44 patients (47.8%). The patients were given an average of 151.2 ± 52.1 mL of contrast medium intra-arterially. Serum creatinine (SCr), urinary N-acetyl-β-glucosaminidase (NAG) excretion, and creatinine clearance (CCr) were measured at baseline, and on days 1 and 3 after the procedure. Baseline risk factors, renal functional parameters, and average CM doses were not statistically different between the two groups. SCr, NAG, and CCr values did not differ significantly between the LOCM and IOCM groups on days 1 and 3 after CM administration. Nephropathy developed in 21 cases (22.8%): 13 (27.1%) after LOCM use and 8 (18.2%) after IOCM; (P = NS). The only significant risk factors of CIN were the diabetes (P = 0.0466) and atherosclerosis (P = 0.0498). We found a high incidence of nephropathy in neurosurgical patients after intra-arterial CM administration. The renal function values and incidence of nephropathy following LOCM administration were not statistically different from those following IOCM administration.

  12. Osmotic control of luminescence and growth in Photobacterium leiognathi from ponyfish light organs.

    PubMed

    Dunlap, P V

    1985-02-01

    Osmolarity was found to control the luminescence and growth of Photobacterium leiognathi strain LN-1a isolated from the light organ of the ponyfish Leiognathus nuchalis (family Leiognathidae). Low osmolarity (ca. 400 mOsm) stimulated luminescence per cell 80 to 100-fold to a level (ca. 2.0 X 10(4) quanta . s-1 . cell-1) equal to that of bacteria taken directly from the light organ and increased the level of luciferase per cell 8 to 10-fold compared to high osmolarity (ca. 800 mOsm). Conversely, high osmolarity stimulated oxygen uptake and growth rate 2 to 4-fold compared to low osmolarity. Of 21 additional tested strains of P. leiognathi from light organs of 9 other ponyfish species, all responded similarly. Low osmolarity may be a host control factor that functions to stimulate the luminescence and restrict the growth of ponyfish light organ bacteria in situ.

  13. Estimating the Osmolarities of Tears During Evaporation Through the “Eyes” of the Corneal Nerves

    PubMed Central

    Hirata, Harumitsu; Mizerska, Kamila; Dallacasagrande, Valentina; Rosenblatt, Mark I.

    2017-01-01

    Purpose A population of corneal neurons in rats preferentially sense and monitor the hyperosmolar conditions of tears when the tears begin to evaporate during corneal dryness. The present study exploited this ability in an effort to estimate tear osmolarities by comparing the responses to corneal dryness to their responses to hyperosmolar stimuli. Methods Extracellular recordings were performed from single neurons in the trigeminal ganglia innervating the corneas of rats. To determine the extent to which the corneal neurons' responses to drying of the cornea were induced via the activation by hyperosmolar stimuli, we assessed the responses to ocular instillation of 500 and 600 mOsm/L, and a graded series of hyperosmolar stimuli ranging from 350 to 1000 mOsm/L. Results The magnitudes of the responses to drying of the cornea were matched almost exactly to those induced by the ocular instillation of the 600 mOsm/L stimuli but not the 500 mOsm/L solutions. The response magnitudes to a graded series of hyperosmolar solutions were nearly linear from the 350 to the 600 mOsm/L stimuli, but reached a plateau or declined slightly thereafter. Conclusions Our results demonstrate that the tear osmolarity in rats could reach 600 to 1000 mOsm/L during ocular dryness. Furthermore, a spontaneous eye blink could be generated at a tear osmolarity of approximately 400 mOsm/L if the blink is solely determined by hyperosmolar tears, but ocular surface cooling also can become a major factor if hyperosmolar tears occurring during ocular dryness lower the threshold of activation of the neurons. PMID:28114576

  14. Estimating the Osmolarities of Tears During Evaporation Through the "Eyes" of the Corneal Nerves.

    PubMed

    Hirata, Harumitsu; Mizerska, Kamila; Dallacasagrande, Valentina; Rosenblatt, Mark I

    2017-01-01

    A population of corneal neurons in rats preferentially sense and monitor the hyperosmolar conditions of tears when the tears begin to evaporate during corneal dryness. The present study exploited this ability in an effort to estimate tear osmolarities by comparing the responses to corneal dryness to their responses to hyperosmolar stimuli. Extracellular recordings were performed from single neurons in the trigeminal ganglia innervating the corneas of rats. To determine the extent to which the corneal neurons' responses to drying of the cornea were induced via the activation by hyperosmolar stimuli, we assessed the responses to ocular instillation of 500 and 600 mOsm/L, and a graded series of hyperosmolar stimuli ranging from 350 to 1000 mOsm/L. The magnitudes of the responses to drying of the cornea were matched almost exactly to those induced by the ocular instillation of the 600 mOsm/L stimuli but not the 500 mOsm/L solutions. The response magnitudes to a graded series of hyperosmolar solutions were nearly linear from the 350 to the 600 mOsm/L stimuli, but reached a plateau or declined slightly thereafter. Our results demonstrate that the tear osmolarity in rats could reach 600 to 1000 mOsm/L during ocular dryness. Furthermore, a spontaneous eye blink could be generated at a tear osmolarity of approximately 400 mOsm/L if the blink is solely determined by hyperosmolar tears, but ocular surface cooling also can become a major factor if hyperosmolar tears occurring during ocular dryness lower the threshold of activation of the neurons.

  15. Assessment of tear osmolarity and other dry eye parameters in post-LASIK eyes.

    PubMed

    Hassan, Ziad; Szalai, Eszter; Berta, Andras; Modis, Laszlo; Nemeth, Gabor

    2013-07-01

    To assess the tear osmolarity using the TearLab device after laser in situ keratomileusis (LASIK) and to compare the values with those obtained by traditional tear film tests before and after the procedure. Thirty eyes of 15 refractive surgery candidates (5 men and 10 women of mean age: 30.55 ± 11.79 years) were examined. Using a special questionnaire (Ocular Surface Disease Index), subjective dry eye complaints were evaluated, and then, the tear osmolarity was measured with the TearLab system (TearLab Corporation) and conventional dry eye tests were carried out. Examinations were performed preoperatively and at 1, 30, and 60 days after the surgery. The mean value of tear osmolarity was 303.62 ± 12.29 mOsm/L before the surgery and 303.58 ± 20.14 mOsm/L at 60 days after the treatment (P = 0.69). Mean lid parallel conjunctival folds value was 0.68 ± 0.68 before the procedure and 0.58 ± 0.65 subsequent to surgery (P = 0.25). Meibomian gland dysfunction was not detected. No significant deviation was observed in the values of Schirmer test, corneal staining, tear break-up time, and lid parallel conjunctival folds when compared with postoperatively obtained values during the follow-up period (P > 0.05). During LASIK flap creation, intact corneal innervation is damaged, and the ocular surface lacrimal functional unit can be impaired. In our study, no abnormal dry eye test results were observed before or after the procedure. Based on our results, LASIK treatment is safe for dry eye involving the administration of adequate artificial tears for a minimum of 3 months.

  16. Reduced tissue osmolarity increases TRPV4 expression and pro-inflammatory cytokines in intervertebral disc cells.

    PubMed

    Walter, B A; Purmessur, D; Moon, A; Occhiogrosso, J; Laudier, D M; Hecht, A C; Iatridis, J C

    2016-07-19

    The mechanical behaviour and cellular metabolism of intervertebral discs (IVDs) and articular cartilage are strongly influenced by their proteoglycan content and associated osmotic properties. This osmotic environment is a biophysical signal that changes with disease and may contribute to the elevated matrix breakdown and altered biologic response to loading observed in IVD degeneration and osteoarthritis. This study tested the hypothesis that changes in osmo-sensation by the transient receptor potential vallinoid-4 (TRPV4) ion channel occur with disease and contribute to the inflammatory environment found during degeneration. Immunohistochemistry on bovine IVDs from an inflammatory organ culture model were used to investigate if TRPV4 is expressed in the IVD and how expression changes with degeneration. Western blot, live-cell calcium imaging, and qRT-PCR were used to investigate whether osmolarity changes or tumour necrosis factor α (TNFα) regulate TRPV4 expression, and how altered TRPV4 expression influences calcium signalling and pro-inflammatory cytokine expression. TRPV4 expression correlated with TNFα expression, and was increased when cultured in reduced medium osmolarity and unaltered with TNFα-stimulation. Increased TRPV4 expression increased the calcium flux following TRPV4 activation and increased interleukin-1β (IL-1β) and IL-6 gene expression in IVD cells. TRPV4 expression was qualitatively elevated in regions of aggrecan depletion in degenerated human IVDs. Collectively, results suggest that reduced tissue osmolarity, likely following proteoglycan degradation, can increase TRPV4 signalling and enhance pro-inflammatory cytokine production, suggesting changes in TRPV4 mediated osmo-sensation may contribute to the progressive matrix breakdown in disease.

  17. REDUCED TISSUE OSMOLARITY INCREASES TRPV4 EXPRESSION AND PRO-INFLAMMATORY CYTOKINES IN INTERVERTEBRAL DISC CELLS

    PubMed Central

    Walter, B.A.; Purmessur, D; Moon, A.; Occhiogrosso, J.; Laudier, D.M.; Hecht, A.C.; Iatridis, J.C.

    2016-01-01

    The mechanical behaviour and cellular metabolism of intervertebral discs (IVDs) and articular cartilage are strongly influenced by their proteoglycan content and associated osmotic properties. This osmotic environment is a biophysical signal that changes with disease and may contribute to the elevated matrix breakdown and altered biologic response to loading observed in IVD degeneration and osteoarthritis. This study tested the hypothesis that changes in osmo-sensation by the transient receptor potential vallinoid-4 (TRPV4) ion channel occur with disease and contribute to the inflammatory environment found during degeneration. Immunohistochemistry on bovine IVDs from an inflammatory organ culture model were used to investigate if TRPV4 is expressed in the IVD and how expression changes with degeneration. Western blot, live-cell calcium imaging, and qRT-PCR were used to investigate whether osmolarity changes or tumour necrosis factor α (TNFα) regulate TRPV4 expression, and how altered TRPV4 expression influences calcium signalling and pro-inflammatory cytokine expression. TRPV4 expression correlated with TNFα expression, and was increased when cultured in reduced medium osmolarity and unaltered with TNFα-stimulation. Increased TRPV4 expression increased the calcium flux following TRPV4 activation and increased interleukin-1β (IL-1β) and IL-6 gene expression in IVD cells. TRPV4 expression was qualitatively elevated in regions of aggrecan depletion in degenerated human IVDs. Collectively, results suggest that reduced tissue osmolarity, likely following proteoglycan degradation, can increase TRPV4 signalling and enhance pro-inflammatory cytokine production, suggesting changes in TRPV4 mediated osmo-sensation may contribute to the progressive matrix breakdown in disease. PMID:27434269

  18. Assessment of dry eye in a GVHD murine model: Approximation through tear osmolarity measurement.

    PubMed

    Martínez-Carrasco, Rafael; Sánchez-Abarca, Luis Ignacio; Nieto-Gómez, Cristina; García, Elisabet Martín; Ramos, Teresa L; Velasco, Almudena; Sánchez-Guijo, Fermín; Aijón, José; Hernández-Galilea, Emiliano

    2017-01-01

    Dry eye disease is one of the most frequent pathological events that take place in the course of the graft versus host disease (GVHD), and is the main cause of deterioration in quality of life for patients. Thus, demonstration of dry eye signs in murine models of oGVHD is crucial for the validation of these models for the study of the disease. Given the increasing evidence that tear osmolarity is an important player of dry eye disease, our purpose in this study was to validate the use of a reliable method to assess tear osmolarity in mice: the electrical impedance method. Then, we wanted to test its utility with an oGVHD model. Tear volume assessment was also performed, using the phenol red thread test. We found differences in tear osmolarity in mice that received a transplant with cells from bone marrow and spleen (the GVHD group) when compared with mice that only received bone marrow cells (the BM group) at day 7 (362 ± 8 mOsm/l and 345 ± 9 mOsm/l respectively; P < 0.01) and day 21 (348 ± 19 mOsm/l vs. 326 ± 15 mOsm/l; P < 0.05). We found also differences in tear volume at day 14 (2.30 ± 0.61 mm in oGVHD group and 2.89 ± 0.62 mm in BM group; P = 0.06) and at day 21 (2.10 ± 0.30 mm in oGVHD group and 2.89 ± 0.32 mm in BM group; P < 0.01). Besides this, we observed reduction in epithelial thickness between the GVHD and BM groups (37.0 ± 6.2 μm and 43.6 ± 3.3 μm respectively; P < 0.05). These data show the usefulness of the electrical impedance method to measure tear osmolarity in mice. We can also conclude that this oGVHD model mimics the tear film alterations found in human dry eye disease, what contributes to give relevance to this model for the study of GVHD.

  19. [Corneal cross-linking with hypo-osmolar riboflavin solution for keratoconus with thin corneas].

    PubMed

    Raiskup, F; Kissner, A; Spoerl, E; Pillunat, L E

    2011-09-01

    The aim of this study was to evaluate the 1-year results of 32 keratoconic eyes with thin corneas which were treated by hypo-osmolar riboflavin solution and ultraviolet A (UVA) collagen cross-linking (CXL). Patients with progressive keratoconus and a corneal thickness (CT) less than 400 µm (without epithelium) were included in this study. The CT was measured with an ultrasound device (Tomey SP-3000, Nishi-ku, Nagoya, Japan). An increase in the maximum topographic K-value at the apex of keratoconus and a reduction in corneal thickness with or without changes in visual acuity (VA) within the last year were considered to be progression. A total of 32 eyes with an additional follow-up within 1 year were evaluated before and after the procedure. Examinations consisted of an evaluation of VA, corneal topography, slit-lamp microscopy and corneal thickness measurements. Preoperatively the mean corneal thickness (with epithelium) was 382.3±41.9 μm and after removal of the epithelium the thickness of the cornea was reduced to 337.0±51.9 μm. After the application of hypo-osmolar riboflavin solution the mean value increased to 451.8±46.7 μm. Preoperatively the mean K-value of the apex of the keratoconus was 65.6±11.2 dopters, and 1 year after treatment this value remained relatively unchanged at 64.9±11.0 diopters (P=0.839). Mean VA at the time of the treatment was 0.63±0.37 logMAR and 1 year after the treatment this value was not statistically different (0.59±0.42 logMAR; P=0.662). In the last follow-up examination 1 year after the procedure all corneas were transparent without any scarring lesions in the stroma. The results of this study using hypo-osmolar riboflavin solution in a cross-linking procedure for thin corneas showed a stability of keratoconus 1 year after CXL. Application of the hypo-osmolar riboflavin solution prevented cross-linked corneas from developing stromal scars.

  20. Hypo-osmolar intravascular volume overload during anaesthesia for transurethral prostatectomy. A report of 2 cases.

    PubMed

    Butt, A D; Wright, I G; Elk, R J

    1985-06-29

    Two cases are reported in which absorption of surgical irrigant into the vascular system during transurethral resection of the prostate gland (TUR) resulted in life-threatening complications due to hypo-osmolar volume overload (also known as water intoxication or the TUR syndrome). Manifestations common to both cases were haemolysis of red cells, cardiac arrhythmias, a drop in the serum sodium level, and an elevated central venous pressure. In addition, one patient developed acute pulmonary oedema and the other hypokalaemia, confusion and visual disturbances due to cerebral oedema. Water as an irrigant for TUR should be superseded by glycine 1,5%, which is safer.

  1. Influence of hyperpnea on airway surface fluid volume and osmolarity in normal humans.

    PubMed

    Kotaru, C; Hejal, Rana B; Finigan, J H; Coreno, A J; Skowronski, M E; Brianas, L J; McFadden, E R

    2002-07-01

    To determine the effect of hyperpnea on the characteristics of periciliary liquid, we collected airway surface fluid (ASF) and measured its osmolarity in 11 normal people while they breathed dry, frigid air (-17 +/- 1.2 degrees C) at minute ventilations (VE) of 10, 40, and 80 l/min through a heat exchanger. The ASF was collected at the fifth tracheal ring by absorption onto filter paper pledgets inserted via fiber-optic bronchoscopy. Hyperpnea had no influence on the amount of ASF recovered (ASF volume at a VE of 10 l/min = 12.0 +/- 2.0 microl; at 80 l/min = 8.8 +/- 1.5 microl; P = 0.28) or its osmolarity (at a VE of 10, 40, and 80 l/min = 326 +/- 15, 323 +/- 11, and 337 +/- 12 mosM, respectively; P = 0.65). These findings demonstrate that the tracheal mucosa of normal subjects does not dessicate during hyperpnea and that hypertonicity of the periciliary fluid does not develop even at high levels of ventilation.

  2. Increased osmolarity with low molecular weight solutes inhibits CTL-mediated cytotoxicity

    SciTech Connect

    Howcroft, T.K.; Lindquist, R.R.

    1986-03-01

    Sucrose induced hyperosmolarity, which has no effect on complement-mediated lysis, was examined for its effect on CTL-mediated cell lysis. Sucrose (0.15M) inhibited H-2/sup b/ anti-H-2/sup d/ PEL specific lysis, as measured by /sup 51/Cr-release, 82.7% (52 +/-1.4 vs. 9 +/- 0.6). The effect of sucrose on the killer cell independent phase was investigated by allowing the killers and targets to interact for 10 minutes at 37/sup 0/C, and then inactivating the killers by a 5 minute incubation at 44/sup 0/C before adjusting the osmolarity. Under these conditions killing was reduced 65.5% (58 +/- 0.5 vs. 20 +/- 0.8) when hit P815 target cells were incubated in 0.15M sucrose; thus indicating inhibition was at the level of the target cell. This effect was not limited to sucrose as Na/sub 2/SO/sub 4/ (.08M) also inhibited /sup 51/Cr-release. Nuclear fragmentation as indicated by release of incorporated /sup 3/H-thymidine also was inhibited in the presence of high osmolarity, although to a lesser extent, 34% (47 +/- 1.6 vs 31 +/- 0.6) after 40 minutes. These data suggest a surprising difference between poly C9 and CTL polyperforins, in light of their reported homologies.

  3. Treatment of Acidified Blood Using Reduced Osmolarity Mixed-Base Solutions

    PubMed Central

    Mason, Thomas G.; Kraut, Jeffrey A.

    2016-01-01

    We hypothesize that reduced osmolarity mixed-base (ROMB) solutions can potentially serve as customizable treatments for acidoses, going beyond standard solutions in clinical use, such as 1.0 M sodium bicarbonate. Through in silico quantitative modeling, by treating acidified canine blood using ROMB solutions, and by performing blood-gas and optical microscopy measurements in vitro, we demonstrate that ROMB solutions having a high proportion of a strong base, such as disodium carbonate or sodium hydroxide, can be effective in reducing carbon dioxide pressure PCO2 while raising pH and bicarbonate ion concentration without causing significant osmotic damage to red blood cells, which can occur during rapid administration of hypertonic solutions of weak bases. These results suggest that a ROMB solution, which is composed mostly of a strong base, could be administered in a safe and effective manner, when compared to a hypertonic solution of sodium bicarbonate. Because of the reduced osmolarity and the customizable content of strong base in ROMB solutions, this approach differs from prior approaches involving hypertonic solutions that only considered a single molar ratio of strong to weak base. Our calculations and measurements suggest that custom-tailored ROMB solutions merit consideration as potentially efficacious treatments for specific types of acidosis, particularly acute metabolic acidosis and acute respiratory acidosis. PMID:28082905

  4. Electrolytes, sugar, calories, osmolarity and pH of beverages and coconut water.

    PubMed

    Chavalittamrong, B; Pidatcha, P; Thavisri, U

    1982-09-01

    Oral rehydration has been recommended in patients with diarrhoea to replace fluid loss from the gastrointestinal tract and reduce the need for intravenous therapy. Beverages (i.e. Cola, Sprite etc.) and coconut water may be used as sources of oral fluid when glucose-electrolyte solution is not available. To evaluate the usefulness and effectiveness of these soft drinks, the basic data such as electrolytes, sugar, calories, osmolarity and pH were determined. The electrolytes of the beverages were significantly lower (p less than 0.001) than the coconut water, especially potassium. The osmolarity of the beverages, which were 693 mOsm/l, was significantly higher (p less than 0.001) than the coconut water (288 mOsm/l); pH of the beverages (3.1) was more acidic (p less than 0.001) than the coconut water (5.4). While the sugar content of the beverages, which were 8.7 gm/dl, was significantly higher (p less than 0.001) than the coconut water (1.1 gm/dl). On comparison, all brands of beverages would give more calories than the coconut water however the coconut water would be absorbed more easily than any brand of soft drink beverage.

  5. Comparison of tear osmolarity and ocular comfort between daily disposable contact lenses: hilafilcon B hydrogel versus narafilcon A silicone hydrogel.

    PubMed

    Sarac, Ozge; Gurdal, Canan; Bostancı-Ceran, Basak; Can, Izzet

    2012-06-01

    The aim of this study was to evaluate tear osmolarity and ocular comfort with two different types of hydrogel daily disposable lenses. The right eyes of 15 first-time contact lens users were included in this prospective study. All eyes wore hilafilcon B silicone hydrogel contact lenses for 8 h (group 1). After 1 week without contact lenses, all eyes wore narafilcon A silicone hydrogel contact lenses for 8 h (group 2). Tear osmolarity measurement was performed before and after 4 and 8 h of each contact lens wear. Ocular comfort was assessed after 4 and 8 h of each contact lens wear. In group 1, the mean baseline, 4- and 8-h tear osmolarity values were 293 ± 10.57, 303.00 ± 10.5 mOsm/L (p = 0.023), and 295.0 ± 1.4 mOsm/L (p > 0.05), respectively. In group 2, the mean baseline, 4- and 8-h tear osmolarity values were 294 ± 13.65, 300.9 ± 11.3 mOsm/L (p = 0.007), and 298.80 ± 7.2 mOsm/L (p > 0.05), respectively. In group 1, the mean comfort score was 7.20 ± 0.45 and 8.60 ± 0.45 at 4 and 8 h, respectively (p = 0.038). In group 2, the mean comfort score significantly decreased from 9.80 ± 0.45 to 7.80 ± 0.84 at 4 h (p = 0.039). Both hydrogel and silicone hydrogel daily disposable contact lenses elevated tear osmolarity during 8 h of contact lens wear. The increase in tear osmolarity with both contact lenses was below the cut-off value for dry eye and was not associated with ocular comfort.

  6. Turn-over of the small non-coding RNA RprA in E. coli is influenced by osmolarity.

    PubMed

    Madhugiri, Ramakanth; Basineni, Sobha Rani; Klug, Gabriele

    2010-10-01

    The sRNA RprA is known to activate rpoS translation in E. coli in an osmolarity-dependent manner. We asked whether RprA stability contributes to osmolarity-dependent regulation and how the RNA binding protein Hfq and the major E. coli endonucleases contribute to this turn-over. The study reveals that osmolarity-dependent turn-over of RprA indeed contributes to its osmolarity-dependent abundance. RprA is stabilized by the RNA chaperone Hfq and in absence of Hfq its turn-over is no longer osmolarity-dependent. The stability of the RprA target mRNA rpoS shows a lower extent of osmolarity dependence, which differs from the profile observed for RprA. Thus, the effect of sucrose is specific for individual RNAs. We can attribute a role of the endoribonuclease RNase E in turn-over of RprA and an indirect effect of the endoribonuclease III in vivo. In addition, RprA is stabilized by the presence of rpoS suggesting that hybrid formation with its target may protect it against ribonucleases. In vitro RprA is cleaved by the RNase E containing degradosome and by RNase III and rpoS interferes with RNase III cleavage. We also show that temperature affects the stabilities of the sRNAs binding to rpoS and of rpoS mRNA itself differentially and that higher stability of DsrA with decreasing temperature may contribute to its high abundance at lower temperatures. This study demonstrates that environmental parameters can affect the stability of sRNAs and consequently their abundance.

  7. Increased osmolarity and cell clustering preserve canine notochordal cell phenotype in culture.

    PubMed

    Spillekom, Sandra; Smolders, Lucas A; Grinwis, Guy C M; Arkesteijn, Irene T M; Ito, Keita; Meij, Björn P; Tryfonidou, Marianna A

    2014-08-01

    Degeneration of the intervertebral disc (IVD) is associated with a loss of notochordal cells (NCs) from the nucleus pulposus (NP) and their replacement by chondrocyte-like cells. NCs are known to maintain extracellular matrix quality and stimulate the chondrocyte-like NP cells, making NCs attractive for designing new tissue engineering approaches for IVD regeneration. However, optimal conditions, such as osmolarity and other characteristics of the culture media, for long-term culture of NCs are not known. The purpose of this study was to investigate the effects of different culture media and osmolarity on the physiology of NCs in vitro. NC clusters isolated from canine IVDs were suspended in alginate beads and cultured at 37°C under normoxic conditions for 28 days. Three different culture conditions were investigated; (1) Dulbecco's modified Eagle's medium (DMEM)/F12 (300 mOsm/L), (2) α-MEM (300 mOsm/L), and (3) α-MEM adjusted to 400 mOsm/L to mimic a hyperosmolar environment. NC morphology, expression of genes related to NC markers, matrix production and remodeling, and DNA- and glycosaminoglycan (GAG) analyses were performed on 1, 7, 14, and 28 days in culture. Large, vesicle-containing cells organized in clusters, characterized as NCs, remained present during 28 days for all culture conditions. However, the proportion of the NC clusters decreased over time, whereas the proportion of spindle-shaped cells increased. Gene expression profiling at 7, 14, and 28 days in culture compared to day 1 indicated a initial loss of NC phenotype followed by some recovery of brachyury and aggrecan gene expression after 28 days of culture supporting a potential recovery of NC phenotype. NCs cultured in α-MEM adjusted to 400 mOsm/L showed the highest gene expression of brachyury, cytokeratin 18, and aggrecan, the highest GAG production, and the lowest collagen 1α1 gene expression. In conclusion, NCs cultured in alginate in native cell clusters, partially retained their

  8. Osmolarity and spectrophotometric property of brilliant blue green define the degree of toxicity on retinal pigment epithelial cells exposed to surgical endoilluminator

    PubMed Central

    Balaiya, Sankarathi; Sambhav, Kumar; Cook, William B; Chalam, Kakarla V

    2016-01-01

    Objective To evaluate the effect of varying concentrations of brilliant blue green (BBG) and their different biochemical characteristics on retinal pigment epithelial (RPE) cells under xenon light source illumination at varying distances to identify safe parameters for intraoperative use. Methods Human retinal RPE cells (ARPE-19) were exposed to two concentrations (0.25 and 0.50 mg/mL) of BBG and illuminated with a xenon surgical illuminator at varying distances (10 and 25 mm), intensity levels, and time intervals (1, 5, and 15 minutes). Additionally, the effect of osmolarity was examined by diluting BBG in different concentrations of glucose. Cytotoxicity of BBG and osmolarity effects on cell viability were evaluated using a WST-1 assay. Light absorption and emission characteristic of BBG in different solvents were measured using a plate reader at different wavelengths. Lastly, the activity of caspase-3 was also studied. Results Cell viability of ARPE-19 cells was 77.4%±12.7%, 78.7%±17.0%, and 65.0%±19.7% at 1, 5, and 15 minutes to exposure of high illumination xenon light at 10 mm (P<0.05) compared to controls. At both distances of illumination (10 and 25 mm), similar cell viabilities were seen between 1 and 5 minutes of exposure. However, there was a decline in viability when the illumination was carried out to 15 minutes in all groups (P<0.05). There was no significant reduction in cell viability in presence or absence of xenon light in different osmolar solutions concentrations of glucose (P>0.05). Maximal light absorption of BBG was noted between 540 and 680 nm. Activated caspase-3 level was not significant in both the concentrations of BBG (P>0.05). Conclusion Our findings suggest that BBG at 0.25 mg/mL during vitreoretinal surgery is safe and not toxic to RPE cells up to 5 minutes under focal high illumination (10 mm) and up to 15 minutes under medium diffuse illumination (25 mm). BBG was safe to be mixed with isotonic glucose solution at the

  9. TolC promotes ExPEC biofilm formation and curli production in response to medium osmolarity.

    PubMed

    Hou, Bo; Meng, Xian-Rong; Zhang, Li-Yuan; Tan, Chen; Jin, Hui; Zhou, Rui; Gao, Jian-Feng; Wu, Bin; Li, Zi-Li; Liu, Mei; Chen, Huan-Chun; Bi, Ding-Ren; Li, Shao-Wen

    2014-01-01

    While a high osmolarity medium activates Cpx signaling and causes CpxR to repress csgD expression, and efflux protein TolC protein plays an important role in biofilm formation in Escherichia coli, whether TolC also responds to an osmolarity change to regulate biofilm formation in extraintestinal pathogenic E. coli (ExPEC) remains unknown. In this study, we constructed ΔtolC mutant and complement ExPEC strains to investigate the role of TolC in the retention of biofilm formation and curli production capability under different osmotic conditions. The ΔtolC mutant showed significantly decreased biofilm formation and lost the ability to produce curli fimbriae compared to its parent ExPEC strain PPECC42 when cultured in M9 medium or 1/2 M9 medium of increased osmolarity with NaCl or sucrose at 28°C. However, biofilm formation and curli production levels were restored to wild-type levels in the ΔtolC mutant in 1/2 M9 medium. We propose for the first time that TolC protein is able to form biofilm even under high osmotic stress. Our findings reveal an interplay between the role of TolC in ExPEC biofilm formation and the osmolarity of the surrounding environment, thus providing guidance for the development of a treatment for ExPEC biofilm formation.

  10. Zinc and low osmolarity oral rehydration salts for diarrhoea: a renewed call to action

    PubMed Central

    Fontaine, Olivier; Young, Mark W; Black, Robert E

    2009-01-01

    Abstract In 2004, WHO and the United Nations Children’s Fund (UNICEF) released a joint statement recommending a new lower osmolarity oral rehydration salts (ORS) formulation and zinc supplementation for diarrhoea management. More than 5 years later, diarrhoea remains the second leading cause of death and few children in developing countries are receiving these life-saving interventions. Many countries are stalled in the technicalities of adapting national policy, while others struggle to find the funds for start-up activities. For nearly all countries, zinc supplements for children are not available locally; thus, zinc procurement continues to be a major obstacle. Global resources have not been sufficient to bring diarrhoea management to the forefront; thus, the introduction of these new recommendations has remained slow. Revitalizing diarrhoea management must become an international priority if we are going to reduce the burden of diarrhoea deaths and overall child mortality around the world. PMID:19876545

  11. Inflammatory cytokine and osmolarity changes in the tears of dry eye patients treated with topical 1% methylprednisolone.

    PubMed

    Lee, Ji Hwan; Min, Kyung; Kim, Se Kyung; Kim, Eung Kweon; Kim, Tae-im

    2014-01-01

    To evaluate changes in clinical outcomes, inflammatory cytokine levels, and tear osmolarity in the tears of patients with moderate to severe dry eye syndrome before and after the application of topical 1% methylprednisolone. Thirty-two patients with moderate to severe dry eye unresponsive to previous aqueous enhancement therapy were enrolled. Five patients were lost to follow up, and twenty-seven patients were eligible for analysis. Patients were instructed to apply topical 1% methylprednisolone four times per day, as well as to continue applying their current therapy of preservative-free 0.1% sodium hyaluronate four times per day. Corneal and conjunctival staining scores, tear film breakup time (TFBUT), Schirmer test, and tear osmolarity were assessed at baseline, 4 weeks, and 8 weeks. Tear samples were collected at every visit for cytokine analysis. Corneal and conjunctival staining scores and TFBUT showed significant improvement at 4 (p<0.001, <0.001, <0.001 respectively) and 8 (p<0.001, <0.001, <0.001 respectively) weeks. Tear osmolarity decreased significantly at 8 weeks (p=0.008). Interleukin (IL)-1β, IL-8, and monocyte chemoattractant protein-1 were significantly decreased at 8 weeks compared with those at baseline (p=0.041, 0.001, 0.008 respectively). Short-term treatment with topical 1% methylprednisolone not only improved clinical outcomes, but also decreased tear osmolarity and cytokine levels. By measuring the changes in cytokine levels and tear osmolarity, we could objectively evaluate the anti-inflammatory effects of topical methylprednisolone applied in the treatment of patients with moderate to severe dry eye syndrome.

  12. A meta-analysis of the renal safety of isosmolar iodixanol compared with low-osmolar contrast media.

    PubMed

    McCullough, Peter A; Bertrand, Michel E; Brinker, Jeffrey A; Stacul, Fulvio

    2006-08-15

    We sought to compare the nephrotoxicity of isosmolar contrast medium (IOCM) iodixanol with low-osmolar contrast media (LOCM) and to identify predictors of contrast-induced nephropathy (CIN). Contrast-induced nephropathy is a serious complication of diagnostic and interventional procedures. Pooled individual patient data (n = 2,727) from 16 double-blind, randomized, controlled trials in which patients received either intra-arterial IOCM iodixanol (n = 1,382) or LOCM (n = 1,345) were included. Patients were stratified according to chronic kidney disease (CKD), diabetes mellitus (DM), or both. Outcome measures were the maximum increase in serum creatinine (Cr) over baseline and the incidence of postprocedural CIN. The maximum Cr increase within 3 days after contrast medium (CM) administration was significantly smaller in the iodixanol group compared with the LOCM group (0.06 mg/dl vs. 0.10 mg/dl, p < 0.001), particularly in patients with CKD (0.07 mg/dl vs. 0.16 mg/dl, p = 0.004) and CKD + DM (0.10 mg/dl vs. 0.33 mg/dl, p = 0.003). Contrast-induced nephropathy, defined as an increase in Cr > or =0.50 mg/dl within 3 days after CM administration, occurred less frequently in the iodixanol group than in the LOCM group in all patients (1.4% vs. 3.5%, p < 0.001), in CKD patients (2.8% vs. 8.4%, p = 0.001), and in CKD + DM patients (3.5% vs. 15.5%, p = 0.003). Independent predictors of CIN included CKD, CKD + DM, and use of LOCM. This meta-analysis of pooled data from 2,727 patients indicates that use of the IOCM iodixanol is associated with smaller rises in Cr and lower rates of CIN than LOCM, especially in patients with CKD or CKD + DM.

  13. Corneal thickness changes during corneal collagen cross-linking with UV-A irradiation and hypo-osmolar riboflavin in thin corneas.

    PubMed

    Nassaralla, Belquiz Amaral; Vieira, Diogo Mafia; Machado, Márcia Leite; Figueiredo, Marisa Novaes Faleiro Chaves de; Nassaralla, João Jorge

    2013-01-01

    To evaluate the thinnest corneal thickness changes during and after corneal collagen cross-linking treatment with ultraviolet-A irradiation, using hypo-osmolar riboflavin solution in thin corneas. Eighteen eyes of 18 patients were included in this study. After epithelium removal, iso-osmolar 0.1% riboflavin solution was instilled to the cornea every 3 minutes for 30 minutes. Hypo-osmolar 0.1% riboflavin solution was then applied every 20 seconds for 5 minutes or until the thinnest corneal thickness reached 400 µm. Ultraviolet-A irradiation was performed for 30 minutes. During irradiation, iso-osmolar 0.1% riboflavin drops were applied every 5 minutes. Ultrasound pachymetry was performed at approximately the thinnest point of the cornea preoperatively, after epithelial removal, after iso-osmolar riboflavin instillation, after hypo-osmolar riboflavin instillation, after ultraviolet-A irradiation, and at 1, 6 and 12 months after treatment. Mean preoperative thinnest corneal thickness was 380 ± 11 µm. After epithelial removal it decreased to 341 ± 11 µm, and after 30 minutes of iso-osmolar 0.1% riboflavin drops, to 330 ± 7.6 µm. After hypo-osmolar 0.1% riboflavin drops, mean thinnest corneal thickness increased to 418 ± 11 µm. After UVA irradiation, it was 384 ± 10 µm. At 1, 6 and 12 months after treatment, it was 372 ± 10 µm, 381 ± 12.7, and 379 ± 15 µm, respectively. No intraoperative, early postoperative, or late postoperative complications were noted. Hypo-osmolar 0.1% riboflavin solution seems to be effective for swelling thin corneas. The swelling effect is transient and short acting. Corneal thickness should be monitored throughout the procedure. Larger sample sizes and longer follow-up are required in order to make meaningful conclusions regarding safety.

  14. Direct and Osmolarity-Dependent Effects of Glycine on Preimplantation Bovine Embryos

    PubMed Central

    Lyons, Sarah M.; Greene, Alison F.; Broeckling, Corey D.; Schoolcraft, William B.; Krisher, Rebecca L.

    2016-01-01

    Concentrations of glycine (Gly) in embryo culture media are often lower (~0.1 mM) than those in oviductal or uterine fluids (≥1.2 mM). The objective of this study was to determine direct and osmolarity-dependent effects of physiological concentrations of Gly on blastocyst formation and hatching, cell allocation to the trophectoderm (TE) and inner cell mass (ICM), and metabolic activity of bovine embryos. In experiment 1, zygotes were cultured with 100 or 120 mM NaCl and 0 or 1 mM Gly for the first 72 h of culture. Blastocyst formation and hatching were improved (P<0.05) when embryos were cultured with 100 compared to 120 mM NaCl. Inclusion of 1 mM Gly improved (P<0.05) blastocyst formation compared to 0 mM Gly, but this effect was only significant (P<0.05) for embryos cultured with 120 mM NaCl, suggesting bovine embryos can utilize Gly as an osmolyte. In experiment 2, embryos were cultured with 0.1, 1.1, 2.1, or 4.1 mM Gly (100 mM NaCl) for the final 96 h of culture. Blastocyst development was not affected (P>0.05) by Gly, but hatching (0.1 mM Gly, 18.2%) was improved (P<0.05) when embryos were cultured with 1.1 (31.4%) or 2.1 (29.4%) mM Gly. Blastocyst, TE, and ICM cell numbers were not affected (P>0.05) by Gly in either experiment. Blastocysts produced alanine, glutamine, pyruvate, and urea and consumed aspartate, but this metabolic profile was not affected (P>0.05) by Gly. In conclusion, Gly (1.0 mM) improves the development of both early and late stage embryos, but beneficial effects are more pronounced for early embryos exposed to elevated osmolarity. PMID:27459477

  15. CpxR/OmpR Interplay Regulates Curli Gene Expression in Response to Osmolarity in Escherichia coli

    PubMed Central

    Jubelin, Gregory; Vianney, Anne; Beloin, Christophe; Ghigo, Jean-Marc; Lazzaroni, Jean-Claude; Lejeune, Philippe; Dorel, Corinne

    2005-01-01

    Curli fibers could be described as a virulence factor able to confer adherence properties to both abiotic and eukaryotic surfaces. The ability to adapt rapidly to changing environmental conditions through signal transduction pathways is crucial for the growth and pathogenicity of bacteria. OmpR was shown to activate csgD expression, resulting in curli production. The CpxR regulator was shown to negatively affect curli gene expression when binding to its recognition site that overlaps the csgD OmpR-binding site. This study was undertaken to clarify how the interplay between the two regulatory proteins, OmpR and CpxR, can affect the transcription of the curli gene in response to variation of the medium osmolarity. Band-shift assays with purified CpxR proteins indicate that CpxR binds to the csgD promoter region at multiple sites that are ideally positioned to explain the csg repression activity of CpxR. To understand the physiological meaning of this in vitro molecular phenomenon, we analyzed the effects of an osmolarity shift on the two-component pathway CpxA/CpxR. We establish here that the Cpx pathway is activated at both transcriptional and posttranscriptional levels in response to a high osmolarity medium and that CpxR represses csgD expression in high-salt-content medium, resulting in low curli production. However, csgD repression in response to high sucrose content is not mediated by CpxR but by the global regulatory protein H-NS. Therefore, multiple systems (EnvZ/OmpR, Cpx, Rcs, and H-NS) appear to be involved in sensing environmental osmolarity, leading to sophisticated regulation of the curli genes. PMID:15743952

  16. CpxR/OmpR interplay regulates curli gene expression in response to osmolarity in Escherichia coli.

    PubMed

    Jubelin, Gregory; Vianney, Anne; Beloin, Christophe; Ghigo, Jean-Marc; Lazzaroni, Jean-Claude; Lejeune, Philippe; Dorel, Corinne

    2005-03-01

    Curli fibers could be described as a virulence factor able to confer adherence properties to both abiotic and eukaryotic surfaces. The ability to adapt rapidly to changing environmental conditions through signal transduction pathways is crucial for the growth and pathogenicity of bacteria. OmpR was shown to activate csgD expression, resulting in curli production. The CpxR regulator was shown to negatively affect curli gene expression when binding to its recognition site that overlaps the csgD OmpR-binding site. This study was undertaken to clarify how the interplay between the two regulatory proteins, OmpR and CpxR, can affect the transcription of the curli gene in response to variation of the medium osmolarity. Band-shift assays with purified CpxR proteins indicate that CpxR binds to the csgD promoter region at multiple sites that are ideally positioned to explain the csg repression activity of CpxR. To understand the physiological meaning of this in vitro molecular phenomenon, we analyzed the effects of an osmolarity shift on the two-component pathway CpxA/CpxR. We establish here that the Cpx pathway is activated at both transcriptional and posttranscriptional levels in response to a high osmolarity medium and that CpxR represses csgD expression in high-salt-content medium, resulting in low curli production. However, csgD repression in response to high sucrose content is not mediated by CpxR but by the global regulatory protein H-NS. Therefore, multiple systems (EnvZ/OmpR, Cpx, Rcs, and H-NS) appear to be involved in sensing environmental osmolarity, leading to sophisticated regulation of the curli genes.

  17. High Osmolarity Environments Activate the Mitochondrial Alternative Oxidase in Debaryomyces Hansenii

    PubMed Central

    Garcia-Neto, Wilson; Cabrera-Orefice, Alfredo; Uribe-Carvajal, Salvador; Kowaltowski, Alicia J.; Alberto Luévano-Martínez, Luis

    2017-01-01

    The oleaginous yeast Debaryomyces hansenii is a good model to understand molecular mechanisms involved in halotolerance because of its impressive ability to survive under a wide range of salt concentrations. Several cellular adaptations are implicated in this response, including the presence of a cyanide-insensitive ubiquinol oxidase (Aox). This protein, which is present in several taxonomical orders, has been related to different stress responses. However, little is known about its role in mitochondria during transitions from low to high saline environments. In this report, we analyze the effects of Aox in shifts from low to high salt concentrations in the culture media. At early stages of a salt insult, we observed that this protein prevents the overflow of electrons on the mitochondrial respiratory chain, thus, decreasing the production of reactive oxygen species. Interestingly, in the presence of high osmolite concentrations, Aox activity is able to sustain a stable membrane potential when coupled to complex I, despite a compromised cytochrome pathway. Taken together, our results suggest that under high osmolarity conditions Aox plays a critical role regulating mitochondrial physiology. PMID:28060946

  18. Hyper-osmolarity and calcium chelation: Effects on cystic fibrosis mucus.

    PubMed

    Ermund, Anna; Meiss, Lauren N; Gustafsson, Jenny K; Hansson, Gunnar C

    2015-10-05

    A non-functional Cystic Fibrosis Transmembrane conductance Regulator (CFTR) leads to the disease cystic fibrosis (CF). Although the CFTR is expressed in multiple organs, pulmonary disease is the major cause of illness and death in patients with CF. Stagnant mucus, causing airway obstruction, bacterial overgrowth, persistent inflammation and tissue destruction characterizes the disease, but how the defect in CFTR function is coupled to the mucus phenotype is still controversial. We have recently shown that bicarbonate ions passing through CFTR are necessary for proper unfolding of the MUC2 mucin, thus highlighting the importance of bicarbonate ion transport via the CFTR and the ability of these ions to raise the pH and chelate calcium bound to the mucin as the important steps in forming normal mucus. In order to find potential CF treatments and expand our knowledge about the usefulness of bicarbonate as an active ingredient in formulations to alleviate mucus plugging, we used an Ussing-type chamber and explants from the F508del-CFTR mutant mouse ileum to test the effect of calcium chelators on mucus attachment, either in isolation or in combination with osmolytes such as mannitol or hypertonic saline. We found that increasing the concentration of bicarbonate, both alone or in combination with increased osmolarity of the solution, detached the otherwise attached CF mucus.

  19. Effects of osmolarity change on the excitation-contraction coupling of bullfrog ventricle.

    PubMed

    Kawata, H; Kawagoe, K; Tateyama, I

    1974-12-01

    The effect of hyper- and hypotonic solutions on the electrical as well as the mechanical activities of the bullfrog ventricle were investigated. Hypertonic solutions up to 400% tonicity, made by adding sucrose, showed two kinds of inhibitory effect; i.e. a consistent, rapid shortening of the action potential duration and a slowly progressing suppression of contractile tension. The inhibitory effect of the hypertonic solution up to 300%, made by adding NaCl, was more pronounced on the contractile process than on the electrical phenomena. In this condition, the inhibition of the twitch tension occurred with two time constants. The first, rapid decline seems to be related to the suppressive effect on some superficial site while the slower decreasing phase showed a similar time course as the development of contracture. Hypotonic (33.3% and 12.5%) perfusion revealed triphasic changes in the time course of single twitch without accompanying any parallel change in the action potential. From these results it was concluded that the bullfrog ventricular muscle has some superficial site for Ca regulation which is very sensitive to osmolarity change.

  20. A role of ionic strength on the inotropic effects of osmolarity change in frog atrium.

    PubMed

    Ohba, M

    1984-01-01

    The influence of varying the ionic strength of the bathing solution on the contraction of chemically skinned frog atrial muscle fibers was studied. The rate of tension development activated by calcium slows as the ionic strength is elevated. The size of caffeine contracture, however, was larger in the fiber preloaded with calcium at a higher ionic strength. There was a decrease in the maintained tension at 10(-6) M Ca when a fiber was bathed in a high ionic strength solution. Returning to a normal ionic strength solution caused a transient tension increase. When the fiber was bathed in a low ionic strength solution, the maintained tension increased transiently to a high value and then declined to reach a plateau. The response was also observed in a solution of pCa 8. In the caffeine-treated fiber or in the fiber bathed in ATP free solution, although the maintained tension level was changed corresponding to the altered ionic strength, the transient responses were blocked. These responses were not much influenced by the kinds of salts used to change the ionic strength. When osmolarity of the medium was altered by sucrose, transient responses were not induced. The results could qualitatively explain the isometric tension change of an intact fiber of frog atrium bathed in a hyper- or hypotonic solution.

  1. Determining equilibrium osmolarity in poly(ethylene glycol)/chondrotin sulfate gels mimicking articular cartilage.

    PubMed

    Sircar, S; Aisenbrey, E; Bryant, S J; Bortz, D M

    2015-01-07

    We present an experimentally guided, multi-phase, multi-species polyelectrolyte gel model to make qualitative predictions on the equilibrium electro-chemical properties of articular cartilage. The mixture theory consists of two different types of polymers: poly(ethylene gylcol) (PEG), chondrotin sulfate (ChS), water (acting as solvent) and several different ions: H(+), Na(+), Cl(-). The polymer chains have covalent cross-links whose effect on the swelling kinetics is modeled via Doi rubber elasticity theory. Numerical studies on equilibrium polymer volume fraction and net osmolarity (difference in the solute concentration across the gel) show a complex interplay between ionic bath concentrations, pH, cross-link fraction and the average charge per monomer. Generally speaking, swelling is aided due to a higher average charge per monomer (or a higher particle fraction of ChS, the charged component of the polymer), low solute concentration in the bath, a high pH or a low cross-link fraction. A peculiar case arises at higher values of cross-link fraction, where it is observed that increasing the average charge per monomer leads to gel deswelling.

  2. Sorbic acid stress activates the Candida glabrata high osmolarity glycerol MAP kinase pathway

    PubMed Central

    Jandric, Zeljkica; Gregori, Christa; Klopf, Eva; Radolf, Martin; Schüller, Christoph

    2013-01-01

    Weak organic acids such as sorbic acid are important food preservatives and powerful fungistatic agents. These compounds accumulate in the cytosol and disturb the cellular pH and energy homeostasis. Candida glabrata is in many aspects similar to Saccharomyces cerevisiae. However, with regard to confrontation to sorbic acid, two of the principal response pathways behave differently in C. glabrata. In yeast, sorbic acid stress causes activation of many genes via the transcription factors Msn2 and Msn4. The C. glabrata homologs CgMsn2 and CgMsn4 are apparently not activated by sorbic acid. In contrast, in C. glabrata the high osmolarity glycerol (HOG) pathway is activated by sorbic acid. Here we show that the MAP kinase of the HOG pathway, CgHog1, becomes phosphorylated and has a function for weak acid stress resistance. Transcript profiling of weak acid treated C. glabrata cells suggests a broad and very similar response pattern of cells lacking CgHog1 compared to wild type which is over lapping with but distinct from S. cerevisiae. The PDR12 gene was the highest induced gene in both species and it required CgHog1 for full expression. Our results support flexibility of the response cues for general stress signaling pathways, even between closely related yeasts, and functional extension of a specific response pathway. PMID:24324463

  3. Effect of fluid countermeasures of varying osmolarity on cardiovascular responses to orthostatic stress

    NASA Technical Reports Server (NTRS)

    Davis, John E.

    1989-01-01

    Current operational procedures for shuttle crewmembers include the ingestion of a fluid countermeasure approximately 2 hours before reentry into the earth's gravitational field. The ingestion of the fluid countermeasure is thought to restore plasma volume and improve orthostatic responses upon reentry. The present countermeasure consists of ingesting salt tablets and water to achieve an isotonic solution. It has yet to be determined whether this is the optimal drink to restore orthostatic tolerance. It is also not known whether the drink solution is effective in increasing plasma volume. The purpose here is to evaluate the effectiveness of drink solutions of different osmolarity on restoring plasma volume and orthostatic responses. A hypertonic drink solution was more effective in restoring plasma volume after dehydration than an isotonic solution. However, there were no differences in their effects on an orthostatic challenge. These data suggest that the plasma volume differences produced in this study were not sufficient to produce differences in the cardiovascular responses to an orthostatic challenge, or there are other changes that occur during space flight that are more important in determining orthostatic intolerance.

  4. High Osmolarity Environments Activate the Mitochondrial Alternative Oxidase in Debaryomyces Hansenii.

    PubMed

    Garcia-Neto, Wilson; Cabrera-Orefice, Alfredo; Uribe-Carvajal, Salvador; Kowaltowski, Alicia J; Alberto Luévano-Martínez, Luis

    2017-01-01

    The oleaginous yeast Debaryomyces hansenii is a good model to understand molecular mechanisms involved in halotolerance because of its impressive ability to survive under a wide range of salt concentrations. Several cellular adaptations are implicated in this response, including the presence of a cyanide-insensitive ubiquinol oxidase (Aox). This protein, which is present in several taxonomical orders, has been related to different stress responses. However, little is known about its role in mitochondria during transitions from low to high saline environments. In this report, we analyze the effects of Aox in shifts from low to high salt concentrations in the culture media. At early stages of a salt insult, we observed that this protein prevents the overflow of electrons on the mitochondrial respiratory chain, thus, decreasing the production of reactive oxygen species. Interestingly, in the presence of high osmolite concentrations, Aox activity is able to sustain a stable membrane potential when coupled to complex I, despite a compromised cytochrome pathway. Taken together, our results suggest that under high osmolarity conditions Aox plays a critical role regulating mitochondrial physiology.

  5. Hyper-osmolarity and calcium chelation: Effects on cystic fibrosis mucus

    PubMed Central

    Ermund, Anna; Meiss, Lauren N.; Gustafsson, Jenny K.; Hansson, Gunnar C.

    2015-01-01

    A non-functional Cystic Fibrosis Transmembrane conductance Regulator (CFTR) leads to the disease cystic fibrosis (CF). Although the CFTR is expressed in multiple organs, pulmonary disease is the major cause of illness and death in patients with CF. Stagnant mucus, causing airway obstruction, bacterial overgrowth, persistent inflammation and tissue destruction characterizes the disease, but how the defect in CFTR function is coupled to the mucus phenotype is still controversial. We have recently shown that bicarbonate ions passing through CFTR are necessary for proper unfolding of the MUC2 mucin, thus highlighting the importance of bicarbonate ion transport via the CFTR and the ability of these ions to raise the pH and chelate calcium bound to the mucin as the important steps in forming normal mucus. In order to find potential CF treatments and expand our knowledge about the usefulness of bicarbonate as an active ingredient in formulations to alleviate mucus plugging, we used an Ussing-type chamber and explants from the F508del-CFTR mutant mouse ileum to test the effect of calcium chelators on mucus attachment, either in isolation or in combination with osmolytes such as mannitol or hypertonic saline. We found that increasing the concentration of bicarbonate, both alone or in combination with increased osmolarity of the solution, detached the otherwise attached CF mucus. PMID:26134505

  6. Actin-myosin network influences morphological response of neuronal cells to altered osmolarity.

    PubMed

    Bober, Brian G; Love, James M; Horton, Steven M; Sitnova, Mariya; Shahamatdar, Sina; Kannan, Ajay; Shah, Sameer B

    2015-04-01

    Acute osmotic fluctuations in the brain occur during a number of clinical conditions and can result in a variety of adverse neurological symptoms. Osmotic perturbation can cause changes in the volumes of intra- and extracellular fluid and, due to the rigidity of the skull, can alter intracranial pressure thus making it difficult to analyze purely osmotic effects in vivo. The present study aims to determine the effects of changes in osmolarity on SH-SY5Y human neuroblastoma cells in vitro, and the role of the actin-myosin network in regulating this response. Cells were exposed to hyper- or hypoosmotic media and morphological and cytoskeletal responses were recorded. Hyperosmotic shock resulted in a drop in cell body volume and planar area, a persisting shape deformation, and increases in cellular translocation. Hypoosmotic shock did not significantly alter planar area, but caused a transient increase in cell body volume and an increase in cellular translocation via the development of small protrusions rich in actin. Disruption of the actin-myosin network with latrunculin and blebbistatin resulted in changes to volume and shape regulation, and a decrease in cellular translocation. In both osmotic perturbations, no apparent disruptions to cytoskeletal integrity were observed by light microscopy. Overall, because osmotically induced changes persisted even after volume regulation occurred, it is possible that osmotic stress may play a larger role in neurological dysfunction than currently believed.

  7. Computation of the excess glucose and Na deficit of hypo-osmolar hyponatremic hyperglycaemia.

    PubMed

    Bartoli, Ettore; Sainaghi, Pier Paolo; Bergamasco, Luca; Castello, Luigi

    2010-06-01

    Exact computations of glucose accumulation (GA, mM) and Na anions deficit (DeltaNa, mEq) can be obtained in hypo-osmolar hyponatremic hyperglycaemia (HHH), where plasma osmolality (POsm) is lower than normal. In this condition, GA - DeltaNa = POsm x TBW (total body water). GA is given by plasma glucose concentration (PG(1)) times extra-cellular volume (ECV), calculated as TBW - ICV (the known intra-cellular volume). The changes in solute content can then be computed from their concentrations. This model was verified on computer-simulated patients to whom GA was added in variable amounts, lower than those of DeltaNa subtracted, generating known ICV, ECV, PNa(1), and PG(1). True computer-generated values were identical (the correlation coefficient R(2) = 1, p < 0.0001) to those computed from solute concentrations with our formulas. These same calculations were applied to patients with HHH, using exclusively the measured PNa(1) and PG(1) to compute solute and solvent changes. The results were significantly correlated to true data obtained by balance studies (R(2) = 0.89, p < 0.001). The mathematical model correctly computes DeltaNa and GA in HHH, where patients can therefore benefit from accurate replacement strategies.

  8. Activation of the Saccharomyces cerevisiae filamentation/invasion pathway by osmotic stress in high-osmolarity glycogen pathway mutants

    NASA Technical Reports Server (NTRS)

    Davenport, K. D.; Williams, K. E.; Ullmann, B. D.; Gustin, M. C.; McIntire, L. V. (Principal Investigator)

    1999-01-01

    Mitogen-activated protein kinase (MAPK) cascades are frequently used signal transduction mechanisms in eukaryotes. Of the five MAPK cascades in Saccharomyces cerevisiae, the high-osmolarity glycerol response (HOG) pathway functions to sense and respond to hypertonic stress. We utilized a partial loss-of-function mutant in the HOG pathway, pbs2-3, in a high-copy suppressor screen to identify proteins that modulate growth on high-osmolarity media. Three high-copy suppressors of pbs2-3 osmosensitivity were identified: MSG5, CAK1, and TRX1. Msg5p is a dual-specificity phosphatase that was previously demonstrated to dephosphorylate MAPKs in yeast. Deletions of the putative MAPK targets of Msg5p revealed that kss1delta could suppress the osmosensitivity of pbs2-3. Kss1p is phosphorylated in response to hyperosmotic shock in a pbs2-3 strain, but not in a wild-type strain nor in a pbs2-3 strain overexpressing MSG5. Both TEC1 and FRE::lacZ expressions are activated in strains lacking a functional HOG pathway during osmotic stress in a filamentation/invasion-pathway-dependent manner. Additionally, the cellular projections formed by a pbs2-3 mutant on high osmolarity are absent in strains lacking KSS1 or STE7. These data suggest that the loss of filamentation/invasion pathway repression contributes to the HOG mutant phenotype.

  9. Activation of the Saccharomyces cerevisiae filamentation/invasion pathway by osmotic stress in high-osmolarity glycogen pathway mutants

    NASA Technical Reports Server (NTRS)

    Davenport, K. D.; Williams, K. E.; Ullmann, B. D.; Gustin, M. C.; McIntire, L. V. (Principal Investigator)

    1999-01-01

    Mitogen-activated protein kinase (MAPK) cascades are frequently used signal transduction mechanisms in eukaryotes. Of the five MAPK cascades in Saccharomyces cerevisiae, the high-osmolarity glycerol response (HOG) pathway functions to sense and respond to hypertonic stress. We utilized a partial loss-of-function mutant in the HOG pathway, pbs2-3, in a high-copy suppressor screen to identify proteins that modulate growth on high-osmolarity media. Three high-copy suppressors of pbs2-3 osmosensitivity were identified: MSG5, CAK1, and TRX1. Msg5p is a dual-specificity phosphatase that was previously demonstrated to dephosphorylate MAPKs in yeast. Deletions of the putative MAPK targets of Msg5p revealed that kss1delta could suppress the osmosensitivity of pbs2-3. Kss1p is phosphorylated in response to hyperosmotic shock in a pbs2-3 strain, but not in a wild-type strain nor in a pbs2-3 strain overexpressing MSG5. Both TEC1 and FRE::lacZ expressions are activated in strains lacking a functional HOG pathway during osmotic stress in a filamentation/invasion-pathway-dependent manner. Additionally, the cellular projections formed by a pbs2-3 mutant on high osmolarity are absent in strains lacking KSS1 or STE7. These data suggest that the loss of filamentation/invasion pathway repression contributes to the HOG mutant phenotype.

  10. Activation of the Saccharomyces cerevisiae filamentation/invasion pathway by osmotic stress in high-osmolarity glycogen pathway mutants.

    PubMed Central

    Davenport, K D; Williams, K E; Ullmann, B D; Gustin, M C

    1999-01-01

    Mitogen-activated protein kinase (MAPK) cascades are frequently used signal transduction mechanisms in eukaryotes. Of the five MAPK cascades in Saccharomyces cerevisiae, the high-osmolarity glycerol response (HOG) pathway functions to sense and respond to hypertonic stress. We utilized a partial loss-of-function mutant in the HOG pathway, pbs2-3, in a high-copy suppressor screen to identify proteins that modulate growth on high-osmolarity media. Three high-copy suppressors of pbs2-3 osmosensitivity were identified: MSG5, CAK1, and TRX1. Msg5p is a dual-specificity phosphatase that was previously demonstrated to dephosphorylate MAPKs in yeast. Deletions of the putative MAPK targets of Msg5p revealed that kss1delta could suppress the osmosensitivity of pbs2-3. Kss1p is phosphorylated in response to hyperosmotic shock in a pbs2-3 strain, but not in a wild-type strain nor in a pbs2-3 strain overexpressing MSG5. Both TEC1 and FRE::lacZ expressions are activated in strains lacking a functional HOG pathway during osmotic stress in a filamentation/invasion-pathway-dependent manner. Additionally, the cellular projections formed by a pbs2-3 mutant on high osmolarity are absent in strains lacking KSS1 or STE7. These data suggest that the loss of filamentation/invasion pathway repression contributes to the HOG mutant phenotype. PMID:10545444

  11. Are there any differences in acute adverse reactions among five low-osmolar non-ionic iodinated contrast media?

    PubMed

    Gomi, Tatsuya; Nagamoto, Masashi; Hasegawa, Makoto; Katoh, Asako; Sugiyama, Miki; Murata, Nozomu; Kunihiro, Toshiyuki; Kohda, Ehiichi

    2010-07-01

    The differences regarding adverse reactions in different low-osmolar non-ionic contrast media had not been investigated previously. Thus, the aims of this study were to identify differences in the incidence of adverse reactions in five different low-osmolar non-ionic contrast media. We prospectively recorded all adverse events associated with five different low-osmolar non-ionic contrast media used in 8,931 consecutive patients for CT. Patients were randomly assigned to five groups: iomeprol 300 mgI/ml, iopamidol 300 mgI/ml, iohexol 300 mgI/ml, iopromide 300 mgI/ml and ioversol 320 mgI/ml. Adverse events were observed in 241 patients (2.7%). The incidence of acute adverse reactions was significantly higher in the following groups: (1) iomeprol (3.9%) and iopromide (3.5%) groups, (2) patients aged 59 years or less (4.5%) compared with those aged 60 years or over (1.9%), (3) the first period (3.5%) compared with the late period (2.3%), (4) those with a past history of adverse reactions to contrast media (11.2%), and (5) patients receiving contrast media for the first time (3.3%) compared with those had received it previously (2.0%). The incidence of acute adverse reactions may be reduced in younger patients by using iopamidol, iohexol and ioversol.

  12. Inhibition of succinic acid production in metabolically engineered Escherichia coli by neutralizing agent, organic acids, and osmolarity.

    PubMed

    Andersson, Christian; Helmerius, Jonas; Hodge, David; Berglund, Kris A; Rova, Ulrika

    2009-01-01

    The economical viability of biochemical succinic acid production is a result of many processing parameters including final succinic acid concentration, recovery of succinate, and the volumetric productivity. Maintaining volumetric productivities >2.5 g L(-1) h(-1) is important if production of succinic acid from renewable resources should be competitive. In this work, the effects of organic acids, osmolarity, and neutralizing agent (NH4OH, KOH, NaOH, K2CO3, and Na2CO3), and Na2CO3) on the fermentative succinic acid production by Escherichia coli AFP184 were investigated. The highest concentration of succinic acid, 77 g L(-1), was obtained with Na2CO3. In general, irrespective of the base used, succinic acid productivity per viable cell was significantly reduced as the concentration of the produced acid increased. Increased osmolarity resulting from base addition during succinate production only marginally affected the productivity per viable cell. Addition of the osmoprotectant glycine betaine to cultures resulted in an increased aerobic growth rate and anaerobic glucose consumption rate, but decreased succinic acid yield. When using NH4OH productivity completely ceased at a succinic acid concentration of approximately 40 g L(-1). Volumetric productivities remained at 2.5 g L(-1) h(-1) for up to 10 h longer when K- or Na-bases where used instead of NH4OH. The decrease in cellular succinic acid productivity observed during the anaerobic phase was found to be due to increased organic acid concentrations rather than medium osmolarity.

  13. Diagnostic accuracy of calculated serum osmolarity to predict dehydration in older people: adding value to pathology laboratory reports

    PubMed Central

    Hooper, Lee; Abdelhamid, Asmaa; Ali, Adam; Bunn, Diane K; Jennings, Amy; John, W Garry; Kerry, Susan; Lindner, Gregor; Pfortmueller, Carmen A; Sjöstrand, Fredrik; Walsh, Neil P; Fairweather-Tait, Susan J; Potter, John F; Hunter, Paul R; Shepstone, Lee

    2015-01-01

    Objectives To assess which osmolarity equation best predicts directly measured serum/plasma osmolality and whether its use could add value to routine blood test results through screening for dehydration in older people. Design Diagnostic accuracy study. Participants Older people (≥65 years) in 5 cohorts: Dietary Strategies for Healthy Ageing in Europe (NU-AGE, living in the community), Dehydration Recognition In our Elders (DRIE, living in residential care), Fortes (admitted to acute medical care), Sjöstrand (emergency room) or Pfortmueller cohorts (hospitalised with liver cirrhosis). Reference standard for hydration status Directly measured serum/plasma osmolality: current dehydration (serum osmolality >300 mOsm/kg), impending/current dehydration (≥295 mOsm/kg). Index tests 39 osmolarity equations calculated using serum indices from the same blood draw as directly measured osmolality. Results Across 5 cohorts 595 older people were included, of whom 19% were dehydrated (directly measured osmolality >300 mOsm/kg). Of 39 osmolarity equations, 5 showed reasonable agreement with directly measured osmolality and 3 had good predictive accuracy in subgroups with diabetes and poor renal function. Two equations were characterised by narrower limits of agreement, low levels of differential bias and good diagnostic accuracy in receiver operating characteristic plots (areas under the curve >0.8). The best equation was osmolarity=1.86×(Na++ K+)+1.15×glucose+urea+14 (all measured in mmol/L). It appeared useful in people aged ≥65 years with and without diabetes, poor renal function, dehydration, in men and women, with a range of ages, health, cognitive and functional status. Conclusions Some commonly used osmolarity equations work poorly, and should not be used. Given costs and prevalence of dehydration in older people we suggest use of the best formula by pathology laboratories using a cutpoint of 295 mOsm/L (sensitivity 85%, specificity 59%), to report

  14. Vitamin D Replacement Improves Tear Osmolarity in Patients with Vitamin D Deficiency.

    PubMed

    Kizilgul, Muhammed; Kan, Seyfullah; Ozcelik, Ozgur; Beysel, Selvihan; Apaydin, Mahmut; Ucan, Bekir; Cakal, Erman

    2017-09-06

    Vitamin D deficiency is a common health problem worldwide. Many parts of the human eye, including the epithelium of the cornea, lens, ciliary body, and retinal pigment epithelium, as well as the corneal endothelium, ganglion cell layer, and retinal photoreceptors, contain vitamin D receptor (VDR). Dry eye is also a common health problem. An adequate tear film is required for maintaining health and function of the eye. Tear hyperosmolarity is considered to be the cause of ocular surface inflammation, symptoms, and tissue damage. It is well-documented that vitamin D has an anti-inflammatory action. We aimed to investigate the effect of vitamin D replacement on tear osmolarity in patients with vitamin D deficiency. A total of 44 patients (38 females, six males, mean age:43.5 ± 12.8 years) with vitamin D deficiency currently managed by the Endocrinology and Metabolism Department of Diskapi Training and Research Hospital in Turkey were enrolled in the study. Patients were given 50,000 units of 25(OH)D3 intramuscularly, once weekly, over a period of eight weeks. All of the patients underwent tear function osmolarity (TFO) measurement initially and eight weeks after vitamin D replacement. Demographic, anthropometric, and biochemistry data of patients were recorded. The mean TFO was significantly decreased (313.7 ± 17.3 mOsm/L; 302.7 ± 14.2 mOsm/L, p<0.001) at the end of the second month; 25(OH)D3 concentrations increased from 8.3 ± 3.5 ng/mL to 68.8 ± 22.3 ng/mL (p<0.001). The mean levels of hsCRP, FPG, P were 2.5 ± 2.5 mg/L, 5.09 ± 0.48 mmol/L, 1.06 ± 0.16 mmol/L initially, and 3.8 ± 5.9 mg/L, 5.11 ± 0.68 mg/dL, 1.09 ± 0.16 mmol/L after vitamin D replacement, respectively (p>0.05). The mean Ca level was 2.37 ± 0.07 mmol/L initially and 2.35 ± 0.07 mmol/L after vitamin D replacement (p<0.05). The change of TFO was negatively correlated with the variation of 25(OH)D3 before and after replacement in patients with dry eye

  15. A maximal incremental effort alters tear osmolarity depending on the fitness level in military helicopter pilots.

    PubMed

    Vera Vilchez, Jesús; Jimenez, Raimundo; Madinabeitia, Iker; Masiulis, Nerijus; Cárdenas, David

    2017-08-04

    Fitness level modulates the physiological responses to exercise for a variety of indices. While intense bouts of exercise have been demonstrated to increase tear osmolarity (Tosm), it is not known if fitness level can affect the Tosm response to acute exercise. This study aims to compare the effect of a maximal incremental test on Tosm between trained and untrained military helicopter pilots. Nineteen military helicopter pilots (ten trained and nine untrained) performed a maximal incremental test on a treadmill. A tear sample was collected before and after physical effort to determine the exercise-induced changes on Tosm. The Bayesian statistical analysis demonstrated that Tosm significantly increased from 303.72 ± 6.76 to 310.56 ± 8.80 mmol/L after performance of a maximal incremental test. However, while the untrained group showed an acute Tosm rise (12.33 mmol/L of increment), the trained group experienced a stable Tosm physical effort (1.45 mmol/L). There was a significant positive linear association between fat indices and Tosm changes (correlation coefficients [r] range: 0.77-0.89), whereas the Tosm changes displayed a negative relationship with the cardiorespiratory capacity (VO2 max; r = -0.75) and performance parameters (r = -0.75 for velocity, and r = -0.67 for time to exhaustion). The findings from this study provide evidence that fitness level is a major determinant of Tosm response to maximal incremental physical effort, showing a fairly linear association with several indices related to fitness level. High fitness level seems to be beneficial to avoid Tosm changes as consequence of intense exercise. Copyright © 2017. Published by Elsevier Inc.

  16. Agents that activate the High Osmolarity Glycerol pathway as a means to combat pathogenic molds.

    PubMed

    Wiedemann, Annegret; Spadinger, Anja; Löwe, Axel; Seeger, Allison; Ebel, Frank

    2016-12-01

    Treatment of invasive fungal infections often fails due to the limited number of therapeutic options. In this study, we have analyzed the impact of agents activating the High Osmolarity Glycerol (HOG) pathway on molds that cause infections in humans and livestock. We found that agents like fludioxonil and iprodione, have a clear anti-fungal activity against pathogenic Aspergillus, Lichtheimia, Rhizopus and Scedosporium species. Only A. terreus turned out to be resistant to fludioxonil, even though it is sensitive to iprodione and able to adapt to hyperosmotic conditions. Moreover, the A. terreus tcsC gene can fully complement an A. fumigatus ΔtcsC mutant, thereby also restoring its sensitivity to fludioxonil. The particular phenotype of A. terreus is therefore likely to be independent of its TcsC kinase. In a second part of this study, we further explored the impact of fludioxonil using A. fumigatus as a model organism. When applied in concentrations of 1-2μg/ml, fludioxonil causes an immediate growth arrest and, after longer exposure, a quantitative killing. Hyphae respond to fludioxonil by the formation of new septa and closure of nearly all septal pores. Mitosis occurs in all compartments and is accompanied by a re-localization of the NimA kinase to the cytoplasm. In the swollen compartments, the massive extension of the cell wall triggers a substantial reorganization resulting in an enhanced incorporation of chitin and, most strikingly, a massive loss of galactomannan. Hence, HOG-activating agents have dramatic cell biological consequences and may represent a valuable, future element in the armory that can be used to combat mold infections.

  17. Volume changes and whole cell membrane currents activated during gradual osmolarity decrease in C6 glioma cells: contribution of two types of K+ channels.

    PubMed

    Ordaz, B; Vaca, L; Franco, R; Pasantes-Morales, H

    2004-06-01

    Volume changes and whole cell ionic currents activated by gradual osmolarity reductions (GOR) of 1.8 mosM/min were characterized in C6 glioma cells. Cells swell less in GOR than after sudden osmolarity reductions (SOR), the extent of swelling being partly Ca(2+) dependent. In nominally Ca(2+)-free conditions, GOR activated predominantly whole cell outward currents. Cells depolarized from the initial -79 mV to a steady state of -54 mV reached at 18% osmolarity reduction [hyposmolarity of -18% (H-18%)]. Recordings of Cl(-) and K(+) currents showed activation at H-3% of an outwardly rectifying Cl(-) current, with conductance of 1.6 nS, sensitive to niflumic acid and 5-nitro-2-(3-phenylpropylamino)benzoic acid, followed at H-18% by an outwardly rectifying K(+) current with conductance of 4.1 nS, inhibited by clofilium but insensitive to the typical K(+) channel blockers. With 200 nM Ca(2+) in the patch pipette, whole cell currents activated at H-3% and at H-13% cells depolarized from -77 to -63 mV. A K(+) current activated at H-1%, showing a rapid increase in conductance, suppressed by charybdotoxin and insensitive to clofilium. These results show the operation of two different K(+) channels in response to GOR in the same cell type, activated by Ca(2+) and osmolarity and with different osmolarity activation thresholds. Taurine and glutamate efflux, monitored by labeled tracers, showed delayed osmolarity thresholds of H-39 and H-33%, respectively. This observation clearly separates the Cl(-) and amino acid osmosensitive pathways. The delayed amino acid efflux may contribute to counteract swelling at more stringent osmolarity reductions.

  18. Heat shock protein (Hsp70) induced by a mild heat shock slightly moderates plasma osmolarity increases upon salinity transfer in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Niu, C J; Rummer, J L; Brauner, C J; Schulte, P M

    2008-11-01

    We have investigated whether mild heat shock, and resulting Hsp70 expression, can confer cross-protection against the stress associated with transfer from freshwater (FW) to seawater (SW) in juvenile rainbow trout (Oncorhynchus mykiss). In experimental Series I, juvenile trout reared in FW were transferred from 13.5 degrees C to 25.5 degrees C in FW, held for 2 h, returned to 13.5 degrees C for 12 h, and then transferred to 32 ppt SW at 13.5 degrees C. Branchial Hsp70 increased approximately 10-fold in the heat-shocked fish relative to the control by the end of recovery and remained high 2, 8, and 24 h post-salinity transfer. However, no clear differences could be detected in blood parameters (blood hemoglobin, hematocrit, MCHC, plasma Na(+) and plasma osmolarity) or muscle water content between heat-shocked and sham-shocked fish in SW at any sampling interval (0, 2, 8, 24, 48, 120, 240 and 360 h post-SW transfer). In experimental Series II, trout acclimated to 8 degrees C were heat-shocked at 22 degrees C for 2 h, allowed to recover 18 h, and exposed to a more severe salinity transfer (either 36 or 45 ppt) than in Series I. Branchial Hsp70 levels increased approximately 6-fold in heat-shocked fish, but had declined to baseline after 120 h in SW. Plasma osmolarity and chloride increased in both groups upon transfer to 36 ppt; however, the increase was significantly less in heat-shocked fish when compared to the increase observed in sham-shocked fish at 24 h. No significant differences could be detected in branchial Na(+)/K(+)-ATPase activity or Na(+)/K(+)-ATPase alpha1a and alpha1b mRNA expression between the two groups. Our data indicate that a mild temperature shock has only modest effects on the ability of rainbow trout to resist osmotic stress during FW to SW transfer.

  19. Increased Serum Sodium and Serum Osmolarity Are Independent Risk Factors for Developing Chronic Kidney Disease; 5 Year Cohort Study

    PubMed Central

    Kuwabara, Masanari; Hisatome, Ichiro; Roncal-Jimenez, Carlos A.; Niwa, Koichiro; Andres-Hernando, Ana; Jensen, Thomas; Bjornstad, Petter; Milagres, Tamara; Cicerchi, Christina; Song, Zhilin; Garcia, Gabriela; Sánchez-Lozada, Laura G.; Ohno, Minoru; Lanaspa, Miguel A.; Johnson, Richard J.

    2017-01-01

    Background Epidemics of chronic kidney disease (CKD) not due to diabetes mellitus (DM) or hypertension have been observed among individuals working in hot environments in several areas of the world. Experimental models have documented that recurrent heat stress and water restriction can lead to CKD, and the mechanism may be mediated by hyperosmolarity that activates pathways (vasopressin, aldose reductase-fructokinase) that induce renal injury. Here we tested the hypothesis that elevated serum sodium, which reflects serum osmolality, may be an independent risk factor for the development of CKD. Methods This study was a large-scale, single-center, retrospective 5-year cohort study at Center for Preventive Medicine, St. Luke’s International Hospital, Tokyo, Japan, between 2004 and 2009. We analyzed 13,201 subjects who underwent annual medical examination of which 12,041 subjects (age 35 to 85) without DM and/or CKD were enrolled. This analysis evaluated age, sex, body mass index, abdominal circumference, hypertension, dyslipidemia, hyperuricemia, fasting glucose, BUN, serum sodium, potassium, chloride and calculated serum osmolarity. Results Elevated serum sodium was an independent risk factor for development of CKD (OR: 1.03, 95% CI, 1.00–1.07) after adjusted regression analysis with an 18 percent increased risk for every 5 mmol/L change in serum sodium. Calculated serum osmolarity was also an independent risk factor for CKD (OR: 1.04; 95% CI, 1.03–1.05) as was BUN (OR: 1.08; 95% CI, 1.06–1.10) (independent of serum creatinine). Conclusions Elevated serum sodium and calculated serum osmolarity are independent risk factors for developing CKD. This finding supports the role of limiting salt intake and preventing dehydration to reduce risk of CKD. PMID:28081152

  20. Increased Serum Sodium and Serum Osmolarity Are Independent Risk Factors for Developing Chronic Kidney Disease; 5 Year Cohort Study.

    PubMed

    Kuwabara, Masanari; Hisatome, Ichiro; Roncal-Jimenez, Carlos A; Niwa, Koichiro; Andres-Hernando, Ana; Jensen, Thomas; Bjornstad, Petter; Milagres, Tamara; Cicerchi, Christina; Song, Zhilin; Garcia, Gabriela; Sánchez-Lozada, Laura G; Ohno, Minoru; Lanaspa, Miguel A; Johnson, Richard J

    2017-01-01

    Epidemics of chronic kidney disease (CKD) not due to diabetes mellitus (DM) or hypertension have been observed among individuals working in hot environments in several areas of the world. Experimental models have documented that recurrent heat stress and water restriction can lead to CKD, and the mechanism may be mediated by hyperosmolarity that activates pathways (vasopressin, aldose reductase-fructokinase) that induce renal injury. Here we tested the hypothesis that elevated serum sodium, which reflects serum osmolality, may be an independent risk factor for the development of CKD. This study was a large-scale, single-center, retrospective 5-year cohort study at Center for Preventive Medicine, St. Luke's International Hospital, Tokyo, Japan, between 2004 and 2009. We analyzed 13,201 subjects who underwent annual medical examination of which 12,041 subjects (age 35 to 85) without DM and/or CKD were enrolled. This analysis evaluated age, sex, body mass index, abdominal circumference, hypertension, dyslipidemia, hyperuricemia, fasting glucose, BUN, serum sodium, potassium, chloride and calculated serum osmolarity. Elevated serum sodium was an independent risk factor for development of CKD (OR: 1.03, 95% CI, 1.00-1.07) after adjusted regression analysis with an 18 percent increased risk for every 5 mmol/L change in serum sodium. Calculated serum osmolarity was also an independent risk factor for CKD (OR: 1.04; 95% CI, 1.03-1.05) as was BUN (OR: 1.08; 95% CI, 1.06-1.10) (independent of serum creatinine). Elevated serum sodium and calculated serum osmolarity are independent risk factors for developing CKD. This finding supports the role of limiting salt intake and preventing dehydration to reduce risk of CKD.

  1. The Extracellular Domain of the Saccharomyces cerevisiae Sln1p Membrane Osmolarity Sensor Is Necessary for Kinase Activity

    PubMed Central

    Ostrander, Darin B.; Gorman, Jessica A.

    1999-01-01

    The function of the extracellular domain (ECD) of Sln1p, a plasma membrane two-transmembrane domain (TMD) sensor of the high-osmolarity glycerol (HOG) response pathway, has been studied in the yeast Saccharomyces cerevisiae. Truncations of SLN1 that retain an intact kinase domain are capable of complementing the lethality of an sln1Δ strain. By observing levels of Hog1p phosphorylation as well as the phosphorylation state of Sln1p, the kinase activities of various SLN1 constructions were determined. In derivatives that do not contain the first TMD, Sln1p activity was no longer dependent on medium osmolarity but appeared to be constitutively active even under conditions of high osmolarity. Removal of the first TMD (ΔTMD1 construct) gave a protein that was strongly phosphorylated whereas Hog1p was largely dephosphorylated, as expected if the active form of Sln1p is phosphorylated. When both TMDs as well as the ECD were deleted, so that the kinase domain is cytosolic, Sln1p was not phosphorylated whereas Hog1p became constitutively hyperphosphorylated. Surprisingly, this hyperactivity of the HOG mitogen-activated protein kinase signaling pathway was not sufficient to result in cell lethality. When the ECD of the ΔTMD1 construct was replaced with a leucine zipper motif, Sln1p was hyperactive, so that Hog1p became mostly unphosphorylated. In contrast, when the Sln1p/leucine zipper construct was crippled by a mutation of one of the internal leucines, the Sln1 kinase was inactive. These experiments are consistent with the hypothesis that the ECD of Sln1p functions as a dimerization and activation domain but that osmotic regulation of activity requires the presence of the first TMD. PMID:10198019

  2. Effects of viscosity on power and hand injection of iso-osmolar iodinated contrast media through thin catheters.

    PubMed

    Zhang, James J; Hogstrom, Barry; Malinak, Jiri; Ikei, Nobuhiro

    2016-05-01

    It can be challenging to achieve adequate vessel opacification during percutaneous coronary interventions when using thin catheters, hand injection, and iso-osmolar contrast media (CM) such as iodixanol (Visipaque™). To explore these limitations and the possibility to overcome them with iosimenol, a novel CM. Three X-ray contrast media with different concentrations were used in this study. A series of in vitro experiments established the relationship between injection pressure and flow rate in angiography catheters under various conditions. The experiments were conducted with power and hand injections and included a double-blind evaluation of user perception. By using hand injection, it was generally not possible to reach a maximum injection pressure exceeding 50 psi. The time within which volunteers were able to complete the injections, the area under the pressure-time curve (AUC), and assessment of ease of injection all were in favor of iosimenol compared with iodixanol, especially when using the 4F thin catheter. Within the pressure ranges tested, the power injections demonstrated that the amount of iodine delivered at a fixed pressure was strongly related to viscosity but unrelated to iodine concentration. There are substantial limitations to the amount of iodine that can be delivered through thin catheters by hand injection when iso-osmolar CM with high viscosity is used. The only viable solution, besides increasing the injection pressure, is to use a CM with lower viscosity, since the cost of increasing the concentration, in terms of increased viscosity and consequent reduction in flow, is too high. Iosimenol, an iso-osmolar CM with lower viscosity than iodixanol might therefore be a better alternative when thinner catheters are preferred, especially when the radial artery is used as the access site. © The Foundation Acta Radiologica 2015.

  3. Calcium and phosphate compatibility in low-osmolarity parenteral nutrition admixtures intended for peripheral vein administration.

    PubMed

    Joy, Julie; Silvestri, Anthony P; Franke, Rolf; Bistrian, Bruce R; Nehne, Jörg; Newton, David W; Driscoll, David F

    2010-01-01

    Precipitation of calcium (Ca) and phosphate (P) salts can lead to potentially lethal outcomes, especially in low-osmolarity parenteral nutrition (LO-PN) formulations. Three concentrations of amino acids (AA) and 2 concentrations of calcium gluconate and sodium phosphate injections on the compatibility of Ca and P in LO-PN admixtures were studied. Final AA concentrations of 1%, 2%, or 3% (n = 3) and 5% glucose (G) were prepared with either 2.5 or 5 mmol/L (5 or 10 mEq) of Ca (n = 2) and 15 or 30 mmol/L of P (n = 2) for a total of 12 base (3 x 2 x 2) formulations. Triplicate bags of each were analyzed for subvisible micro-precipitates using the light obscuration (or extinction) method for particle counts per milliliter (PC) in the size range of 1.8-50 mum at 7 time intervals over 48 hours stored at 30 degrees C +/- 0.2 degrees C. Visual evaluation was performed using a high-intensity lamp against a black background for detection of macro-precipitates. The pH of all 36 admixtures was measured at 0 and 48 hours. Any precipitated material was isolated and characterized by polarized light microscopy and infrared spectroscopy. Of the 12 base LO-PN formulations tested, those containing 1% and 2% AA with 5 mmol/L of Ca and 30 mmol/L of P showed significant increases in PC, and some resulted in visible dibasic calcium phosphate precipitation. Analyses of variance based on concentrations of AA, Ca, P, and time were highly significant independent variables for increases in the PC of potentially embolic particles, that is, sizes >5 mum (P < .0001). The lowest concentrations of Ca and P, 2.5 and 15 mmol/L, respectively, had significantly lower PC (P < .05) for all sizes compared with the other Ca and P combinations. LO-PN admixtures (AA

  4. Butoxyacetic acid-induced hemolysis of rat red blood cells: effect of external osmolarity and cations.

    PubMed

    Udden, M M; Patton, C S

    2005-03-28

    Hemolysis is the principal toxicity of acute exposure to ethylene glycol monobutyl ether (EGBE) in rats. EGBE itself is not an active hemolytic agent, but its metabolite, butoxyacetic acid (BAA) formed as a result of dehydrogenase activity is a potent hemolysin. Here we address the role of osmolarity and cation composition of the suspending buffers in the mechanism of BAA-induced hemolysis of rat red blood cells in vitro. Rat erythrocytes were protected from BAA-induced cell swelling and hemolysis by the addition of sucrose to the suspending media. Hemolysis and cell swelling were also reduced by replacing external sodium with potassium. When calcium was not present in the suspending medium or when chelated by EGTA, hemolysis was increased after 2 h incubation with 1 mM or 2 mM BAA. Addition of as little as 0.05 mM CaCl(2) reduced hemolysis significantly while the addition of MgCl(2) had no effect. The dose-response relationship between BAA concentration and hemolysis determined in the presence or absence of calcium showed an increased effect of BAA in the absence of calcium. BAA-induced spherocytosis and cell fragmentation were more pronounced in the absence of calcium. The time course of BAA-induced hemolysis in the presence and absence of calcium demonstrated that the effect of calcium is to delay the onset of hemolysis. Increased intracellular calcium as a result of exposure to BAA was verified by atomic absorption spectroscopy. Charybdotoxin, an inhibitor of the calcium activated potassium channel, blocked the protective effect of calcium suggesting that the delay of onset of hemolysis in the presence of calcium is due to potassium loss caused by this channel. We conclude that the mode of action of BAA is to cause a colloid osmotic lysis of the rat red blood cell. Hemolysis requires external sodium and is associated with calcium uptake. Calcium appears to delay the onset of hemolysis. We speculate that: (1) BAA causes sodium and calcium to enter the cell; (2

  5. Intra-arterial and intravenous applications of Iosimenol 340 injection, a new non-ionic, dimeric, iso-osmolar radiographic contrast medium: phase 2 experience

    PubMed Central

    Laniado, Michael; Hosten, Norbert; Kelsch, Bettina; Hogstrom, Barry

    2015-01-01

    Background Iosimenol 340 injection is a new, dimeric, iso-osmolar, iodinated contrast medium for X-ray angiography. Purpose To compare the safety and efficacy of iosimenol injection to iodixanol injection in two randomized, controlled phase 2 trials. Material and Methods One hundred and forty-four adult patients were enrolled in the two trials, one for evaluation during arteriography and the other for evaluation during computed tomography. Safety was compared by assessing adverse events, vital signs, ECGs, and laboratory parameters. Efficacy was assessed as X-ray attenuation in the computed tomography (CT) trial and as the quality of contrast enhancement in the arteriography trial. Results There were no statistically significant differences in terms of safety or efficacy between the two contrast media. Both were well tolerated upon intravenous as well as intra-arterial injection. The most common adverse event was a feeling of warmth (observed in 35.1% of the patients with Iosimenol injection and 44.3% with iodixanol injection). Conclusion Iosimenol upon intravenous as well as upon intra-arterial injection exhibits a safety profile and shows an efficacy similar to that of iodixanol. PMID:24938661

  6. Functional role of follicular cells in the generation of osmolarity-dependent Cl- currents in Xenopus follicles.

    PubMed Central

    Arellano, R O; Miledi, R

    1995-01-01

    1. Osmolarity-dependent (osmo-dependent) ionic currents from follicle-enclosed Xenopus oocytes (follicles) were studied using the two-microelectrode voltage-clamp technique, combined with intra-oocyte pressure injection of sucrose or polyethylene glycols (PEGs). 2. Intra-oocyte injections of sucrose or PEG (3-25 nmol) generated inward membrane currents (follicles held at -60 mV) associated with an increase in membrane conductance. These currents were carried mainly by chloride ions (ICl(osm)), and were strongly attenuated by increasing the tonicity of the external medium, or by external application of La3+ (0.1-1 mM). 3. The ability to generate ICl(osm) depended on the molecular weight of the injected PEG. Injections of PEG 200 or 300 generated ICl(osm) in 95% of the follicles tested, PEG 600 generated comparable currents in only 20% of the follicles, while similar injections of PEG 1000 did not elicit ICl(osm). 4. Octanol (1-1.5 mM), a gap junction channel blocker, reversibly inhibited 50-90% of the ICl(osm) generated by injections of sucrose or PEG 300. Moreover, sucrose or PEG injections did not elicit ICl(osm) in defolliculated oocytes. 5. It is concluded that an increase in the internal osmolarity of the follicular cells activates a mechanism, probably involving cellular swelling, which leads to the opening of ICl(osm) channels most probably located in the follicular cell membrane. PMID:8568675

  7. Medium Osmolarity and Pericellular Matrix Development Improves Chondrocyte Survival When Photoencapsulated in Poly(Ethylene Glycol) Hydrogels at Low Densities

    PubMed Central

    Villanueva, Idalis; Bishop, Nikki L.

    2009-01-01

    The ability to encapsulate cells over a range of cell densities is important toward mimicking cell densities of native tissues and rationally designing strategies where cell source and/or cell numbers are clinically limited. Our preliminary findings demonstrate that survival of freshly isolated adult bovine chondrocytes dramatically decreases when photoencapsulated in poly(ethylene glycol) hydrogels at low densities (4 million cells/mL). During enzymatic digestion of cartilage, chondrocytes undergo a harsh change in their microenvironment. We hypothesize that the absence of exogenous antioxidants, the hyposmotic environment, and the loss of a protective pericellular matrix (PCM) increase chondrocytes' susceptibility to free radical damage during photoencapsulation. Incorporation of antioxidants and serum into the encapsulation medium improved cell survival twofold compared to phosphate-buffered saline. Increasing medium osmolarity from 330 to 400 mOsm (physiological) improved cell survival by 40% and resulted in ∼2-fold increase in adenosine triphosphate (ATP) production 24 h postencapsulation. However, cell survival was only temporary. Allowing cells to reproduce some PCM before photoencapsulation in 400 mOsm medium resulted in superior cell survival during and postencapsulation for up to 15 days. In summary, the combination of antioxidants, physiological osmolarity, and the development of some PCM result in an improved robustness against free radical damage during photoencapsulation. PMID:19331581

  8. Network of nutrient-sensing pathways and a conserved kinase cascade integrate osmolarity and carbon sensing in Neurospora crassa.

    PubMed

    Huberman, Lori B; Coradetti, Samuel T; Glass, N Louise

    2017-09-25

    Identifying nutrients available in the environment and utilizing them in the most efficient manner is a challenge common to all organisms. The model filamentous fungus Neurospora crassa is capable of utilizing a variety of carbohydrates, from simple sugars to the complex carbohydrates found in plant cell walls. The zinc binuclear cluster transcription factor CLR-1 is necessary for utilization of cellulose, a major, recalcitrant component of the plant cell wall; however, expression of clr-1 in the absence of an inducer is not sufficient to induce cellulase gene expression. We performed a screen for unidentified actors in the cellulose-response pathway and identified a gene encoding a hypothetical protein (clr-3) that is required for repression of CLR-1 activity in the absence of an inducer. Using clr-3 mutants, we implicated the hyperosmotic-response pathway in the tunable regulation of glycosyl hydrolase production in response to changes in osmolarity. The role of the hyperosmotic-response pathway in nutrient sensing may indicate that cells use osmolarity as a proxy for the presence of free sugar in their environment. These signaling pathways form a nutrient-sensing network that allows Ncrassa cells to tightly regulate gene expression in response to environmental conditions.

  9. Medium osmolarity and pericellular matrix development improves chondrocyte survival when photoencapsulated in poly(ethylene glycol) hydrogels at low densities.

    PubMed

    Villanueva, Idalis; Bishop, Nikki L; Bryant, Stephanie J

    2009-10-01

    The ability to encapsulate cells over a range of cell densities is important toward mimicking cell densities of native tissues and rationally designing strategies where cell source and/or cell numbers are clinically limited. Our preliminary findings demonstrate that survival of freshly isolated adult bovine chondrocytes dramatically decreases when photoencapsulated in poly(ethylene glycol) hydrogels at low densities (4 million cells/mL). During enzymatic digestion of cartilage, chondrocytes undergo a harsh change in their microenvironment. We hypothesize that the absence of exogenous antioxidants, the hyposmotic environment, and the loss of a protective pericellular matrix (PCM) increase chondrocytes' susceptibility to free radical damage during photoencapsulation. Incorporation of antioxidants and serum into the encapsulation medium improved cell survival twofold compared to phosphate-buffered saline. Increasing medium osmolarity from 330 to 400 mOsm (physiological) improved cell survival by 40% and resulted in approximately 2-fold increase in adenosine triphosphate (ATP) production 24 h postencapsulation. However, cell survival was only temporary. Allowing cells to reproduce some PCM before photoencapsulation in 400 mOsm medium resulted in superior cell survival during and postencapsulation for up to 15 days. In summary, the combination of antioxidants, physiological osmolarity, and the development of some PCM result in an improved robustness against free radical damage during photoencapsulation.

  10. The inner membrane protein YhiM is necessary for Escherichia coli growth at high temperatures and low osmolarity.

    PubMed

    Anderson, M A; Mann, M D; Evans, M A; Sparks-Thissen, R L

    2017-01-01

    To survive, Escherichia coli must be able to survive in rapidly changing environmental conditions including changes in temperature and osmolarity. We have studied the role of the inner membrane protein YhiM in changing environmental conditions. Our data indicate that YhiM is required for normal growth at 37 and 41 °C but not 21 °C. YhiM-deficient cells grown at high temperatures spend more time in lag phase and stop growing at lower cell densities in comparison with their wild-type counterparts. They also have growth defects in low NaCl medium at 37 °C and do not grow at all at 41 °C. The effects of low NaCl can be rescued by addition of KCl or sucrose to the low salt medium. Finally, YhiM-deficient cells fail to grow in dilute medium at 41 °C. These data suggest that YhiM may be important in protecting the cells from changes in temperature and osmolarity.

  11. Modification of sodium, glucose, potassium, and osmolarity in packed red blood cells and fresh frozen plasma using a desktop hemoconcentrator setup.

    PubMed

    Striker, Carrie Whittaker; Woldorf, Stacia; Holt, David

    2012-06-01

    Massive transfusion with packed blood cells (PRBCs) or fresh frozen plasma (FFP) can result in dangerous complications including stroke, kidney failure, and cardiac arrest. A simple, bench top technique using a hemoconcentrator and dialysate solution is described to correct critical values of sodium, glucose, potassium, and osmolarity in PRBCs and FFP. Sodium, glucose, and osmolarity were corrected to normal or near normal values. Elevated potassium was reduced by 65%, but not completely normalized. A simple, bench top method for correcting dangerous abnormalities with PRBCs and FFP can be used to improve the safety of massive blood transfusion.

  12. Rectal application of a highly osmolar personal lubricant in a macaque model induces acute cytotoxicity but does not increase risk of SHIV infection.

    PubMed

    Vishwanathan, Sundaram A; Morris, Monica R; Wolitski, Richard J; Luo, Wei; Rose, Charles E; Blau, Dianna M; Tsegaye, Theodros; Zaki, Sherif R; Garber, David A; Jenkins, Leecresia T; Henning, Tara C; Patton, Dorothy L; Hendry, R Michael; McNicholl, Janet M; Kersh, Ellen N

    2015-01-01

    Personal lubricant use is common during anal intercourse. Some water-based products with high osmolality and low pH can damage genital and rectal tissues, and the polymer polyquaternium 15 (PQ15) can enhance HIV replication in vitro. This has raised concerns that lubricants with such properties may increase STD/HIV infection risk, although in vivo evidence is scarce. We use a macaque model to evaluate rectal cytotoxicity and SHIV infection risk after use of a highly osmolar (>8,000 mOsm/kg) water-based lubricant with pH of 4.4, and containing PQ15. Cytotoxicity was documented by measuring inflammatory cytokines and epithelial tissue sloughing during six weeks of repeated, non-traumatic lubricant or control buffer applications to rectum and anus. We measured susceptibility to SHIVSF162P3 infection by comparing virus doses needed for rectal infection in twenty-one macaques treated with lubricant or control buffer 30 minutes prior to virus exposure. Lubricant increased pro-inflammatory cytokines and tissue sloughing while control buffer (phosphate buffered saline; PBS) did not. However, the estimated AID50 (50% animal infectious dose) was not different in lubricant- and control buffer-treated macaques (p = 0.4467; logistic regression models). Although the test lubricant caused acute cytotoxicity in rectal tissues, it did not increase susceptibility to infection in this macaque model. Thus neither the lubricant-induced type/extent of inflammation nor the presence of PQ15 affected infection risk. This study constitutes a first step in the in vivo evaluation of lubricants with regards to HIV transmission.

  13. Rectal Application of a Highly Osmolar Personal Lubricant in a Macaque Model Induces Acute Cytotoxicity but Does Not Increase Risk of SHIV Infection

    PubMed Central

    Vishwanathan, Sundaram A.; Morris, Monica R.; Wolitski, Richard J.; Luo, Wei; Rose, Charles E.; Blau, Dianna M.; Tsegaye, Theodros; Zaki, Sherif R.; Garber, David A.; Jenkins, Leecresia T.; Henning, Tara C.; Patton, Dorothy L.; Hendry, R. Michael; McNicholl, Janet M.; Kersh, Ellen N.

    2015-01-01

    Background Personal lubricant use is common during anal intercourse. Some water-based products with high osmolality and low pH can damage genital and rectal tissues, and the polymer polyquaternium 15 (PQ15) can enhance HIV replication in vitro. This has raised concerns that lubricants with such properties may increase STD/HIV infection risk, although in vivo evidence is scarce. We use a macaque model to evaluate rectal cytotoxicity and SHIV infection risk after use of a highly osmolar (>8,000 mOsm/kg) water-based lubricant with pH of 4.4, and containing PQ15. Methods Cytotoxicity was documented by measuring inflammatory cytokines and epithelial tissue sloughing during six weeks of repeated, non-traumatic lubricant or control buffer applications to rectum and anus. We measured susceptibility to SHIVSF162P3 infection by comparing virus doses needed for rectal infection in twenty-one macaques treated with lubricant or control buffer 30 minutes prior to virus exposure. Results Lubricant increased pro-inflammatory cytokines and tissue sloughing while control buffer (phosphate buffered saline; PBS) did not. However, the estimated AID50 (50% animal infectious dose) was not different in lubricant- and control buffer-treated macaques (p = 0.4467; logistic regression models). Conclusions Although the test lubricant caused acute cytotoxicity in rectal tissues, it did not increase susceptibility to infection in this macaque model. Thus neither the lubricant-induced type/extent of inflammation nor the presence of PQ15 affected infection risk. This study constitutes a first step in the in vivo evaluation of lubricants with regards to HIV transmission. PMID:25853710

  14. [Calcium concentrations in the urine of recurrent stone-formers and their controls (author's transl)].

    PubMed

    Leskovar, P; Hartung, R; Siebert, A; Wellnhofer, E

    1980-07-01

    Over a period of 4--6 weeks the urinary concentrations of (total calcium, ionized calcium, creatinine and osmolarity in recurrent stone-formers and healthy controls were measured in morning, midday and evening urine samples. The mean urinary concentrations of the (total) calcium were in both groups the same. However, 31% of the stone-formers and only 18% of the controls showed a mean calcium concentration > 5 mmol/l. The ionized calcium, on the contrary, was significantly higher in the stone-formers than in the controls. The lower urinary osmolarity of the recurrent stone-formers led to significantly higher Ca/osmolarity and Ca2+/osmolarity ratios; analogously, the quotient Ca2+/creatinine was also significantly raised in stone-formers.

  15. Limited multiplication of Mycobacterium lepraemurium in parabiotic culture, as influenced by osmolarity of an alkaline-galactomannan medium.

    PubMed

    Kato, L; Gozsy, B

    1966-05-01

    Kato, Laszlo (Institut de Microbiologie et d'Hygiène de l'Université de Montréal, Montreal, Quebec, Canada), and Bela Gozsy. Limited multiplication of Mycobacterium lepraemurium in parabiotic culture, as influenced by osmolarity of an alkaline-galactomannan medium. J. Bacteriol. 91:1859-1862. 1966.-Limited multiplication of Mycobacterium lepraemurium has been achieved in an alkaline (pH 8.4) galactomannan-containing medium, when cultivated alone or in parabiosis with a feeder strain, Torula minuta. Hyperosmolarity (NaCl, 2.0%) enhanced multiplication in both cases. With 2.0% NaCl in the medium, selective lysis of the feeder cells occurred, without damage to M. lepraemurium. Multiplication depends more on the physical properties (viscosity, hyperosmolarity, and alkaline pH) of the medium than on its chemical composition. The described conditions are proposed as a model for cultivation trials with other "apparently noncultivable" microorganisms.

  16. Correlation of Tear Film Osmolarity and 2 Different MMP-9 Tests With Common Dry Eye Tests in a Cohort of Non-Dry Eye Patients.

    PubMed

    Schargus, Marc; Ivanova, Svetlana; Kakkassery, Vinodh; Dick, H Burkhard; Joachim, Stephanie

    2015-07-01

    Given that early-stage dry eye is difficult to diagnose, the purpose of this study was to evaluate the performance of matrix metalloproteinase 9 (MMP-9) and tear film osmolarity (TFO) in a cohort of elderly patients with potential dry eye disease (DED). A group of 20 patients, aged 60 years and above, previously undiagnosed with DED were selected. The following DED tests were performed: tear osmolarity, MMP-9 (InflammaDry), Schirmer test, tear film break-up time, Ocular Surface Disease Index (OSDI) questionnaire, corneal fluorescein staining, and conjunctival lissamine green staining. MMP-9 concentrations in tears collected through Schirmer strips were analyzed by an MMP-9 enzyme-linked immunosorbent assay [ELISA]. Subjects were classified by symptoms (classification A: OSDI ≥10, n = 9), based on suspected mild dry eye (classification B: n = 14), TFO difference >8 mOsm/L between both eyes (classification C: n = 13), and TFO cutoff at 308 mOsm/L (classification D: >308 mOsm/L, n = 11). Eleven percent (1/9) of the symptomatic and 14% (2/14) of the suspected mild dry eye were positive for MMP-9. InflammaDry MMP-9 tests were confirmed to be accurate through an ELISA. Sixty-seven percent (6/9) of the symptomatic and 64% (9/14) of the suspected mild dry eye were positive for tear osmolarity. None of the evaluated tear film parameters showed a significant correlation, although tear osmolarity and symptoms trended toward significance (r = 0.433, P = 0.06), whereas MMP-9 and corneal staining showed a positive association (r = 0.376, P = 0.10). Similar to corneal staining, the MMP-9 is likely a late-stage sign that is rarely overexpressed in mild subjects, whereas tear osmolarity tends to be a more frequent early indicator of ocular surface disequilibrium within mild subjects.

  17. Mouse embryos stressed by physiological levels of osmolarity become arrested in the late 2-cell stage before entry into M phase.

    PubMed

    Wang, Fang; Kooistra, Megan; Lee, Martin; Liu, Lin; Baltz, Jay M

    2011-10-01

    Preimplantation mouse embryos of many strains become arrested at the 2-cell stage if the osmolarity of culture medium that normally supports development to blastocysts is raised to approximately that of their normal physiological environment in the oviduct. Arrest can be prevented if molecules that serve as "organic osmolytes" are present in the medium, because organic osmolytes, principally glycine, are accumulated by embryos to provide intracellular osmotic support and regulate cell volume. Medium with an osmolarity of 310 mOsM induced arrest of approximately 80% of CF1 mouse embryos at the 2-cell stage, in contrast to the approximately 100% that progressed beyond the 2-cell stage at 250 or 301 mOsM with glycine. The nature of this arrest induced by physiological levels of osmolarity is unknown. Arrest was reversible by transfer to lower-osmolarity medium at any point during the 2-cell stage, but not after embryos would normally have progressed to the 4-cell stage. Cessation of development likely was not due to apoptosis, as shown by lack of external annexin V binding, detectable cytochrome c release from mitochondria, or nuclear DNA fragmentation. Two-cell embryos cultured at 310 mOsM progressed through the S phase, and zygotic genome activation markers were expressed. However, most embryos failed to initiate the M phase, as evidenced by intact nuclei with decondensed chromosomes, low M-phase promoting factor activity, and an inactive form of CDK1, although a few blastomeres were arrested in metaphase. Thus, embryos become arrested late in the G(2) stage of the second embryonic cell cycle when stressed by physiological osmolarity in the absence of organic osmolytes.

  18. Mouse Embryos Stressed by Physiological Levels of Osmolarity Become Arrested in the Late 2-Cell Stage Before Entry into M Phase1

    PubMed Central

    Wang, Fang; Kooistra, Megan; Lee, Martin; Liu, Lin; Baltz, Jay M.

    2011-01-01

    Preimplantation mouse embryos of many strains become arrested at the 2-cell stage if the osmolarity of culture medium that normally supports development to blastocysts is raised to approximately that of their normal physiological environment in the oviduct. Arrest can be prevented if molecules that serve as “organic osmolytes” are present in the medium, because organic osmolytes, principally glycine, are accumulated by embryos to provide intracellular osmotic support and regulate cell volume. Medium with an osmolarity of 310 mOsM induced arrest of approximately 80% of CF1 mouse embryos at the 2-cell stage, in contrast to the approximately 100% that progressed beyond the 2-cell stage at 250 or 301 mOsM with glycine. The nature of this arrest induced by physiological levels of osmolarity is unknown. Arrest was reversible by transfer to lower-osmolarity medium at any point during the 2-cell stage, but not after embryos would normally have progressed to the 4-cell stage. Cessation of development likely was not due to apoptosis, as shown by lack of external annexin V binding, detectable cytochrome c release from mitochondria, or nuclear DNA fragmentation. Two-cell embryos cultured at 310 mOsM progressed through the S phase, and zygotic genome activation markers were expressed. However, most embryos failed to initiate the M phase, as evidenced by intact nuclei with decondensed chromosomes, low M-phase promoting factor activity, and an inactive form of CDK1, although a few blastomeres were arrested in metaphase. Thus, embryos become arrested late in the G2 stage of the second embryonic cell cycle when stressed by physiological osmolarity in the absence of organic osmolytes. PMID:21697513

  19. Extraction of water labeled with oxygen 15 during single-capillary transit. Influence of blood pressure, osmolarity, and blood-brain barrier damage

    SciTech Connect

    Go, K.G.; Lammertsma, A.A.; Paans, A.M.; Vaalburg, W.; Woldring, M.G.

    1981-09-01

    By external detection, the influence of arterial blood pressure (BP), osmolarity, and cold-induced blood-brain barrier damage was assessed on the extraction of water labeled with oxygen 15 during single-capillary transit in the rat. There was an inverse relation between arterial BP and extraction that was attributable to the influence of arterial BP on cerebral blood flow (CBF) and the relation between CBF and extraction. Neither arterial BP nor osmolarity of the injected bolus had any direct effect on extraction of water 15O, signifying that the diffusional exchange component (determined by blood flow) of extraction greatly surpasses the convection flow contribution by hydrostatic or osmotic forces. Damage to the blood-brain barrier did not change its permeability to water.

  20. The HU Regulon Is Composed of Genes Responding to Anaerobiosis, Acid Stress, High Osmolarity and SOS Induction

    PubMed Central

    Oberto, Jacques; Nabti, Sabrina; Jooste, Valérie; Mignot, Hervé; Rouviere-Yaniv, Josette

    2009-01-01

    Background The Escherichia coli heterodimeric HU protein is a small DNA-bending protein associated with the bacterial nucleoid. It can introduce negative supercoils into closed circular DNA in the presence of topoisomerase I. Cells lacking HU grow very poorly and display many phenotypes. Methodology/Principal Findings We analyzed the transcription profile of every Escherichia coli gene in the absence of one or both HU subunits. This genome-wide in silico transcriptomic approach, performed in parallel with in vivo genetic experimentation, defined the HU regulon. This large regulon, which comprises 8% of the genome, is composed of four biologically relevant gene classes whose regulation responds to anaerobiosis, acid stress, high osmolarity, and SOS induction. Conclusions/Significance The regulation a large number of genes encoding enzymes involved in energy metabolism and catabolism pathways by HU explains the highly pleiotropic phenotype of HU-deficient cells. The uniform chromosomal distribution of the many operons regulated by HU strongly suggests that the transcriptional and nucleoid architectural functions of HU constitute two aspects of a unique protein-DNA interaction mechanism. PMID:19194530

  1. Limited Multiplication of Mycobacterium lepraemurium in Parabiotic Culture, as Influenced by Osmolarity of an Alkaline-Galactomannan Medium

    PubMed Central

    Kato, Laszlo; Gozsy, Bela

    1966-01-01

    Kato, Laszlo (Institut de Microbiologie et d'Hygiène de l'Université de Montréal, Montreal, Quebec, Canada), and Bela Gozsy. Limited multiplication of Mycobacterium lepraemurium in parabiotic culture, as influenced by osmolarity of an alkaline-galactomannan medium. J. Bacteriol. 91:1859–1862. 1966.—Limited multiplication of Mycobacterium lepraemurium has been achieved in an alkaline (pH 8.4) galactomannan-containing medium, when cultivated alone or in parabiosis with a feeder strain, Torula minuta. Hyperosmolarity (NaCl, 2.0%) enhanced multiplication in both cases. With 2.0% NaCl in the medium, selective lysis of the feeder cells occurred, without damage to M. lepraemurium. Multiplication depends more on the physical properties (viscosity, hyperosmolarity, and alkaline pH) of the medium than on its chemical composition. The described conditions are proposed as a model for cultivation trials with other “apparently noncultivable” microorganisms. PMID:5937242

  2. Outcomes of corticosteroid prophylaxis for hypersensitivity reactions to low osmolar contrast media in high-risk patients.

    PubMed

    Jung, Jae-Woo; Choi, Young Hun; Park, Chang Min; Park, Heung Woo; Cho, Sang-Heon; Kang, Hye-Ryun

    2016-09-01

    Corticosteroid prophylaxis has been widely adopted for the prevention of acute allergic-like reactions to iodinated contrast media, but its use is still controversial because there is no strong evidence supporting its efficacy before administration of nonionic low osmolar contrast media (LOCM). To assess the outcomes of premedication in patients with previous acute allergic-like reactions to LOCM in clinical practice. A retrospective study was performed on 322 high-risk patients who were reexposed to LOCM after premedication composed of antihistamines and/or systemic corticosteroids because of a previous history of acute allergic-like reactions to LOCM. After premedication, 275 patients (85.4%) did not experience any reaction, but 47 patients (14.6%) still experienced a breakthrough reaction. The premedication rate and amount of corticosteroid administered were significantly higher in the nonrecurrence group than in the recurrence group (P = .04 and P = .04, respectively), and a linear trend was observed in the use of corticosteroid premedication and the efficacy of prevention (P for trend = .02). Multivariate binary logistic regression revealed that corticosteroid premedication was effective in preventing recurrence (odds ratio, 0.284; 95% confidence interval, 0.103-0.784). Nonetheless, despite corticosteroid premedication, 3.4% of high-risk patients still experienced moderate to severe reactions, and 14.3% of patients with a severe index reaction again had a severe reaction. Premedication with corticosteroids seems to be helpful in reducing the overall rate of recurrence of acute allergic-like reactions to LOCM in high-risk patients, but patients with severe index reactions are still at risk of developing severe reactions despite corticosteroid premedication. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  3. A kinetic model for quantitative evaluation of the effect of hydrogen and osmolarity on hydrogen production by Caldicellulosiruptor saccharolyticus

    PubMed Central

    2011-01-01

    Background Caldicellulosiruptor saccharolyticus has attracted increased interest as an industrial hydrogen (H2) producer. The aim of the present study was to develop a kinetic growth model for this extreme thermophile. The model is based on Monod kinetics supplemented with the inhibitory effects of H2 and osmotic pressure, as well as the liquid-to-gas mass transfer of H2. Results Mathematical expressions were developed to enable the simulation of microbial growth, substrate consumption and product formation. The model parameters were determined by fitting them to experimental data. The derived model corresponded well with experimental data from batch fermentations in which the stripping rates and substrate concentrations were varied. The model was used to simulate the inhibition of growth by H2 and solute concentrations, giving a critical dissolved H2 concentration of 2.2 mmol/L and an osmolarity of 0.27 to 29 mol/L. The inhibition by H2, being a function of the dissolved H2 concentration, was demonstrated to be mainly dependent on H2 productivity and mass transfer rate. The latter can be improved by increasing the stripping rate, thereby allowing higher H2 productivity. The experimentally determined degree of oversaturation of dissolved H2 was 12 to 34 times the equilibrium concentration and was comparable to the values given by the model. Conclusions The derived model is the first mechanistically based model for fermentative H2 production and provides useful information to improve the understanding of the growth behavior of C. saccharolyticus. The model can be used to determine optimal operating conditions for H2 production regarding the substrate concentration and the stripping rate. PMID:21914204

  4. Reconstruction of the High-Osmolarity Glycerol (HOG) Signaling Pathway from the Halophilic Fungus Wallemia ichthyophaga in Saccharomyces cerevisiae

    PubMed Central

    Konte, Tilen; Terpitz, Ulrich; Plemenitaš, Ana

    2016-01-01

    The basidiomycetous fungus Wallemia ichthyophaga grows between 1.7 and 5.1 M NaCl and is the most halophilic eukaryote described to date. Like other fungi, W. ichthyophaga detects changes in environmental salinity mainly by the evolutionarily conserved high-osmolarity glycerol (HOG) signaling pathway. In Saccharomyces cerevisiae, the HOG pathway has been extensively studied in connection to osmotic regulation, with a valuable knock-out strain collection established. In the present study, we reconstructed the architecture of the HOG pathway of W. ichthyophaga in suitable S. cerevisiae knock-out strains, through heterologous expression of the W. ichthyophaga HOG pathway proteins. Compared to S. cerevisiae, where the Pbs2 (ScPbs2) kinase of the HOG pathway is activated via the SHO1 and SLN1 branches, the interactions between the W. ichthyophaga Pbs2 (WiPbs2) kinase and the W. ichthyophaga SHO1 branch orthologs are not conserved: as well as evidence of poor interactions between the WiSho1 Src-homology 3 (SH3) domain and the WiPbs2 proline-rich motif, the absence of a considerable part of the osmosensing apparatus in the genome of W. ichthyophaga suggests that the SHO1 branch components are not involved in HOG signaling in this halophilic fungus. In contrast, the conserved activation of WiPbs2 by the S. cerevisiae ScSsk2/ScSsk22 kinase and the sensitivity of W. ichthyophaga cells to fludioxonil, emphasize the significance of two-component (SLN1-like) signaling via Group III histidine kinase. Combined with protein modeling data, our study reveals conserved and non-conserved protein interactions in the HOG signaling pathway of W. ichthyophaga and therefore significantly improves the knowledge of hyperosmotic signal processing in this halophilic fungus. PMID:27379041

  5. Erythrocytes as Volume Markers in Experimental PD Show that Albumin Transport in the Extracellular Space Depends on PD Fluid Osmolarity.

    PubMed

    Braide, Magnus; Delbro, Dick; Waniewski, Jacek

    2016-01-01

    ♦ Macromolecules, when used as intraperitoneal volume markers, have the disadvantage of leaking into the surrounding tissue. Therefore, (51)Cr-labeled erythrocytes were evaluated as markers of intraperitoneal volume and used in combination with (125)I-labeled bovine serum albumin to study albumin transport into peritoneal tissues in a rat model of peritoneal dialysis (PD). ♦ Single dwells of 20 mL of lactate-buffered filter-sterilized PD fluid at glucose concentrations of 0.5%, 2.5%, and 3.9% were performed for 1 or 4 hours. Tissue biopsies from abdominal muscle, diaphragm, liver, and intestine, and blood and dialysate samples, were analyzed for radioactivity. ♦ The dialysate distribution volume of labeled erythrocytes, measured after correction for lymphatic clearance to blood, was strongly correlated with, but constantly 3.3 mL larger than, drained volumes. Erythrocyte activity of rinsed peritoneal tissue biopsies corresponded to only 1 mL of dialysate, supporting our utilization of erythrocytes as markers of intraperitoneal volume. The difference between the distribution volumes of albumin and erythrocytes was analyzed to represent the albumin loss into the peritoneal tissues, which increased rapidly during the first few minutes of the dwell and then leveled out at 2.5 mL. It resumed when osmotic ultrafiltration turned into reabsorption and, at the end of the dwell, it was significantly lower for the highest osmolarity PD fluid (3.9% glucose). Biopsy data showed the lowest albumin accumulation and edema formation in abdominal muscle for the 3.9% fluid. ♦ Labeled erythrocytes are acceptable markers of intraperitoneal volume and, combined with labeled albumin, provided novel kinetic data on albumin transport in peritoneal tissues. Copyright © 2016 International Society for Peritoneal Dialysis.

  6. A delayed, unusual non-cardiogenic pulmonary edema after intravascular administration of non-ionic, low osmolar radiocontrast media for coronary angiography.

    PubMed

    Kang, Min-Ho; Nah, Jong-Chun

    2013-07-01

    Non-cardiogenic pulmonary edema (NCPE) is a rare adverse reaction to iodinated radiocontrast media (RCM), in which all previous cases were immediate reactions. A 56-year-old male was given iopamidol, a non-ionic, low osmolar RCM, during coronary artery angiography. He developed pulmonary edema and fever a day after the procedure. Despite diuretic therapy, the patient's pulmonary edema worsened and his high fever persisted. The patient's pulmonary edema was eventually resolved with intravenous steroid treatment. We interpreted the patient's condition as NCPE manifesting as a delayed reaction to RCM. To our knowledge, our case is the first to show NCPE as a delayed hypersensitivity reaction.

  7. Influence of dietary protein content and source on fecal quality, electrolyte concentrations, and osmolarity, and digestibility in dogs differing in body size.

    PubMed

    Nery, J; Biourge, V; Tournier, C; Leray, V; Martin, L; Dumon, H; Nguyen, P

    2010-01-01

    When fed the same diet, large-breed dogs tend to produce feces of poorer quality compared with small-breed dogs. Moreover, German shepherds, although having a BW similar to Giant Schnauzers, are particularly prone to digestive intolerance, producing feces of poor consistency and increased moisture. Digestive tolerance reflects the reaction of the animal to the diet, and it can be assessed by determining fecal quality (consistency, moisture, volume, odor, and color). This study was conducted to assess the effect of protein source and content on fecal quality, and to determine whether greater digestibility and lesser fecal osmolarity and electrolyte concentrations are associated with improved fecal quality in dogs differing in body size and digestive tolerance. Twenty-seven healthy female dogs were divided into 4 groups according to BW and digestive tolerance: small, medium, large tolerant, and large sensitive. Five diets, varying in protein source (wheat gluten, poultry meal, and a 50:50 mixture of both sources) and concentration (22, 29, and 39% CP on a DM basis for low, medium, and high, respectively) were tested. The present study was divided in 2 phases: 2 diets were studied in a crossover design in phase I, and 3 diets were studied in a Latin square design in phase II. Diets were fed for 14 d, followed by a 12-d transition period. Fecal score (1 = dry and hard feces, to 5 = liquid diarrhea), moisture, electrolytes (Na and K), and osmolarity, and digestibility of DM, energy, fat, CP, and ash were determined. Fecal score and moisture (P < 0.001) were less and overall digestibility (P < 0.001 for DM, CP, fat, ash, and energy) was greater for wheat gluten than for poultry meal diets. Large dogs had the greatest fecal score and moisture (P < 0.001), together with the greatest overall digestibility (P < 0.001 for DM, P = 0.054 for CP, P = 0.005 for ash, and P = 0.003 for energy). Osmolarity was less for wheat gluten-based diets (P < 0.001), and was not affected by

  8. Incubation temperature, osmolarity, and salicylate affect the expression of resistance-nodulation-division efflux pumps and outer membrane porins in Acinetobacter baumannii ATCC19606T.

    PubMed

    Bazyleu, Andrei; Kumar, Ayush

    2014-08-01

    In this study, we examined the impact of various environmental conditions on the expression of resistance-nodulation-division (RND) efflux pumps and outer membrane (OM) porins, two key determinants of Acinetobacter baumannii's intrinsic resistance, an organism known to cause various multidrug resistant infections in immunocompromised individuals. Quantitative RT-PCR was used to analyze the expression of adeB, adeG, and adeJ (genes encoding RND pumps) and 33 kDa, carO, and oprD (genes encoding OM porins) of A. baumannii ATCC19606(T) under different incubation temperatures (30, 37, and 42 °C) and in the presence of high osmolarity and salicylate. Downregulation of all three RND pumps was observed at 30 °C, while downregulation of all three porins tested was observed at increased osmolarity. Downregulation of RND efflux pumps, particularly AdeABC, was consistent with increased susceptibility to antibiotics that are substrates of this pump. Expression of the adeR response regulator gene of the AdeRS system, the activator of the AdeABC pump, was also analyzed. Our work shows that various environmental stress conditions can influence the expression of RND pumps and porins in A. baumannii ATCC19606(T) and thus may play a role in the modulation of its antibiotic resistance.

  9. Adenylyl cyclase G, an osmosensor controlling germination of Dictyostelium spores.

    PubMed

    van Es, S; Virdy, K J; Pitt, G S; Meima, M; Sands, T W; Devreotes, P N; Cotter, D A; Schaap, P

    1996-09-27

    Dictyostelium cells express a G-protein-coupled adenylyl cyclase, ACA, during aggregation and an atypical adenylyl cyclase, ACG, in mature spores. The ACG gene was disrupted by homologous recombination. acg- cells developed into normal fruiting bodies with viable spores, but spore germination was no longer inhibited by high osmolarity, a fairly universal constraint for spore and seed germination. ACG activity, measured in aca-/ACG cells, was strongly stimulated by high osmolarity with optimal stimulation occurring at 200 milliosmolar. RdeC mutants, which display unrestrained protein kinase A (PKA) activity and a cell line, which overexpresses PKA under a prespore specific promoter, germinate very poorly, both at high and low osmolarity. These data indicate that ACG is an osmosensor controlling spore germination through activation of protein kinase A.

  10. Two-Component Signaling Regulates Osmotic Stress Adaptation via SskA and the High-Osmolarity Glycerol MAPK Pathway in the Human Pathogen Talaromyces marneffei

    PubMed Central

    Cao, Cunwei; Andrianopoulos, Alex

    2016-01-01

    ABSTRACT For successful infection to occur, a pathogen must be able to evade or tolerate the host’s defense systems. This requires the pathogen to first recognize the host environment and then signal this response to elicit a complex adaptive program in order to activate its own defense strategies. In both prokaryotes and eukaryotes, two-component signaling systems are utilized to sense and respond to changes in the external environment. The hybrid histidine kinases (HHKs) at the start of the two-component signaling pathway have been well characterized in human pathogens. However, how these HHKs regulate processes downstream currently remains unclear. This study describes the role of a response regulator downstream of these HHKs, sskA, in Talaromyces marneffei, a dimorphic human pathogen. sskA is required for asexual reproduction, hyphal morphogenesis, cell wall integrity, osmotic adaptation, and the morphogenesis of yeast cells both in vitro at 37°C and during macrophage infection, but not during dimorphic switching. Comparison of the ΔsskA mutant with a strain in which the mitogen-activated protein kinase (MAPK) of the high-osmolarity glycerol pathway (SakA) has been deleted suggests that SskA acts upstream of this pathway in T. marneffei to regulate these morphogenetic processes. This was confirmed by assessing the amount of phosphorylated SakA in the ΔsskA mutant, antifungal resistance due to a lack of SakA activation, and the ability of a constitutively active sakA allele (sakAF316L) to suppress the ΔsskA mutant phenotypes. We conclude that SskA regulates morphogenesis and osmotic stress adaptation in T. marneffei via phosphorylation of the SakA MAPK of the high-osmolarity glycerol pathway. IMPORTANCE This is the first study in a dimorphic fungal pathogen to investigate the role of a response regulator downstream of two-component signaling systems and its connection to the high-osmolarity glycerol pathway. This study will inspire further research into

  11. Pain in femoral arteriography. A double-blind, randomized, clinical study comparing safety and efficacy of the iso-osmolar iodixanol 270 mgI/ml and the low-osmolar iomeprol 300 mgI/ml in 9 European centers.

    PubMed

    Manke, C; Marcus, C; Page, A; Puey, J; Batakis, O; Fog, A

    2003-11-01

    To compare the injection-associated pain and heat sensation after administration of the iso-osmolar contrast medium (IOCM) iodixanol (Visipaque trade mark 270 mg I/ml) and the low osmolar contrast medium (LOCM) iomeprol (Iomeron trade mark 300 mg I/ml) in femoral arteriography. 352 patients received iodixanol or iomeprol in a prospective, double-blind, randomized, parallel-group clinical trial. The first injection during femoral arteriography (DSA with automated stepping) was standardized. Injection-associated pain and heat sensation, efficacy and safety up to 72 h were evaluated. The iodixanol group reported significant less injection-associated pain than the iomeprol group after the first injection (7.4% vs. 17.6%; p = 0.007), and after all injections (11% vs. 19.4%; p = 0.045). Iodixanol caused less heat sensation after the first injection (p = 0.007) and after all injections (p = 0.029). Heat sensations in the iodixanol group were less intense after all injections (p < 0.0001). No difference was found between the groups regarding the frequency of patients having adverse reactions (5.1% vs. 4%). The IOCM iodixanol caused significantly less frequent injection-associated pain and heat sensation than the LOCM iomeprol during femoral arteriography.

  12. The safety and cost-effectiveness of low osmolar contrast media. Can economic analysis determine the real worth of a new technology?

    PubMed

    Henry, D A; Evans, D B; Robertson, J

    1991-06-03

    To estimate the reduction in mortality associated with a reduced adverse reaction rate following the substitution of older high osmolar radiocontrast media (HOCM) by the newer and more expensive low osmolar contrast media (LOCM), and to assess the cost-effectiveness of switching from HOCM to LOCM in patients with and without underlying risk factors for adverse reactions from radiocontrast agents. Data from large prospective studies of adverse reactions to HOCM and LOCM were used to estimate the expected number of deaths and severe non-fatal reactions in a hypothetical population receiving one million intravenous radiocontrast injections with HOCM, and the expected reduction in the frequency of these outcomes after substitution by LOCM in high-risk and low-risk groups respectively. Life-years lost with each radiocontrast-related death were estimated from an audit of fatal adverse reaction reports submitted to the Adverse Drug Reactions Advisory Committee. The direct costs considered in the study were the increased costs of LOCM and the hospital costs of treating radiocontrast reactions which were estimated from an audit of cases admitted to public hospitals in Newcastle. The literature search included Medline (1966-1989) and bibliographies of original and review articles. We included only studies which were prospective, monitored patients in a formal way, described a mechanism for the recording of adverse events and were of sufficient size to have been capable of detecting severe reactions to radiocontrast agents. Data were extracted independently by two investigators, unblinded, with disagreements resolved by consensus. Mortality data from individual reports were pooled and exact confidence intervals were calculated on the assumption of a Poisson distribution. In the case of comparative studies the relative risks of severe reactions in low-risk versus high-risk patients and with LOCM compared with HOCM were treated for homogeneity, and pooled odds ratios and 95

  13. A Mitogen-Activated Protein Kinase Tmk3 Participates in High Osmolarity Resistance, Cell Wall Integrity Maintenance and Cellulase Production Regulation in Trichoderma reesei

    PubMed Central

    Wang, Mingyu; Zhao, Qiushuang; Yang, Jinghua; Jiang, Baojie; Wang, Fangzhong; Liu, Kuimei; Fang, Xu

    2013-01-01

    The mitogen-activated protein kinase (MAPK) pathways are important signal transduction pathways conserved in essentially all eukaryotes, but haven't been subjected to functional studies in the most important cellulase-producing filamentous fungus Trichoderma reesei. Previous reports suggested the presence of three MAPKs in T. reesei: Tmk1, Tmk2, and Tmk3. By exploring the phenotypic features of T. reesei Δtmk3, we first showed elevated NaCl sensitivity and repressed transcription of genes involved in glycerol/trehalose biosynthesis under higher osmolarity, suggesting Tmk3 participates in high osmolarity resistance via derepression of genes involved in osmotic stabilizer biosynthesis. We also showed significant downregulation of genes encoding chitin synthases and a β-1,3-glucan synthase, decreased chitin content, ‘budded’ hyphal appearance typical to cell wall defective strains, and increased sensitivity to calcofluor white/Congo red in the tmk3 deficient strain, suggesting Tmk3 is involved in cell wall integrity maintenance in T. reesei. We further observed the decrease of cellulase transcription and production in T. reesei Δtmk3 during submerged cultivation, as well as the presence of MAPK phosphorylation sites on known transcription factors involved in cellulase regulation, suggesting Tmk3 is also involved in the regulation of cellulase production. Finally, the expression of cell wall integrity related genes, the expression of cellulase coding genes, cellulase production and biomass accumulation were compared between T. reesei Δtmk3 grown in solid state media and submerged media, showing a strong restoration effect in solid state media from defects resulted from tmk3 deletion. These results showed novel physiological processes that fungal Hog1-type MAPKs are involved in, and present the first experimental investigation of MAPK signaling pathways in T. reesei. Our observations on the restoration effect during solid state cultivation suggest that T. reesei

  14. Effects of Intra-Arterial and Intravenous Iso-Osmolar Contrast Medium (Iodixanol) on the Risk of Contrast-Induced Acute Kidney Injury: A Meta-Analysis

    PubMed Central

    McCullough, Peter A.; Brown, Jeremiah R.

    2011-01-01

    Background The iso-osmolar contrast agent iodixanol may be associated with a lower incidence of contrast-induced acute kidney injury (CI-AKI) than low-osmolar contrast media (LOCM), but previous meta-analyses have yielded mixed results. Objectives: To compare the incidence of CI-AKI between iodixanol and LOCM. Methods Studies were identified from literature searches to December 2009, clinicaltrials.gov, and conference abstracts from the past 2 years including 2010. Only prospective, randomized comparisons between iodixanol and LOCM with CI-AKI [increase in serum creatinine (sCr) ≥0.5 mg/dl or ≥25% from baseline, as defined in the trial] as a primary and/or secondary endpoint and a Jadad score ≥2 were included. A random-effects model was used to obtain pooled relative risks (RRs) for CI-AKI in analyses based on route of administration [intra-arterial (IA) or intravenous (IV)], definition of CI-AKI, and timing of sCr measurements. Results 145 potential articles were identified, of which 25 were included in the meta-analysis. Following IA administration (n = 19), the RR for CI-AKI (≥0.5 mg/dl definition) with iodixanol, compared with LOCM, was 0.462 [95% confidence interval (CI): 0.272–0.786, p = 0.004, 15 studies]. Using the ≥25% definition, there was a lower incidence of CI-AKI with iodixanol versus LOCM, but the difference was not statistically significant (RR: 0.577, 95% CI: 0.297–1.12, p = 0.104, 11 studies). In the IV trials, there was no significant difference in the incidence of CI-AKI using either definition (≥0.5 mg/dl definition: RR: 0.967, 95% CI: 0.188–4.972, p = 0.968, 3 trials; ≥25% definition: RR: 0.656, 95% CI: 0.316–1.360, p = 0.257, 4 trials). Conclusions IA but not IV administration of iodixanol is associated with a significantly lower risk of CI-AKI than LOCM. PMID:22164156

  15. Salt-sensitivity of σH and Spo0A prevents sporulation of Bacillus subtilis at high osmolarity avoiding death during cellular differentiation

    PubMed Central

    Widderich, Nils; Rodrigues, Christopher D.A.; Commichau, Fabian M.; Fischer, Kathleen E.; Ramirez-Guadiana, Fernando H.; Rudner, David Z.; Bremer, Erhard

    2016-01-01

    Summary The spore-forming bacterium Bacillus subtilis frequently experiences high osmolarity as a result of desiccation in the soil. The formation of a highly desiccation-resistant endospore might serve as a logical osmostress escape route when vegetative growth is no longer possible. However, sporulation efficiency drastically decreases concomitant with an increase in the external salinity. Fluorescence microscopy of sporulation-specific promoter fusions to gfp revealed that high salinity blocks entry into the sporulation pathway at a very early stage. Specifically, we show that both Spo0A- and SigH-dependent transcription are impaired. Furthermore, we demonstrate that the association of SigH with core RNA polymerase is reduced under these conditions. Suppressors that modestly increase sporulation efficiency at high salinity map to the coding region of sigH and in the regulatory region of kinA, encoding one the sensor kinases that activates Spo0A. These findings led us to discover that B. subtilis cells that overproduce KinA can bypass the salt-imposed block in sporulation. Importantly, these cells are impaired in the morphological process of engulfment and late forespore gene expression and frequently undergo lysis. Altogether our data indicate that B. subtilis blocks entry into sporulation in high-salinity environments preventing commitment to a developmental program that it cannot complete. PMID:26712348

  16. Cell wall integrity and high osmolarity glycerol pathways are required for adaptation of Alternaria brassicicola to cell wall stress caused by brassicaceous indolic phytoalexins.

    PubMed

    Joubert, Aymeric; Bataille-Simoneau, Nelly; Campion, Claire; Guillemette, Thomas; Hudhomme, Piétrick; Iacomi-Vasilescu, Béatrice; Leroy, Thibault; Pochon, Stéphanie; Poupard, Pascal; Simoneau, Philippe

    2011-01-01

    Camalexin, the characteristic phytoalexin of Arabidopsis thaliana, inhibits growth of the fungal necrotroph Alternaria brassicicola. This plant metabolite probably exerts its antifungal toxicity by causing cell membrane damage. Here we observed that activation of a cellular response to this damage requires cell wall integrity (CWI) and the high osmolarity glycerol (HOG) pathways. Camalexin was found to activate both AbHog1 and AbSlt2 MAP kinases, and activation of the latter was abrogated in a AbHog1 deficient strain. Mutant strains lacking functional MAP kinases showed hypersensitivity to camalexin and brassinin, a structurally related phytoalexin produced by several cultivated Brassica species. Enhanced susceptibility to the membrane permeabilization activity of camalexin was observed for MAP kinase deficient mutants. These results suggest that the two signalling pathways have a pivotal role in regulating a cellular compensatory response to preserve cell integrity during exposure to camalexin. AbHog1 and AbSlt2 deficient mutants had reduced virulence on host plants that may, at least for the latter mutants, partially result from their inability to cope with defence metabolites such as indolic phytoalexins. This constitutes the first evidence that a phytoalexin activates fungal MAP kinases and that outputs of activated cascades contribute to protecting the fungus against antimicrobial plant metabolites. © 2010 Blackwell Publishing Ltd.

  17. Salt-sensitivity of σ(H) and Spo0A prevents sporulation of Bacillus subtilis at high osmolarity avoiding death during cellular differentiation.

    PubMed

    Widderich, Nils; Rodrigues, Christopher D A; Commichau, Fabian M; Fischer, Kathleen E; Ramirez-Guadiana, Fernando H; Rudner, David Z; Bremer, Erhard

    2016-04-01

    The spore-forming bacterium Bacillus subtilis frequently experiences high osmolarity as a result of desiccation in the soil. The formation of a highly desiccation-resistant endospore might serve as a logical osmostress escape route when vegetative growth is no longer possible. However, sporulation efficiency drastically decreases concomitant with an increase in the external salinity. Fluorescence microscopy of sporulation-specific promoter fusions to gfp revealed that high salinity blocks entry into the sporulation pathway at a very early stage. Specifically, we show that both Spo0A- and SigH-dependent transcription are impaired. Furthermore, we demonstrate that the association of SigH with core RNA polymerase is reduced under these conditions. Suppressors that modestly increase sporulation efficiency at high salinity map to the coding region of sigH and in the regulatory region of kinA, encoding one the sensor kinases that activates Spo0A. These findings led us to discover that B. subtilis cells that overproduce KinA can bypass the salt-imposed block in sporulation. Importantly, these cells are impaired in the morphological process of engulfment and late forespore gene expression and frequently undergo lysis. Altogether our data indicate that B. subtilis blocks entry into sporulation in high-salinity environments preventing commitment to a developmental program that it cannot complete. © 2015 John Wiley & Sons Ltd.

  18. Evidence of a New Role for the High-Osmolarity Glycerol Mitogen-Activated Protein Kinase Pathway in Yeast: Regulating Adaptation to Citric Acid Stress†

    PubMed Central

    Lawrence, Clare L.; Botting, Catherine H.; Antrobus, Robin; Coote, Peter J.

    2004-01-01

    Screening the Saccharomyces cerevisiae disruptome, profiling transcripts, and determining changes in protein expression have identified an important new role for the high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathway in the regulation of adaptation to citric acid stress. Deletion of HOG1, SSK1, PBS2, PTC2, PTP2, and PTP3 resulted in sensitivity to citric acid. Furthermore, citric acid resulted in the dual phosphorylation, and thus activation, of Hog1p. Despite minor activation of glycerol biosynthesis, the inhibitory effect of citric acid was not due to an osmotic shock. HOG1 negatively regulated the expression of a number of proteins in response to citric acid stress, including Bmh1p. Evidence suggests that BMH1 is induced by citric acid to counteract the effect of amino acid starvation. In addition, deletion of BMH2 rendered cells sensitive to citric acid. Deletion of the transcription factor MSN4, which is known to be regulated by Bmh1p and Hog1p, had a similar effect. HOG1 was also required for citric acid-induced up-regulation of Ssa1p and Eno2p. To counteract the cation chelating activity of citric acid, the plasma membrane Ca2+ channel, CCH1, and a functional vacuolar membrane H+-ATPase were found to be essential for optimal adaptation. Also, the transcriptional regulator CYC8, which mediates glucose derepression, was required for adaptation to citric acid to allow cells to metabolize excess citrate via the tricarboxylic acid (TCA) cycle. Supporting this, Mdh1p and Idh1p, both TCA cycle enzymes, were up-regulated in response to citric acid. PMID:15060153

  19. Evidence of a new role for the high-osmolarity glycerol mitogen-activated protein kinase pathway in yeast: regulating adaptation to citric acid stress.

    PubMed

    Lawrence, Clare L; Botting, Catherine H; Antrobus, Robin; Coote, Peter J

    2004-04-01

    Screening the Saccharomyces cerevisiae disruptome, profiling transcripts, and determining changes in protein expression have identified an important new role for the high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathway in the regulation of adaptation to citric acid stress. Deletion of HOG1, SSK1, PBS2, PTC2, PTP2, and PTP3 resulted in sensitivity to citric acid. Furthermore, citric acid resulted in the dual phosphorylation, and thus activation, of Hog1p. Despite minor activation of glycerol biosynthesis, the inhibitory effect of citric acid was not due to an osmotic shock. HOG1 negatively regulated the expression of a number of proteins in response to citric acid stress, including Bmh1p. Evidence suggests that BMH1 is induced by citric acid to counteract the effect of amino acid starvation. In addition, deletion of BMH2 rendered cells sensitive to citric acid. Deletion of the transcription factor MSN4, which is known to be regulated by Bmh1p and Hog1p, had a similar effect. HOG1 was also required for citric acid-induced up-regulation of Ssa1p and Eno2p. To counteract the cation chelating activity of citric acid, the plasma membrane Ca(2+) channel, CCH1, and a functional vacuolar membrane H(+)-ATPase were found to be essential for optimal adaptation. Also, the transcriptional regulator CYC8, which mediates glucose derepression, was required for adaptation to citric acid to allow cells to metabolize excess citrate via the tricarboxylic acid (TCA) cycle. Supporting this, Mdh1p and Idh1p, both TCA cycle enzymes, were up-regulated in response to citric acid.

  20. Exposure to low- vs iso-osmolar contrast agents reduces NADPH-dependent reactive oxygen species generation in a cellular model of renal injury.

    PubMed

    Netti, Giuseppe Stefano; Prattichizzo, Clelia; Montemurno, Eustacchio; Simone, Simona; Cafiero, Cesira; Rascio, Federica; Stallone, Giovanni; Ranieri, Elena; Grandaliano, Giuseppe; Gesualdo, Loreto

    2014-03-01

    Contrast-induced nephropathy represents the third cause of hospital-acquired acute renal failure. This study investigated the effects of low- vs iso-osmolar contrast medium (CM) exposure on NADPH-dependent reactive oxygen species (ROS) generation by tubular cells. X-ray attenuation of iohexol, iopamidol, and iodixanol was assessed at equimolar iodine concentrations and their effects on human renal proximal tubular cells (PTCs) were evaluated with equally attenuating solutions of each CM. Cytotoxicity, apoptosis, and necrosis were investigated by trypan blue exclusion, MTT assay, and annexin V/propidium iodide assay, respectively. ROS production was assessed by DCF assay, NADPH oxidase activity by the lucigenin-enhanced chemiluminescence method, and Nox4 expression by immunoblot. Yielding the same X-ray attenuation, CM cytotoxicity was assessed in PTCs at equimolar iodine concentrations. More necrosis was present after incubation with iohexol and iopamidol than after incubation with equal concentrations of iodixanol. Iohexol and iodixanol at low iodine concentrations induced less cytotoxicity than iopamidol. Moreover, both iohexol and iopamidol induced more apoptosis than iodixanol, with a dose-dependent effect. ROS generation was significantly higher with iopamidol and iohexol compared to iodixanol. NADPH oxidase activity and Nox4 protein expression significantly increased after exposure to iopamidol and iohexol, with a dose-dependent effect, compared with iodixanol. CM-induced Nox4 expression and activity depended upon Src activation. In conclusion, at angiographic concentrations, iodixanol induces fewer cytotoxic effects on cultured tubular cells than iohexol and iopamidol along with a lower induction of Nox4-dependent ROS generation. This enzyme may, thus, represent a potential therapeutic target to prevent iodinated CM-related oxidative stress.

  1. Re-exposure to low osmolar iodinated contrast media in patients with prior moderate-to-severe hypersensitivity reactions: A multicentre retrospective cohort study.

    PubMed

    Park, Hye Jung; Park, Jung-Won; Yang, Min-Suk; Kim, Mi-Yeong; Kim, Sae-Hoon; Jang, Gwang Cheon; Nam, Young-Hee; Kim, Gun-Woo; Kim, Sujeong; Park, Hye-Kyung; Jung, Jae-Woo; Park, Jong-Sook; Kang, Hye-Ryun

    2017-07-01

    To evaluate the outcomes of re-exposure to low-osmolar iodinated contrast medium (LOCM) in patients with a history of moderate-to-severe hypersensitivity reaction (HSR). We retrospectively evaluated a cohort comprising all subjects satisfying the following conditions at 11 centres: (1) experienced a moderate-to-severe HSR to LOCM by December 2014, and (2) underwent contrast-enhanced computed tomography after the initial HSR between January 2014 and December 2014. A total of 150 patients with 328 instances of re-exposure were included; the recurrence rate of HSR was 19.5%. Patients with severe initial HSR exhibited a higher recurrence rate of severe HSR compared to patients with moderate initial HSR, despite more intensive premedication. In the multivariate analysis, the independent risk factors for recurrence of HSR were diabetes, chronic urticaria, drug allergy other than to iodinated contrast media (ICM) and severe initial HSR. The risk of recurrent HSR was 67.1% lower in cases where the implicated ICM was changed to another one (odds ratio: 0.329; P = 0.001). However, steroid premedication did not show protective effects against recurrent HSR. In high-risk patients who have previously experienced a moderate-to-severe initial HSR to LOCM, we should consider changing the implicated ICM to reduce recurrence risk. • In patients with moderate-to-severe HSR, steroid premedication only shows limited effectiveness. • Changing the implicated ICM can reduce the recurrence of HSR to ICM. • Diabetes, chronic urticaria and drug allergies increase the risk of ICM HSR.

  2. Expression of Pseudomonas syringae type III effectors in yeast under stress conditions reveals that HopX1 attenuates activation of the high osmolarity glycerol MAP kinase pathway.

    PubMed

    Salomon, Dor; Bosis, Eran; Dar, Daniel; Nachman, Iftach; Sessa, Guido

    2012-11-01

    The Gram-negative bacterium Pseudomonas syringae pv. tomato (Pst) is the causal agent of speck disease in tomato. Pst pathogenicity depends on a type III secretion system that delivers effector proteins into host cells, where they promote disease by manipulating processes to the advantage of the pathogen. Previous studies identified seven Pst effectors that inhibit growth when expressed in yeast under normal growth conditions, suggesting that they interfere with cellular processes conserved in yeast and plants. We hypothesized that effectors also target conserved cellular processes that are required for yeast growth only under stress conditions. We therefore examined phenotypes induced by expression of Pst effectors in yeast grown in the presence of various stressors. Out of 29 effectors tested, five (HopX1, HopG1, HopT1-1, HopH1 and AvrPtoB) displayed growth inhibition phenotypes only in combination with stress conditions. Viability assays revealed that the HopX1 effector caused loss of cell viability under prolonged osmotic stress. Using transcription reporters, we found that HopX1 attenuated the activation of the high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathway, which is responsible for yeast survival under osmotic stress, while other MAPK pathways were mildly affected by HopX1. Interestingly, HopX1-mediated phenotypes in yeast were dependent on the putative transglutaminase catalytic triad of the effector. This study enlarges the pool of phenotypes available for the functional analysis of Pst type III effectors in yeast, and exemplifies how analysis of phenotypes detected in yeast under stress conditions can lead to the identification of eukaryotic cellular processes affected by bacterial effectors.

  3. Influence of osmolarity of contrast medium and saline flush on computed tomography angiography: comparison of monomeric and dimeric iodinated contrast media with different iodine concentrations at an identical iodine delivery rate.

    PubMed

    Kishimoto, Miori; Doi, Shoko; Shimizu, Junichiro; Lee, Ki-Ja; Iwasaki, Toshiroh; Miyake, Yoh-Ichi; Yamada, Kazutaka

    2010-10-01

    To evaluate the influence of osmolarity of iodinated contrast media and saline flush on the contrast effect in thoracic computed tomography angiography (CTA) at an identical iodine delivery rate (IDR). Seven beagles were used in a cross-over experiment. The contrast media used were iohexol 350 mgI/ml (IOH350; osmolarity 844 mmol/kg) and iodixanol 320 mgI/ml (IDX320; osmolarity 290 mmol/kg). Each contrast medium was administered to groups with and without saline flush at 40.0 mgI/kg/s for all experiments. Dynamic CT scanning was performed at the ninth thoracic vertebra level. The peak value, area under the curve (AUC), and time to peak (TTP) were calculated from the time attenuation curves of the pulmonary artery and aorta. There was no significant difference between IOH350 and IDX320 with or without saline flush in the peak values for the pulmonary artery and aorta. AUC was significantly higher in groups with saline flush for both contrast media and arteries (p<0.05) with no significant difference between contrast media. TTP was significantly longer in groups with saline flush than without saline flush for both contrast media and arteries (p<0.05), with no significant difference between contrast media. There were no significant differences in the contrast effects of monomeric IOH350 and dimeric IDX320 in thoracic CTA when used at an identical IDR. Moreover, saline flush prolonged the peak duration at 600 mgI/kg. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

  4. Cadmium-induced activation of high osmolarity glycerol pathway through its Sln1 branch is dependent on the MAP kinase kinase kinase Ssk2, but not its paralog Ssk22, in budding yeast.

    PubMed

    Jiang, Linghuo; Cao, Chunlei; Zhang, Lilin; Lin, Wei; Xia, Jing; Xu, Huihui; Zhang, Yan

    2014-12-01

    Cadmium ions disrupt reactive oxygen species/Ca(2+) homeostasis and subsequently elicit cell death and adaptive signaling cascades in eukaryotic cells. Through a functional genomics approach, we have identified deletion mutants of 106 yeast genes, including three MAP kinase genes (HOG1, SLT2, and KSS1), are sensitive to a sublethal concentration of cadmium, and 64 mutants show elevated intracellular cadmium concentrations upon exposure to cadmium. Hog1 is phosphorylated, reaching a peak 30 min after the cadmium treatment. Both Sln1 and Sho1 upstream branches are involved in the cadmium-induced activation of high osmolarity glycerol (HOG) pathway. Cadmium-induced HOG activation is dependent on the MAP kinase kinase kinase Ssk2, but not its paralog Ssk22, in the Sln1 branch.

  5. Effects of Adipokines and Insulin on Intracellular pH, Calcium Concentration, and Responses to Hypo-Osmolarity in Human Articular Chondrocytes from Healthy and Osteoarthritic Cartilage

    PubMed Central

    López-Zapata, Diego F.

    2015-01-01

    Objective: To evaluate the effects of adipokines and insulin on intracellular calcium concentration ([Ca2+]i) and pH (pHi) in human articular chondrocytes from healthy (CHC) and osteoarthritic cartilage (COC). Design: pHi and [Ca2+]i were measured using BCECF and Fura-2 fluorometric probes in CHC and COC under control conditions and following a hypotonic shock. The effects of interleukin-1β (IL1β), tumor necrosis factor-α (TNFα), insulin, leptin, resistin, and adiponectin were assessed. Results: pHi was lower in COC than in CHC. Only IL1β β decreased pHi in both cell types; all the agents enhanced pHi recovery following an ammonium prepulse in CHC, effect that was attenuated by Na+–H+ exchanger inhibitors, but they had no effect in COC. Hypotonic shock (HTS) caused a pHi increase, which was significantly smaller in COC. All the hormones attenuated this response and the effect of IL1β was greater. The basal [Ca2+]i was similar in COC and CHC; IL1β, TNFα, and insulin increased the [Ca2+]i, but leptin, resistin, and adiponectin did not. These effects were greater in COC. This [Ca2+]i increase was dependent on extracellular Ca2+ and attenuated by Na+–Ca2+ exchanger inhibitors. HTS caused a [Ca2+]i increase, which was inhibited by transient receptor potential vanilloid blockers and attenuated by all the hormones tested with the exception of adiponectin. Conclusions: These findings may help explain the association between obesity and osteoarthritis, in which these hormones are altered. The responses of CHC and COC are different, which suggests that a modification of pH and Ca2+ homeostasis is part of the osteoarthritis pathophysiology. PMID:26069708

  6. Expression of neutrophil gelatinase-associated lipocalin in low osmolar contrast-induced nephropathy in rats and the effect of N-acetylcysteine

    PubMed Central

    Li, Wen-Hua; Wang, Lin; He, Hai-Yan; Chen, Jing; Yu, Ya-Ren

    2016-01-01

    Serum creatinine (Scr), which is a conventional indicator of contrast-induced nephropathy (CIN), is unable to reflect the damage of kidney promptly. The present study aimed to investigate the value of neutrophil gelatinase-associated lipocalin (NGAL) in kidney and serum of CIN rats to observe whether NGAL can be used as a superior indicator of CIN. Furthermore, N-acetylcysteine (NAC) was used to assess its effect on CIN. A total of 120 adult male Sprague Dawley rats were randomly divided into four groups (n=30/group): CIN rats (CIN), normal rats treated with NAC (NAC), CIN rats treated with NAC (NAC+CIN) and the control group (CON). Serum Scr and NGAL values were measured at 2, 12, 24, 48 and 72 h following the procedure. Immunohistochemistry and western blot analysis were used to detect NGAL within the kidney tissue. Hematoxylin and eosin staining were used to access the renal injury score. Oxidative stress within the kidney was analyzed via malondialdehyde (MDA) and superoxide dismutase (SOD). The level of NGAL in the serum and tissue of the CIN group increased significantly 2 h after the procedure (P<0.05). However, the Scr value did not exhibit a significantly change until 48 h later. Based on the renal injury scores, NAC reduced the kidney damage caused by the contrast. NAC treatment was associated with a decrease in SOD levels and an increase in MDA. These findings suggested that NGAL was a superior indicator of CIN than Scr, as NGAL was able to detect kidney damage much earlier. Furthermore, NAC treatment inhibited oxidative stress, thus protecting against CIN. PMID:27882134

  7. Control by osmotic pressure of voltage-induced permeabilization and gene transfer in mammalian cells.

    PubMed Central

    Golzio, M; Mora, M P; Raynaud, C; Delteil, C; Teissié, J; Rols, M P

    1998-01-01

    Cells can be transiently permeabilized by a membrane potential difference increase induced by the application of high electric pulses. This was shown to be under the control of the pulsing buffer osmotic pressure, when short pulses were applied. In this paper, the effects of buffer osmotic pressure during electric treatment and during the following 10 min were investigated in Chinese hamster ovary cells subjected to long (ms) square wave pulses, a condition needed to mediate gene transfer. No effect on cell permeabilization for a small molecule such as propidium iodide was observed. The use of a hypoosmolar buffer during pulsation allows more efficient loading of cells with beta-galactosidase, a tetrameric protein, but no effect of the postpulse buffer osmolarity was observed. The resulting expression of plasmid coding for beta-galactosidase was strongly controlled by buffer osmolarity during as well as after the pulse. The results, tentatively explained in terms of the effect of osmotic pressure on cell swelling, membrane organization, and interaction between molecules and membrane, support the existence of key steps in plasmid-membrane interaction in the mechanism of cell electrically mediated gene transfer. PMID:9635756

  8. Genetic and environmental control of salmonella invasion.

    PubMed

    Altier, Craig

    2005-02-01

    An early step in the pathogenesis of non-typhoidal Salmonella species is the ability to penetrate the intestinal epithelial monolayer. This process of cell invasion requires the production and transport of secreted effector proteins by a type III secretion apparatus encoded in Salmonella pathogenicity island I (SPI-1). The control of invasion involves a number of genetic regulators and environmental stimuli in complex relationships. SPI-1 itself encodes several transcriptional regulators (HilA, HilD, HilC, and InvF) with overlapping sets of target genes. These regulators are, in turn, controlled by both positive and regulators outside SPI-1, including the two-component regulators BarA/SirA and PhoP/Q, and the csr post-transcriptional control system. Additionally, several environmental conditions are known to regulate invasion, including pH, osmolarity, oxygen tension, bile, Mg2+ concentration, and short chain fatty acids. This review will discuss the current understanding of invasion control, with emphasis on the interaction of environmental factors with genetic regulators that leads to productive infection.

  9. Efficacy and Safety of Continuous Micro-Pump Infusion of 3% Hypertonic Saline combined with Furosemide to Control Elevated Intracranial Pressure

    PubMed Central

    Li, Yuqian; Li, Zhihong; Li, Min; Yang, Yanlong; Wang, Bao; Gao, Li; Zhang, Xingye; Cheng, Hongyu; Fang, Wei; Zhao, Bo; Wang, Boliang; Gao, Guodong; Li, Lihong

    2015-01-01

    Background Elevated intracranial pressure is one of the most common problems in patients with diverse intracranial disorders, leading to increased morbidity and mortality. Effective management for increased intracranial pressure is based mainly on surgical and medical techniques with hyperosmolar therapy as one of the core medical treatments. The study aimed to explore the effects of continuous micro-pump infusions of 3% hypertonic saline combined with furosemide on intracranial pressure control. Material/Methods We analyzed data on 56 eligible participants with intracranial pressure >20 mmHg from March 2013 to July 2014. The target was to increase and maintain plasma sodium to a level between 145 and 155 mmol/L and osmolarity to a level of 310 to 320 mOsmol/kg. Results Plasma sodium levels significantly increased from 138±5 mmol/L at admission to 151±3 mmol/L at 24 h (P<0.01). Osmolarity increased from 282±11 mOsmol/kg at baseline to 311±8 mOsmol/kg at 24 h (P<0.01). Intracranial pressure significantly decreased from 32±7 mmHg to 15±6 mmHg at 24 h (P<0.01). There was a significant improvement in CPP (P<0.01). Moreover, central venous pressure, mean arterial pressure, and Glasgow Coma Scale slightly increased. However, these changes were not statistically significant. Conclusions Continuous infusion of 3% hypertonic saline + furosemide is effective and safe for intracranial pressure control. PMID:26082293

  10. Commandeering Channel Voltage Sensors for Secretion, Cell Turgor, and Volume Control.

    PubMed

    Karnik, Rucha; Waghmare, Sakharam; Zhang, Ben; Larson, Emily; Lefoulon, Cécile; Gonzalez, Wendy; Blatt, Michael R

    2017-01-01

    Control of cell volume and osmolarity is central to cellular homeostasis in all eukaryotes. It lies at the heart of the century-old problem of how plants regulate turgor, mineral and water transport. Plants use strongly electrogenic H(+)-ATPases, and the substantial membrane voltages they foster, to drive solute accumulation and generate turgor pressure for cell expansion. Vesicle traffic adds membrane surface and contributes to wall remodelling as the cell grows. Although a balance between vesicle traffic and ion transport is essential for cell turgor and volume control, the mechanisms coordinating these processes have remained obscure. Recent discoveries have now uncovered interactions between conserved subsets of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins that drive the final steps in secretory vesicle traffic and ion channels that mediate in inorganic solute uptake. These findings establish the core of molecular links, previously unanticipated, that coordinate cellular homeostasis and cell expansion.

  11. Osmotically-induced genes are controlled by the transcription factor TonEBP in cultured cardiomyocytes.

    PubMed

    Navarro, Paola; Chiong, Mario; Volkwein, Karen; Moraga, Francisco; Ocaranza, María Paz; Jalil, Jorge E; Lim, Sun Woo; Kim, Jeong-Ah; Kwon, H Moo; Lavandero, Sergio

    2008-07-25

    Changes in cardiac osmolarity occur in myocardial infarction. Osmoregulatory mechanisms may, therefore, play a crucial role in cardiomyocyte survival. Tonicity-responsive enhancer binding protein (TonEBP) is a key transcription factor participating in the adaptation of cells to increases in tonicity. However, it is unknown whether cardiac TonEBP is activated by tonicity. Hypertonicity activated transcriptional activity of TonEBP, increased the amounts of both TonEBP mRNA and protein, and induced both the mRNA and protein of TonEBP target genes (aldose reductase and heat shock protein-70). Hypotonicity decreased the amount of TonEBP protein indicating bidirectional osmoregulation of this transcription factor. Adenoviral expression of a dominant negative TonEBP suppressed the hypertonicity-dependent increase of aldose reductase protein. These results indicated that TonEBP controls osmoregulatory mechanisms in cardiomyocytes.

  12. Osmotically- induced genes are controlled by the transcription factor TonEBP in cultured cardiomyocytes

    PubMed Central

    Navarro, Paola; Chiong, Mario; Volkwein, Karen; Moraga, Francisco; Ocaranza, María Paz; Jalil, Jorge E.; Lim, Sun Woo; Kim, Jeong-Ah; Kwon, H. Moo; Lavandero, Sergio

    2008-01-01

    Changes in cardiac osmolarity occur in myocardial infarction. Osmoregulatory mechanisms may, therefore, play a crucial role in cardiomyocyte survival. Tonicity-responsive enhancer binding protein (TonEBP) is a key transcription factor participating in the adaptation of cells to increases in tonicity. However, it is unknown whether cardiac TonEBP is activated by tonicity. Hypertonicity activated transcriptional activity of TonEBP, increased the amounts of both TonEBP mRNA and protein, and induced both the mRNA and protein of TonEBP target genes (aldose reductase and heat shock protein-70). Hypotonicity decreased the amount of TonEBP protein indicating bidirectional osmoregulation of this transcription factor. Adenoviral expression of a dominant negative TonEBP suppressed the hypertonicity-dependent increase of aldose reductase protein. These results indicated that TonEBP controls osmoregulatory mechanisms in cardiomyocytes. PMID:18502201

  13. [Efficacy of the subcutaneous route compared to intravenous hydration in the elderly hospitalised patient: a randomised controlled study].

    PubMed

    Duems Noriega, Oscar; Ariño Blasco, Sergio

    2014-01-01

    The subcutaneous (SC) route has recently emerged as a rehydration method with potential advantages in the geriatric population. Nevertheless, little is known about its application during hospitalization. The objective of the present study is to evaluate the subcutaneous non-inferiority efficacy in hydration against the intravenous (IV) route in elderly patients with dehydration. A prospective, randomized and controlled interventional trial of patients 65 years and older admitted to an Acute Geriatric Unit with mild to moderate dehydration and oral intolerance, evaluating the non-inferiority of subcutaneous fluid therapy versus the intravenous route. The intervention consisted of the administration of up to 1.5 l/day/route for 72 hours subcutaneous vs. intravenous, evaluating the variations in biochemical parameters (urea, creatinine, osmolarity), clinical outcome, and route related complications. Sixty seven patients completed the study (34 SC, age 86.4 ± 8.5 years, 41% women, vs. 33 IV, 84.3 ± 6.6, 54.5% women, with no significant differences). The amount of fluid administered per day by route was 1.320 ml ± 400 SC vs. 1.480 ml ± 340 IV, P = .092. During follow similar reductions were observed between groups without any statistical significance, with mean differences pre-postintervention of urea (49.6 ± 52.3 SC vs. 50.3 ± 52.3 IV, P=.96); creatinine (0.68 ± 0.66 SC vs. 0.60 ± 0.49 IV, P=.58), and osmolarity (15.6 ± 24.4 SC vs. 21.1 ± 31 IV, P=.43). Fewer catheter extraction episodes were observed in the SC group, which also was the group most prone to peri-clysis edema. The efficacy of subcutaneous rehydration in elderly hospitalized patients with mild-moderate dehydration is not inferior to that obtained intravenously, and may even have additional advantages. Copyright © 2013 SEGG. Published by Elsevier Espana. All rights reserved.

  14. [No free water in the treatment of "hyperosmolar diabetic coma": treatment control by comparing serum and CSF (author's transl)].

    PubMed

    Irsigler, K; Kaspar, L; Bruneder, H; Lageder, H

    1977-11-18

    Some serum and CSF concentrations were measured in five patients with severe hyperosmolar coma (mean blood sugar = 58.9 mmol/l; osmolarity = 406 mosmol/l). A gradual decrease of serum osmolarity prevented the development of an osmotic gradient between CSF and extracellular space. Insulin treatment (1-20 IU/h) with a motor infusion pump and infusion of hypertonic solutions decreased serum osmolarity by 2-4 mosmol/l X h. The faster fall of glucose in the extracellular space was compensated by hypertonic saline infusions (up to 365 mosmol/l). All patients survived.

  15. [Contrast-induced nephropathy in patients at risk of renal failure undergoing computed tomography: systematic review and meta-analysis of randomized controlled trials].

    PubMed

    Arana, Estanislao; Catalá-López, Ferrán

    2010-09-11

    We evaluated and quantified by meta-analysis techniques the incidence of contrast-induced nephropathy (CIN) in patients at risk undergoing computed tomography (CT). We conducted a systematic review of randomized controlled clinical trials designated to evaluate the nephrotoxicity related to iso-osmolar contrast media (IOCM) compared to low-osmolar contrast media (LOCM). Main electronic databases searched included PubMed/MEDLINE, EMBASE, ISI Web of Knowledge and Virtual Health Library (BVS-BIREME), as well as abstracts presented at related scientific societies meetings. Prior to data extraction, definitions of nephrotoxicity and risk population were established. Besides meta-analysis, the global agreement between CIN definitions was evaluated with Mantel-Haenszel stratified test. Five studies were included with 716 randomized patients. When CIN was defined as increased serum creatinine (SCr)>or=25%, the relative risk (RR) was 0.71 (CI95%: 0.40-1.26)-in favor of IOCM-and when it was defined as SCr>or=0.5mg/dL it showed a RR 1.48 (CI95%: 0.37-5.87)-favoring LOCM-in the four studies used this criterion. Mantel-Haenszel stratified test was chi2=2.51 (p=0.8). In patients with renal failure undergoing CT there is a similar risk of CIN with the administration of any contrast media studied. CIN incidence depends on the chosen criteria and is lower with the definition of SCr>or=0.5mg/dL at 24-72h. No agreement was found between CIN definitions were adopted. Copyright © 2009 Elsevier España, S.L. All rights reserved.

  16. Long-term model predictive control of gene expression at the population and single-cell levels

    PubMed Central

    Uhlendorf, Jannis; Miermont, Agnès; Delaveau, Thierry; Charvin, Gilles; Fages, François; Bottani, Samuel; Batt, Gregory; Hersen, Pascal

    2012-01-01

    Gene expression plays a central role in the orchestration of cellular processes. The use of inducible promoters to change the expression level of a gene from its physiological level has significantly contributed to the understanding of the functioning of regulatory networks. However, from a quantitative point of view, their use is limited to short-term, population-scale studies to average out cell-to-cell variability and gene expression noise and limit the nonpredictable effects of internal feedback loops that may antagonize the inducer action. Here, we show that, by implementing an external feedback loop, one can tightly control the expression of a gene over many cell generations with quantitative accuracy. To reach this goal, we developed a platform for real-time, closed-loop control of gene expression in yeast that integrates microscopy for monitoring gene expression at the cell level, microfluidics to manipulate the cells’ environment, and original software for automated imaging, quantification, and model predictive control. By using an endogenous osmostress responsive promoter and playing with the osmolarity of the cells environment, we show that long-term control can, indeed, be achieved for both time-constant and time-varying target profiles at the population and even the single-cell levels. Importantly, we provide evidence that real-time control can dynamically limit the effects of gene expression stochasticity. We anticipate that our method will be useful to quantitatively probe the dynamic properties of cellular processes and drive complex, synthetically engineered networks. PMID:22893687

  17. Signal Transduction and Regulatory Mechanisms Involved in Control of the σS (RpoS) Subunit of RNA Polymerase

    PubMed Central

    Hengge-Aronis, Regine

    2002-01-01

    The σS (RpoS) subunit of RNA polymerase is the master regulator of the general stress response in Escherichia coli and related bacteria. While rapidly growing cells contain very little σS, exposure to many different stress conditions results in rapid and strong σS induction. Consequently, transcription of numerous σS-dependent genes is activated, many of which encode gene products with stress-protective functions. Multiple signal integration in the control of the cellular σS level is achieved by rpoS transcriptional and translational control as well as by regulated σS proteolysis, with various stress conditions differentially affecting these levels of σS control. Thus, a reduced growth rate results in increased rpoS transcription whereas high osmolarity, low temperature, acidic pH, and some late-log-phase signals stimulate the translation of already present rpoS mRNA. In addition, carbon starvation, high osmolarity, acidic pH, and high temperature result in stabilization of σS, which, under nonstress conditions, is degraded with a half-life of one to several minutes. Important cis-regulatory determinants as well as trans-acting regulatory factors involved at all levels of σS regulation have been identified. rpoS translation is controlled by several proteins (Hfq and HU) and small regulatory RNAs that probably affect the secondary structure of rpoS mRNA. For σS proteolysis, the response regulator RssB is essential. RssB is a specific direct σS recognition factor, whose affinity for σS is modulated by phosphorylation of its receiver domain. RssB delivers σS to the ClpXP protease, where σS is unfolded and completely degraded. This review summarizes our current knowledge about the molecular functions and interactions of these components and tries to establish a framework for further research on the mode of multiple signal input into this complex regulatory system. PMID:12208995

  18. Fluid filtration and reabsorption across microvascular walls: control by oncotic or osmotic pressure? (secondary publication).

    PubMed

    Bulat, Marin; Klarica, Marijan

    2014-08-28

    Relationships between hydrostatic and oncotic (colloid osmotic) pressures in both capillaries and interstitium are used to explain fluid filtration and reabsorption across microvascular walls. These pressures are incorporated in the Starling oncotic hypothesis of capillaries which fails, however, to explain fluid homeostasis when hydrostatic capillary pressure is high (in feet during orthostasis) and low (in lungs), or when oncotic plasma pressure is significantly decreased in experiments and some clinical states such as genetic analbuminaemia. To explain fluid homeostasis we propose osmotic counterpressure hypothesis of capillaries which claims: 1) during water filtration across microvascular wall in arterial capillary, the plasma osmolytes are sieved (retained) so that plasma osmotic counterpressure is generated, 2) this osmotic counterpressure rises along the length of capillary and when it reaches capillary hydrostatic pressure the water filtration is halted, and 3) in venous capillaries and postcapillary venules where hydrostatic pressure is low, the osmotic counterpressure is instrumental in water reabsorption from interstitium what leads to dissipation of osmotic counterpressure. According to modified van’t Hoff’s equation the generation of osmotic counterpressure depends on plasma concentration of osmolytes and their restricted passage (reflection coefficient) across microvascular wall in comparison to water. Plasma NaCl makes 83% of plasma osmolarity and shows restricted passage across the walls of cerebral and peripheral continuous capillaries, so that Na and Cl are the most important osmolytes for generation of osmotic counterpressure. Our calculation indicates that at various rates of water filtration the osmotic counterpressure of NaCl acts as negative feedback control: higher hydrostatic pressure and water filtration rate create higher osmotic counterpressure which opposes filtration and leads to higher water reabsorption rate. Furthermore, our

  19. Effect of administration route on the renal safety of contrast agents: a meta-analysis of randomized controlled trials.

    PubMed

    Dong, Mei; Jiao, Zhanquan; Liu, Tong; Guo, Fangming; Li, Guangping

    2012-01-01

    The objective of this study was to examine the association between administration route and relative renal safety of contrast agents. We searched all published articles indexed in Embase, Medline and the Cochrane Central Register of Controlled Trials, from January 1980 to November 2010, to identify relevant studies. Of the 1,047 initially identified studies, 11 randomized controlled trials (RCTs) including 2,210 patients with intra-arterial route and 7 RCTs including 919 patients with intravenous route were finally analyzed. With regard to intra-arterial route, our meta-analysis showed that iodixanol significantly decreased the risk of contrast-induced acute kidney injury (CI-AKI) when compared with a pool of low-osmolar contrast media (LOCM; risk ratio [RR] = 0.68; 95% confidence interval [95% CI], 0.50-0.92; Z=2.47; p=0.01), with no significant heterogeneity between individual studies (p=0.14, I2=32.4%). However, iodixanol was not associated with a reduction in CI-AKI compared with the LOCM pooled together (RR=0.75; 95% CI, 0.44-1.26; Z=1.10; p=0.27) with intravenous application, again with no significant heterogeneity between individual studies (p=0.40, I2=3.6%). Our meta-analysis suggests that administration route may affect the renal safety of contrast agents. Specifically, iodixanol may be a better choice for patients in the interventional cardiology setting.

  20. Efficacy of standardized and quality-controlled cord blood serum eye drop therapy in the healing of severe corneal epithelial damage in dry eye.

    PubMed

    Versura, Piera; Profazio, Vincenzo; Buzzi, Marina; Stancari, Alessandra; Arpinati, Mario; Malavolta, Nazzarena; Campos, Emilio C

    2013-04-01

    We standardized quality-controlled cord blood serum (CBS)-based eye drops and evaluated the efficacy of 1-month CBS treatment in the healing of diseased corneal epithelium in severe dry eye (DE) patients. Seventeen graft-versus-host disease (GVHD) and 13 Sjogren syndrome patients with severe persistent corneal defects were enrolled in the framework of a registered clinical trial (ClinicalTrials.gov NCT01234623). Sterile CBS eye drops were prepared to supply 0.15 ng per eye per day epithelial growth factor and administered for 1 month in a 1-day dose dispensing. The extent of epithelial defect was evaluated in square millimeters area, and subjective symptom score (Ocular Surface Disease Index score), Schirmer test I, break-up time, tear osmolarity, corneal esthesiometry (Cochet-Bonnet esthesiometer), conjunctival scraping, and imprint cytology with goblet cell count were performed at baseline (V0) and after 15 (V1) and 30 (V2, endpoint) days of treatment. Satisfaction and tolerability questionnaires were evaluated at V1 and V2. A significant reduction was shown at the endpoint versus baseline in corneal epithelial damage (mean ± SD, 16.1 ± 13.7 vs. 40.9 ± 30 mm²/area, respectively), discomfort symptoms (Ocular Surface Disease Index score, 22.3 ± 10.3 vs. 39.3 ± 16.9), scraping cytology score (3.8 ± 1.2 vs. 6.6 ± 2.1), and tear osmolarity (312.5 ± 7 vs. 322 ± 9.1 mOsm/L), whereas a significant improvement was shown in corneal esthesiometry (48.2 ± 2.1 vs. 49.7 ± 2.1 nylon/mm/length, P < 0.05). All patients reported a high degree of satisfaction upon drop instillation. Heterologous CBS-based eye drops represent a promising therapeutic approach in the healing of severely injured corneal epithelium and in subjective symptom relief. These drops can be obtained as readily available and quality-controlled blood derivative from cord blood banks on a routine basis.

  1. A screen for nigericin-resistant yeast mutants revealed genes controlling mitochondrial volume and mitochondrial cation homeostasis.

    PubMed

    Kucejova, Blanka; Kucej, Martin; Petrezselyova, Silvia; Abelovska, Lenka; Tomaska, Lubomir

    2005-10-01

    Little is known about the regulation of ion transport across the inner mitochondrial membrane in Saccharomyces cerevisiae. To approach this problem, we devised a screening procedure for facilitating the identification of proteins involved in mitochondrial ion homeostasis. Taking advantage of the growth inhibition of yeast cells by electroneutral K(+)/H(+) ionophore nigericin, we screened for genetic mutations that would render cells tolerant to this drug when grown on a nonfermentable carbon source and identified several candidate genes including MDM31, MDM32, NDI1, YMR088C (VBA1), CSR2, RSA1, YLR024C, and YNL136W (EAF7). Direct examination of intact cells by electron microscopy indicated that mutants lacking MDM31 and/or MDM32 genes contain dramatically enlarged, spherical mitochondria and that these morphological abnormalities can be alleviated by nigericin. Mitochondria isolated from the Deltamdm31 and Deltamdm32 mutants exhibited limited swelling in an isotonic solution of potassium acetate even in the presence of an exogenous K(+)/H(+) antiport. In addition, growth of the mutants was inhibited on ethanol-containing media in the presence of high concentrations of salts (KCl, NaCl, or MgSO(4)) and their mitochondria exhibited two- (Deltamdm31 and Deltamdm32) to threefold (Deltamdm31Deltamdm32) elevation in magnesium content. Taken together, these data indicate that Mdm31p and Mdm32p control mitochondrial morphology through regulation of mitochondrial cation homeostasis and the maintenance of proper matrix osmolarity.

  2. Birth Control

    MedlinePlus

    ... girlshealth.gov/ Home Body Your sexuality Birth control Birth control Birth control (also called contraception) may seem confusing ... more. What do I need to know about birth control? top The more you know about birth control, ...

  3. A Randomized, Double-Masked, Placebo-Controlled Clinical Trial of Two Forms of Omega-3 Supplements for Treating Dry Eye Disease.

    PubMed

    Deinema, Laura A; Vingrys, Algis J; Wong, Chinn Yi; Jackson, David C; Chinnery, Holly R; Downie, Laura E

    2017-01-01

    To assess the efficacy of 2 forms of oral long-chain omega-3 (ω-3) essential fatty acid (EFA) supplements, phospholipid (krill oil) and triacylglyceride (fish oil), for treating dry eye disease (DED). Randomized, double-masked, placebo-controlled clinical trial. This study was conducted at a single site and involved 60 participants with mild to moderate DED who were randomized (1:1:1) to 1 of 3 groups: placebo (olive oil), krill oil, or fish oil supplements. Participants received 1 of the 3 interventions: placebo (olive oil 1500 mg/day), krill oil (945 mg/day eicosapentaenoic acid [EPA], + 510 mg/day docosahexaenoic acid [DHA]), or fish oil (1000 mg/day EPA + 500 mg/day DHA) for 90 days, with monthly study visits. Primary outcome measures were mean change in (1) tear osmolarity and (2) DED symptoms (Ocular Surface Disease Index [OSDI] score) between days 1 and 90. Secondary outcomes included mean change in key clinical signs (tear stability, tear production, ocular surface staining, bulbar and limbal redness, tear volume, anterior blepharitis, meibomian gland capping) and tear inflammatory cytokine levels. In total, 54 participants completed the study. At day 90, tear osmolarity was reduced from baseline with both krill oil (mean ± standard error of the mean: -18.6±4.5 mOsmol/l; n = 18; P < 0.001) and fish oil (-19.8±3.9 mOsmol/l; n = 19; P < 0.001) supplements, compared with placebo (-1.5±4.4 mOsmol/l; n = 17). OSDI score was significantly reduced at day 90 relative to baseline in the krill oil group only, compared with placebo (-18.6±2.4 vs. -10.5±3.3; P = 0.02). At day 90, there were also relative improvements in tear breakup time and ocular bulbar redness, compared with placebo, for both forms of ω-3 EFAs. Basal tear levels of the proinflammatory cytokine interleukin 17A were significantly reduced in the krill oil group, compared with placebo, at day 90 (-27.1±10.9 vs. 46.5±30.4 pg/ml; P = 0.02). A moderate daily dose of both forms of long

  4. Patient Discomfort Associated with the Use of Intra-arterial Iodinated Contrast Media: A Meta-Analysis of Comparative Randomized Controlled Trials

    PubMed Central

    2011-01-01

    Background Discomfort characterized by pain and warmth are common adverse effects associated with the use of intra-arterial iodinated contrast media (CM). The objective of this review was to pool patient-reported outcomes available from head-to-head randomized controlled trials (RCTs) and to compare the discomfort rates associated with iso-osmolar contrast media (IOCM; i.e., iodixanol) to those reported with various low-osmolar contrast media (LOCM). Methods A review of the literature published between 1990 and 2009 available through Medline, Medline Preprints, Embase, Biological Abstracts, BioBase, Cab Abstracts, International Pharmaceutical Abstracts, Life Sciences Collection, Inside Conferences, Energy Database, Engineering Index and Technology Collection was performed to compare rates of discomfort associated with the use of the IOCM (iodixanol) vs. various LOCM agents in head-to-head RCTs. All trials with a Jadad score ≥2 that reported patient discomfort data following intra-arterial administration of CM were reviewed, coded, and extracted. Results A total of 22 RCTs (n = 8087) were included. Overall discomfort (regardless of severity) was significantly different between patients receiving IOCM and various LOCMs (risk difference [RD] -0.049; 95% confidence interval [CI]: -0.076, -0.021; p = 0.001). IOCM was favored over all LOCMs combined with a summary RD value of -0.188 (95% CI: -0.265, -0.112; p < 0.001) for incidence of pain, regardless of severity. A greater reduction in the magnitude of pain was observed with IOCM (iodixanol), particularly with selective limb and carotid/intracerebral procedures. Similarly, the meta-analysis of warmth sensation, regardless of severity, favored IOCM over LOCMs with an RD of -0.043 (95% CI: -0.074, -0.011; p = 0.008). A positive linear relationship was observed between the discomfort effect size and age and a negative relationship with increasing proportion of women. The opposite trends were observed with warmth

  5. Patient discomfort associated with the use of intra-arterial iodinated contrast media: a meta-analysis of comparative randomized controlled trials.

    PubMed

    McCullough, Peter A; Capasso, Patrizio

    2011-05-24

    Discomfort characterized by pain and warmth are common adverse effects associated with the use of intra-arterial iodinated contrast media (CM). The objective of this review was to pool patient-reported outcomes available from head-to-head randomized controlled trials (RCTs) and to compare the discomfort rates associated with iso-osmolar contrast media (IOCM; i.e., iodixanol) to those reported with various low-osmolar contrast media (LOCM). A review of the literature published between 1990 and 2009 available through Medline, Medline Preprints, Embase, Biological Abstracts, BioBase, Cab Abstracts, International Pharmaceutical Abstracts, Life Sciences Collection, Inside Conferences, Energy Database, Engineering Index and Technology Collection was performed to compare rates of discomfort associated with the use of the IOCM (iodixanol) vs. various LOCM agents in head-to-head RCTs. All trials with a Jadad score ≥2 that reported patient discomfort data following intra-arterial administration of CM were reviewed, coded, and extracted. A total of 22 RCTs (n = 8087) were included. Overall discomfort (regardless of severity) was significantly different between patients receiving IOCM and various LOCMs (risk difference [RD] -0.049; 95% confidence interval [CI]: -0.076, -0.021; p = 0.001). IOCM was favored over all LOCMs combined with a summary RD value of -0.188 (95% CI: -0.265, -0.112; p < 0.001) for incidence of pain, regardless of severity. A greater reduction in the magnitude of pain was observed with IOCM (iodixanol), particularly with selective limb and carotid/intracerebral procedures. Similarly, the meta-analysis of warmth sensation, regardless of severity, favored IOCM over LOCMs with an RD of -0.043 (95% CI: -0.074, -0.011; p = 0.008). A positive linear relationship was observed between the discomfort effect size and age and a negative relationship with increasing proportion of women. The opposite trends were observed with warmth sensation. IOCM was associated with

  6. Dream controller

    DOEpatents

    Cheng, George Shu-Xing; Mulkey, Steven L; Wang, Qiang; Chow, Andrew J

    2013-11-26

    A method and apparatus for intelligently controlling continuous process variables. A Dream Controller comprises an Intelligent Engine mechanism and a number of Model-Free Adaptive (MFA) controllers, each of which is suitable to control a process with specific behaviors. The Intelligent Engine can automatically select the appropriate MFA controller and its parameters so that the Dream Controller can be easily used by people with limited control experience and those who do not have the time to commission, tune, and maintain automatic controllers.

  7. Histone H2AX phosphorylation in response to changes in chromatin structure induced by altered osmolarity.

    PubMed

    Baure, Jennifer; Izadi, Atefeh; Suarez, Vannina; Giedzinski, Erich; Cleaver, James E; Fike, John R; Limoli, Charles L

    2009-03-01

    DNA strand breaks trigger marked phosphorylation of histone H2AX (i.e. gamma-H2AX). While DNA double-strand breaks (DSBs) provide a strong stimulus for this event, the accompanying structural alterations in chromatin may represent the actual signal that elicits gamma-H2AX. Our data show that changes in chromatin structure are sufficient to elicit extensive gamma-H2AX formation in the relative absence of DNA strand breaks. Cells subjected to hypotonic (0.05 M) treatment exhibit gamma-H2AX levels that are equivalent to those found after the induction of 80-200 DNA DSBs (i.e. 2-5 Gy). Despite this significant increase in phosphorylation, cell survival remains relatively unaffected (<10% cytotoxicity), and there is no significant increase in apoptosis. Nuclear staining profiles indicate that gamma-H2AX-positive cells induced under altered tonicity exhibit variable levels of staining, ranging from uniform pan staining to discrete punctate foci more characteristic of DNA strand breakage. The capability to induce significant gamma-H2AX formation under altered tonicity in the relative absence of DNA strand breaks suggests that this histone modification evolved in response to changes in chromatin structure.

  8. AGREEMENT BETWEEN DIFFERENT EQUATIONS TO ESTIMATE OSMOLARITY OF PARENTERAL NUTRITION SOLUTIONS.

    PubMed

    Valero Zanuy, M A; Pablos Bravo, S; Lazaro Cebas, A; Garcia Sanchez, J; Gomis Muñoz, P; Moreno Villares, J M; Leon Sanz, M

    2015-12-01

    Objetivo: nuestro objetivo era medir la osmolaridad de varias fórmulas de nutrición parenteral (NP) compuestas por diferentes componentes para determinar si las ecuaciones para calcular la osmolaridad de la solución, descritas en la literatura, predicen su osmolalidad en la práctica clínica. Método: se midió mediante osmometría la osmolalidad de 12 fórmulas de NP diferentes: 9 para acceso venoso central y 3 para acceso periférico, en un estudio transversal. Se analizó el acuerdo (test de correlación de Pearson) y las diferencias entre la osmolalidad medida y la osmolaridad calculada mediante tres fórmulas diferentes: ecuación de Pereira Da Silva, ecuación del manual de práctica clínica de ASPEN y ecuación de las guías de ASPEN. Resultados: la media ± desviación estándar de las soluciones era 1.789 ± 256 (rango 1.540 – 2.372) y 751 ± 64 mOsm/kg (rango 689 – 817) para perfusión central y periférica, respectivamente. La osmolalidad era debida principalmente a la glucosa (r = 0,975) y a los aminoacidos (r = 0,948). Todas las ecuaciones presentaban una buena correlación en el análisis bivariante (p = 0,000). Todas las ecuaciones tendían a infraestimar la osmolalidad, en comparación con el valor medido. Sin embargo, la ecuación de las guías de la ASPEN sobreestimaba la osmolalidad de las NP periféricas. Conclusiones: conocer la osmolaridad de la solución de NP periférica es importante para reducir el riesgo de flebitis. Las diferentes ecuaciones descritas en la literatura muestran una buena correlación entre ellas, aunque en general infraestiman la osmolalidad.

  9. Influence of clearing solutions osmolarity on the optical properties of RBC

    NASA Astrophysics Data System (ADS)

    Zhestkov, Dmitry M.; Bashkatov, Alexey N.; Genina, Elina A.; Tuchin, Valery V.

    2004-08-01

    The possibility of immersion clearing of human blood in visible and NIR spectral range has been discussed. Based on presented model the spectral behavior of scattering and absorption characteristics of blood caused by immersion properties of glucose solution has been analyzed. The influence of osmotic properties of glucose solution on blood erythrocytes has been shown.

  10. Red blood cell micromanipulation with elliptical laser beam profile optical tweezers in different osmolarity conditions

    NASA Astrophysics Data System (ADS)

    Spyratou, E.; Makropoulou, M.; Serafetinides, A. A.

    2011-07-01

    In this work optical tweezers with elliptical beam profiles have been developed in order to examine the effect of optical force on fresh red blood cells (RBC) in isotonic, hypertonic and hypotonic buffer solutions. Considering that the optical force depends essentially on the cell surface and the cytoplasmic refractive index, it is obvious that biochemical modifications associated with different states of the cell will influence its behaviour in the optical trap. Line optical tweezers were used to manipulate simultaneously more than one red blood cell. After we have been manipulated a RBC with an elliptical laser beam profile in an isotonic or hypertonic buffer, we noticed that it rotates by itself when gets trapped by optical tweezers and undergoes folding. Further shape deformations can be observed attributed to the competition between alignment and rotational torque which are transferred by laser light to the cell. In hypotonic buffer RBCs become spherical and do not rotate or fold since the resultant force due to rays emerging from diametrically opposite points of the cell leads to zero torque. Manipulation of fresh red blood cells in isotonic solution by line optical tweezers leads to folding and elongation of trapped RBCs. Membrane elasticity properties such as bending modulus can be estimated by measuring RBC's folding time in function with laser power.

  11. The use of low-osmolar water-soluble contrast in videofluoroscopic swallowing exams.

    PubMed

    Harris, Julie A; Bartelt, Detlef; Campion, Molly; Gayler, Bob W; Jones, Bronwyn; Hayes, Andrea; Haynos, Judith; Herbick, Seanne; Kling, Therese; Lingaraj, Arpana; Singer, Michele; Starmer, Heather; Smith, Christine; Webster, Kim

    2013-12-01

    The selection of the contrast agent used during fluoroscopic exams is an important clinical decision. The purpose of this article is to document the usage of a nonionic, water-soluble contrast (iohexol) and barium contrast in adult patients undergoing fluoroscopic exams of the pharynx and/or esophagus and provide clinical indications for the use of each. For 1 year, data were collected on the use of iohexol and barium during fluoroscopic exams. The contrast agent used was selected by the speech language pathologist (SLP) or the radiologist based on the exam's indications. A total of 1,978 fluoroscopic exams were completed in the 12-month period of documentation. Of these exams, 60.6 % were completed for medical reasons and 39.4 % for surgical reasons. Fifty-five percent of the exams were performed jointly by a SLP and a radiologist and 45 % were performed by a radiologist alone. Aspiration was present in 22 % of the exams, vestibular penetration occurred in 38 %, extraluminal leakage of contrast was observed in 4.6 %, and both aspiration and leakage were seen in 1 % of the exams. In cases with aspiration, iohexol was used alone in 8 %, iohexol and barium were both used in 45 %, and barium was used alone in 47 %. In cases with extraluminal leakage, iohexol was used alone in 58 %, iohexol and barium were both used in 31 %, and barium was used alone in 11 %. No adverse effects were seen with the use of iohexol. When barium was used in cases of aspiration and extraluminal leakage, the amount of aspirated barium was small and the extraluminal barium in the instances of leakage was small. Iohexol is a useful screening contrast agent and can safely provide information, and its use reduces the risk of aspiration and the chance of leakage of large amounts of barium.

  12. Osmolar regulation of endothelin-1 production by rat inner medullary collecting duct.

    PubMed Central

    Kohan, D E; Padilla, E

    1993-01-01

    Recent evidence has implicated endothelin-1 (ET-1) as an autocrine inhibitor of inner medullary collecting duct (IMCD) sodium and water transport. The regulators of IMCD ET-1 production are, however, largely unknown. Because of the unique hypertonic environment of the IMCD, the effect of varying extracellular tonicity on IMCD ET-1 production was evaluated. Increasing media osmolality from 300 to 450 mosmol with NaCl or mannitol but not urea caused a marked dose- and time-dependent reduction in ET-1 release by and ET-1 mRNA in cultured rat IMCD cells. In contrast, increasing osmolality had no effect on ET-1 production by rat endothelial or mesangial cells. To see if ET-1 varies in a similar manner in vivo, ET-1 production was assessed in volume expanded (lower medullary tonicity) or volume depleted (high medullary tonicity) rats. Urinary ET-1 excretion and inner medulla ET-1 mRNA were significantly reduced in volume depleted as compared to volume expanded animals. These results indicate that extracellular sodium concentration inhibits ET-1 production specifically in IMCD cells. We speculate that extracellular sodium concentration, via regulation of ET-1 production, provides a link between volume status and IMCD sodium and water reabsorption. PMID:8450052

  13. Birth Control

    MedlinePlus

    Birth control, also known as contraception, is designed to prevent pregnancy. Birth control methods may work in a number of different ... releasing eggs that could be fertilized. Types include birth control pills, patches, shots, vaginal rings, and emergency contraceptive ...

  14. Rodent Control

    ERIC Educational Resources Information Center

    Indian Journal of Adult Education, 1975

    1975-01-01

    Strategies for rodent control in crop fields, threshing yards, and rural residential areas are presented together with an operational plan for implementing a program for rodent control at the national level. Training personnel in rodent control procedures and procedures for educating the public in the necessity for control are covered. (EC)

  15. Rodent Control

    ERIC Educational Resources Information Center

    Indian Journal of Adult Education, 1975

    1975-01-01

    Strategies for rodent control in crop fields, threshing yards, and rural residential areas are presented together with an operational plan for implementing a program for rodent control at the national level. Training personnel in rodent control procedures and procedures for educating the public in the necessity for control are covered. (EC)

  16. All-trans retinol and retinol-binding protein from embryonic cerebrospinal fluid exhibit dynamic behaviour during early central nervous system development.

    PubMed

    Parada, Carolina; Gato, Angel; Bueno, David

    2008-06-11

    Embryonic cerebrospinal fluid (E-CSF) is involved in the regulation of survival, proliferation and neurogenesis of neuroectodermal progenitor cells, as well as in the control of mesencephalic gene expression in collaboration with the isthmic organizer. Recently, we showed the presence of retinol-binding protein (RBP) within the E-CSF proteome. RBP is an all-trans retinol carrier, a molecule that can be metabolized into retinoic acid, a morphogen involved in central nervous system (CNS) morphogenesis and patterning. Here we demonstrate the presence of all-trans retinol within the E-CSF and analyse the dynamics of RBP and all-trans retinol within this fluid, as well as the expression of retinoic acid-synthesizing enzymes during early CNS development. Our results suggest a relationship between the dynamics of these molecules and the early events of CNS patterning.

  17. Propulsion controls

    NASA Technical Reports Server (NTRS)

    Harkney, R. D.

    1980-01-01

    Increased system requirements and functional integration with the aircraft have placed an increased demand on control system capability and reliability. To provide these at an affordable cost and weight and because of the rapid advances in electronic technology, hydromechanical systems are being phased out in favor of digital electronic systems. The transition is expected to be orderly from electronic trimming of hydromechanical controls to full authority digital electronic control. Future propulsion system controls will be highly reliable full authority digital electronic with selected component and circuit redundancy to provide the required safety and reliability. Redundancy may include a complete backup control of a different technology for single engine applications. The propulsion control will be required to communicate rapidly with the various flight and fire control avionics as part of an integrated control concept.

  18. Restructurable Controls

    NASA Technical Reports Server (NTRS)

    Montoya, R. J. (Compiler); Howell, W. E. (Compiler); Bundick, W. T. (Compiler); Ostroff, A. J. (Compiler); Hueschen, R. M. (Compiler); Belcastro, C. M. (Compiler)

    1983-01-01

    Restructurable control system theory, robust reconfiguration for high reliability and survivability for advanced aircraft, restructurable controls problem definition and research, experimentation, system identification methods applied to aircraft, a self-repairing digital flight control system, and state-of-the-art theory application are addressed.

  19. Controlling Fertility.

    ERIC Educational Resources Information Center

    Donnay, France

    1991-01-01

    Recent developments in fertility control are presented in relation to the global demographic situation. Discussion focuses on changes in scientific knowledge and concepts that have shifted the focus from birth control to planned parenthood to the notion of controlled fertility. The place of family planning programs, including their socioeconomic…

  20. Controlling Fertility.

    ERIC Educational Resources Information Center

    Donnay, France

    1991-01-01

    Recent developments in fertility control are presented in relation to the global demographic situation. Discussion focuses on changes in scientific knowledge and concepts that have shifted the focus from birth control to planned parenthood to the notion of controlled fertility. The place of family planning programs, including their socioeconomic…

  1. Complex Regulatory Network Controls Initial Adhesion and Biofilm Formation in Escherichia coli via Regulation of the csgD Gene

    PubMed Central

    Prigent-Combaret, Claire; Brombacher, Eva; Vidal, Olivier; Ambert, Arnaud; Lejeune, Philippe; Landini, Paolo; Dorel, Corinne

    2001-01-01

    The Escherichia coli OmpR/EnvZ two-component regulatory system, which senses environmental osmolarity, also regulates biofilm formation. Up mutations in the ompR gene, such as the ompR234 mutation, stimulate laboratory strains of E. coli to grow as a biofilm community rather than in a planktonic state. In this report, we show that the OmpR234 protein promotes biofilm formation by binding the csgD promoter region and stimulating its transcription. The csgD gene encodes the transcription regulator CsgD, which in turn activates transcription of the csgBA operon encoding curli, extracellular structures involved in bacterial adhesion. Consistent with the role of the ompR gene as part of an osmolarity-sensing regulatory system, we also show that the formation of biofilm by E. coli is inhibited by increasing osmolarity in the growth medium. The ompR234 mutation counteracts adhesion inhibition by high medium osmolarity; we provide evidence that the ompR234 mutation promotes biofilm formation by strongly increasing the initial adhesion of bacteria to an abiotic surface. This increase in initial adhesion is stationary phase dependent, but it is negatively regulated by the stationary-phase-specific sigma factor RpoS. We propose that this negative regulation takes place via rpoS-dependent transcription of the transcription regulator cpxR; cpxR-mediated repression of csgB and csgD promoters is also triggered by osmolarity and by curli overproduction, in a feedback regulation loop. PMID:11717281

  2. Complex regulatory network controls initial adhesion and biofilm formation in Escherichia coli via regulation of the csgD gene.

    PubMed

    Prigent-Combaret, C; Brombacher, E; Vidal, O; Ambert, A; Lejeune, P; Landini, P; Dorel, C

    2001-12-01

    The Escherichia coli OmpR/EnvZ two-component regulatory system, which senses environmental osmolarity, also regulates biofilm formation. Up mutations in the ompR gene, such as the ompR234 mutation, stimulate laboratory strains of E. coli to grow as a biofilm community rather than in a planktonic state. In this report, we show that the OmpR234 protein promotes biofilm formation by binding the csgD promoter region and stimulating its transcription. The csgD gene encodes the transcription regulator CsgD, which in turn activates transcription of the csgBA operon encoding curli, extracellular structures involved in bacterial adhesion. Consistent with the role of the ompR gene as part of an osmolarity-sensing regulatory system, we also show that the formation of biofilm by E. coli is inhibited by increasing osmolarity in the growth medium. The ompR234 mutation counteracts adhesion inhibition by high medium osmolarity; we provide evidence that the ompR234 mutation promotes biofilm formation by strongly increasing the initial adhesion of bacteria to an abiotic surface. This increase in initial adhesion is stationary phase dependent, but it is negatively regulated by the stationary-phase-specific sigma factor RpoS. We propose that this negative regulation takes place via rpoS-dependent transcription of the transcription regulator cpxR; cpxR-mediated repression of csgB and csgD promoters is also triggered by osmolarity and by curli overproduction, in a feedback regulation loop.

  3. A Screen for Nigericin-Resistant Yeast Mutants Revealed Genes Controlling Mitochondrial Volume and Mitochondrial Cation Homeostasis

    PubMed Central

    Kucejova, Blanka; Kucej, Martin; Petrezselyova, Silvia; Abelovska, Lenka; Tomaska, Lubomir

    2005-01-01

    Little is known about the regulation of ion transport across the inner mitochondrial membrane in Saccharomyces cerevisiae. To approach this problem, we devised a screening procedure for facilitating the identification of proteins involved in mitochondrial ion homeostasis. Taking advantage of the growth inhibition of yeast cells by electroneutral K+/H+ ionophore nigericin, we screened for genetic mutations that would render cells tolerant to this drug when grown on a nonfermentable carbon source and identified several candidate genes including MDM31, MDM32, NDI1, YMR088C (VBA1), CSR2, RSA1, YLR024C, and YNL136W (EAF7). Direct examination of intact cells by electron microscopy indicated that mutants lacking MDM31 and/or MDM32 genes contain dramatically enlarged, spherical mitochondria and that these morphological abnormalities can be alleviated by nigericin. Mitochondria isolated from the Δmdm31 and Δmdm32 mutants exhibited limited swelling in an isotonic solution of potassium acetate even in the presence of an exogenous K+/H+ antiport. In addition, growth of the mutants was inhibited on ethanol-containing media in the presence of high concentrations of salts (KCl, NaCl, or MgSO4) and their mitochondria exhibited two- (Δmdm31 and Δmdm32) to threefold (Δmdm31Δmdm32) elevation in magnesium content. Taken together, these data indicate that Mdm31p and Mdm32p control mitochondrial morphology through regulation of mitochondrial cation homeostasis and the maintenance of proper matrix osmolarity. PMID:16020778

  4. Computer controlled cryogenic temperature controller

    NASA Astrophysics Data System (ADS)

    Perrin, Ronald E.

    1990-01-01

    In laboratories which do materials characterization it is necessary to have a temperature controller which can be computer controlled, is accurate to within .1 to .2 K, can control temperature from 15 to 350 K with a drift of no more than .1, and is relatively unaffected by the presence of a magnetic field on the sample container. The subject controller uses two thermometers to meet these requirements. One is a commercially available calibrated silicon diode manufactured expressly for this type of application. The second thermometer is used for control. Once the sample has reached the setpoint according to the calibrated thermometer the control thermometer's value is sampled and used as the new setpoint. Since the control thermometer should be insensitive to a mag field the sample will remain at the desired temperature when the magnetic field is applied.

  5. Voltage Controller

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Power Efficiency Corporation, specifically formed to manufacture and develop products from NASA technology, has a license to a three-phase power factor controller originally developed by Frank Nola, an engineer at Marshall Space Flight Center. Power Efficiency and two major distributors, Performance Control and Edison Power Technologies, use the electronic control boards to assemble three different motor controllers: Power Commander, Performance Controller, and Energy Master. The company Power Factor Controller reduces excessive energy waste in AC induction motors. It is used in industries and applications where motors operate under variable loads, including elevators and escalators, machine tools, intake and exhaust fans, oil wells, conveyors, pumps, die casting, and compressors. Customer lists include companies such as May Department Stores, Caesars Atlantic City, Ford Motors, and American Axle.

  6. Control Software

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Real-Time Innovations, Inc. (RTI) collaborated with Ames Research Center, the Jet Propulsion Laboratory and Stanford University to leverage NASA research to produce ControlShell software. RTI is the first "graduate" of Ames Research Center's Technology Commercialization Center. The ControlShell system was used extensively on a cooperative project to enhance the capabilities of a Russian-built Marsokhod rover being evaluated for eventual flight to Mars. RTI's ControlShell is complex, real-time command and control software, capable of processing information and controlling mechanical devices. One ControlShell tool is StethoScope. As a real-time data collection and display tool, StethoScope allows a user to see how a program is running without changing its execution. RTI has successfully applied its software savvy in other arenas, such as telecommunications, networking, video editing, semiconductor manufacturing, automobile systems, and medical imaging.

  7. Control Theory.

    ERIC Educational Resources Information Center

    Toso, Robert B.

    2000-01-01

    Inspired by William Glasser's Reality Therapy ideas, Control Theory (CT) is a disciplinary approach that stresses people's ability to control only their own behavior, based on internal motivations to satisfy five basic needs. At one North Dakota high school, CT-trained teachers are the program's best recruiters. (MLH)

  8. CONTROL ROD

    DOEpatents

    Walker, D.E.; Matras, S.

    1963-04-30

    This patent shows a method of making a fuel or control rod for a nuclear reactor. Fuel or control material is placed within a tube and plugs of porous metal wool are inserted at both ends. The metal wool is then compacted and the tube compressed around it as by swaging, thereby making the plugs liquid- impervious but gas-pervious. (AEC)

  9. Power Controller

    NASA Astrophysics Data System (ADS)

    1983-01-01

    The power factor controller (PFC) senses shifts in the relationship between voltage and current, and matches them with a motor's need. This prevents waste as motors do not need a high voltage when they are not operating at full load conditions. PFC is manufactured by Nordic Controls Company, among others, and has proved extremely cost effective.

  10. Control Theory.

    ERIC Educational Resources Information Center

    Toso, Robert B.

    2000-01-01

    Inspired by William Glasser's Reality Therapy ideas, Control Theory (CT) is a disciplinary approach that stresses people's ability to control only their own behavior, based on internal motivations to satisfy five basic needs. At one North Dakota high school, CT-trained teachers are the program's best recruiters. (MLH)

  11. Environmental Controls.

    ERIC Educational Resources Information Center

    Schneiderman, Helen, Ed.

    1994-01-01

    Environmental control units, or ECUs, are devices or systems which allow for alternate access to electronic or electrical devices and those objects, like draperies and doors, which may be adapted for use with electricity. Such devices offer the person with a mobility limitation the opportunity to control his or her environment, thus enhancing the…

  12. Detonation control

    SciTech Connect

    Mace, Jonathan L.; Seitz, Gerald J.; Bronisz, Lawrence E.

    2016-10-25

    Detonation control modules and detonation control circuits are provided herein. A trigger input signal can cause a detonation control module to trigger a detonator. A detonation control module can include a timing circuit, a light-producing diode such as a laser diode, an optically triggered diode, and a high-voltage capacitor. The trigger input signal can activate the timing circuit. The timing circuit can control activation of the light-producing diode. Activation of the light-producing diode illuminates and activates the optically triggered diode. The optically triggered diode can be coupled between the high-voltage capacitor and the detonator. Activation of the optically triggered diode causes a power pulse to be released from the high-voltage capacitor that triggers the detonator.

  13. Symptom control.

    PubMed

    Chang, Victor T; Ingham, Jane

    2003-01-01

    Symptom control has become increasingly recognized as an important goal in patient care. In this article, advances in symptom assessment, and various definitions of symptom improvement are reviewed. Theoretical concepts underlying symptom control and clinically significant change are presented, as well as the role of symptom control as an endpoint in clinical trials. Symptom control is then surveyed in two broad categories for selected symptoms. The first area is therapy related symptoms, secondary to chemotherapy, radiation, hormonal therapy, and surgery. Symptoms reviewed include chemotherapy related mucositis, emesis, fatigue; hot flashes; and radiation related dermatitis, xerostomia, and mucositis. The second area is palliative oncologic approaches to disease-related symptoms. Results in palliative chemotherapy, palliative radiation therapy, cancer pain, and lack of appetite are summarized. Areas requiring further research are noted. Findings are presented in both a clinical and research context to help guide the reader with interpreting symptom control studies.

  14. Control consciousness.

    PubMed

    Mandik, Pete

    2010-10-01

    Control consciousness is the awareness or experience of seeming to be in control of one's actions. One view, which I will be arguing against in the present paper, is that control consciousness is a form of sensory consciousness. In such a view, control consciousness is exhausted by sensory elements such as tactile and proprioceptive information. An opposing view, which I will be arguing for, is that sensory elements cannot be the whole story and must be supplemented by direct contributions of nonsensory, motor elements. More specifically, I will be arguing for the view that the neural basis of control consciousness is constituted by states of recurrent activation in relatively intermediate levels of the motor hierarchy. Copyright © 2010 Cognitive Science Society, Inc.

  15. Controller for thermostatically controlled loads

    SciTech Connect

    Lu, Ning; Zhang, Yu; Du, Pengwei; Makarov, Yuri V.

    2016-06-07

    A system and method of controlling aggregated thermostatically controlled appliances (TCAs) for demand response is disclosed. A targeted load profile is formulated and a forecasted load profile is generated. The TCAs within an "on" or "off" control group are prioritized based on their operating temperatures. The "on" or "off" status of the TCAs is determined. Command signals are sent to turn on or turn off the TCAs.

  16. Aiming Control.

    DTIC Science & Technology

    1987-10-01

    positive definite solution of A1Qy+QyAo+I--QyBBTQY=O (5.2) The logarithmic residence time of system (3.1) with the stabilizing control (5.1) in a I...a bounded is E bou,,,,dby, ii I)-2=(6 2 This completes the prooof the necesity. Suffidency: The proof is by conatnction. Select a stabilizing control u...a - . Q.LD. Proof of Theorem 3.3: It follows from the results of [151, [21] that for each y > 0, K? defined by (3.4) is a stabilizing control and

  17. CONTROL ROD

    DOEpatents

    Zinn, W.H.; Ross, H.V.

    1958-11-18

    A control rod is described for a nuclear reactor. In certaln reactor designs it becomes desirable to use a control rod having great width but relatively llttle thickness. This patent is addressed to such a need. The neutron absorbing material is inserted in a triangular tube, leaving volds between the circular insert and the corners of the triangular tube. The material is positioned within the tube by the use of dummy spacers to achleve the desired absorption pattern, then the ends of the tubes are sealed with suitable plugs. The tubes may be welded or soldered together to form two flat surfaces of any desired width, and covered with sheetmetal to protect the tubes from damage. This design provides a control member that will not distort under the action of outside forces or be ruptured by gases generated within the jacketed control member.

  18. Drug Control

    ERIC Educational Resources Information Center

    Leviton, Harvey S.

    1975-01-01

    This article attempts to assemble pertinent information about the drug problem, particularily marihuana. It also focuses on the need for an educational program for drug control with the public schools as the main arena. (Author/HMV)

  19. Under Control.

    ERIC Educational Resources Information Center

    Henry, Rich

    2001-01-01

    Offers advice on how school administrators can properly plan and monitor school construction projects to contain costs. Cost control tips discussed include project scope definition, contract bidding and awarding practice, and project management techniques. (GR)

  20. REACTOR CONTROL

    DOEpatents

    Fortescue, P.; Nicoll, D.

    1962-04-24

    A control system employed with a high pressure gas cooled reactor in which a control rod is positioned for upward and downward movement into the neutron field from a position beneath the reactor is described. The control rod is positioned by a coupled piston cylinder releasably coupled to a power drive means and the pressurized coolant is directed against the lower side of the piston. The coolant pressure is offset by a higher fiuid pressure applied to the upper surface of the piston and means are provided for releasing the higher pressure on the upper side of the piston so that the pressure of the coolant drives the piston upwardly, forcing the coupled control rod into the ncutron field of the reactor. (AEC)

  1. Mosquito Control

    MedlinePlus

    ... Environmental Protection Agency Search Search Contact Us Share Mosquito Control About Mosquitoes General Information Life Cycle Information ... virus Preventing Mosquitoes Tips to prevent mosquito bites Mosquito Repellents Using Repellent Products to Protect against Mosquito- ...

  2. Under Control.

    ERIC Educational Resources Information Center

    Henry, Rich

    2001-01-01

    Offers advice on how school administrators can properly plan and monitor school construction projects to contain costs. Cost control tips discussed include project scope definition, contract bidding and awarding practice, and project management techniques. (GR)

  3. Drug Control

    ERIC Educational Resources Information Center

    Leviton, Harvey S.

    1975-01-01

    This article attempts to assemble pertinent information about the drug problem, particularily marihuana. It also focuses on the need for an educational program for drug control with the public schools as the main arena. (Author/HMV)

  4. CONTROL SYSTEM

    DOEpatents

    Shannon, R.H.; Williamson, H.E.

    1962-10-30

    A boiling water type nuclear reactor power system having improved means of control is described. These means include provisions for either heating the coolant-moderator prior to entry into the reactor or shunting the coolantmoderator around the heating means in response to the demand from the heat engine. These provisions are in addition to means for withdrawing the control rods from the reactor. (AEC)

  5. Controlling Inference.

    DTIC Science & Technology

    1986-04-01

    CHAPTER 1. INTRODUCTION parents, fathers are male parents, child and parent are inverse relationships, sons are male children and daughters are female... children , respectively. Given a small collection of kinship data, such as Brother(Rob, Larry) Father(Rob, Bill) Mother(Rob, Terry) (1.2) Father(Pat...the laws of control, not with the language in which they are expressed. Predicate calculus is ’Actually, there may be control decisions where the

  6. Control rod

    SciTech Connect

    Dixon, R.C.; Cearley, J.E.; VanDiemen, P.; Sayre, E.D.; Gordon, G.M.

    1990-02-20

    This patent describes in a nuclear reactor control rod having elongate planar members for absorption of neutrons within a nuclear reactor for control of the nuclear reaction, the elongate planar members being formed of a plurality of tubes arranged side-by-side in abutting contact and joined together. The tube comprises: a tube defining a cylindrical pressure vessel for containment of neutron absorbing poisons. The tube defining constant side wall thickness sufficient to define there within a cylindrical volume for the containment of neutron absorbing poisons and having sufficient side wall thickness to retain the poisons under all anticipated pressures from decomposition of the neutron absorbing poisons; and the tube integrally defining in addition to the cylindrical pressure vessel four discrete right angle corner sections placed at 90{degree} intervals to the side wall of the constant side wall thickness tube; and neutron absorbing poisons confined within the tube for absorption of neutrons for control of the nuclear reaction.

  7. Inventory control.

    PubMed

    Levin, Roger

    2004-09-01

    By establishing clear inventory ordering targets and following the guidelines outlined in this column, the staff member handling the process will understand the high and low levels of inventory control and be able to maintain an accurate system. Inventory control represents approximately 6 to 8 percent of practice purchasing. The main goal of the advice in this column is not to reduce the cost, unless there is waste involved, but rather to establish a process that allows the practice to purchase supplies on a regular basis, avoid mistakes and maintain a steady expense level.

  8. Motor Controllers

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Kollmorgen Corporation's Mermaid II two person submersible is propeller-driven by a system of five DC brushless motors with new electronic controllers that originated in work performed in a NASA/DOE project managed by Lewis Research Center. A key feature of the system is electric commutation rather than mechanical commutation for converting AC current to DC.

  9. Controlling turbulence

    NASA Astrophysics Data System (ADS)

    Kühnen, Jakob; Hof, Björn

    2015-11-01

    We show that a simple modification of the velocity profile in a pipe can lead to a complete collapse of turbulence and the flow fully relaminarises. The annihilation of turbulence is achieved by a steady manipulation of the streamwise velocity component alone, greatly reducing control efforts. Several different control techniques are presented: one with a local modification of the flow profile by means of a stationary obstacle, one employing a nozzle injecting fluid through a small gap at the pipe wall and one with a moving wall, where a part of the pipe is shifted in the streamwise direction. All control techniques act on the flow such that the streamwise velocity profile becomes more flat and turbulence gradually grows faint and disappears. In a smooth straight pipe the flow remains laminar downstream of the control. Hence a reduction in skin friction by a factor of 8 and more can be accomplished. Stereoscopic PIV-measurements and movies of the development of the flow during relaminarisation are presented.

  10. Dynamics & Control

    DTIC Science & Technology

    2012-03-06

    This project takes the first steps towards a “Compressive Information Extraction” paradigm: Unmanned vehicles Flight and perch sensors Human in the...the program has solid efforts in control of MAVs, hypersonic vehicles , smart materials and biological systems. • Support of fundamental research...BRIEF DESCRIPTION OF PORTFOLIO: Developing mathematical theory and algorithms based on the interplay of dynamical systems and

  11. Asymptotic controllability and optimal control

    NASA Astrophysics Data System (ADS)

    Motta, M.; Rampazzo, F.

    We consider a control problem where the state must approach asymptotically a target C while paying an integral cost with a non-negative Lagrangian l. The dynamics f is just continuous, and no assumptions are made on the zero level set of the Lagrangian l. Through an inequality involving a positive number p and a Minimum Restraint FunctionU=U(x) - a special type of Control Lyapunov Function - we provide a condition implying that (i) the system is asymptotically controllable, and (ii) the value function is bounded by U/p. The result has significant consequences for the uniqueness issue of the corresponding Hamilton-Jacobi equation. Furthermore it may be regarded as a first step in the direction of a feedback construction.

  12. COPD - control drugs

    MedlinePlus

    Chronic obstructive pulmonary disease - control drugs; Bronchodilators - COPD - control drugs; Beta agonist inhaler - COPD - control drugs; Anticholinergic inhaler - COPD - control drugs; Long-acting inhaler - COPD - control drugs; ...

  13. Vehicle Controller

    NASA Technical Reports Server (NTRS)

    1985-01-01

    UNISTICK is an airplane-like joystick being developed by Johnson Engineering under NASA and VA sponsorship. It allows a driver to control a vehicle with one hand, and is based upon technology developed for the Apollo Lunar Landings of the 1970's. It allows severely handicapped drivers to operate an automobile or van easily. The system is expected to be in production by March 1986.

  14. Airspace Control

    DTIC Science & Technology

    2011-02-02

    working group charters and coordinated quarterly meetings between the deputy CFACC (DCFACC)/deputy ACA ( DACA ), ACCE, regional air movement control...coordination with the DCFACC/ DACA and other AOC airspace offices; distraction from AFFOR airfield operations responsibilities; and short duration tour...the AOC to allow improved access to the DCFACC/ DACA , providing close working coordination with ACP developers. CAPG strategy and policy continuity

  15. Autonomous control

    NASA Technical Reports Server (NTRS)

    Brown, Barbara

    1990-01-01

    KSC has been developing the Knowledge-Based Autonomous Test Engineer (KATE), which is a tool for performing automated monitoring, diagnosis, and control of electromechanical devices. KATE employs artificial intelligence computing techniques to perform these functions. The KATE system consists of a generic shell and a knowledge base. The KATE shell is the portion of the system which performs the monitoring, diagnosis, and control functions. It is generic in the sense that it is application independent. This means that the monitoring activity, for instance, will be performed with the same algorithms regardless of the particular physical device being used. The knowledge base is the portion of the system which contains specific functional and behavorial information about the physical device KATE is working with. Work is nearing completion on a project at KSC to interface a Texas Instruments Explorer running a LISP version of KATE with a Generic Checkout System (GCS) test-bed to control a physical simulation of a shuttle tanking system (humorously called the Red Wagon because of its color and mobility). The Autonomous Control System (ACS) project supplements and extends the KATE/GCS project by adding three other major activities. The activities include: porting KATE from the Texas Instruments Explorer machine to an Intel 80386-based UNIX workstation in the LISP language; rewriting KATE as necessary to run on the same 80386 workstation but in the Ada language; and investigating software and techniques to translate ANSI Standard Common LISP to Mil Standard Ada. Primary goals of this task are as follows: (1) establish the advantages of using expert systems to provide intelligent autonomous software for Space Station Freedom applications; (2) determine the feasibility of using Ada as the run-time environment for model-based expert systems; (3) provide insight into the advantages and disadvantagesof using LISP or Ada in the run-time environment for expert systems; and (4

  16. REACTOR CONTROL

    DOEpatents

    Ruano, W.J.

    1957-12-10

    This patent relates to nuclear reactors of the type which utilize elongited rod type fuel elements immersed in a liquid moderator and shows a design whereby control of the chain reaction is obtained by varying the amount of moderator or reflector material. A central tank for containing liquid moderator and fuel elements immersed therein is disposed within a surrounding outer tank providing an annular space between the two tanks. This annular space is filled with liquid moderator which functions as a reflector to reflect neutrons back into the central reactor tank to increase the reproduction ratio. Means are provided for circulating and cooling the moderator material in both tanks and additional means are provided for controlling separately the volume of moderator in each tank, which latter means may be operated automatically by a neutron density monitoring device. The patent also shows an arrangement for controlling the chain reaction by injecting and varying an amount of poisoning material in the moderator used in the reflector portion of the reactor.

  17. Current status of oral rehydration as a strategy for the control of diarrhoeal diseases.

    PubMed

    Mahalanabis, D

    1996-07-01

    For more than two decades, WHO and UNICEF have recommended a single formulation of oral rehydration salts (ORS) solution based on glucose and three salts. This product has proven safe and highly effective in treating and preventing dehydration from diarrhoea of all causes and in all age groups in worldwide use and has substantially contributed to the saving of lives in developing countries. However, oral rehydration therapy (ORT) using this formulation does not make diarrhoea any less severe or stop it sooner; which is what is required. During the last 16 yr numerous studies were undertaken to develop an improved ORS that could, in addition to being effective therapy to treat and prevent dehydration, reduce severity and duration of diarrhoea. Controlled clinical trials of ORS formulations containing aminoacids showed that, while they were substantially more absorption efficient in cholera, they were no more effective than standard ORS in infants and children with noncholera diarrhoea; none of these formulations are considered a suitable replacement for standard ORS. Rice-based ORS, in a number of studies, was found superior to standard ORS in adults and children with cholera and its use in such patients is recommended. However, the benefit of using rice-based ORS in infants and small children was either small or insignificant compared to standard ORS, when feeding during ORT was actively pursued. Rice-based ORS was also as effective as standard ORS in infants under 6 months of age and in severely malnourished children. Recently, several studies evaluated glucose-based ORS made hypoosmolar by reducing the concentration of glucose and sodium (with glucose concentration of 75-90 and sodium 60-75 mmol/l and osmolarity of 225-250 mosm/l). These hypoosmolar solutions showed clinically significant benefit in reducing the severity of diarrhoea and the need for supplemental i.v. therapy in infants and children. In limited studies, similar results were obtained in adults

  18. Thermal control

    NASA Astrophysics Data System (ADS)

    Haslett, B.

    1984-02-01

    There are basically three key ingredients to the thermal control system for any large space platform or space station. These are heat rejection (from a centralized radiator or from body mounted radiators), heat acquisition (from payloads), and heat transport (via a transport loop to the radiator). The echnical approach in the heat rejection area is to construct the radiator from individual elements so that it can be built on-orbit, is very insensitive to meteoroid and debris hazards, and is repairable. In the area of thermal acquisition and transport an added effort to better understand two phase flow in zero gravity by analysis and testing is suggested.

  19. Signature control

    NASA Astrophysics Data System (ADS)

    Pyati, Vittal P.

    The reduction of vehicle radar signature is accomplished by means of vehicle shaping, the use of microwave frequencies-absorbent materials, and either passive or active cancellation techniques; such techniques are also useful in the reduction of propulsion system-associated IR emissions. In some anticipated scenarios, the objective is not signature-reduction but signature control, for deception, via decoy vehicles that mimic the signature characteristics of actual weapons systems. As the stealthiness of airframes and missiles increases, their propulsion systems' exhaust plumes assume a more important role in detection by an adversary.

  20. [Tuberculosis control].

    PubMed

    Schoch, Otto

    2011-07-01

    Tuberculosis control activities focus on identification and treatment of sputum smear positive tuberculosis patients. As soon as these patients can be treated, they not only have an optimal chance for cure, they also no longer spread Mycobacterium tuberculosis (M.tb) in the community. Screening is a systematic search for tuberculosis disease, often performed by radiological or by sputum smear examinations. On the other hand, Screening for Infection with M.tb is with immunological tests. Persons infected with M.tb have an increased risk to develop active tuberculosis in the future. Screening for infection is recommended in tuberculosis contact tracing and in several risk groups for the progression to tuberculosis disease, specifically before the start of immunosuppressive therapy with tumor necrosis factor antagonists or in transplant recipients. Several immunological tests are available. If compared to the traditional in vivo Mantoux tuberculin skin test, in vitro blood tests called Interferon Gamma Release Assays (IGRA) are more specific because the cell wall antigens used for the tests are not present in the wall of Bacille Calmitte Guerin BCG and most atypical mycobacteria. Another advantage of IGRA is the mitogen positive control, which detects unreliable tests in immunodeficiency. Persons found to be infected with M.tb are treated with prophylactic isoniacid for 9 months.

  1. Heliostat control

    DOEpatents

    Kaehler, James A.

    1984-01-01

    An improvement in a system and method of controlling heliostat in which the heliostat is operable in azimuth and elevation by respective stepper motors and including the respective steps or means for calculating the position for the heliostat to be at a commanded position, determining the number of steps in azimuth and elevation for each respective motor to get to the commanded position and energizing both the azimuth and elevation stepper motors to run in parallel until predetermined number of steps away from the closest commanded position in azimuth and elevation so that the closest position has been achieved, and thereafter energizing only the remaining motor to bring it to its commanded position. In this way, the heliostat can be started from a stowed position in the morning and operated by a computer means to its commanded position and kept correctly oriented throughout the day using only the time of the day without requiring the usual sensors and feedback apparatus. A computer, or microprocessor, can then control a plurality of many heliostats easily and efficiently throughout the day.

  2. [Controlled hypernatremia].

    PubMed

    Petit, L; Masson, F; Cottenceau, V; Sztark, F

    2006-08-01

    Hypernatremia exerts its main effect on the brain through the osmotic gradient it creates on either side of the blood brain barrier, which is impermeable to sodium. This generates a transfer of water from the intracellular to the vascular sector leading to temporary cell shrinkage. Osmoregulation permits cerebral cells to accumulate osmoactive molecules in order to restore their initial volume. It has been demonstrated in animals with brain injury that intracellular dehydration occurs essentially in the nonlesioned hemisphere. In most experimental studies, the reduction in cerebral volume obtained by hypertonic saline (HS) perfusion is accompanied by an intracranial pressure decrease, even under hemorrhagic shock conditions. Initially, clinical studies successfully used HS, as an alternative to mannitol, in the treatment of acute and refractory intracranial hypertension. Then continuous infusion of HS, with the objective of inducing hypernatremia, had produced encouraging effects on intracranial pressure control. However, these results were limited to non-randomized studies, without control groups and mainly in pediatric patients. Nevertheless, the use of HS on intracranial hypertension, refractory to conventional treatments, could be reasonable under strict monitoring of natremia as well as its adverse effects.

  3. The mitogen-activated protein kinase homolog HOG1 gene controls glycerol accumulation in the pathogenic fungus Candida albicans.

    PubMed Central

    San José, C; Monge, R A; Pérez-Díaz, R; Pla, J; Nombela, C

    1996-01-01

    The Candida albicans HOG1 gene (HOG1CA) was cloned by functional complementation of the osmosensitive phenotype associated with Saccharomyces cerevisiae hog1 delta mutants. HOG1CA codes for a 377-amino-acid protein, 78% identical to S. cerevisiae Hog1p. A C. albicans hog1 null mutant was found to be sensitive to osmotic stress and failed to accumulate glycerol on high-osmolarity media. PMID:8824643

  4. Control apparatus

    NASA Technical Reports Server (NTRS)

    Derkacs, Thomas (Inventor); Fetheroff, Charles W. (Inventor); Matay, Istvan M. (Inventor); Toth, Istvan J. (Inventor)

    1982-01-01

    Although the method and apparatus of the present invention can be utilized to apply either a uniform or a nonuniform covering of material over many different workpieces, the apparatus (20) is advantageously utilized to apply a thermal barrier covering (64) to an airfoil (22) which is used in a turbine engine. The airfoil is held by a gripper assembly (86) while a spray gun (24) is effective to apply the covering over the airfoil. When a portion of the covering has been applied, a sensor (28) is utilized to detect the thickness of the covering. A control apparatus (32) compares the thickness of the covering of material which has been applied with the desired thickness and is subsequently effective to regulate the operation of the spray gun to adaptively apply a covering of a desired thickness with an accuracy of at least plus or minus 0.0015 inches (1.5 mils) despite unanticipated process variations.

  5. Custom controls

    NASA Astrophysics Data System (ADS)

    Butell, Bart

    1996-02-01

    Microsoft's Visual Basic (VB) and Borland's Delphi provide an extremely robust programming environment for delivering multimedia solutions for interactive kiosks, games and titles. Their object oriented use of standard and custom controls enable a user to build extremely powerful applications. A multipurpose, database enabled programming environment that can provide an event driven interface functions as a multimedia kernel. This kernel can provide a variety of authoring solutions (e.g. a timeline based model similar to Macromedia Director or a node authoring model similar to Icon Author). At the heart of the kernel is a set of low level multimedia components providing object oriented interfaces for graphics, audio, video and imaging. Data preparation tools (e.g., layout, palette and Sprite Editors) could be built to manage the media database. The flexible interface for VB allows the construction of an infinite number of user models. The proliferation of these models within a popular, easy to use environment will allow the vast developer segment of 'producer' types to bring their ideas to the market. This is the key to building exciting, content rich multimedia solutions. Microsoft's VB and Borland's Delphi environments combined with multimedia components enable these possibilities.

  6. The role of the peripheral cannabinoid system in the pathogenesis of detrusor overactivity evoked by increased intravesical osmolarity in rats.

    PubMed

    Juszczak, Kajetan; Maciukiewicz, Piotr

    2015-08-01

    The cannabinoid receptors CB1 and CB2 are localized in the urinary bladder and play a role in the regulation of its function. We investigated the pathomechanisms through which hyperosmolarity induces detrusor overactivity (DO). We compared urinary bladder activity in response to blockade of CB1 and CB2 receptors using AM281 and AM630, respectively, in normal rats and after hyperosmolar stimulation. Experiments were performed on 44 rats. DO was induced by intravesical instillation of hyperosmolar saline. Surgical procedures and cystometry were performed under urethane anaesthesia. The measurements represent the average of 5 bladder micturition cycles. We analysed basal, threshold, and micturition voiding pressure; intercontraction interval; compliance; functional bladder capacity; motility index; and detrusor overactivity index. The blockage of CB1 and CB2 receptors diminished the severity of hyperosmolar-induced DO. In comparison with naïve animals the increased frequency of voiding with no significant effect on intravesical voiding pressure profile was observed as a result of the blockage of CB1 and CB2 receptors. These results demonstrate that hyperosmolar-induced DO is mediated by CB1 and CB2 receptors. Therefore, the cannabinoid pathway could potentially be a target for the treatment of urinary bladder dysfunction.

  7. Sodium hyaluronate eye drops of different osmolarity for the treatment of dry eye in Sjögren's syndrome patients

    PubMed Central

    Aragona, P; Di Stefano, G; Ferreri, F; Spinella, R; Stilo, A

    2002-01-01

    Aim: To study the effect of the treatment of dry eye in Sjögren's syndrome patients with hypotonic or isotonic hyaluronate eye drops. Methods: 40 Sjögren's syndrome patients were divided in two groups and treated as follows: group 1 with hypotonic (150 mOsm/l) 0.4% hyaluronate eye drops; group 2 with isotonic 0.4% hyaluronate eye drops. The eye drops were instilled six times a day for 90 days. Grading of subjective symptoms, break up time (BUT), corneal fluorescein staining, conjunctival rose bengal staining, Schirmer's I test, and conjunctival impression cytology were carried out at 0 and 15, 30, 90 days from the beginning of the study. Patients were examined in a blind fashion. For the statistical analysis the Student's t test, Mann-Whitney U test, and χ2 test were performed. Results: Symptoms were statistically significantly improved at day 15 in both groups but group 1 patients had a global score statistically significantly better group 2 (p=0.02). At day 15 group 1 patients had an improvement from baseline values of BUT (p=0.003), fluorescein, and rose bengal score (p=0.000001 and p=0.0004 respectively). Group 2 patients had, at day 15, an improvement of BUT and fluorescein score compared to baseline values (p=0.05 and p=0.0001 respectively). A comparison between the two groups showed better results for group 1 patients at day 15 for rose bengal stain (p=0.01) and for BUT (p=0.05) and fluorescein score (p=0.0003) at day 90. The conjunctival impression cytology showed that group 1 had a statistically significant better total score than group 2 starting from day 15 and lasting throughout the study (p<0.02). Also group 2 patients showed an improvement from baseline values starting from day 30 (p=0.000005). Conclusion: Hyaluronate eye drops are useful for treating severe dry eye in Sjögren's syndrome patients. The use of a formulation with pronounced hypotonicity showed better effects on corneoconjunctival epithelium than the isotonic solution. PMID:12140209

  8. Dimethyl adenosine transferase (KsgA) deficiency in Salmonella Enteritidis confers susceptibility to high osmolarity and virulence attenuation in chickens

    USDA-ARS?s Scientific Manuscript database

    : Dimethyladenosine transferase (KsgA) performs diverse roles in bacteria including ribosomal maturation, DNA mismatch repair, and synthesis of KsgA is responsive to antibiotics and cold temperature. We previously showed that ksgA mutation in Salmonella Enteritidis results in impaired invasiveness i...

  9. Adaptation of extremely halotolerant black yeast Hortaea werneckii to increased osmolarity: a molecular perspective at a glance.

    PubMed

    Plemenitas, A; Vaupotic, T; Lenassi, M; Kogej, T; Gunde-Cimerman, N

    2008-01-01

    Halophilic adaptations have been studied almost exclusively on prokaryotic microorganisms. Discovery of the black yeast Hortaea werneckii as the dominant fungal species in hypersaline waters enabled the introduction of a new model organism to study the mechanisms of salt tolerance in eukaryotes. Its strategies of cellular osmotic adaptations on the physiological and molecular level revealed novel, intricate mechanisms to combat fluctuating salinity. H. werneckii is an extremely halotolerant eukaryotic microorganism and thus a promising source of transgenes for osmotolerance improvement of industrially important yeasts, as well as in crops.

  10. Birth Control Methods

    MedlinePlus

    ... Z Health Topics Birth control methods Birth control methods > A-Z Health Topics Birth control methods fact ... Publications email updates Enter email Submit Birth control methods Birth control (contraception) is any method, medicine, or ...

  11. Controlling Separation in Turbomachines

    NASA Technical Reports Server (NTRS)

    Evans, Simon; Himmel, Christoph; Power, Bronwyn; Wakelam, Christian; Xu, Liping; Hynes, Tom; Hodson, Howard

    2010-01-01

    Four examples of flow control: 1) Passive control of LP turbine blades (Laminar separation control). 2) Aspiration of a conventional axial compressor blade (Turbulent separation control). 3) Compressor blade designed for aspiration (Turbulent separation control). 4.Control of intakes in crosswinds (Turbulent separation control).

  12. Continuous controlled-infusion of hypertonic saline solution in traumatic brain-injured patients: a 9-year retrospective study

    PubMed Central

    2011-01-01

    Introduction Description of a continuous hypertonic saline solution (HSS) infusion using a dose-adaptation of natremia in traumatic brain injured (TBI) patients with refractory intracranial hypertension (ICH). Methods We performed a single-center retrospective study in a surgical intensive care unit of a tertiary hospital. Fifty consecutive TBI patients with refractory ICH treated with continuous HSS infusion adapted to a target of natremia. In brief, a physician set a target of natremia adapted to the evolution of intracranial pressure (ICP). Flow of NaCl 20% was a priori calculated according to natriuresis, and the current and target natremia that were assessed every 4 hours. Results The HSS infusion was initiated for a duration of 7 (5 to 10) (8 ± 4) days. ICP decreased from 29 (26 to 34) (31 ± 9) mm Hg at H0 to 20 (15 to 26) (21 ± 8) mm Hg at H1 (P < 0.05). Cerebral perfusion pressure increased from 61 (50 to 70) (61 ± 13) mm Hg at H0 up to 67 (60 to 79) (69 ± 12) mm Hg at H1 (P < 0.05). No rebound of ICH was reported after stopping continuous HSS infusion. Natremia increased from 140 (138 to 143) (140 ± 4) at H0 up to 144 (141 to 148) (144 ± 4) mmol/L at H4 (P < 0.05). Plasma osmolarity increased from 275 (268 to 281) (279 ± 17) mmol/L at H0 up to 290 (284 to 307) (297 ± 17) mmol/L at H24 (P < 0.05). The main side effect observed was an increase in chloremia from 111 (107 to 119) (113 ± 8) mmol/L at H0 up to 121 (117 to 124) (121 ± 6) mmol/L at H24 (P < 0.05). Neither acute kidney injury nor pontine myelinolysis was recorded. Conclusions Continuous HSS infusion adapted to close biologic monitoring enables long-lasting control of natremia in TBI patients along with a decreased ICP without any rebound on infusion discontinuation. PMID:22035596

  13. The effects of transdermal testosterone and oestrogen therapy on dry eye in postmenopausal women: a randomised, placebo-controlled, pilot study.

    PubMed

    Golebiowski, Blanka; Badarudin, Noor; Eden, John; Gerrand, Leanne; Robinson, Jennifer; Liu, Jinzhu; Hampel, Ulrike; You, Jingjing; Stapleton, Fiona

    2017-07-01

    Sex hormones could provide a future treatment avenue for dry eye post menopause. However, there are few well-controlled studies. This study investigates the impact of testosterone and oestrogen on dry eye symptoms and signs in postmenopausal women. A randomised double-blind placebo-controlled pilot study was conducted involving 40 women with dry eye (age 63.9±5.1 years, 13.2±6.3 years post menopause). Ten women were assigned to each of four treatment groups: transdermal testosterone, oestradiol, testosterone/oestradiol combination and placebo. Assessment at baseline and after 8 weeks: ocular symptoms, tear osmolarity, tear stability, tear secretion, meibomian gland assessment, corneal and conjunctival sensitivity, serum concentrations of 17β-oestradiol, 3-α-androstanediol-glucuronide and dehydroepiandrosterone sulfate. Differences from placebo were examined using one-way analysis of variance and Dunnett's t-test. Within-group analyses included paired t-tests and Spearman correlation. Dryness intensity after 8 weeks was significantly worse in the oestrogen group compared with placebo (p=0.04). No significant changes in other symptoms, tear function, meibomian gland function, lid morphology, corneal or conjunctival sensitivity were observed in any of the groups when compared with the change in placebo after 8 weeks. Within-group analyses showed increased tear secretion in the testosterone/oestradiol combination group (p=0.03) and a strong association between increased serum androgen and improved tear stability in the testosterone group (ρ=0.83,p=0.01). Oestrogen supplementation may worsen ocular symptoms in postmenopausal women with dry eye, whereas no impact of testosterone therapy on symptoms was apparent. The positive effects of oestrogen and testosterone on tear function require confirmation in a larger study, with sample size calculated from the data generated herein. Placebo control is essential in studies of dry eye therapies. ACTRN

  14. [Oral hydratation with a low osmolality solution in dehydrated children with diarrheic diseases: controlled clinical trial].

    PubMed

    Bernal, Carlos; Velásquez, Claudia; García, Guillermo; Uribe, Gustavo; Palacio, Carlos Mauricio

    2003-03-01

    A clinical trial was conducted to compare the efficacy of a low-osmolarity solution (245 mOsm/L), and a standard oral rehydration solution (ORS) recommended by WHO for children dehydrated by diarrhea. Group 1 (69 children) received WHO/ORS (311 mOsml/L) and group 2 (71 children) received a low-osmolarity solution (245 mOsm/L). Rehydration was successful in 88.4% in group 1 and 92.9% in group 2 (p = 0.35). Rehydration was completed in 5.2 h (SD +/- 1.8) in group 1 and 5.5 (SD +/- 1.7) in group 2 (p = 0.31). Stool output was 6.3 g/kg/h (SD +/- 5.0) in group 1 and 5.6 g/kg/h (SD +/- 5.1) in group 2 (p = 0.94). Sodium at rehydration-completion was 139.3 mEq/L (SD +/- 7.1) in group 1 and 136.7 mEq/L (SD +/- 4.3) in group 2 (p = 0.014). Group 1 was under observation for 21 hours (SD +/- 5.7) and group 2, for 22 hours (SD +/- 5.6). Stool output in group 1 was 5.2 g/kg/h (SD 4.1) and 4.2 gr./kg/h (SD +/- 4.1) in group 2 (p = 0.16). In group 1, 23.1% required intravenous solutions and 9.8% in group 2 (p = 0.03). In treating dehydrated children, the low-osmolarity solution diminished the need for intravenous solutions, corrected most plasmatic sodium disorders, and produced no-risk of developing hyponatremia.

  15. CONTROL ROOM WITH SPRINKLER SYSTEM CONTROLS, INCLUDING MANUAL CONTROL BOXES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CONTROL ROOM WITH SPRINKLER SYSTEM CONTROLS, INCLUDING MANUAL CONTROL BOXES FOR THE VENTILATION SYSTEM AND A PLC SWITCH FOR AUTOMATIC CO (CARBON MONOXIDE) SYSTEM. THE AIR TESTING SYSTEM IS FREE STANDING AND THE FANS ARE COMPUTER-OPERATED. - Alaskan Way Viaduct and Battery Street Tunnel, Seattle, King County, WA

  16. Contact Control, Version 1

    SciTech Connect

    von Sternberg, Alex

    2016-07-21

    The contact control code is a generalized force control scheme meant to interface with a robotic arm being controlled using the Robot Operating System (ROS). The code allows the user to specify a control scheme for each control dimension in a way that many different control task controllers could be built from the same generalized controller. The input to the code includes maximum velocity, maximum force, maximum displacement, and a control law assigned to each direction and the output is a 6 degree of freedom velocity command that is sent to the robot controller.

  17. Quantum feedback control and classical control theory

    SciTech Connect

    Doherty, Andrew C.; Habib, Salman; Jacobs, Kurt; Mabuchi, Hideo; Tan, Sze M.

    2000-07-01

    We introduce and discuss the problem of quantum feedback control in the context of established formulations of classical control theory, examining conceptual analogies and essential differences. We describe the application of state-observer-based control laws, familiar in classical control theory, to quantum systems and apply our methods to the particular case of switching the state of a particle in a double-well potential. (c) 2000 The American Physical Society.

  18. Neural control: Chaos control sets the pace

    NASA Astrophysics Data System (ADS)

    Schöll, Eckehard

    2010-03-01

    Even simple creatures, such as cockroaches, are capable of complex responses to changes in their environment. But robots usually require complicated dedicated control circuits to perform just a single action. Chaos control theory could allow simpler control strategies to realize more complex behaviour.

  19. Superconducting fault current controller/current controller

    DOEpatents

    Cha, Yung S.

    2004-06-15

    A superconducting fault current controller/current controller employs a superconducting-shielded core reactor (SSCR) with a variable impedance in a secondary circuit to control current in a primary circuit such as an electrical distribution system. In a second embodiment, a variable current source is employed in a secondary circuit of an SSCR to control current in the primary circuit. In a third embodiment, both a variable impedance in one secondary circuit and a variable current source in a second circuit of an SSCR are employed for separate and independent control of current in the primary circuit.

  20. Vehicle Dynamics and Control

    NASA Astrophysics Data System (ADS)

    Rajamani, Rajesh

    Vehicle Dynamics and Control provides a comprehensive coverage of vehicle control systems and the dynamic models used in the development of these control systems. The control system topics covered in the book include cruise control, adaptive cruise control, ABS, automated lane keeping, automated highway systems, yaw stability control, engine control, passive, active and semi-active suspensions, tire models and tire-road friction estimation. In developing the dynamic model for each application, an effort is made to both keep the model simple enough for control system design but at the same time rich enough to capture the essential features of the dynamics.

  1. Substructural controller synthesis

    NASA Technical Reports Server (NTRS)

    Su, Tzu-Jeng; Craig, Roy R., Jr.

    1989-01-01

    A decentralized design procedure which combines substructural synthesis, model reduction, decentralized controller design, subcontroller synthesis, and controller reduction is proposed for the control design of flexible structures. The structure to be controlled is decomposed into several substructures, which are modeled by component mode synthesis methods. For each substructure, a subcontroller is designed by using the linear quadratic optimal control theory. Then, a controller synthesis scheme called Substructural Controller Synthesis (SCS) is used to assemble the subcontrollers into a system controller, which is to be used to control the whole structure.

  2. Controllability of asynchronous Boolean multiplex control networks

    NASA Astrophysics Data System (ADS)

    Luo, Chao; Wang, Xingyuan; Liu, Hong

    2014-09-01

    In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) is studied. First, the model of Boolean multiplex control networks under Harvey' asynchronous update is presented. By means of semi-tensor product approach, the logical dynamics is converted into linear representation, and a generalized formula of control-depending network transition matrices is achieved. Second, a necessary and sufficient condition is proposed to verify that only control-depending fixed points of ABMCNs can be controlled with probability one. Third, using two types of controls, the controllability of system is studied and formulae are given to show: (a) when an initial state is given, the reachable set at time s under a group of specified controls; (b) the reachable set at time s under arbitrary controls; (c) the specific probability values from a given initial state to destination states. Based on the above formulae, an algorithm to calculate overall reachable states from a specified initial state is presented. Moreover, we also discuss an approach to find the particular control sequence which steers the system between two states with maximum probability. Examples are shown to illustrate the feasibility of the proposed scheme.

  3. Structural Pest Control.

    ERIC Educational Resources Information Center

    Kahn, M. S.; Hoffman, W. M.

    This manual is designed for those who seek certification as pesticide applicators for industrial, institutional, structural, and health-related pest control. It is divided into six sections covering general pest control, wood-destroying organisms, bird control, fumigation, rodent control, and industrial weed control. The manual gives information…

  4. Malagasy Backward Object Control

    ERIC Educational Resources Information Center

    Potsdam, Eric

    2009-01-01

    Backward control is an obligatory interpretational dependency between an overt controller and a nonovert controllee in which the controllee is structurally superior to the controller: "Meg persuaded [Delta]i" ["Roni to give up"]. It contrasts with ordinary forward control, in which the controller is structurally higher: "Meg persuaded Roni"…

  5. Malagasy Backward Object Control

    ERIC Educational Resources Information Center

    Potsdam, Eric

    2009-01-01

    Backward control is an obligatory interpretational dependency between an overt controller and a nonovert controllee in which the controllee is structurally superior to the controller: "Meg persuaded [Delta]i" ["Roni to give up"]. It contrasts with ordinary forward control, in which the controller is structurally higher: "Meg persuaded Roni"…

  6. Directions in propulsion control

    NASA Technical Reports Server (NTRS)

    Lorenzo, Carl F.

    1990-01-01

    Discussed here is research at NASA Lewis in the area of propulsion controls as driven by trends in advanced aircraft. The objective of the Lewis program is to develop the technology for advanced reliable propulsion control systems and to integrate the propulsion control with the flight control for optimal full-system control.

  7. PID controllers' fragility.

    PubMed

    Alfaro, Víctor M

    2007-10-01

    In this paper, an index for measuring fragility of proportional integral derivative (PID) controllers is proposed. This index relates the losses of robustness of the control loop when controller parameters change, to the nominal robustness of the control loop. Furthermore, it defines when a PID controller is fragile, nonfragile or resilient.

  8. Structural Pest Control.

    ERIC Educational Resources Information Center

    Kahn, M. S.; Hoffman, W. M.

    This manual is designed for those who seek certification as pesticide applicators for industrial, institutional, structural, and health-related pest control. It is divided into six sections covering general pest control, wood-destroying organisms, bird control, fumigation, rodent control, and industrial weed control. The manual gives information…

  9. Integrated Control Using the SOFFT Control Structure

    NASA Technical Reports Server (NTRS)

    Halyo, Nesim

    1996-01-01

    The need for integrated/constrained control systems has become clearer as advanced aircraft introduced new coupled subsystems such as new propulsion subsystems with thrust vectoring and new aerodynamic designs. In this study, we develop an integrated control design methodology which accomodates constraints among subsystem variables while using the Stochastic Optimal Feedforward/Feedback Control Technique (SOFFT) thus maintaining all the advantages of the SOFFT approach. The Integrated SOFFT Control methodology uses a centralized feedforward control and a constrained feedback control law. The control thus takes advantage of the known coupling among the subsystems while maintaining the identity of subsystems for validation purposes and the simplicity of the feedback law to understand the system response in complicated nonlinear scenarios. The Variable-Gain Output Feedback Control methodology (including constant gain output feedback) is extended to accommodate equality constraints. A gain computation algorithm is developed. The designer can set the cross-gains between two variables or subsystems to zero or another value and optimize the remaining gains subject to the constraint. An integrated control law is designed for a modified F-15 SMTD aircraft model with coupled airframe and propulsion subsystems using the Integrated SOFFT Control methodology to produce a set of desired flying qualities.

  10. Xenon International Automated Control

    SciTech Connect

    2016-08-05

    The Xenon International Automated Control software monitors, displays status, and allows for manual operator control as well as fully automatic control of multiple commercial and PNNL designed hardware components to generate and transmit atmospheric radioxenon concentration measurements every six hours.

  11. AIR POLLUTION CONTROL TECHNOLOGIES

    EPA Science Inventory

    This is a chapter for John Wiley & Son's Mechanical Engineers' Handbook, and covers issues involving air pollution control. Various technologies for controlling sulfur oxides is considered including fuel desulfurization. It also considers control of nitrogen oxides including post...

  12. Birth control pills - combination

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000655.htm Birth control pills - combination To use the sharing features on ... contain both progestin and estrogen. What Are Combination Birth Control Pills? Birth control pills help keep you from ...

  13. Essure Permanent Birth Control

    MedlinePlus

    ... and Prosthetics Essure Permanent Birth Control Essure Permanent Birth Control Share Tweet Linkedin Pin it More sharing options ... Essure System Essure is a a permanently implanted birth control device for women (female sterilization). Implantation of Essure ...

  14. Contraception and Birth Control

    MedlinePlus

    ... Birth Control > About Page Content ​About Contraception and Birth Control Contraception is the prevention of pregnancy. Contraception, or birth control, also allows couples to plan the timing of ...

  15. AIR POLLUTION CONTROL TECHNOLOGIES

    EPA Science Inventory

    This is a chapter for John Wiley & Son's Mechanical Engineers' Handbook, and covers issues involving air pollution control. Various technologies for controlling sulfur oxides is considered including fuel desulfurization. It also considers control of nitrogen oxides including post...

  16. OPTIMUM SYSTEMS CONTROL,

    DTIC Science & Technology

    Variational calculus and continuous optimal control, (4) The maximum principle and Hamilton Jacobi theory, (5) Optimum systems control examples, (6...Discrete variational calculus and the discrete maximum principle, (7) Optimum control of distributed parameter systems, (8) Optimum state estimation in

  17. Gross motor control

    MedlinePlus

    Gross motor control is the ability to make large, general movements (such as waving an arm or lifting a ... Gross motor control is a milestone in the development of an infant. Infants develop gross motor control before they ...

  18. Control System Damps Vibrations

    NASA Technical Reports Server (NTRS)

    Kopf, E. H., Jr.; Brown, T. K.; Marsh, E. L.

    1983-01-01

    New control system damps vibrations in rotating equipment with help of phase-locked-loop techniques. Vibrational modes are controlled by applying suitable currents to drive motor. Control signals are derived from sensors mounted on equipment.

  19. Wisdom Appliance Control System

    NASA Astrophysics Data System (ADS)

    Hendrick; Jheng, Jyun-Teng; Tsai, Chen-Chai; Liou, Jia-Wei; Wang, Zhi-Hao; Jong, Gwo-Jia

    2017-07-01

    Intelligent appliances wisdom involves security, home care, convenient and energy saving, but the home automation system is still one of the core unit, and also using micro-processing electronics technology to centralized and control the home electrical products and systems, such as: lighting, television, fan, air conditioning, stereo, it composed of front-controller systems and back-controller panels, user using front-controller to control command, and then through the back-controller to powered the device.

  20. CONTROL LIMITER DEVICE

    DOEpatents

    DeShong, J.A.

    1960-03-01

    A control-limiting device for monltoring a control system is described. The system comprises a conditionsensing device, a condition-varying device exerting a control over the condition, and a control means to actuate the condition-varying device. A control-limiting device integrates the total movement or other change of the condition-varying device over any interval of time during a continuum of overlapping periods of time, and if the tothl movement or change of the condition-varying device exceeds a preset value, the control- limiting device will switch the control of the operated apparatus from automatic to manual control.

  1. Biological Control in Agroecosystems

    NASA Astrophysics Data System (ADS)

    Batra, Suzanne W. T.

    1982-01-01

    Living organisms are used as biological pest control agents in (i) classical biological control, primarily for permanent control of introduced perennial weed pests or introduced pests of perennial crops; (ii) augmentative biological control, for temporary control of native or introduced pests of annual crops grown in monoculture; and (iii) conservative or natural control, in which the agroecosystem is managed to maximize the effect of native or introduced biological control agents. The effectiveness of biological control can be improved if it is based on adequate ecological information and theory, and if it is integrated with other pest management practices.

  2. Intelligent control in robotics

    SciTech Connect

    Meystel, A.

    1988-08-01

    A new paradigm of solving control problems is considered: intelligent control. Conventional control theory does not offer adequate analytical and design tools for a number of systems: robots, automated manufacturing, multidimensional nonlinear and stochastic systems, multisensor systems, systems under human supervision, etc. Issues of dissatisfaction with conventional control theory are discussed. Several major domains of interest are formulated for the theory of intelligent control, as well as several possible avenues of their approaching in a nonconventional way. Nested hierarchical information structures are introduced typical for the problems formulated within the theory of intelligent control such as building multiresolutional multiloop controllers, providing continuity of planning/control processes, etc. 42 references.

  3. Dynamic power flow controllers

    DOEpatents

    Divan, Deepakraj M.; Prasai, Anish

    2017-03-07

    Dynamic power flow controllers are provided. A dynamic power flow controller may comprise a transformer and a power converter. The power converter is subject to low voltage stresses and not floated at line voltage. In addition, the power converter is rated at a fraction of the total power controlled. A dynamic power flow controller controls both the real and the reactive power flow between two AC sources having the same frequency. A dynamic power flow controller inserts a voltage with controllable magnitude and phase between two AC sources; thereby effecting control of active and reactive power flows between two AC sources.

  4. Integrated blending control system

    SciTech Connect

    Cogbill, R.B.; Dodd, T.J.; Heilman, P.W.; Heronemus, D.L.; Sears, L.R.; Berryman, L.N.; Baker, R.L.; Guffee, L.E.; Prucha, D.A.; Roberts, D.M.

    1989-07-25

    This patent describes a proppant control system. It comprises: storage bin means for storing particulate material; surge bin means for receiving a flow of the particulate material from the storage bin means; first conveyor means for providing a flow of particulate material to the surge bin means from the storage bin means; second conveyor means for transferring a controllable quantity of the particulate material from the surge bin means; and proppant control means. The control means include: first speed control means for remotely controlling the speed of the first conveyor means; and second speed control means for remotely controlling the speed of the second conveyor means.

  5. Predictive fuzzy controller for robotic motion control

    SciTech Connect

    Huang, S.J.; Hu, C.F.

    1995-12-31

    A system output prediction strategy incorporated with a fuzzy controller is proposed to manipulate the robotic motion control. Usually, the current position and velocity errors are used to operate the fuzzy logic controller for picking out a corresponding rule. When the system has fast planning speed or time varying behavior, the required tracking accuracy is difficult to achieve by adjusting the fuzzy rules. In order to improve the position control accuracy and system robustness for the industrial application, the current position error in the fuzzy rules look-up table is substituted by the predictive position error of the next step by using the grey predictive algorithm. This idea is implemented on a five degrees of freedom robot. The experimental results show that this fuzzy controller has effectively improve the system performance and achieved the facilitation of fuzzy controller implementation.

  6. Unfalsified control based on the ? controller parameterisation

    NASA Astrophysics Data System (ADS)

    Sánchez-Peña, R. S.; Colmegna, P.; Bianchi, F.

    2015-11-01

    This paper presents an implementation of the unfalsified control (UC) method using the Riccati-based parameterisation of ? controllers. The method provides an infinite controller set to (un)falsify the real-time data streams seeking for the best performance. Different sets may be designed to increase the degrees of freedom of the set of controller candidates to perform UC. In general, a set of m central controllers could be designed, each one seeking different objectives and all with their own parameterisation as a function of a stable and bounded transfer matrix. For example, one controller parameterisation could be designed to solve the robust stability of a model set which covers the physical system, therefore guaranteeing feasibility. The implementation requires the online optimisation of either quadratic fractional or quadratic problems, depending on the selection of the cost function. A multi-input, multi-output (MIMO) time-varying model of a permanent magnet synchronous generator illustrates the use of this technique.

  7. Space Digital Controller for Improved Motor Control

    NASA Astrophysics Data System (ADS)

    Alves-Nunes, Samuel; Daras, Gaetan; Dehez, Bruno; Maillard, Christophe; Bekemans, Marc; Michel, Raymond

    2014-08-01

    Performing digital motor control into space equipment is a new challenge. The new DPC (Digital Programmable Controller) is the first chip that we can use as a micro-controller, allowing us to drive motors with digital control schemes. In this paper, the digital control of hybrid stepper motors is considered. This kind of motor is used for solar array rotation and antenna actuation. New digital control technology brings a lot of advantages, allowing an important reduction of thermal losses inside the motor, and a reduction of thermal constraints on power drive electronic components. The opportunity to drive motors with a digital controller also brings many new functionalities like post-failure torque analysis, micro- vibrations and cogging torque reduction, or electro- mechanical damping of solar array oscillations. To evaluate the performance of the system, Field-Oriented Control (FOC) is implemented on a hybrid stepper motor. A test-bench, made of an active load, has been made to emulate the mechanical behaviour of the solar array, by the use of a torsionally-compliant model. The experimental results show that we can drastically reduce electrical power consumption, compared with the currently used open-loop control scheme.

  8. Aircraft Attitude Control by Fuzzy Control

    NASA Astrophysics Data System (ADS)

    Kato, Akio; Matsuba, Takashi

    The fuzzy control law to improve dutch roll characteristics of aircraft was designed and its control performance was evaluated. First, the control law was designed for a small-high speed aircraft at low altitude and low-speed flight conditions. The control law was then applied to flight conditions from minimum speed to supersonic speed and from sea level to high altitude. The control performance for these conditions was evaluated. Furthermore, this control law was adapted to a large transport aircraft with no parameter changes. The evaluation showed good control performance to improve the dutch roll characteristics under all flight conditions for both small high-speed aircraft and large transport aircraft without the parameter changes. This means that the fuzzy control proved to provide effective flexible application to aircraft stability augmentation. If an aircraft in actual flight is in strong air turbulence, inputs to the fuzzy controller may exceed the limit of its effective range. To cope with this problem, the countermeasures were introduced, their methods tested, and their effectiveness proved.

  9. Improving Control of Two Motor Controllers

    NASA Technical Reports Server (NTRS)

    Toland, Ronald W.

    2004-01-01

    A computer program controls motors that drive translation stages in a metrology system that consists of a pair of two-axis cathetometers. This program is specific to Compumotor Gemini (or equivalent) motors and the Compumotor 6K-series (or equivalent) motor controller. Relative to the software supplied with the controller, this program affords more capabilities and is easier to use. Written as a Virtual Instrument in the LabVIEW software system, the program presents an imitation control panel that the user can manipulate by use of a keyboard and mouse. There are three modes of operation: command, movement, and joystick. In command mode, single commands are sent to the controller for troubleshooting. In movement mode, distance, speed, and/or acceleration commands are sent to the controller. Position readouts from the motors and from position encoders on the translation stages are displayed in marked fields. At any time, the position readouts can be recorded in a file named by the user. In joystick mode, the program yields control of the motors to a joystick. The program sends commands to, and receives data from, the controller via a serial cable connection, using the serial-communication portion of the software supplied with the controller.

  10. Osmotic control of glycine betaine biosynthesis and degradation in Rhizobium meliloti

    SciTech Connect

    Smith, L.T.; Pocard, J.A.; Bernard, T.; Le Rudulier, D.

    1988-07-01

    Intracellular accumulation of glycine betaine has been shown to confer an enhanced level of osmotic stress tolerance in Rhizobium meliloti. In this study, the authors used a physiological approach to investigate the mechanism by which glycine betaine is accumulated in osmotically stressed R. meliloti. Results from growth experiments, /sup 14/C labeling of intermediates, and enzyme activity assays are presented. The results provide evidence for the pathway of biosynthesis and degradation of glycine betaine and the osmotic effects on this pathway. High osmolarity in the medium decreased the activities of the enzymes involved in the degradation of glycine betaine but not those of enzymes that lead to its biosynthesis from choline. Thus, the concentration of the osmoprotectant glycine betaine is increased in stressed cells. This report demonstrates the ability of the osmolarity of the growth medium to regulate the use of glycine betaine as a carbon and nitrogen source or as an osmoprotectant. The mechanisms of osmoregulation in R. meliloti and Escherichia coli are compared.

  11. Osmotic control of glycine betaine biosynthesis and degradation in Rhizobium meliloti.

    PubMed Central

    Smith, L T; Pocard, J A; Bernard, T; Le Rudulier, D

    1988-01-01

    Intracellular accumulation of glycine betaine has been shown to confer an enhanced level of osmotic stress tolerance in Rhizobium meliloti. In this study, we used a physiological approach to investigate the mechanism by which glycine betaine is accumulated in osmotically stressed R. meliloti. Results from growth experiments, 14C labeling of intermediates, and enzyme activity assays are presented. The results provide evidence for the pathway of biosynthesis and degradation of glycine betaine and the osmotic effects on this pathway. High osmolarity in the medium decreased the activities of the enzymes involved in the degradation of glycine betaine but not those of enzymes that lead to its biosynthesis from choline. Thus, the concentration of the osmoprotectant glycine betaine is increased in stressed cells. This report demonstrates the ability of the osmolarity of the growth medium to regulate the use of glycine betaine as a carbon and nitrogen source or as an osmoprotectant. The mechanisms of osmoregulation in R. meliloti and Escherichia coli are compared. PMID:3290197

  12. Electrolyte changes after bowel preparation for colonoscopy: A randomized controlled multicenter trial.

    PubMed

    Lee, Kyong Joo; Park, Hong Jun; Kim, Hyun-Soo; Baik, Kwang Ho; Kim, Yeon Soo; Park, Sung Chul; Seo, Hyun Il

    2015-03-14

    To investigate the electrolyte changes between 2-L polyethylene glycol with ascorbic acid 20 g (PEG-Asc) and 4-L PEG solutions. From August 2012 to February 2013, a total of 226 patients were enrolled at four tertiary hospitals. All patients were randomly allocated to a PEG-Asc group or a 4-L PEG. Before colonoscopy, patients completed a questionnaire to assess bowel preparation-related symptoms, satisfaction, and willingness. Endoscopists assessed the bowel preparation using the Boston Bowel Preparation Scale (BBPS). In addition, blood tests, including serum electrolytes, serum osmolarity, and urine osmolarity were evaluated both before and after the procedure. A total of 226 patients were analyzed. BBPS scores were similar and the adequate bowel preparation rate (BBPS ≥ 6) was not different between the two groups (PEG-Asc vs 4-L PEG, 73.2% vs 76.3%, P = 0.760). Bowel preparation-related symptoms also were not different between the two groups. The taste of PEG-Asc was better (41.1% vs 16.7%, P < 0.001), and the willingness to undergo repeated bowel preparation was higher in the PEG-Asc group (73.2% vs 59.3%, P = 0.027) than in 4-L PEG. There were no significant changes in serum electrolytes in either group. In this multicenter trial, bowel preparation with PEG-Asc was better than 4-L PEG in terms of patient satisfaction, with similar degrees of bowel preparation and electrolyte changes.

  13. Control augmentation for lateral control wheel steering

    NASA Technical Reports Server (NTRS)

    Foulkes, R. H., Jr.

    1981-01-01

    Flight control system design for lateral control wheel steering is discussed. Two alternate designs are presented. The first design is a roll-rate command, bank-angle hold system with a wings-level track-hold submode. The second is a curved-track-hold system. Design details and real-time flight simulator results are included.

  14. Microprocessor control for standardized power control systems

    NASA Technical Reports Server (NTRS)

    Green, D. G.; Perry, E.

    1978-01-01

    The use of microcomputers in space-oriented power systems as a replacement for existing inflexible analog type controllers has been proposed. This study examines multiprocessor systems, various modularity concepts and presents a conceptualized power system incorporating a multiprocessor controller as well as preliminary results from a breadboard model of the proposed system.

  15. Voice controlled wheelchairs: fine control by humming.

    PubMed

    Peixoto, Nathalia; Nik, Hossein Ghaffari; Charkhkar, Hamid

    2013-10-01

    People without disabilities seamlessly control devices with their hands. Interestingly, their hands can perform coarse and fine control. Implementing smooth control for computerized systems is not straightforward and most of the time it is not intuitive either. Here we offer a solution to that problem: smooth control through humming. Voice commands have become ubiquitous in modern technology. Speech-to-text applications abound. Smooth control, on the other hand, has not been tackled yet. Here we design and implement a humming control technique, and demonstrate a hardware implementation with a powered wheelchair. Once actuated, the speed with which the chair moves will depend on the subtle variation on the fundamental frequency of the user's humming, acquired through an accelerometer measuring vocal cord vibration. We also discuss two signal processing techniques that handle commonly encountered issues when trying to resolve frequencies in real time data. The hardware implementation shows performance of 80% and higher in speech recognition for signal-to-noise ratio (SNR) higher than 8dB and 100% in smooth control and frequency detection for all tested SNRs. We also discuss potential applications of smooth humming control to other assistive technology. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. Robot Manipulator Control.

    DTIC Science & Technology

    1983-03-07

    This report presents a synthetic approach for calculating the control of robot manipulators. The initial control problem is broken down into linear ... control and modelling problems. The approach allows derivation of numerous schemes (adaptive or not) of control proposed in the literature and suggests

  17. Aircraft adaptive learning control

    NASA Technical Reports Server (NTRS)

    Lee, P. S. T.; Vanlandingham, H. F.

    1979-01-01

    The optimal control theory of stochastic linear systems is discussed in terms of the advantages of distributed-control systems, and the control of randomly-sampled systems. An optimal solution to longitudinal control is derived and applied to the F-8 DFBW aircraft. A randomly-sampled linear process model with additive process and noise is developed.

  18. Programable Multicrate Controller

    NASA Technical Reports Server (NTRS)

    Mook, G. L.; Phillips, M. R.

    1985-01-01

    High-speed, environmentally hardened controller developed for use with commercially available system crates for both experiment control and data handling. Programable crate controller consists of three functional areas: control section utilizes high-speed bit-slice circuitry, memory, and data way interface.

  19. Adaptive Cruise Control

    NASA Astrophysics Data System (ADS)

    Winner, Hermann; Danner, Bernd; Steinle, Joachim

    Mit Adaptive Cruise Control, abgekürzt ACC, wird eine Fahrgeschwindigkeitsregelung bezeichnet, die sich an die Verkehrssituation anpasst. Synonyme Bezeichnungen sind Aktive Geschwindigkeitsregelung, Automatische Distanzregelung oder Abstandsregeltempomat. Im englischen Sprachraum fnden sich die weiteren Bezeichnungen Active Cruise Control, Automatic Cruise Control oder Autonomous Intelligent Cruise Control. Als markengeschützte Bezeichnungen sind Distronic und Automatische Distanz-Regelung (ADR) eingetragen.

  20. Nuclear reactor control apparatus

    DOEpatents

    Sridhar, Bettadapur N.

    1983-11-01

    Nuclear reactor core safety rod release apparatus comprises a control rod having a detent notch in the form of an annular peripheral recess at its upper end, a control rod support tube for raising and lowering the control rod under normal conditions, latches pivotally mounted on the control support tube with free ends thereof normally disposed in the recess in the control rod, and cam means for pivoting the latches out of the recess in the control rod when a scram condition occurs. One embodiment of the invention comprises an additional magnetically-operated latch for releasing the control rod under two different conditions, one involving seismic shock.

  1. HYDRAULIC SERVO CONTROL MECHANISM

    DOEpatents

    Hussey, R.B.; Gottsche, M.J. Jr.

    1963-09-17

    A hydraulic servo control mechanism of compact construction and low fluid requirements is described. The mechanism consists of a main hydraulic piston, comprising the drive output, which is connected mechanically for feedback purposes to a servo control piston. A control sleeve having control slots for the system encloses the servo piston, which acts to cover or uncover the slots as a means of controlling the operation of the system. This operation permits only a small amount of fluid to regulate the operation of the mechanism, which, as a result, is compact and relatively light. This mechanism is particuiarly adaptable to the drive and control of control rods in nuclear reactors. (auth)

  2. An intelligent traffic controller

    SciTech Connect

    Kagolanu, K.; Fink, R.; Smartt, H.; Powell, R.; Larsen, E.

    1995-12-01

    A controller with advanced control logic can significantly improve traffic flows at intersections. In this vein, this paper explores fuzzy rules and algorithms to improve the intersection operation by rationalizing phase changes and green times. The fuzzy logic for control is enhanced by the exploration of neural networks for families of membership functions and for ideal cost functions. The concepts of fuzzy logic control are carried forth into the controller architecture. Finally, the architecture and the modules are discussed. In essence, the control logic and architecture of an intelligent controller are explored.

  3. Control of space stations

    NASA Technical Reports Server (NTRS)

    Lee, K. Y.

    1983-01-01

    A study is made to develop controllers for the NASA-JSC Triangular Space Station and evaluate their performances to make recommendations for structural design and/or control alternatives. The control system design assumes the rigid body of the Space Station and developes the lumped parameter control system by using the Inverse Optimal Control Theory. In order to evaluate the performance of the control system, a Parameter Estimation algorithm is being developed which will be used in modeling an equivalent but simpler Space Station model. Finally, a scaled version of the Space Station is being built for the purpose of physical experiments to evaluate the control system performance.

  4. Engine roughness control means

    SciTech Connect

    Matsuura, M.; Doi, N.; Yoshioka, S.; Okimoto, H.; Veda, K.

    1987-08-04

    This patent describes a control system for a vehicle engine comprising engine condition detecting means for detecting an engine operating condition and producing an engine condition signal representing the engine operating condition, engine combustion control means for controlling a condition of combustion in the engine; and a control factor storage means for storing control factors for controlling the engine combustion. A modifying means connect the comparator means to receive the output signal and to modify the control factor from the storage means by the output of the comparator means so that the combustion control means is controlled by the modified control factor in a direction that the engine vibrations are suppressed. A reference signal changes means connected with the engine condition detecting means to change the reference roughness signal in accordance with the engine operating condition so that the reference signal is decreased when the engine is in idling operation.

  5. Precision digital control systems

    NASA Astrophysics Data System (ADS)

    Vyskub, V. G.; Rozov, B. S.; Savelev, V. I.

    This book is concerned with the characteristics of digital control systems of great accuracy. A classification of such systems is considered along with aspects of stabilization, programmable control applications, digital tracking systems and servomechanisms, and precision systems for the control of a scanning laser beam. Other topics explored are related to systems of proportional control, linear devices and methods for increasing precision, approaches for further decreasing the response time in the case of high-speed operation, possibilities for the implementation of a logical control law, and methods for the study of precision digital control systems. A description is presented of precision automatic control systems which make use of electronic computers, taking into account the existing possibilities for an employment of computers in automatic control systems, approaches and studies required for including a computer in such control systems, and an analysis of the structure of automatic control systems with computers. Attention is also given to functional blocks in the considered systems.

  6. Fuzzy and neural control

    NASA Technical Reports Server (NTRS)

    Berenji, Hamid R.

    1992-01-01

    Fuzzy logic and neural networks provide new methods for designing control systems. Fuzzy logic controllers do not require a complete analytical model of a dynamic system and can provide knowledge-based heuristic controllers for ill-defined and complex systems. Neural networks can be used for learning control. In this chapter, we discuss hybrid methods using fuzzy logic and neural networks which can start with an approximate control knowledge base and refine it through reinforcement learning.

  7. TFTR diagnostic vacuum controller

    SciTech Connect

    Olsen, D.; Persons, R.

    1981-01-01

    The TFTR diagnostic vacuum controller (DVC) provides in conjunction with the Central Instrumentation Control and Data Acquisition System (CICADA), control and monitoring for the pumps, valves and gauges associated with each individual diagnostic vacuum system. There will be approximately 50 systems on TFTR. Two standard versions of the controller (A and B) wil be provided in order to meet the requirements of two diagnostic manifold arrangements. All pump and valve sequencing, as well as protection features, will be implemented by the controller.

  8. Embryonic cerebrospinal fluid regulates neuroepithelial survival, proliferation, and neurogenesis in chick embryos.

    PubMed

    Gato, Angel; Moro, J A; Alonso, M I; Bueno, D; De La Mano, A; Martín, C

    2005-05-01

    Early in development, the behavior of neuroepithelial cells is controlled by several factors, which act in a developmentally regulated manner. Diffusible factors are secreted locally by the neuroepithelium itself, although other nearby structures may also be involved. Evidence suggests a physiological role for the cerebrospinal fluid in the development of the brain. Here, using organotypic cultures of chick embryo neuroepithelial explants from the mesencephalon, we show that the neuroepithelium in vitro is not able to self-induce cell survival, replication, and neurogenesis. We also show that the embryonic cerebrospinal fluid (E-CSF) promotes neuroepithelial stem cell survival and induces proliferation and neurogenesis in mesencephalic explants. These data strongly suggest that E-CSF is involved in the regulation of neuroepithelial cells behavior, supporting the hypothesis that this fluid plays a key role during the early development of the central nervous system.

  9. SODR Memory Control Buffer Control ASIC

    NASA Technical Reports Server (NTRS)

    Hodson, Robert F.

    1994-01-01

    The Spacecraft Optical Disk Recorder (SODR) is a state of the art mass storage system for future NASA missions requiring high transmission rates and a large capacity storage system. This report covers the design and development of an SODR memory buffer control applications specific integrated circuit (ASIC). The memory buffer control ASIC has two primary functions: (1) buffering data to prevent loss of data during disk access times, (2) converting data formats from a high performance parallel interface format to a small computer systems interface format. Ten 144 p in, 50 MHz CMOS ASIC's were designed, fabricated and tested to implement the memory buffer control function.

  10. Spacecraft stability and control

    NASA Technical Reports Server (NTRS)

    Barret, Chris

    1992-01-01

    The Earth's first artificial satellite, Sputnik 1, slowly tumbled in orbit. The first U.S. satellite, Explorer 1, also tumbled out of control. Today, satellite stability and control has become a higher priority. For a satellite design that is to have a life expectancy of 14 years, appropriate spacecraft flight control systems will be reviewed, stability requirements investigated, and an appropriate flight control system recommended in order to see the design process. Disturbance torques, including aerodynamic, magnetic, gravity gradient, solar, micrometeorite, debris, collision, and internal torques, will be assessed to quantify the disturbance environment so that the required compensating torques can be determined. The control torques, including passive versus active, momentum control, bias momentum, spin stabilization, dual spin, gravity gradient, magnetic, reaction wheels, control moment gyros, inertia augmentation techniques, three-axis control, and reaction control systems (RCSs), will be considered. Conditions for stability will also be considered.

  11. Constrained control allocation

    NASA Technical Reports Server (NTRS)

    Durham, Wayne C.

    1992-01-01

    This paper addresses the problem of the allocation of several flight controls to the generation of specified body-axis moments. The number of controls is greater than the number of moments being controlled, and the ranges of the controls are constrained to certain limits. The controls are assumed to be individually linear in their effect throughout their ranges of motion, and independent of one another in their effects. The geometries of the subset of the constrained controls and of its image in moment space are examined. A direct method of allocating these several controls is presented, that guarantees the maximum possible moment is generated within the constraints of the controls. The results are illustrated by an example problem involving three controls and two moments.

  12. Boiler control systems engineering

    SciTech Connect

    Gilman, J.

    2005-07-01

    The book provides in-depth coverage on how to safely and reliably control the firing of a boiler. Regardless of the capacity or fuel, certain fundamental control systems are required for boiler control. Large utility systems are more complex due to the number of burners and the overall capacity and equipment. This book covers engineering details on control systems and provides specific examples of boiler control including configuration and tuning. References to requirements are based on the 2004 NFPA 85 along with other ISA standards. Detailed chapters cover: Boiler fundamentals including piping and instrument diagrams (P&IDs) and a design basis checklist; Control of boilers, from strategies and bumpless transfer to interlock circuitry and final control elements; Furnace draft; Feedwater; Coal-fired boilers; Fuel and air control; Steam temperature; Burner management systems; Environment; and Control valve sizing. 2 apps.

  13. Control rod drive

    SciTech Connect

    Hawke, Basil C.

    1986-01-01

    A control rod drive uses gravitational forces to insert one or more control rods upwardly into a reactor core from beneath the reactor core under emergency conditions. The preferred control rod drive includes a vertically movable weight and a mechanism operatively associating the weight with the control rod so that downward movement of the weight is translated into upward movement of the control rod. The preferred control rod drive further includes an electric motor for driving the control rods under normal conditions, an electrically actuated clutch which automatically disengages the motor during a power failure and a decelerator for bringing the control rod to a controlled stop when it is inserted under emergency conditions into a reactor core.

  14. Digital Optical Control System

    NASA Astrophysics Data System (ADS)

    Jordan, David H.; Tipton, Charles A.; Christmann, Charles E.; Hochhausler, Nils P.

    1988-09-01

    We describe the digital optical control system (DOGS), a state-of-the-art controller for electrical feedback in an optical system. The need for a versatile optical controller arose from a number of unique experiments being performed by the Air Force Weapons Laboratory. These experiments use similar detectors and actuator-controlled mirrors, but the control requirements vary greatly. The experiments have in common a requirement for parallel control systems. The DOGS satisfies these needs by allowing several control systems to occupy a single chassis with one master controller. The architecture was designed to allow upward compatibility with future configurations. Combinations of off-the-shelf and custom boards are configured to meet the requirements of each experiment. The configuration described here was used to control piston error to X/80 at a wavelength of 0.51 Am. A peak sample rate of 8 kHz, yielding a closed loop bandwidth of 800 Hz, was achieved.

  15. Propulsion Controls, 1979. [air breathing engine control

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The state of the art of multivariable engine control is examined in order to determine future needs and problem areas and to establish the appropriate roles of government, industries, and universities in addressing these problems.

  16. Control system design method

    DOEpatents

    Wilson, David G [Tijeras, NM; Robinett, III, Rush D.

    2012-02-21

    A control system design method and concomitant control system comprising representing a physical apparatus to be controlled as a Hamiltonian system, determining elements of the Hamiltonian system representation which are power generators, power dissipators, and power storage devices, analyzing stability and performance of the Hamiltonian system based on the results of the determining step and determining necessary and sufficient conditions for stability of the Hamiltonian system, creating a stable control system based on the results of the analyzing step, and employing the resulting control system to control the physical apparatus.

  17. CONTROL ROD DRIVE

    DOEpatents

    Chapellier, R.A.; Rogers, I.

    1961-06-27

    Accurate and controlled drive for the control rod is from an electric motor. A hydraulic arrangement is provided to balance a piston against which a control rod is urged by the application of fluid pressure. The electric motor drive of the control rod for normal operation is made through the aforementioned piston. In the event scramming is required, the fluid pressure urging the control rod against the piston is relieved and an opposite fluid pressure is applied. The lack of mechanical connection between the electric motor and control rod facilitates the scramming operation.

  18. Wing Flutter Control

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Through Small Business Innovation Research (SBIR) contracts from Langley Research Center, Orbital Research Inc. developed the Orbital Research Intelligent Control Algorithm (ORICA), the first practical hardware-independent adaptive predictive control structure, specifically suited for optimal control of complex, time-varying systems. ORICA technology has been applied to the problem of controlling aircraft wing flutter. Coupled with NASA expertise, the technology has the possibility of making jet travel safer, more cost effective by extending distance range, and lowering overall aircraft operating costs. Future application areas for ORICA include control of robots, power trains, systems with arrays of sensors, or regulating chemical plants or electrical power plant control.

  19. Aircraft control system

    NASA Technical Reports Server (NTRS)

    Kendall, Greg T. (Inventor); Morgan, Walter R. (Inventor)

    2010-01-01

    A span-loaded, highly flexible flying wing, having horizontal control surfaces mounted aft of the wing on extended beams to form local pitch-control devices. Each of five spanwise wing segments of the wing has one or more motors and photovoltaic arrays, and produces its own lift independent of the other wing segments, to minimize inter-segment loads. Wing dihedral is controlled by separately controlling the local pitch-control devices consisting of a control surface on a boom, such that inboard and outboard wing segment pitch changes relative to each other, and thus relative inboard and outboard lift is varied.

  20. Industrial linguistic control

    SciTech Connect

    King, R.E.; Karonis, F.

    1983-01-01

    The use of various types of controllers and control techniques for industrial process is discussed. An ongoing research and development project is reported on the application of intelligent linguistic controllers to processes in the cement industry in Greece which have, in the past, been controllable only by human operators. Prototype linguistic controllers using fuzzy logic have been implemented and tested on a rotary kiln precalciner flash furnace (3-input 3-output) and on a cement mill separator (3-input 2-output) with good results. Originally implemented on a supervisory minicomputer, the algorithms have been transferred to microcomputers which form the heart of this class of intelligent linguistic controllers. 6 references.

  1. Robot welding process control

    NASA Technical Reports Server (NTRS)

    Romine, Peter L.

    1991-01-01

    This final report documents the development and installation of software and hardware for Robotic Welding Process Control. Primary emphasis is on serial communications between the CYRO 750 robotic welder, Heurikon minicomputer running Hunter & Ready VRTX, and an IBM PC/AT, for offline programming and control and closed-loop welding control. The requirements for completion of the implementation of the Rocketdyne weld tracking control are discussed. The procedure for downloading programs from the Intergraph, over the network, is discussed. Conclusions are made on the results of this task, and recommendations are made for efficient implementation of communications, weld process control development, and advanced process control procedures using the Heurikon.

  2. Programmable Digital Controller

    NASA Technical Reports Server (NTRS)

    Wassick, Gregory J.

    2012-01-01

    An existing three-channel analog servo loop controller has been redesigned for piezoelectric-transducer-based (PZT-based) etalon control applications to a digital servo loop controller. This change offers several improvements over the previous analog controller, including software control over proportional-integral-derivative (PID) parameters, inclusion of other data of interest such as temperature and pressure in the control laws, improved ability to compensate for PZT hysteresis and mechanical mount fluctuations, ability to provide pre-programmed scanning and stepping routines, improved user interface, expanded data acquisition, and reduced size, weight, and power.

  3. Supervisory Control of Networked Control Systems

    DTIC Science & Technology

    2006-01-15

    consisting of 3 Koala robots [Lem06b]. The robots are controlled by MICA2 wireless processor modules. The robots communicate over the MICA2’s...preliminary documentation of a wireless autonomous robotic testbed. The system consists of 3 Koala (K-team Inc.) robots that are controlled by the MICA2...by this project. MICA-KoalaBot Hardware: The Koala robot is an autonomous wheeled vehicle that has 16 infrared (IR) proximity sensors around its

  4. Towards autonomous fuzzy control

    NASA Technical Reports Server (NTRS)

    Shenoi, Sujeet; Ramer, Arthur

    1993-01-01

    The efficient implementation of on-line adaptation in real time is an important research problem in fuzzy control. The goal is to develop autonomous self-organizing controllers employing system-independent control meta-knowledge which enables them to adjust their control policies depending on the systems they control and the environments in which they operate. An autonomous fuzzy controller would continuously observe system behavior while implementing its control actions and would use the outcomes of these actions to refine its control policy. It could be designed to lie dormant when its control actions give rise to adequate performance characteristics but could rapidly and autonomously initiate real-time adaptation whenever its performance degrades. Such an autonomous fuzzy controller would have immense practical value. It could accommodate individual variations in system characteristics and also compensate for degradations in system characteristics caused by wear and tear. It could also potentially deal with black-box systems and control scenarios. On-going research in autonomous fuzzy control is reported. The ultimate research objective is to develop robust and relatively inexpensive autonomous fuzzy control hardware suitable for use in real time environments.

  5. Prevention and Control of Cryptosporidiosis

    MedlinePlus

    ... Email Address Submit Button What's this? Parasites Home Prevention & Control Recommend on Facebook Tweet Share Compartir Prevention & Control Topics Prevention & Control - General Public Prevention & Control - ...

  6. Embryonic blood-cerebrospinal fluid barrier formation and function

    PubMed Central

    Bueno, David; Parvas, Maryam; Hermelo, Ismaïl; Garcia-Fernàndez, Jordi

    2014-01-01

    During embryonic development and adult life, brain cavities and ventricles are filled with cerebrospinal fluid (CSF). CSF has attracted interest as an active signaling medium that regulates brain development, homeostasis and disease. CSF is a complex protein-rich fluid containing growth factors and signaling molecules that regulate multiple cell functions in the central nervous system (CNS). The composition and substance concentrations of CSF are tightly controlled. In recent years, it has been demonstrated that embryonic CSF (eCSF) has a key function as a fluid pathway for delivering diffusible signals to the developing brain, thus contributing to the proliferation, differentiation and survival of neural progenitor cells, and to the expansion and patterning of the brain. From fetal stages through to adult life, CSF is primarily produced by the choroid plexus. The development and functional activities of the choroid plexus and other blood–brain barrier (BBB) systems in adults and fetuses have been extensively analyzed. However, eCSF production and control of its homeostasis in embryos, from the closure of the anterior neuropore when the brain cavities become physiologically sealed, to the formation of the functional fetal choroid plexus, has not been studied in as much depth and remains open to debate. This review brings together the existing literature, some of which is based on experiments conducted by our research group, concerning the formation and function of a temporary embryonic blood–CSF barrier in the context of the crucial roles played by the molecules in eCSF. PMID:25389383

  7. MPC improves reformer control

    SciTech Connect

    Jung, C.S.; Noh, K.K.; Yi, S.; Kim, J.S.; Song, H.K.; Hyun, J.C.

    1995-04-01

    A model predictive control strategy was applied to a synthesis gas reformer of Samsung-BP Chemicals in Korea that produces carbon monoxide and hydrogen from naphtha. A strongly endothermic reaction occurs in a catalytic reformer, and reformer outlet temperature is considered to have the most significant effect on product composition. The newly developed reformer is known to be a cost-effective process operating at high reaction temperatures and low steam-to-carbon ratio, but its drawback is temperature control difficulty due to the use of offgas as a part of the fuel. Without smooth control of the reformer outlet temperature, stable operation of the downstream separation units cannot be expected. Therefore, it is a great challenge to apply a model predictive control technique for tight control of reformer outlet temperature. The paper describes model predictive control, the process advanced control project, computer system architecture, analysis of operating condition, control structure, sampling rate, and disturbance estimation.

  8. SETI data controllers

    NASA Technical Reports Server (NTRS)

    Gosline, R. M.

    1988-01-01

    Three data controllers developed for the SETI project are described. Two are used primarily for recording and playback of SETI data from the Radio Science Surveillance System (RSSS). The third is used as a SETI station controller for DSS 13.

  9. Scabies: Prevention and Control

    MedlinePlus

    ... Diagnostic Assistance [DPDx] Error processing SSI file Prevention & Control Recommend on Facebook Tweet Share Compartir When a ... avoid outbreaks. Institutional outbreaks can be difficult to control and require a rapid, aggressive, and sustained response. ...

  10. Solar Control design package

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Information used in the evaluation of design of Solar Control's solar heating and cooling system controller and the Solarstat is given. Some of the information includes system performance specifications, design data brochures, and detailed design drawings.

  11. Consciousness and cognitive control

    PubMed Central

    Kunde, Wilfried; Reuss, Heiko; Kiesel, Andrea

    2012-01-01

    The implementation or change of information processing routines, known as cognitive control, is traditionally believed to be closely linked to consciousness. It seems that we exert control over our behavior if we know the reasons for, and consequences of, doing so. Recent research suggests, however, that several behavioral phenomena that have been construed as instances of cognitive control can be prompted by events of which actors are not aware. Here we give a brief review of this research, discuss possible reasons for inconsistencies in the empirical evidence, and suggest some lines of future research. Specifically, we suggest to differentiate cognitive control evoked either because of explicit or because of implicit control cues. While the former type of control seems to work outside of awareness, the latter type of control seems to be restricted to consciously registered events that call for control. PMID:22419962

  12. Aeroelastic structural acoustic control.

    PubMed

    Clark, R L; Frampton, K D

    1999-02-01

    Static, constant-gain, output-feedback control compensators were designed to increase the transmission loss across a panel subjected to mean flow on one surface and a stationary, acoustic half-space on the opposite surface. The multi-input, multi-output control system was based upon the use of an array of colocated transducer pairs. The performance of the static-gain, output-feedback controller was compared to that of the full state-feedback controller using the same control actuator arrays, and was found to yield comparable levels of performance for practical limitations on control effort. Additionally, the resulting static compensators proved to be dissipative in nature, and thus the design varied little as a function of the aeroelastic coupling induced by the fluid-structure interaction under subsonic flow conditions. Several parametric studies were performed, comparing the effects of control-effort penalty as well as the number of transducer pairs used in the control system.

  13. ENGINEERING CONTROL INTO MEDICINE

    PubMed Central

    Stone, David J.; Celi, Leo Anthony; Csete, Marie

    2015-01-01

    The human body is a tightly controlled engineering miracle. However, medical training generally does not cover ‘control’ (in the engineering sense) in physiology, pathophysiology and therapeutics. A better understanding of how evolved controls maintain normal homeostasis is critical for understanding the failure mode of controlled systems, i.e., disease. We believe that teaching and research must incorporate an understanding of the control systems in physiology, and take advantage of the quantitative tools used by engineering to understand complex systems. Control systems are ubiquitous in physiology, though often unrecognized. Here we provide selected examples of the role of control in physiology (heart rate variability, immunity), pathophysiology (inflammation in sepsis), and therapeutic devices (diabetes and the artificial pancreas). We also present a high level background to the concept of robustly controlled systems and examples of clinical insights using the controls framework. PMID:25680579

  14. Nutrient Control Seminars

    EPA Science Inventory

    These Nutrient Control Seminars will present an extensive state-of-the-technology review of the engineering design and operation of nitrogen and phosphorous control technologies and techniques applied at municipal wastewater treatment plants (WWTPs). These seminars will present ...

  15. Nutrient Control Design Manual

    EPA Science Inventory

    The Nutrient Control Design Manual will present an extensive state-of-the-technology review of the engineering design and operation of nitrogen and phosphorous control technologies and techniques applied at municipal wastewater treatment plants (WWTPs). This manual will present ...

  16. Nutrient Control Seminars

    EPA Science Inventory

    These Nutrient Control Seminars will present an extensive state-of-the-technology review of the engineering design and operation of nitrogen and phosphorous control technologies and techniques applied at municipal wastewater treatment plants (WWTPs). These seminars will present ...

  17. Nutrient Control Design Manual

    EPA Science Inventory

    The Nutrient Control Design Manual will present an extensive state-of-the-technology review of the engineering design and operation of nitrogen and phosphorous control technologies and techniques applied at municipal wastewater treatment plants (WWTPs). This manual will present ...

  18. Controlling quantum bits

    NASA Astrophysics Data System (ADS)

    2010-08-01

    Can excitons be used to achieve scalable control of quantum light? Steffen Michaelis de Vasconcellos explained to Nature Photonics that the optoelectrical control of exciton qubits in quantum dots offers great promise.

  19. Birth control pill - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100108.htm Birth control pill - series—Normal female anatomy To use the ... to produce a successful pregnancy. To prevent pregnancy, birth control pills affect how these organs normally function. Review ...

  20. Birth control pills overdose

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002599.htm Birth control pill overdose To use the sharing features on this page, please enable JavaScript. Birth control pills, also called oral contraceptives, are prescription medicines ...

  1. SETI data controllers

    NASA Astrophysics Data System (ADS)

    Gosline, R. M.

    1988-02-01

    Three data controllers developed for the SETI project are described. Two are used primarily for recording and playback of SETI data from the Radio Science Surveillance System (RSSS). The third is used as a SETI station controller for DSS 13.

  2. Cholera Prevention and Control

    MedlinePlus

    ... submit" name="commit" type="submit" value="Submit" /> Prevention & Control Recommend on Facebook Tweet Share Compartir Prevention ... basics of cholera and other diarrheal disease prevention. Prevention Control Topics Six Basic Cholera Prevention Messages I ...

  3. Multivariable Control Systems

    DTIC Science & Technology

    1968-01-01

    one). Examples abound of systems with numerous controlled variables, and the modern tendency is toward ever greater utilization of systems and plants of this kind. We call them multivariable control systems (MCS).

  4. Control and dynamic systems

    SciTech Connect

    Leondes, C.T. . Dept. of Electrical Engineering)

    1991-01-01

    This volume contains papers on analysis and control system techniques for electric power systems. Topics include: modeling and control of electric power systems, dynamic state estimation techniques, optimal power flow algorithms, and neural networks in power systems.

  5. Linear decentralized learning control

    NASA Technical Reports Server (NTRS)

    Lee, Soo C.; Longman, Richard W.; Phan, Minh

    1992-01-01

    The new field of learning control develops controllers that learn to improve their performance at executing a given task, based on experience performing this task. The simplest forms of learning control are based on the same concept as integral control, but operating in the domain of the repetitions of the task. This paper studies the use of such controllers in a decentralized system, such as a robot with the controller for each link acting independently. The basic result of the paper is to show that stability of the learning controllers for all subsystems when the coupling between subsystems is turned off, assures stability of the decentralized learning in the coupled system, provided that the sample time in the digital learning controller is sufficiently short.

  6. Applications of control theory

    NASA Technical Reports Server (NTRS)

    Taft, C. K.; Pokoski, J. L.; Murdoch, J. B.; Limbert, D. E.; Alperi, R. W.

    1972-01-01

    Applications of control theory are considered in the areas of decoupling and wake steering control of submersibles, a method of electrohydraulic conversion with no moving parts, and socio-economic system modelling.

  7. Microtron Modelling and Control

    SciTech Connect

    Krist, Pavel; Bila, Jiri

    2010-01-05

    The article describes the design of the mathematical model and automatic control system of the microtron (high frequency cyclic electron accelerator). This type of accelerator was controlled manually till now. The critical values have been set up empirically on the basis of the previous operational experiences. The designed automatic control system with fuzzy controller should increase the accelerated electrons current value and improve the beam stability.

  8. Adaptive Decentralized Control

    DTIC Science & Technology

    1985-04-01

    computational requirements and response time provide strong incentives for the use of distributed control architectures. The basic focus of our research is on...ADCON (for Adaptive Decentralized CONtrol) comes from the following observations about the current status of control theory . An important aspect of...decentralized control of completely known systems still has many unresolved issues and some basic problems are yet to be answered. Under these conditions

  9. Gas Flow Controller

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The Mass Flowmeter is a device used to measure flow of oxygen in spacecraft's life support system. Tylan Corporation's Mass Flow Controller's major application is accurate control of reactive gases-- such as hydrogen, phosphine and silane as they are diffused at extremely high temperatures into silicon wafers. Wafers are ultimately cut up into integrated circuits or "chips" for electronic products. Precise process control afforded by the Mass Flow Controller makes it possible to produce circuit chips of greater performance at lower cost.

  10. System for controlling apnea

    DOEpatents

    Holzrichter, John F

    2015-05-05

    An implanted stimulation device or air control device are activated by an external radar-like sensor for controlling apnea. The radar-like sensor senses the closure of the air flow cavity, and associated control circuitry signals (1) a stimulator to cause muscles to open the air passage way that is closing or closed or (2) an air control device to open the air passage way that is closing or closed.

  11. MEANS FOR CONTROLLING REACTIONS

    DOEpatents

    Nordheim, L.W.; Wigner, E.P.

    1961-06-27

    The patented means is described for controlling a nuclear reactor which comprises a tank containing a dispersion of a thermally fissionable material in a liquid moderator and a material convertible to a thermally fissionable material in a container disposed about the tank. The control means comprises a control rod chamber, containing only a liquid moderator, disposed within the container and adjacent to the tank and a control rod designed to be inserted into the chamber.

  12. Topical Fluorometholone Protects the Ocular Surface of Dry Eye Patients from Desiccating Stress: A Randomized Controlled Clinical Trial.

    PubMed

    Pinto-Fraga, José; López-Miguel, Alberto; González-García, María J; Fernández, Itziar; López-de-la-Rosa, Alberto; Enríquez-de-Salamanca, Amalia; Stern, Michael E; Calonge, Margarita

    2016-01-01

    To assess the efficacy of topical 0.1% fluorometholone in dry eye disease (DED) patients for ameliorating the worsening of the ocular surface when exposed to adverse environments. Single-center, double-masked, randomized, vehicle-controlled clinical trial. Forty-one patients showing moderate to severe DED. Patients randomly received 1 drop 4 times daily of either topical 0.1% fluorometholone (FML group) or topical polyvinyl alcohol (PA group) for 22 days. Corneal and conjunctival staining, conjunctival hyperemia, tear film breakup time (TBUT), tear osmolarity, and the Symptom Assessment in Dry Eye (SANDE) questionnaire scores were determined at baseline. Variables were reassessed on day 21 before and after undergoing a 2-hour controlled adverse environment exposure and again on day 22. Percentage of patients showing an increase 1 point or more in corneal staining and a reduction of 2 points or more (0-10 scale) in SANDE score, after the controlled adverse environment exposure and 24 hours later. After 21 days of treatment, the FML group showed greater improvements in corneal and conjunctival staining, hyperemia, and TBUT than the PA group (P≤0.03). After the adverse exposure, the percentage of patients having a 1-grade or more increase in corneal staining was significantly (P = 0.03) higher in the PA group (63.1% vs. 23.8%, respectively). Additionally, the FML group showed no significant changes in corneal staining (mean, 0.86; 95% confidence interval [CI], 0.47-1.25; vs. mean, 1.05; 95% CI, 0.59-1.51, for visit 2 and 3, respectively), conjunctival staining (mean, 0.95; 95% CI, 0.54-1.37 vs. mean, 1.19; 95% CI, 0.75-1.63), and hyperemia (mean, 0.71; 95% CI, 0.41-1.02 vs. 1.14; 95% CI, 0.71-1.58) after the exposure, whereas for the PA group, there was significant worsening (P≤0.009) in these variables (corneal staining: mean, 1.95; 95% CI, 1.57-2.33 vs. mean, 2.58; 95% CI, 2.17-2.98; conjunctival staining: mean, 1.68; 95% CI, 1.29-2.08 vs. mean, 2.47; 95% CI

  13. Adaptive, predictive controller for optimal process control

    SciTech Connect

    Brown, S.K.; Baum, C.C.; Bowling, P.S.; Buescher, K.L.; Hanagandi, V.M.; Hinde, R.F. Jr.; Jones, R.D.; Parkinson, W.J.

    1995-12-01

    One can derive a model for use in a Model Predictive Controller (MPC) from first principles or from experimental data. Until recently, both methods failed for all but the simplest processes. First principles are almost always incomplete and fitting to experimental data fails for dimensions greater than one as well as for non-linear cases. Several authors have suggested the use of a neural network to fit the experimental data to a multi-dimensional and/or non-linear model. Most networks, however, use simple sigmoid functions and backpropagation for fitting. Training of these networks generally requires large amounts of data and, consequently, very long training times. In 1993 we reported on the tuning and optimization of a negative ion source using a special neural network[2]. One of the properties of this network (CNLSnet), a modified radial basis function network, is that it is able to fit data with few basis functions. Another is that its training is linear resulting in guaranteed convergence and rapid training. We found the training to be rapid enough to support real-time control. This work has been extended to incorporate this network into an MPC using the model built by the network for predictive control. This controller has shown some remarkable capabilities in such non-linear applications as continuous stirred exothermic tank reactors and high-purity fractional distillation columns[3]. The controller is able not only to build an appropriate model from operating data but also to thin the network continuously so that the model adapts to changing plant conditions. The controller is discussed as well as its possible use in various of the difficult control problems that face this community.

  14. Spacecraft nonlinear control

    NASA Technical Reports Server (NTRS)

    Sheen, Jyh-Jong; Bishop, Robert H.

    1992-01-01

    The feedback linearization technique is applied to the problem of spacecraft attitude control and momentum management with control moment gyros (CMGs). The feedback linearization consists of a coordinate transformation, which transforms the system to a companion form, and a nonlinear feedback control law to cancel the nonlinear dynamics resulting in a linear equivalent model. Pole placement techniques are then used to place the closed-loop poles. The coordinate transformation proposed here evolves from three output functions of relative degree four, three, and two, respectively. The nonlinear feedback control law is presented. Stability in a neighborhood of a controllable torque equilibrium attitude (TEA) is guaranteed and this fact is demonstrated by the simulation results. An investigation of the nonlinear control law shows that singularities exist in the state space outside the neighborhood of the controllable TEA. The nonlinear control law is simplified by a standard linearization technique and it is shown that the linearized nonlinear controller provides a natural way to select control gains for the multiple-input, multiple-output system. Simulation results using the linearized nonlinear controller show good performance relative to the nonlinear controller in the neighborhood of the TEA.

  15. Reflective Database Access Control

    ERIC Educational Resources Information Center

    Olson, Lars E.

    2009-01-01

    "Reflective Database Access Control" (RDBAC) is a model in which a database privilege is expressed as a database query itself, rather than as a static privilege contained in an access control list. RDBAC aids the management of database access controls by improving the expressiveness of policies. However, such policies introduce new interactions…

  16. Floating Point Control Library

    SciTech Connect

    Lee, G. L.; Shereda, C.

    2007-08-02

    Floating Point Control is a Library that allows for the manipulation of floating point unit exception masking funtions control exceptions in both the Streaming "Single Instruction, Multiple Data" Extension 2 (SSE2) unit and the floating point unit simultaneously. FPC also provides macros to set floating point rounding and precision control.

  17. Finite Control in Korean

    ERIC Educational Resources Information Center

    Lee, Kum Young

    2009-01-01

    This thesis explores finite control in Korean. An overview of the previous studies of control shows that the mainstream literature on control has consistently argued that referential dependence between an overt matrix argument and an embedded null subject is characteristic of non-finite clauses which contain a PRO subject. Moreover, although some…

  18. Birth Control Pill

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Pill KidsHealth > For Teens > Birth Control Pill Print A A A What's in this ... español La píldora anticonceptiva What Is It? The birth control pill (also called "the Pill") is a daily ...

  19. Birth Control Ring

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Ring KidsHealth > For Teens > Birth Control Ring Print A A A What's in this ... español Anillo vaginal anticonceptivo What Is It? The birth control ring is a soft, flexible, doughnut-shaped ring ...

  20. Birth Control Explorer

    MedlinePlus

    ... Relationships STIs Media Facebook Twitter Tumblr Shares · 472 Birth Control Explorer Sort by all methods most effective methods ... MORE You are here Home » Birth Control Explorer Birth Control Explorer If you’re having sex —or if ...

  1. Birth Control Patch

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Patch KidsHealth > For Teens > Birth Control Patch Print A A A What's in this ... Much Does It Cost? What Is It? The birth control patch is a thin, beige, 1¾-inch (4½- ...

  2. Birth Control Shot

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Shot KidsHealth > For Teens > Birth Control Shot Print A A A What's in this ... español La inyección anticonceptiva What Is It? The birth control shot is a long-acting form of progesterone, ...

  3. Birth Control Pill

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Pill KidsHealth > For Teens > Birth Control Pill A A A What's in this article? ... español La píldora anticonceptiva What Is It? The birth control pill (also called "the Pill") is a daily ...

  4. Birth Control Patch

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Patch KidsHealth > For Teens > Birth Control Patch A A A What's in this article? ... Much Does It Cost? What Is It? The birth control patch is a thin, beige, 1¾-inch (4½- ...

  5. Birth Control Shot

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Shot KidsHealth > For Teens > Birth Control Shot A A A What's in this article? ... español La inyección anticonceptiva What Is It? The birth control shot is a long-acting form of progesterone, ...

  6. Survivability via Control Objectives

    SciTech Connect

    CAMPBELL,PHILIP L.

    2000-08-11

    Control objectives open an additional front in the survivability battle. A given set of control objectives is valuable if it represents good practices, it is complete (it covers all the necessary areas), and it is auditable. CobiT and BS 7799 are two examples of control objective sets.

  7. Control of Extrusion

    NASA Astrophysics Data System (ADS)

    Zhuromskii, V. M.

    2016-03-01

    The principle and engineering of a system for automatic control of the tension of the thread and the productivity of the process of extrusion of polyacrylonitrile fibers have been presented. The control system is based on the use of functional features of a modern frequency controlled electric drive.

  8. Indirect decentralized repetitive control

    NASA Technical Reports Server (NTRS)

    Lee, Soo Cheol; Longman, Richard W.

    1993-01-01

    Learning control refers to controllers that learn to improve their performance at executing a given task, based on experience performing this specific task. In a previous work, the authors presented a theory of indirect decentralized learning control based on use of indirect adaptive control concepts employing simultaneous identification and control. This paper extends these results to apply to the indirect repetitive control problem in which a periodic (i.e., repetitive) command is given to a control system. Decentralized indirect repetitive control algorithms are presented that have guaranteed convergence to zero tracking error under very general conditions. The original motivation of the repetitive control and learning control fields was learning in robots doing repetitive tasks such as on an assembly line. This paper starts with decentralized discrete time systems, and progresses to the robot application, modeling the robot as a time varying linear system in the neighborhood of the desired trajectory. Decentralized repetitive control is natural for this application because the feedback control for link rotations is normally implemented in a decentralized manner, treating each link as if it is independent of the other links.

  9. Reflective Database Access Control

    ERIC Educational Resources Information Center

    Olson, Lars E.

    2009-01-01

    "Reflective Database Access Control" (RDBAC) is a model in which a database privilege is expressed as a database query itself, rather than as a static privilege contained in an access control list. RDBAC aids the management of database access controls by improving the expressiveness of policies. However, such policies introduce new interactions…

  10. Numerical methods in control

    NASA Astrophysics Data System (ADS)

    Mehrmann, Volker; Xu, Hongguo

    2000-11-01

    We study classical control problems like pole assignment, stabilization, linear quadratic control and H[infinity] control from a numerical analysis point of view. We present several examples that show the difficulties with classical approaches and suggest reformulations of the problems in a more general framework. We also discuss some new algorithmic approaches.

  11. Intermittent Control Systems

    ERIC Educational Resources Information Center

    Montgomery, Thomas L.; And Others

    1975-01-01

    The technique of intermittent control systems for air quality control as developed and used by the Tennessee Valley Authority is investigated. Although controversial, all Tennessee Valley Authority sulfur dioxide elimination programs are scheduled to be operational this year. Existing or anticipated intermittent control systems are identified. (BT)

  12. Air Traffic Control Radar

    NASA Image and Video Library

    2003-08-13

    An Air Traffic Control radar has been constructed at Shiloh for the NASA control tower at the Shuttle Landing Facility. It will be used by NASA and the Eastern Range for surveillance of controlled air space in Kennedy Space Center and Cape Canaveral Air Force Station restricted areas. Shiloh is on the northern end of Merritt Island.

  13. Air Traffic Control Radar

    NASA Image and Video Library

    2003-08-13

    An Air Traffic Control radar is being constructed at Shiloh for the NASA control tower at the Shuttle Landing Facility. It will be used by NASA and the Eastern Range for surveillance of controlled air space in Kennedy Space Center and Cape Canaveral Air Force Station restricted areas. Shiloh is on the northern end of Merritt Island.

  14. CAS. Controlled Access Security

    SciTech Connect

    Martinez, B.; Pomeroy, G.

    1989-12-01

    The Security Alarm System is a data acquisition and control system which collects data from intrusion sensors and displays the information in a real-time environment for operators. The Access Control System monitors and controls the movement of personnel with the use of card readers and biometrics hand readers.

  15. Lithography overlay controller formulation

    NASA Astrophysics Data System (ADS)

    Bode, Christopher A.; Toprac, Anthony J.; Edwards, Richard D.; Edgar, Thomas F.

    2000-08-01

    Lithography overlay refers to the measurement of the alignment of successive patterns within the manufacture of semiconductor devices. Control of overlay has become of great importance in semiconductor manufacturing, as the tolerance for overlay error is continually shrinking in order to manufacture next-generation semiconductor products. Run-to-run control has become an attractive solution to many control problems within the industry, including overlay. The term run-to-run control refers to any automated procedure whereby recipe settings are updated between successive process runs in order to keep the process under control. The following discussion will present the formulation of such a controller by examining control of overlay. A brief introduction of overlay will be given, highlighting the control challenge overlay presents. A data management methodology that groups like processes together in order to improve controllability, referred to as control threads, will then be presented. Finally, a discussion of linear model predictive control will show its utility in feedback run-to-run control.

  16. Indirect decentralized learning control

    NASA Technical Reports Server (NTRS)

    Longman, Richard W.; Lee, Soo C.; Phan, M.

    1992-01-01

    The new field of learning control develops controllers that learn to improve their performance at executing a given task, based on experience performing this specific task. In a previous work, the authors presented a theory of indirect learning control based on use of indirect adaptive control concepts employing simultaneous identification and control. This paper develops improved indirect learning control algorithms, and studies the use of such controllers in decentralized systems. The original motivation of the learning control field was learning in robots doing repetitive tasks such as on an assembly line. This paper starts with decentralized discrete time systems, and progresses to the robot application, modeling the robot as a time varying linear system in the neighborhood of the nominal trajectory, and using the usual robot controllers that are decentralized, treating each link as if it is independent of any coupling with other links. The basic result of the paper is to show that stability of the indirect learning controllers for all subsystems when the coupling between subsystems is turned off, assures convergence to zero tracking error of the decentralized indirect learning control of the coupled system, provided that the sample time in the digital learning controller is sufficiently short.

  17. Intermittent Control Systems

    ERIC Educational Resources Information Center

    Montgomery, Thomas L.; And Others

    1975-01-01

    The technique of intermittent control systems for air quality control as developed and used by the Tennessee Valley Authority is investigated. Although controversial, all Tennessee Valley Authority sulfur dioxide elimination programs are scheduled to be operational this year. Existing or anticipated intermittent control systems are identified. (BT)

  18. Control of wastewater using multivariate control chart

    NASA Astrophysics Data System (ADS)

    Nugraha, Jaka; Fatimah, Is; Prabowo, Rino Galang

    2017-03-01

    Wastewater treatment is a crucial process in industry cause untreated or improper treatment of wastewater may leads some problems affecting to the other parts of environmental aspects. For many kinds of wastewater treatments, the parameters of Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and the Total Suspend Solid (TSS) are usual parameters to be controlled as a standard. In this paper, the application of multivariate Hotteling T2 Individual was reported to control wastewater treatment. By using wastewater treatment data from PT. ICBP, east Java branch, while the fulfillment of quality standards are based on East Java Governor Regulation No. 72 Year 2013 on Standards of Quality of Waste Water Industry and / or Other Business Activities. The obtained results are COD and TSS has a correlation with BOD values with the correlation coefficient higher than 50%, and it is is also found that influence of the COD and TSS to BOD values are 82% and 1.9% respectively. Based on Multivariate control chart Individual T2 Hotteling, it is found that BOD-COD and BOD-TSS are each one subgroup that are outside the control limits. Thus, it can be said there is a process that is not multivariate controlled, but univariately the variables of BOD, COD and TSS are within specification (standard quality) that has been determined.

  19. Controls Considerations for Turbine Active Clearance Control

    NASA Technical Reports Server (NTRS)

    Melcher, Kevin J.

    2004-01-01

    This presentation discusses active control of turbine tip clearance from a control systems perspective. It is a subset of charts that were presented at the 2003 meeting of the International Society of Air Breathing Engines which was held August 31 through September 5 in Cleveland, Ohio. The associated reference paper is cited at the end of the presentation. The presentation describes active tip clearance control research being conducted by NASA to improve turbine engine systems. The target application for this effort is commercial aircraft engines. However, it is believed that the technologies developed as part of this research will benefit a broad spectrum of current and future turbomachinery. The first part of the presentation discusses the concept of tip clearance, problems associated with it, and the benefits of controlling it. It lays out a framework for implementing tip clearance controls that enables the implementation to progress from purely analytical to hardware-in-the-loop to fully experimental. And it briefly discusses how the technologies developed will be married to the previously described ACC Test Rig for hardware-in-the-loop demonstrations. The final portion of the presentation, describes one of the key technologies in some detail by presenting equations and results for a functional dynamic model of the tip clearance phenomena. As shown, the model exhibits many of the clearance dynamics found in commercial gas turbine engines. However, initial attempts to validate the model identified limitations that are being addressed to make the model more realistic.

  20. Arbitrating Control of Control and Display Units

    NASA Technical Reports Server (NTRS)

    Sugden, Paul C.

    2007-01-01

    The ARINC 739 Switch is a computer program that arbitrates control of two multi-function control and display units (MCDUs) between (1) a commercial flight-management computer (FMC) and (2) NASA software used in research on transport aircraft. (MCDUs are the primary interfaces between pilots and FMCs on many commercial aircraft.) This program was recently redesigned into a software library that can be embedded in research application programs. As part of the redesign, this software was combined with software for creating custom pages of information to be displayed on a CDU. This software commands independent switching of the left (pilot s) and right (copilot s) MCDUs. For example, a custom CDU page can control the left CDU while the FMC controls the right CDU. The software uses menu keys to switch control of the CDU between the FMC or a custom CDU page. The software provides an interface that enables custom CDU pages to insert keystrokes into the FMC s CDU input interface. This feature allows the custom CDU pages to manipulate the FMC as if it were a pilot.

  1. Intelligent flight control systems

    NASA Technical Reports Server (NTRS)

    Stengel, Robert F.

    1993-01-01

    The capabilities of flight control systems can be enhanced by designing them to emulate functions of natural intelligence. Intelligent control functions fall in three categories. Declarative actions involve decision-making, providing models for system monitoring, goal planning, and system/scenario identification. Procedural actions concern skilled behavior and have parallels in guidance, navigation, and adaptation. Reflexive actions are spontaneous, inner-loop responses for control and estimation. Intelligent flight control systems learn knowledge of the aircraft and its mission and adapt to changes in the flight environment. Cognitive models form an efficient basis for integrating 'outer-loop/inner-loop' control functions and for developing robust parallel-processing algorithms.

  2. Conscious Control over Action

    PubMed Central

    Shepherd, Joshua

    2015-01-01

    The extensive involvement of nonconscious processes in human behaviour has led some to suggest that consciousness is much less important for the control of action than we might think. In this article I push against this trend, developing an understanding of conscious control that is sensitive to our best models of overt (that is, bodily) action control. Further, I assess the cogency of various zombie challenges—challenges that seek to demote the importance of conscious control for human agency. I argue that though nonconscious contributions to action control are evidently robust, these challenges are overblown. PMID:26113753

  3. Conscious Control over Action.

    PubMed

    Shepherd, Joshua

    2015-06-01

    The extensive involvement of nonconscious processes in human behaviour has led some to suggest that consciousness is much less important for the control of action than we might think. In this article I push against this trend, developing an understanding of conscious control that is sensitive to our best models of overt (that is, bodily) action control. Further, I assess the cogency of various zombie challenges-challenges that seek to demote the importance of conscious control for human agency. I argue that though nonconscious contributions to action control are evidently robust, these challenges are overblown.

  4. SPS antenna pointing control

    NASA Technical Reports Server (NTRS)

    Hung, J. C.

    1980-01-01

    The pointing control of a microwave antenna of the Satellite Power System was investigated emphasizing: (1) the SPS antenna pointing error sensing method; (2) a rigid body pointing control design; and (3) approaches for modeling the flexible body characteristics of the solar collector. Accuracy requirements for the antenna pointing control consist of a mechanical pointing control accuracy of three arc-minutes and an electronic phased array pointing accuracy of three arc-seconds. Results based on the factors considered in current analysis, show that the three arc-minute overall pointing control accuracy can be achieved in practice.

  5. Control and optimization system

    DOEpatents

    Xinsheng, Lou

    2013-02-12

    A system for optimizing a power plant includes a chemical loop having an input for receiving an input parameter (270) and an output for outputting an output parameter (280), a control system operably connected to the chemical loop and having a multiple controller part (230) comprising a model-free controller. The control system receives the output parameter (280), optimizes the input parameter (270) based on the received output parameter (280), and outputs an optimized input parameter (270) to the input of the chemical loop to control a process of the chemical loop in an optimized manner.

  6. Water heater control module

    SciTech Connect

    Hammerstrom, Donald J

    2013-11-26

    An advanced electric water heater control system that interfaces with a high temperature cut-off thermostat and an upper regulating thermostat. The system includes a control module that is electrically connected to the high-temperature cut-off thermostat and the upper regulating thermostat. The control module includes a switch to open or close the high-temperature cut-off thermostat and the upper regulating thermostat. The control module further includes circuitry configured to control said switch in response to a signal selected from the group of an autonomous signal, a communicated signal, and combinations thereof.

  7. Intelligent Control Systems Research

    NASA Technical Reports Server (NTRS)

    Loparo, Kenneth A.

    1994-01-01

    Results of a three phase research program into intelligent control systems are presented. The first phase looked at implementing the lowest or direct level of a hierarchical control scheme using a reinforcement learning approach assuming no a priori information about the system under control. The second phase involved the design of an adaptive/optimizing level of the hierarchy and its interaction with the direct control level. The third and final phase of the research was aimed at combining the results of the previous phases with some a priori information about the controlled system.

  8. Intelligent Welding Controller

    NASA Technical Reports Server (NTRS)

    Cook, George E.; Kumar, Ramaswamy; Prasad, Tanuji; Andersen, Kristinn; Barnett, Robert J.

    1989-01-01

    Control system adapts to changing design requirements and operating conditions. Proposed control system for gas/tungsten arc welding requires only that operator specifies such direct parameters of welds as widths and depths of penetration. In control system for robotic welder, components and functions intimately connected with welding process assigned to controller domain. More general functions assigned to supervisor domain. Initial estimate of indirect parameters of welding process applied to system only at beginning of weld (t=0); after start of welding, outputs from multivariable controller takes place of estimate.

  9. Magnetically Controlled Variable Transformer

    NASA Technical Reports Server (NTRS)

    Kleiner, Charles T.

    1994-01-01

    Improved variable-transformer circuit, output voltage and current of which controlled by use of relatively small current supplied at relatively low power to control windings on its magnetic cores. Transformer circuits of this type called "magnetic amplifiers" because ratio between controlled output power and power driving control current of such circuit large. This ratio - power gain - can be as large as 100 in present circuit. Variable-transformer circuit offers advantages of efficiency, safety, and controllability over some prior variable-transformer circuits.

  10. [Controlling instruments in radiology].

    PubMed

    Maurer, M

    2013-10-01

    Due to the rising costs and competitive pressures radiological clinics and practices are now facing, controlling instruments are gaining importance in the optimization of structures and processes of the various diagnostic examinations and interventional procedures. It will be shown how the use of selected controlling instruments can secure and improve the performance of radiological facilities. A definition of the concept of controlling will be provided. It will be shown which controlling instruments can be applied in radiological departments and practices. As an example, two of the controlling instruments, material cost analysis and benchmarking, will be illustrated.

  11. Controls and guidance research

    NASA Technical Reports Server (NTRS)

    Homaifar, Abdollah; Dunn, Derome; Song, Yong-Duan; Lai, Steven H.-Y.

    1992-01-01

    The objectives of the control group are concentrated on research and education. The control problem of the hypersonic space vehicle represents an important and challenging issue in aerospace engineering. The work described in this report is part of our effort in developing advanced control strategies for such a system. In order to achieve the objectives stated in the NASA-CORE proposal, the tasks were divided among the group based upon their educational expertise. Within the educational component we are offering a Linear Systems and Control course for students in electrical and mechanical engineering. Also, we are proposing a new course in Digital Control Systems with a corresponding laboratory.

  12. STOVL Control Integration Program

    NASA Technical Reports Server (NTRS)

    Weiss, C.; Mcdowell, P.; Watts, S.

    1994-01-01

    An integrated flight/propulsion control for an advanced vector thrust supersonic STOVL aircraft, was developed by Pratt & Whitney and McDonnell Douglas Aerospace East. The IFPC design was based upon the partitioning of the global requirements into flight control and propulsion control requirements. To validate the design, aircraft and engine models were also developed for use on a NASA Ames piloted simulator. Different flight control implementations, evaluated for their handling qualities, are documented in the report along with the propulsion control, engine model, and aircraft model.

  13. Remotely controllable mixing system

    NASA Technical Reports Server (NTRS)

    Belew, R. R. (Inventor)

    1986-01-01

    This invention relates to a remotely controllable mixing system in which a plurality of mixing assemblies are arranged in an annular configuration, and wherein each assembly employs a central chamber and two outer, upper and lower chambers. Valves are positioned between chambers, and these valves for a given mixing assembly are operated by upper and lower control rotors, which in turn are driven by upper and lower drive rotors. Additionally, a hoop is compressed around upper control rotors and a hoop is compressed around lower control rotors to thus insure constant frictional engagement between all control rotors and drive rotors. The drive rollers are driven by a motor.

  14. Recursive Deadbeat Controller Design

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Phan, Minh Q.

    1997-01-01

    This paper presents a recursive algorithm for a deadbeat predictive controller design. The method combines together the concepts of system identification and deadbeat controller designs. It starts with the multi-step output prediction equation and derives the control force in terms of past input and output time histories. The formulation thus derived satisfies simultaneously system identification and deadbeat controller design requirements. As soon as the coefficient matrices are identified satisfying the output prediction equation, no further work is required to compute the deadbeat control gain matrices. The method can be implemented recursively just as any typical recursive system identification techniques.

  15. CONTROL FOR NEUTRONIC REACTOR

    DOEpatents

    Lichtenberger, H.V.; Cameron, R.A.

    1959-03-31

    S>A control rod operating device in a nuclear reactor of the type in which the control rod is gradually withdrawn from the reactor to a position desired during stable operation is described. The apparatus is comprised essentially of a stop member movable in the direction of withdrawal of the control rod, a follower on the control rod engageable with the stop and means urging the follower against the stop in the direction of withdrawal. A means responsive to disengagement of the follower from the stop is provided for actuating the control rod to return to the reactor shut-down position.

  16. Modeling and control of thermostatically controlled loads

    SciTech Connect

    Backhaus, Scott N; Sinitsyn, Nikolai; Kundu, S.; Hiskens, I.

    2011-01-04

    As the penetration of intermittent energy sources grows substantially, loads will be required to play an increasingly important role in compensating the fast time-scale fluctuations in generated power. Recent numerical modeling of thermostatically controlled loads (TCLs) has demonstrated that such load following is feasible, but analytical models that satisfactorily quantify the aggregate power consumption of a group of TCLs are desired to enable controller design. We develop such a model for the aggregate power response of a homogeneous population of TCLs to uniform variation of all TCL setpoints. A linearized model of the response is derived, and a linear quadratic regulator (LQR) has been designed. Using the TCL setpoint as the control input, the LQR enables aggregate power to track reference signals that exhibit step, ramp and sinusoidal variations. Although much of the work assumes a homogeneous population of TCLs with deterministic dynamics, we also propose a method for probing the dynamics of systems where load characteristics are not well known.

  17. Integrated Biological Control

    SciTech Connect

    JOHNSON, A.R.

    2002-09-01

    Biological control is any activity taken to prevent, limit, clean up, or remediate potential environmental, health and safety, or workplace quality impacts from plants, animals, or microorganisms. At Hanford the principal emphasis of biological control is to prevent the transport of radioactive contamination by biological vectors (plants, animals, or microorganisms), and where necessary, control and clean up resulting contamination. Other aspects of biological control at Hanford include industrial weed control (e.g.; tumbleweeds), noxious weed control (invasive, non-native plant species), and pest control (undesirable animals such as rodents and stinging insects; and microorganisms such as molds that adversely affect the quality of the workplace environment). Biological control activities may be either preventive (apriori) or in response to existing contamination spread (aposteriori). Surveillance activities, including ground, vegetation, flying insect, and other surveys, and apriori control actions, such as herbicide spraying and placing biological barriers, are important in preventing radioactive contamination spread. If surveillance discovers that biological vectors have spread radioactive contamination, aposteriori control measures, such as fixing contamination, followed by cleanup and removal of the contamination to an approved disposal location are typical response functions. In some cases remediation following the contamination cleanup and removal is necessary. Biological control activities for industrial weeds, noxious weeds and pests have similar modes of prevention and response.

  18. Integrated Biological Control

    SciTech Connect

    JOHNSON, A.R.

    2003-10-09

    Biological control is any activity taken to prevent, limit, clean up, or remediate potential environmental, health and safety, or workplace quality impacts from plants, animals, or microorganisms. At Hanford the principal emphasis of biological control is to prevent the transport of radioactive contamination by biological vectors (plants, animals, or microorganisms), and where necessary, control and clean up resulting contamination. Other aspects of biological control at Hanford include industrial weed control (e.g.; tumbleweeds), noxious weed control (invasive, non-native plant species), and pest control (undesirable animals such as rodents and stinging insects, and microorganisms such as molds that adversely affect the quality of the workplace environment). Biological control activities may be either preventive (a priori) or in response to existing contamination spread (a posteriori). Surveillance activities, including ground, vegetation, flying insect, and other surveys, and a priori control actions, such as herbicide spraying and placing biological barriers, are important in preventing radioactive contamination spread. If surveillance discovers that biological vectors have spread radioactive contamination, a posteriori control measures, such as fixing contamination, followed by cleanup and removal of the contamination to an approved disposal location are typical response functions. In some cases remediation following the contamination cleanup and removal is necessary. Biological control activities for industrial weeds, noxious weeds and pests have similar modes of prevention and response.

  19. CRUCIFORM CONTROL ROD JOINT

    DOEpatents

    Thorp, A.G. II

    1962-08-01

    An invention is described which relates to nuclear reactor control rod components and more particularly to a joint between cruciform control rod members and cruciform control rod follower members. In one embodiment this invention provides interfitting crossed arms at adjacent ends of a control rod and its follower in abutting relation. This holds the members against relative opposite longitudinal movement while a compression member keys the arms against relative opposite rotation around a common axis. Means are also provided for centering the control rod and its follower on a common axis and for selectively releasing the control rod from its follower for the insertion of a replacement of the control rod and reuse of the follower. (AEC)

  20. On the Switching Control

    NASA Astrophysics Data System (ADS)

    Balas, Valentina E.; Balas, Marius M.

    2009-04-01

    The paper is discussing the measures able to reject the instability that may unexpectedly appear in particular conditions, in switching controllers applications. The switching controllers' effect is explained by the combined effects of the unsuitable choice of the switching moments (in the first or third quadrants of the phase trajectory of the switching error) and of the temporal aliasing that can distort the digital control systems when the sampling rate is close to the frequency of the oscillations that are produced by the commutation. The correct switching moments are located into the second and fourth quadrants of the phase trajectory of the switching error, but an active preparation of the commutation may be simply achieved by using a tracking controller, that is driving the output of open loop controller to follow the output of the close loop controller, permanently minimizing the switching error. Simulations issued from a dc driver speed controller and from an aircraft are provided.

  1. LSST camera control system

    NASA Astrophysics Data System (ADS)

    Marshall, Stuart; Thaler, Jon; Schalk, Terry; Huffer, Michael

    2006-06-01

    The LSST Camera Control System (CCS) will manage the activities of the various camera subsystems and coordinate those activities with the LSST Observatory Control System (OCS). The CCS comprises a set of modules (nominally implemented in software) which are each responsible for managing one camera subsystem. Generally, a control module will be a long lived "server" process running on an embedded computer in the subsystem. Multiple control modules may run on a single computer or a module may be implemented in "firmware" on a subsystem. In any case control modules must exchange messages and status data with a master control module (MCM). The main features of this approach are: (1) control is distributed to the local subsystem level; (2) the systems follow a "Master/Slave" strategy; (3) coordination will be achieved by the exchange of messages through the interfaces between the CCS and its subsystems. The interface between the camera data acquisition system and its downstream clients is also presented.

  2. Controlling chaos faster

    SciTech Connect

    Bick, Christian; Kolodziejski, Christoph; Timme, Marc

    2014-09-01

    Predictive feedback control is an easy-to-implement method to stabilize unknown unstable periodic orbits in chaotic dynamical systems. Predictive feedback control is severely limited because asymptotic convergence speed decreases with stronger instabilities which in turn are typical for larger target periods, rendering it harder to effectively stabilize periodic orbits of large period. Here, we study stalled chaos control, where the application of control is stalled to make use of the chaotic, uncontrolled dynamics, and introduce an adaptation paradigm to overcome this limitation and speed up convergence. This modified control scheme is not only capable of stabilizing more periodic orbits than the original predictive feedback control but also speeds up convergence for typical chaotic maps, as illustrated in both theory and application. The proposed adaptation scheme provides a way to tune parameters online, yielding a broadly applicable, fast chaos control that converges reliably, even for periodic orbits of large period.

  3. Controlling chaos faster.

    PubMed

    Bick, Christian; Kolodziejski, Christoph; Timme, Marc

    2014-09-01

    Predictive feedback control is an easy-to-implement method to stabilize unknown unstable periodic orbits in chaotic dynamical systems. Predictive feedback control is severely limited because asymptotic convergence speed decreases with stronger instabilities which in turn are typical for larger target periods, rendering it harder to effectively stabilize periodic orbits of large period. Here, we study stalled chaos control, where the application of control is stalled to make use of the chaotic, uncontrolled dynamics, and introduce an adaptation paradigm to overcome this limitation and speed up convergence. This modified control scheme is not only capable of stabilizing more periodic orbits than the original predictive feedback control but also speeds up convergence for typical chaotic maps, as illustrated in both theory and application. The proposed adaptation scheme provides a way to tune parameters online, yielding a broadly applicable, fast chaos control that converges reliably, even for periodic orbits of large period.

  4. Robust Control Design for Flight Control

    DTIC Science & Technology

    1989-07-01

    to achieve desired performance over the full flight envelope when linear feedback is employed. Exact linearization methods [48] provide means for...designing nonlinear feedback laws which satisfy these requirements. However, exact linearization is not always compatible with control authority...specific situations. The most promising approaches appear to be those associated with methods of exact linearization . This procedure is based on some

  5. Proteome analysis of chick embryonic cerebrospinal fluid.

    PubMed

    Parada, Carolina; Gato, Angel; Aparicio, Mariano; Bueno, David

    2006-01-01

    During early stages of embryo development, the brain cavity is filled with embryonic cerebrospinal fluid (E-CSF), a complex fluid containing different protein fractions that contributes to the regulation of the survival, proliferation and neurogenesis of the neuroectodermal stem cells. Using 2-DE, protein sequencing and database searches, we identified and analyzed the proteome of the E-CSF from chick embryos (Gallus gallus). We identified 26 different gene products, including proteins related to the extracellular matrix, proteins associated with the regulation of osmotic pressure and metal transport, proteins related to cell survival, MAP kinase activators, proteins involved in the transport of retinol and vitamin D, antioxidant and antimicrobial proteins, intracellular proteins and some unknown proteins. Most of these gene products are involved in the regulation of developmental processes during embryogenesis in systems other than E-CSF. Interestingly, 14 of them are also present in adult human CSF proteome, and it has been reported that they are altered in the CSF of patients suffering neurodegenerative diseases and/or neurological disorders. Understanding these molecules and the mechanisms they control during embryonic neurogenesis is a key contribution to the general understanding of CNS development, and may also contribute to greater knowledge of these human diseases.

  6. Nuclear reactor control

    DOEpatents

    Cawley, William E.; Warnick, Robert F.

    1982-01-01

    1. In a nuclear reactor incorporating a plurality of columns of tubular fuel elements disposed in horizontal tubes in a mass of graphite wherein water flows through the tubes to cool the fuel elements, the improvement comprising at least one control column disposed in a horizontal tube including fewer fuel elements than in a normal column of fuel elements and tubular control elements disposed at both ends of said control column, and means for varying the horizontal displacement of the control column comprising a winch at the upstream end of the control column and a cable extending through the fuel and control elements and attached to the element at the downstream end of the column.

  7. Chimpanzee Cognitive Control

    PubMed Central

    Beran, Michael J.

    2015-01-01

    Cognitive control processes are a feature of human cognition. Recent comparative tests have shown that some nonhuman animals also might share aspects of cognitive control with humans. Two of the executive processes that constitute cognitive control are metacognition and self-control, and recent experiments with chimpanzees are described that demonstrate metacognitive monitoring and control when these animals engage in an information-seeking task. Chimpanzees also show strategic responding in a self-control task by exhibiting self-distraction as an aid to delay of gratification. These demonstrations indicate continuity with similar human cognitive capacities, and the performances of chimpanzees in these kinds of tests have implications for considering the nature of the intelligence of these animals. PMID:26478660

  8. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2004-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  9. Designing Genetic Feedback Controllers.

    PubMed

    Harris, Andreas W K; Dolan, James A; Kelly, Ciarán L; Anderson, James; Papachristodoulou, Antonis

    2015-08-01

    By incorporating feedback around systems we wish to manipulate, it is possible to improve their performance and robustness properties to meet pre-specified design objectives. For decades control engineers have been successfully implementing feedback controllers for complex mechanical and electrical systems such as aircraft and sports cars. Natural biological systems use feedback extensively for regulation and adaptation but apart from the most basic designs, there is no systematic framework for designing feedback controllers in Synthetic Biology. In this paper we describe how classical approaches from linear control theory can be used to close the loop. This includes the design of genetic circuits using feedback control and the presentation of a biological phase lag controller.

  10. Unpacking Self-Control

    PubMed Central

    Duckworth, Angela; Steinberg, Laurence

    2014-01-01

    Self-controlled behavior refers to actions aligned with valued, longer-term goals in the face of conflicting impulses to seek immediate gratification. In this article, we argue that the psychological processes that contribute to self-controlled behavior can be grouped into two functionally distinct categories: Volitional processes facilitate self-controlled behavior and include executive functions as well as learned metacognitive strategies like planning, attention deployment, and psychological distancing. In contrast, impulsigenic processes undermine self-controlled behavior and include reward sensitivity, sensation seeking, and domain-specific cravings. A disproportionate amount of research has addressed the former at the expense of understanding individual and developmental differences in the latter. This imbalance is now being rectified. Distinguishing between self-controlled behavior and its antecedent psychological processes helps illuminate normative developmental changes in self-control and points to directions for measurement and intervention. PMID:25821515

  11. Fuzzy logic controller optimization

    DOEpatents

    Sepe, Jr., Raymond B; Miller, John Michael

    2004-03-23

    A method is provided for optimizing a rotating induction machine system fuzzy logic controller. The fuzzy logic controller has at least one input and at least one output. Each input accepts a machine system operating parameter. Each output produces at least one machine system control parameter. The fuzzy logic controller generates each output based on at least one input and on fuzzy logic decision parameters. Optimization begins by obtaining a set of data relating each control parameter to at least one operating parameter for each machine operating region. A model is constructed for each machine operating region based on the machine operating region data obtained. The fuzzy logic controller is simulated with at least one created model in a feedback loop from a fuzzy logic output to a fuzzy logic input. Fuzzy logic decision parameters are optimized based on the simulation.

  12. Advanced Aerodynamic Control Effectors

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Bauer, Steven X. S.

    1999-01-01

    A 1990 research program that focused on the development of advanced aerodynamic control effectors (AACE) for military aircraft has been reviewed and summarized. Data are presented for advanced planform, flow control, and surface contouring technologies. The data show significant increases in lift, reductions in drag, and increased control power, compared to typical aerodynamic designs. The results presented also highlighted the importance of planform selection in the design of a control effector suite. Planform data showed that dramatic increases in lift (greater than 25%) can be achieved with multiple wings and a sawtooth forebody. Passive porosity and micro drag generator control effector data showed control power levels exceeding that available from typical effectors (moving surfaces). Application of an advanced planform to a tailless concept showed benefits of similar magnitude as those observed in the generic studies.

  13. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2006-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  14. Physiological and genetic responses of bacteria to osmotic stress.

    PubMed Central

    Csonka, L N

    1989-01-01

    The capacity of organisms to respond to fluctuations in their osmotic environments is an important physiological process that determines their abilities to thrive in a variety of habitats. The primary response of bacteria to exposure to a high osmotic environment is the accumulation of certain solutes, K+, glutamate, trehalose, proline, and glycinebetaine, at concentrations that are proportional to the osmolarity of the medium. The supposed function of these solutes is to maintain the osmolarity of the cytoplasm at a value greater than the osmolarity of the medium and thus provide turgor pressure within the cells. Accumulation of these metabolites is accomplished by de novo synthesis or by uptake from the medium. Production of proteins that mediate accumulation or uptake of these metabolites is under osmotic control. This review is an account of the processes that mediate adaptation of bacteria to changes in their osmotic environment. PMID:2651863

  15. Modular Battery Controller

    NASA Technical Reports Server (NTRS)

    Button, Robert M (Inventor); Gonzalez, Marcelo C (Inventor)

    2017-01-01

    Some embodiments of the present invention describe a battery including a plurality of master-less controllers. Each controller is operatively connected to a corresponding cell in a string of cells, and each controller is configured to bypass a fraction of current around the corresponding cell when the corresponding cell has a greater charge than one or more other cells in the string of cells.

  16. Control of Nonlinear Systems.

    DTIC Science & Technology

    1980-02-26

    6-7 C. Minimum Energy Regulators for Commutative Bilinear Systems .................... ........ 8-9 D. Control Law.s for Certain Aerospace...class of nonlinear systems (3,10]. (c) Minimum energy regulators for commutative bilinear systems [3,10]. (D) Control laws for certain aerospace...With Delay in Control," IEEE Trans. on Auto Contr., Vol. AC-20, pp. 702-704, 1975, and [3].) - !. 8 C. Minimum Energy Regulators for Commutative Bilinear

  17. Supervisory control systems

    NASA Technical Reports Server (NTRS)

    Sheridan, T. B.

    1974-01-01

    The various functions of a computer are considered that serve in connecting the man, with his displays and controls, to an external environment, manipulator activators and the interoceptors that are in the actuators, and to the interosensors and the motors or the actuators to drive the sensors. Projected is an improved exoskeleton mechanism with computer control and some supervisory control that may give a quadriplegic the ability to walk and run around.

  18. Proprioception in Aircraft Control

    DTIC Science & Technology

    1989-10-12

    stuurknuppol 17 De passieve stuurknuppel die in het experiment gebruikt werd was een standaard isometrische stuurknuppel van het merk Measurements Systems Inc...flight simulator. Report VTH- 178, Delft, The Netherlands: Delft University of Technology. Crossman, E.R.F.W. & Cooke, J.E. (1962). Manual control of slow... manual control. NASr 54(06), Langley, NASA. Hosman, R.J.A.W. & Vaart J.C. van der (1987). Active and passive side stick controllers: tracking task

  19. Blast furnace stove control

    SciTech Connect

    Muske, K.R.; Hansen, G.A.; Howse, J.W.; Cagliostro, D.J.; Chaubal, P.C.

    1998-12-31

    This paper outlines the process model and model-based control techniques implemented on the hot blast stoves for the No. 7 Blast Furnace at the Inland Steel facility in East Chicago, Indiana. A detailed heat transfer model of the stoves is developed. It is then used as part of a predictive control scheme to determine the minimum amount of fuel necessary to achieve the blast air requirements. The controller also considers maximum and minimum temperature constraints within the stove.

  20. Controls for unstable structures

    NASA Astrophysics Data System (ADS)

    Guenther, Oliver; Hogg, Tad; Huberman, Bernardo A.

    1997-06-01

    We study the behavior of several organizations for a market based distributed control of unstable physical systems and show how a hierarchical organization is a reasonable compromise between rapid local responses with simple communication and the use of global knowledge. We also introduce a new control organization, the multihierarchy, and show that is uses less power than a hierarchy in achieving stability. The multihierarchy also has a position invariant response that can control disturbances at the appropriate scale and location.

  1. Adaptive hierarchical fuzzy controller

    SciTech Connect

    Raju, G.V.S.; Jun Zhou

    1993-07-01

    A methodology for designing adaptive hierarchical fuzzy controllers is presented. In order to evaluate this concept, several suitable performance indices were developed and converted to linguistic fuzzy variables. Based on those variables, a supervisory fuzzy rule set was constructed and used to change the parameters of a hierarchical fuzzy controller to accommodate the variations of system parameters. The proposed algorithm was used in feedwater flow control to a steam generator. Simulation studies are presented that illustrate the effectiveness of the approach

  2. Rotor control system

    NASA Technical Reports Server (NTRS)

    Bradford, Michael P. (Inventor); Maciolek, Joseph R. (Inventor)

    1987-01-01

    A helicopter rotor control system (13) including a stop azimuth controller (32) for establishing the value of a deceleration command (15') to a deceleration controller (23), a transition azimuth predictor (41) and a position reference generator (55), which are effective during the last revolution of said rotor (14) to establish a correction indication (38) to adjust the deceleration command (15') to ensure that one of the rotor blades (27) stops at a predetermined angular position.

  3. Control Systems & LEED

    SciTech Connect

    Cooperman, Alissa; Dieckmann, John; Brodrick, James

    2012-06-01

    This article discusses the LEED guidelines (2009 v3), and corresponding points, that can only be attained using control systems for lighting, HVAC, and/or the entire building. Integrating and centralizing control systems allows for better building management, energy savings and can potentially award 29 points towards certification across the following categories: Sustainable Sites, Energy & Atmosphere, and Indoor Air Quality. In closing, potential energy savings are highlighted and the overall market potential for control systems are summarized.

  4. Supervisory control systems

    NASA Technical Reports Server (NTRS)

    Sheridan, T. B.

    1974-01-01

    The various functions of a computer are considered that serve in connecting the man, with his displays and controls, to an external environment, manipulator activators and the interoceptors that are in the actuators, and to the interosensors and the motors or the actuators to drive the sensors. Projected is an improved exoskeleton mechanism with computer control and some supervisory control that may give a quadriplegic the ability to walk and run around.

  5. Innovation for Pollution Control

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Kinetic Controls Inc.'s refuse-fired steam generating facility led to the development of an air pollution equipment control device. The device is currently marketed by two NASA/Langley Research Center employees. It automatically senses and compensates for the changes in smoke composition when refuse is used as a fuel by adjusting the precipitator's voltage and current to permit maximum collection of electrically charged dust particles. The control adapts to any electrostatic precipitator and should have extensive commercial applications.

  6. Cooled, temperature controlled electrometer

    DOEpatents

    Morgan, John P.

    1992-08-04

    A cooled, temperature controlled electrometer for the measurement of small currents. The device employs a thermal transfer system to remove heat from the electrometer circuit and its environment and dissipate it to the external environment by means of a heat sink. The operation of the thermal transfer system is governed by a temperature regulation circuit which activates the thermal transfer system when the temperature of the electrometer circuit and its environment exceeds a level previously inputted to the external variable temperature control circuit. The variable temperature control circuit functions as subpart of the temperature control circuit. To provide temperature stability and uniformity, the electrometer circuit is enclosed by an insulated housing.

  7. Cooled, temperature controlled electrometer

    DOEpatents

    Morgan, John P.

    1992-01-01

    A cooled, temperature controlled electrometer for the measurement of small currents. The device employs a thermal transfer system to remove heat from the electrometer circuit and its environment and dissipate it to the external environment by means of a heat sink. The operation of the thermal transfer system is governed by a temperature regulation circuit which activates the thermal transfer system when the temperature of the electrometer circuit and its environment exceeds a level previously inputted to the external variable temperature control circuit. The variable temperature control circuit functions as subpart of the temperature control circuit. To provide temperature stability and uniformity, the electrometer circuit is enclosed by an insulated housing.

  8. Device Oriented Project Controller

    SciTech Connect

    Dalesio, Leo; Kraimer, Martin

    2013-11-20

    This proposal is directed at the issue of developing control systems for very large HEP projects. A de-facto standard in accelerator control is the Experimental Physics and Industrial Control System (EPICS), which has been applied successfully to many physics projects. EPICS is a channel based system that requires that each channel of each device be configured and controlled. In Phase I, the feasibility of a device oriented extension to the distributed channel database was demonstrated by prototyping a device aware version of an EPICS I/O controller that functions with the current version of the channel access communication protocol. Extensions have been made to the grammar to define the database. Only a multi-stage position controller with limit switches was developed in the demonstration, but the grammar should support a full range of functional record types. In phase II, a full set of record types will be developed to support all existing record types, a set of process control functions for closed loop control, and support for experimental beam line control. A tool to configure these records will be developed. A communication protocol will be developed or extensions will be made to Channel Access to support introspection of components of a device. Performance bench marks will be made on both communication protocol and the database. After these records and performance tests are under way, a second of the grammar will be undertaken.

  9. Satellite attitude control simulations

    NASA Technical Reports Server (NTRS)

    Debra, D. B.; Powell, J. D.

    1973-01-01

    Work was conducted to develop an extremely low drift rate gyroscope and a very precise star tracker. A proposed relativity satellite will measure very accurately the theoretically predicted 'relativistic' precession of the gyroscope relative to an inertial reference frame provided by the star tracker. Aspects of precision spinning attitude control are discussed together with questions of gyro operation, and the hopping mode for lunar transportation. For the attitude control system of the lunar hopper, a number of control laws were investigated. The studies indicated that some suboptimal controls should be adequate for the system.

  10. Controlled wind motor

    SciTech Connect

    Boswell, F.A.

    1983-12-27

    A mechanical sail including a rotatable mast, the mast including a top vane mount and a bottom vane mount, the mounts being spaced from each other on the mast and rotatable therewith, a series of rotatable vanes spaced from and surrounding the mast and supported by and between the mounts, cam operaters extending between the mounts and connected to the vanes for controlling the rotation of the vanes, a first controller associated with the mast below the bottom vane mount for controlling the cam operators, the first controller being movable vertically with respect to the mast, a second controller for moving the first controller vertically with respect to the mast, the vanes being flexible and bowed outwardly, the bottom vane mount being movable with respect to the mast and connected to the second controller whereby when the second controller is operated, the bottom vane mount will move toward the top vane mount causing the vanes to bow outwardly at a desired arc and whereby when the first controller is moved, the vanes are caused to rotate to the desired angle of attack with respect to wind velocity and direction. When the sail is connected to a motor drive, the vessel may be driven forward or rearward depending on the angle of attack of the vanes through 180/sup 0/.

  11. Satellite attitude control simulations

    NASA Technical Reports Server (NTRS)

    Debra, D. B.; Powell, J. D.

    1973-01-01

    Work was conducted to develop an extremely low drift rate gyroscope and a very precise star tracker. A proposed relativity satellite will measure very accurately the theoretically predicted 'relativistic' precession of the gyroscope relative to an inertial reference frame provided by the star tracker. Aspects of precision spinning attitude control are discussed together with questions of gyro operation, and the hopping mode for lunar transportation. For the attitude control system of the lunar hopper, a number of control laws were investigated. The studies indicated that some suboptimal controls should be adequate for the system.

  12. SSRF Beamline Control System

    SciTech Connect

    Zheng, L. F.; Liu, P.; Zhang, Z. H.; Hu, C.; Mi, Q. R.; Wu, Y. F.; Gong, P. R.; Zhu, Z. X.; Li, Z.

    2010-06-23

    There are seven beamlines in the Phase-I of SSRF. Five of them are equipped with Insertion Devices, while two with Bending Magnets. The beamline control system is based on the standard hardware and software architecture. The VME(PowerPC) with VxWorks is used for motion control, while the personal computers with Scientific Linux are the front end controllers of equipment protection and personnel safety systems. The control software is developed under EPICS which makes various experimental programs of Blu-Ice, LabView, VC and SPEC conveniently access Monochromators, mirror chambers and other optical components.

  13. The ISOLDE control system

    NASA Astrophysics Data System (ADS)

    Deloose, I.; Pace, A.

    1994-12-01

    The two CERN isotope separators named ISOLDE have been running on the new Personal Computer (PC) based control system since April 1992. The new architecture that makes heavy use of the commercial software and hardware of the PC market has been implemented on the 1700 geographically distributed control channels of the two separators and their experimental area. Eleven MSDOS Intel-based PCs with approximately 80 acquisition and control boards are used to access the equipment and are controlled from three PCs running Microsoft Windows used as consoles through a Novell Local Area Network. This paper describes the interesting solutions found and discusses the reduced programming workload and costs that have been obtained.

  14. Optimal Linear Control.

    DTIC Science & Technology

    1979-12-01

    OPTIMAL LINEAR CONTROL C.A. HARVEY M.G. SAFO NOV G. STEIN J.C. DOYLE HONEYWELL SYSTEMS & RESEARCH CENTER j 2600 RIDGWAY PARKWAY j [ MINNEAPOLIS...RECIPIENT’S CAT ALC-’ W.IMIJUff’? * J~’ CR2 15-238-4F TP P EI)ŕll * (~ Optimal Linear Control ~iOGRPR UBA m a M.G Lnar o Con_ _ _ _ _ _ R PORT__ _ _ I RE...Characterizations of optimal linear controls have been derived, from which guides for selecting the structure of the control system and the weights in

  15. Helicopter high gain control

    NASA Technical Reports Server (NTRS)

    Cunningham, T. B.; Nunn, E. C.

    1979-01-01

    High gain control is explored through a design study of the CH-47B helicopter. The plans are designed to obtain the maximum bandwidth possible given the hardware constraints. Controls are designed with modal control theory to specific bandwidths and closed loop mode shapes. Comparisons are made to an earlier complementary filter approach. Bandwidth improvement by removal of limitations is explored in order to establish hardware and mechanization options. Improvements in the pitch axis control system and in the rate gyro sensor noise characteristics in all axes are discussed. The use of rotor state feedback is assessed.

  16. Control of air toxics

    SciTech Connect

    Livengood, C.D.

    1995-03-01

    For more than 10 years, Argonne National Laboratory has supported the US DOE`s Flue Gas Cleanup Program objective by developing new or improved environmental controls for industries that use fossil fuels. Argonne`s pollutant emissions research has ranged from experiments in the basic chemistry of pollution-control systems, through laboratory-scale process development and testing, to pilot-scale field tests of several technologies. The work on air toxics is currently divided into two components: Investigating measures to improve the removal of mercury in existing pollution-control systems applied to coal combustion; and, Developing sensors and control techniques for emissions found in the textile industry.

  17. Optimal control computer programs

    NASA Technical Reports Server (NTRS)

    Kuo, F.

    1992-01-01

    The solution of the optimal control problem, even with low order dynamical systems, can usually strain the analytical ability of most engineers. The understanding of this subject matter, therefore, would be greatly enhanced if a software package existed that could simulate simple generic problems. Surprisingly, despite a great abundance of commercially available control software, few, if any, address the part of optimal control in its most generic form. The purpose of this paper is, therefore, to present a simple computer program that will perform simulations of optimal control problems that arise from the first necessary condition and the Pontryagin's maximum principle.

  18. Detonation command and control

    DOEpatents

    Mace, Jonathan L.; Seitz, Gerald J.; Echave, John A.; Le Bas, Pierre-Yves

    2016-05-31

    The detonation of one or more explosive charges and propellant charges by a detonator in response to a fire control signal from a command and control system comprised of a command center and instrumentation center with a communications link there between. The fire control signal is selectively provided to the detonator from the instrumentation center if plural detonation control switches at the command center are in a fire authorization status, and instruments, and one or more interlocks, if included, are in a ready for firing status. The instrumentation and command centers are desirably mobile, such as being respective vehicles.

  19. Automatic control of bioprocesses.

    PubMed

    Stanke, Marc; Hitzmann, Bernd

    2013-01-01

    In this chapter, different approaches for open-loop and closed-loop control applied in bioprocess automation are discussed. Although in recent years many contributions dealing with closed-loop control have been published, only a minority were actually applied in real bioprocesses, the majority being simulations. As a result of the diversity of bioprocess requirements, a single control algorithm cannot be applied in all cases; rather, different approaches are necessary. Most publications combine different closed-loop control techniques to construct hybrid systems. These systems are supposed to combine the advantages of each approach into a well-performing control strategy. The majority of applications are soft sensors in combination with a proportional-integral-derivative (PID) controller. The fact that soft sensors have become this importance for control purposes demonstrates the lack of direct measurements or their large additional expense for robust and reliable online measurement systems. The importance of model predictive control is increasing; however, reliable and robust process models are required, as well as very powerful computers to address the computational needs. The lack of theoretical bioprocess models is compensated by hybrid systems combining theoretical models, fuzzy logic, and/or artificial neural network methodology. Although many authors suggest a possible transfer of their presented control application to other bioprocesses, the algorithms are mostly specialized to certain organisms or certain cultivation conditions as well as to a specific measurement system.

  20. Detonation command and control

    DOEpatents

    Mace, Jonathan L.; Seitz, Gerald J.; Echave, John A.; Le Bas, Pierre-Yves

    2015-11-10

    The detonation of one or more explosive charges and propellant charges by a detonator in response to a fire control signal from a command and control system comprised of a command center and instrumentation center with a communications link therebetween. The fire control signal is selectively provided to the detonator from the instrumentation center if plural detonation control switches at the command center are in a fire authorization status, and instruments, and one or more interlocks, if included, are in a ready for firing status. The instrumentation and command centers are desirably mobile, such as being respective vehicles.

  1. Quantum controlled fusion

    NASA Astrophysics Data System (ADS)

    Berrios, Eduardo; Gruebele, Martin; Wolynes, Peter G.

    2017-09-01

    Quantum-controlled motion of nuclei, starting from the nanometer-size ground state of a molecule, can potentially overcome some of the difficulties of thermonuclear fusion by compression of a fuel pellet or in a bulk plasma. Coherent laser control can manipulate nuclear motion precisely, achieving large phase space densities for the colliding nuclei. We combine quantum wavepacket propagation of D and T nuclei in a field-bound molecule with coherent control by a shaped laser pulse to demonstrate enhancement of nuclear collision rates. Atom-smashers powered by coherent control may become laboratory sources of particle bursts, and even assist muonic fusion.

  2. MOSFET Power Controller

    NASA Technical Reports Server (NTRS)

    Mitchell, J.; Jones, K.

    1986-01-01

    High current and voltage controlled remotely. Remote Power Conroller includes two series-connected banks of parallel-connected MOSFET's to withstand high current and voltage. Voltage sharing between switch banks, low-impedance, gate-drive circuits used. Provided controlled range for turn on. Individually trimmable to insure simultaneous switching within few nanoseconds during both turn on and turn off. Control circuit for each switch bank and over-current trip circuit float independently and supplied power via transformer T1 from inverter. Control of floating stages by optocouplers.

  3. Exhaust gas control actuator

    SciTech Connect

    Motosugi, K.; Sumiyoshi, M.

    1980-11-11

    An exhaust gas control actuator is described wherein the feed of secondary air fed to an exhaust piping is controlled by an oxygen concentration detector disposed in the stream of exhaust gas of an internal combustion engine and an air-fuel ratio of the exhaust gas entering a catalyst disposed downstream of the exhaust piping is maintained within a given range. The actuator comprises a flow control valve and a flow control device for controlling the flow control valve. The flow control valve is provided with a flow-in port communicated with an air pump and the valve body, a flow-out port communicated with an exhaust manifold and a bypass port communicated with an air cleaner. Furthermore, the flow control device is actuated by an electronic control circuit and comprises an actuating chamber partitioned by a diaphragm for actuating the valve body and including a negative pressure introducing port communicated with an intake manifold and an atmosphere introducing port constantly communicated with atmosphere, and a nozzle flapper mechanism provided in the actuating chamber and varying resistances to flow through the negative pressure introducing port and the atmosphere introducing port in accordance with the actuating position of the valve body in such a manner that an output signal of the oxygen concentration detector is negatively fed back to the feed of secondary air.

  4. Bimodality in Network Control

    NASA Astrophysics Data System (ADS)

    Jia, Tao; Liu, Yang-Yu; Posfai, Marton; Slotine, Jean-Jacques; Barabasi, Albert-Laszlo

    2013-03-01

    Controlling complex systems is a fundamental challenge of network science. Recent tools enable us to identify the minimum driver nodes, from which we can control a system. They also indicate a multiplicity of minimum driver node sets (MDS's): multiple combinations of the same number of nodes can achieve control over the system. This multiplicity allows us to classify individual nodes as critical if they are involved in all control configurations, intermittent if they occasionally act as driver nodes and redundant if they do not play any role in control. We develop computational and analytical framework analyzing nodes in each category in both model and real networks. We find that networks with identical degree distribution can be in two distinct control modes, ``centralized'' or ``distributed'', with drastic change on the role of each node in maintaining the controllability and orders of magnitude difference in the number of MDS's. In analyzing both model and real networks, we find that the two modes can be inferred directly from the network's degree distribution. Finally we show that the two control modes can be switched by small structural perturbations, leading to potential applications of control theory in real systems.

  5. Tokamak burn control

    SciTech Connect

    Sager, G.T.

    1988-06-01

    Research of the fusion plasma thermal instability and its control is reviewed. General models of the thermonuclear plasma are developed. Techniques of stability analysis commonly employed in burn control research are discussed. Methods for controlling the plasma against the thermal instability are reviewed. Emphasis is placed on applications to tokamak confinement concepts. Additional research which extends the results of previous research is suggested. Issues specific to the development of control strategies for mid-term engineering test reactors are identified and addressed. 100 refs., 24 figs., 10 tabs.

  6. Throttle valve control device

    SciTech Connect

    Nishida, M.; Katashiba, H.

    1988-03-01

    This patent describes a valve control device which comprises: a valve shaft for operating a throttle valve; a differential gear device having first and second drive gears, for driving the valve shaft; first and second electronic control actuators for rotating the first and second drive gear, respectively; and a sensor for detecting the degree of opening of the throttle valve, so that the operation of the throttle valve is controlled by the electronic control actuators while the degree of opening of the throttle valve is being detected.

  7. Control system design guide

    SciTech Connect

    Sellers, David; Friedman, Hannah; Haasl, Tudi; Bourassa, Norman; Piette, Mary Ann

    2003-05-01

    The ''Control System Design Guide'' (Design Guide) provides methods and recommendations for the control system design process and control point selection and installation. Control systems are often the most problematic system in a building. A good design process that takes into account maintenance, operation, and commissioning can lead to a smoothly operating and efficient building. To this end, the Design Guide provides a toolbox of templates for improving control system design and specification. HVAC designers are the primary audience for the Design Guide. The control design process it presents will help produce well-designed control systems that achieve efficient and robust operation. The spreadsheet examples for control valve schedules, damper schedules, and points lists can streamline the use of the control system design concepts set forth in the Design Guide by providing convenient starting points from which designers can build. Although each reader brings their own unique questions to the text, the Design Guide contains information that designers, commissioning providers, operators, and owners will find useful.

  8. Control of robot dynamics using acceleration control

    NASA Technical Reports Server (NTRS)

    Workman, G. L.; Prateru, S.; Li, W.; Hinman, Elaine

    1992-01-01

    Acceleration control of robotic devices can provide improvements to many space-based operations using flexible manipulators and to ground-based operations requiring better precision and efficiency than current industrial robots can provide. This paper reports on a preliminary study of acceleration measurement on robotic motion during parabolic flights on the NASA KC-135 and a parallel study of accelerations with and without gravity arising from computer simulated motions using TREETOPS software.

  9. Controls for space structures

    NASA Astrophysics Data System (ADS)

    Balas, Mark

    1991-11-01

    Assembly and operation of large space structures (LSS) in orbit will require robot-assisted docking and berthing of partially-assembled structures. These operations require new solutions to the problems of controls. This is true because of large transient and persistent disturbances, controller-structure interaction with unmodeled modes, poorly known structure parameters, slow actuator/sensor dynamical behavior, and excitation of nonlinear structure vibrations during control and assembly. For on-orbit assembly, controllers must start with finite element models of LSS and adapt on line to the best operating points, without compromising stability. This is not easy to do, since there are often unmodeled dynamic interactions between the controller and the structure. The indirect adaptive controllers are based on parameter estimation. Due to the large number of modes in LSS, this approach leads to very high-order control schemes with consequent poor stability and performance. In contrast, direct model reference adaptive controllers operate to force the LSS to track the desirable behavior of a chosen model. These schemes produce simple control algorithms which are easy to implement on line. One problem with their use for LSS has been that the model must be the same dimension as the LSS - i.e., quite large. A control theory based on the command generator tracker (CGT) ideas of Sobel, Mabins, Kaufman and Wen, Balas to obtain very low-order models based on adaptive algorithms was developed. Closed-loop stability for both finite element models and distributed parameter models of LSS was proved. In addition, successful numerical simulations on several LSS databases were obtained. An adaptive controller based on our theory was also implemented on a flexible robotic manipulator at Martin Marietta Astronautics. Computation schemes for controller-structure interaction with unmodeled modes, the residual mode filters or RMF, were developed. The RMF theory was modified to compensate

  10. Controls for space structures

    NASA Technical Reports Server (NTRS)

    Balas, Mark

    1991-01-01

    Assembly and operation of large space structures (LSS) in orbit will require robot-assisted docking and berthing of partially-assembled structures. These operations require new solutions to the problems of controls. This is true because of large transient and persistent disturbances, controller-structure interaction with unmodeled modes, poorly known structure parameters, slow actuator/sensor dynamical behavior, and excitation of nonlinear structure vibrations during control and assembly. For on-orbit assembly, controllers must start with finite element models of LSS and adapt on line to the best operating points, without compromising stability. This is not easy to do, since there are often unmodeled dynamic interactions between the controller and the structure. The indirect adaptive controllers are based on parameter estimation. Due to the large number of modes in LSS, this approach leads to very high-order control schemes with consequent poor stability and performance. In contrast, direct model reference adaptive controllers operate to force the LSS to track the desirable behavior of a chosen model. These schemes produce simple control algorithms which are easy to implement on line. One problem with their use for LSS has been that the model must be the same dimension as the LSS - i.e., quite large. A control theory based on the command generator tracker (CGT) ideas of Sobel, Mabins, Kaufman and Wen, Balas to obtain very low-order models based on adaptive algorithms was developed. Closed-loop stability for both finite element models and distributed parameter models of LSS was proved. In addition, successful numerical simulations on several LSS databases were obtained. An adaptive controller based on our theory was also implemented on a flexible robotic manipulator at Martin Marietta Astronautics. Computation schemes for controller-structure interaction with unmodeled modes, the residual mode filters or RMF, were developed. The RMF theory was modified to compensate

  11. Compact, Reliable EEPROM Controller

    NASA Technical Reports Server (NTRS)

    Katz, Richard; Kleyner, Igor

    2010-01-01

    A compact, reliable controller for an electrically erasable, programmable read-only memory (EEPROM) has been developed specifically for a space-flight application. The design may be adaptable to other applications in which there are requirements for reliability in general and, in particular, for prevention of inadvertent writing of data in EEPROM cells. Inadvertent writes pose risks of loss of reliability in the original space-flight application and could pose such risks in other applications. Prior EEPROM controllers are large and complex and do not provide all reasonable protections (in many cases, few or no protections) against inadvertent writes. In contrast, the present controller provides several layers of protection against inadvertent writes. The controller also incorporates a write-time monitor, enabling determination of trends in the performance of an EEPROM through all phases of testing. The controller has been designed as an integral subsystem of a system that includes not only the controller and the controlled EEPROM aboard a spacecraft but also computers in a ground control station, relatively simple onboard support circuitry, and an onboard communication subsystem that utilizes the MIL-STD-1553B protocol. (MIL-STD-1553B is a military standard that encompasses a method of communication and electrical-interface requirements for digital electronic subsystems connected to a data bus. MIL-STD- 1553B is commonly used in defense and space applications.) The intent was to both maximize reliability while minimizing the size and complexity of onboard circuitry. In operation, control of the EEPROM is effected via the ground computers, the MIL-STD-1553B communication subsystem, and the onboard support circuitry, all of which, in combination, provide the multiple layers of protection against inadvertent writes. There is no controller software, unlike in many prior EEPROM controllers; software can be a major contributor to unreliability, particularly in fault

  12. Temperature Control. Honeywell Planning Guide.

    ERIC Educational Resources Information Center

    Honeywell, Inc., Minneapolis, Minn.

    Presents planning considerations in selecting proper temperature control systems. Various aspects are discussed including--(1) adequate environmental control, (2) adequate control area, (3) control system design, (4) operators rate their systems, (5) type of control components, (6) basic control system, (7) automatic control systems, and (8)…

  13. Inward Flux of Lactate- through Monocarboxylate Transporters Contributes to Regulatory Volume Increase in Mouse Muscle Fibres

    PubMed Central

    Lindinger, Michael I.; Leung, Matthew J.; Hawke, Thomas J.

    2013-01-01

    Mouse and rat skeletal muscles are capable of a regulatory volume increase (RVI) after they shrink (volume loss resultant from exposure to solutions of increased osmolarity) and that this RVI occurs mainly by a Na-K-Cl-Cotransporter (NKCC) - dependent mechanism. With high-intensity exercise, increased extracellular osmolarity is accompanied by large increases in extracellular [lactate-]. We hypothesized that large increases in [lactate-] and osmolarity augment the NKCC-dependent RVI response observed with a NaCl (or sucrose) - induced increase in osmolarity alone; a response that is dependent on lactate- influx through monocarboxylate transporters (MCTs). Single mouse muscle fibres were isolated and visualized under light microscopy under varying osmolar conditions. When solution osmolarity was increased by adding NaLac by 30 or 60 mM, fibres lost significantly less volume and regained volume sooner compared to when NaCl was used. Phloretin (MCT1 inhibitor) accentuated the volume loss compared to both NaLac controls, supporting a role for MCT1 in the RVI response in the presence of elevated [lactate-]. Inhibition of MCT4 (with pCMBS) resulted in a volume loss, intermediate to that seen with phloretin and NaLac controls. Bumetanide (NKCC inhibitor), in combination with pCMBS, reduced the magnitude of volume loss, but volume recovery was complete. While combined phloretin-bumetanide also reduced the magnitude of the volume loss, it also largely abolished the cell volume recovery. In conclusion, RVI in skeletal muscle exposed to raised tonicity and [lactate-] is facilitated by inward flux of solute by NKCC- and MCT1-dependent mechanisms. This work demonstrates evidence of a RVI response in skeletal muscle that is facilitated by inward flux of solute by MCT-dependent mechanisms. These findings further expand our understanding of the capacities for skeletal muscle to volume regulate, particularly in instances of raised tonicity and lactate- concentrations, as occurs

  14. Inward flux of lactate⁻ through monocarboxylate transporters contributes to regulatory volume increase in mouse muscle fibres.

    PubMed

    Lindinger, Michael I; Leung, Matthew J; Hawke, Thomas J

    2013-01-01

    Mouse and rat skeletal muscles are capable of a regulatory volume increase (RVI) after they shrink (volume loss resultant from exposure to solutions of increased osmolarity) and that this RVI occurs mainly by a Na-K-Cl-Cotransporter (NKCC)-dependent mechanism. With high-intensity exercise, increased extracellular osmolarity is accompanied by large increases in extracellular [lactate⁻]. We hypothesized that large increases in [lactate⁻] and osmolarity augment the NKCC-dependent RVI response observed with a NaCl (or sucrose)-induced increase in osmolarity alone; a response that is dependent on lactate⁻ influx through monocarboxylate transporters (MCTs). Single mouse muscle fibres were isolated and visualized under light microscopy under varying osmolar conditions. When solution osmolarity was increased by adding NaLac by 30 or 60 mM, fibres lost significantly less volume and regained volume sooner compared to when NaCl was used. Phloretin (MCT1 inhibitor) accentuated the volume loss compared to both NaLac controls, supporting a role for MCT1 in the RVI response in the presence of elevated [lactate⁻]. Inhibition of MCT4 (with pCMBS) resulted in a volume loss, intermediate to that seen with phloretin and NaLac controls. Bumetanide (NKCC inhibitor), in combination with pCMBS, reduced the magnitude of volume loss, but volume recovery was complete. While combined phloretin-bumetanide also reduced the magnitude of the volume loss, it also largely abolished the cell volume recovery. In conclusion, RVI in skeletal muscle exposed to raised tonicity and [lactate⁻] is facilitated by inward flux of solute by NKCC- and MCT1-dependent mechanisms. This work demonstrates evidence of a RVI response in skeletal muscle that is facilitated by inward flux of solute by MCT-dependent mechanisms. These findings further expand our understanding of the capacities for skeletal muscle to volume regulate, particularly in instances of raised tonicity and lactate⁻ concentrations, as

  15. Avian influenza control strategies

    USDA-ARS?s Scientific Manuscript database

    Control strategies for avian influenza in poultry vary depending on whether the goal is prevention, management, or eradication. Components used in control programs include: 1) education which includes communication, public awareness, and behavioral change, 2) changes to production and marketing sys...

  16. Computationally efficient control allocation

    NASA Technical Reports Server (NTRS)

    Durham, Wayne (Inventor)

    2001-01-01

    A computationally efficient method for calculating near-optimal solutions to the three-objective, linear control allocation problem is disclosed. The control allocation problem is that of distributing the effort of redundant control effectors to achieve some desired set of objectives. The problem is deemed linear if control effectiveness is affine with respect to the individual control effectors. The optimal solution is that which exploits the collective maximum capability of the effectors within their individual physical limits. Computational efficiency is measured by the number of floating-point operations required for solution. The method presented returned optimal solutions in more than 90% of the cases examined; non-optimal solutions returned by the method were typically much less than 1% different from optimal and the errors tended to become smaller than 0.01% as the number of controls was increased. The magnitude of the errors returned by the present method was much smaller than those that resulted from either pseudo inverse or cascaded generalized inverse solutions. The computational complexity of the method presented varied linearly with increasing numbers of controls; the number of required floating point operations increased from 5.5 i, to seven times faster than did the minimum-norm solution (the pseudoinverse), and at about the same rate as did the cascaded generalized inverse solution. The computational requirements of the method presented were much better than that of previously described facet-searching methods which increase in proportion to the square of the number of controls.

  17. NUCLEAR REACTOR CONTROL SYSTEM

    DOEpatents

    Epler, E.P.; Hanauer, S.H.; Oakes, L.C.

    1959-11-01

    A control system is described for a nuclear reactor using enriched uranium fuel of the type of the swimming pool and other heterogeneous nuclear reactors. Circuits are included for automatically removing and inserting the control rods during the course of normal operation. Appropriate safety circuits close down the nuclear reactor in the event of emergency.

  18. Pattern Recognition Control Design

    NASA Technical Reports Server (NTRS)

    Gambone, Elisabeth A.

    2018-01-01

    Spacecraft control algorithms must know the expected vehicle response to any command to the available control effectors, such as reaction thrusters or torque devices. Spacecraft control system design approaches have traditionally relied on the estimated vehicle mass properties to determine the desired force and moment, as well as knowledge of the effector performance to efficiently control the spacecraft. A pattern recognition approach was used to investigate the relationship between the control effector commands and spacecraft responses. Instead of supplying the approximated vehicle properties and the thruster performance characteristics, a database of information relating the thruster ring commands and the desired vehicle response was used for closed-loop control. A Monte Carlo simulation data set of the spacecraft dynamic response to effector commands was analyzed to establish the influence a command has on the behavior of the spacecraft. A tool developed at NASA Johnson Space Center to analyze flight dynamics Monte Carlo data sets through pattern recognition methods was used to perform this analysis. Once a comprehensive data set relating spacecraft responses with commands was established, it was used in place of traditional control methods and gains set. This pattern recognition approach was compared with traditional control algorithms to determine the potential benefits and uses.

  19. Plating Tank Control Software

    SciTech Connect

    Krafcik, John

    1998-03-01

    The Plating Tank Control Software is a graphical user interface that controls and records plating process conditions for plating in high aspect ratio channels that require use of low current and long times. The software is written for a Pentium II PC with an 8 channel data acquisition card, and the necessary shunt resistors for measuring currents in the millampere range.

  20. DIESEL NOX CONTROL APPLICATION

    EPA Science Inventory

    The paper gives results of a project to design, develop, and demonstrate a diesel engine nitrogen oxide (NOx) and particulate matter (PM) control package that will meet the U.S. Navy's emission control requirements. (NOTE: In 1994, EPA issued a Notice for Proposed Rule Making (NP...

  1. Foot Operation of Controls

    DTIC Science & Technology

    1971-01-01

    in which the maximum force may be applied ’. 2.6. Foot versus Hand Operation of Controls Grether (1946) investigated tracking accuracy with...airplane controls. Technical Note 550, National Advisory Committee for Aeronautics, Washington, D.C. GRETHER , W. P., 1946, A study of several

  2. QUALITY CONTROLS FOR PCR

    EPA Science Inventory

    The purpose of this presentation is to present an overview of the quality control (QC) sections of a draft EPA document entitled, "Quality Assurance/Quality Control Guidance for Laboratories Performing PCR Analyses on Environmental Samples." This document has been prepared by th...

  3. Novel microsatellite control system

    SciTech Connect

    Moore, K.R.; Frigo, J.R.; Tilden, M.W.

    1996-12-31

    The authors are developing extremely simple yet quite capable analog pulse-coded neural networks for smaller-faster-cheaper spacecraft attitude and control systems. They will demonstrate a prototype microsatellite that uses the novel control system to autonomously stabilize itself in the ambient magnetic field and point itself at the brightest available light source.

  4. Hair follicle growth controls.

    PubMed

    Stenn, K S; Combates, N J; Eilertsen, K J; Gordon, J S; Pardinas, J R; Parimoo, S; Prouty, S M

    1996-10-01

    Research in hair biology has embarked in the pursuit for molecules that control hair growth. Many molecules already have been associated with the controls of hair patterning, hair maturation, and hair cycling and differentiation. Knowing how these molecules work gives us the tools for understanding and treating patients with hair disorders.

  5. Serial interface controller

    SciTech Connect

    Kandasamy, A.

    1995-04-14

    The idea of building a Serial Interface Controller (SIC) proposed by Paul O`Connor, Instrumentation Division, BNL is to determine the feasibility of incorporating a Serial Interface Controlled CMOS IC`s for charge amplification, shaping, analog storage and multiplexing used in particle detectors for high energy physics experiments. The serial data pumped into the CMOS ICs will be used to control many circuit parameters like digitally controlled gain, shaping time, precision preamplifier calibration circuits and many other parameters like timing discriminators mode of operation. The SIC board built will be tested on a Serial Interface Controlled Digital - to - Analog Convertor, which follows either Motorola`s SPI/QSPI or National Semiconductors Microwire interface technique. The DAC chosen for this was MAXIM`s MAX537, a Quad, 12-bit DAC. The function of this controller can be achieved by using some on-shelf micro-controllers like the Motorola`s MC68HC11, which offers dedicated SPI ports. The drawback encountered in using this controller is the overhead involved in putting together an user interface where the user can dynamically change its settings and load the SIC device. This is very critical in testing fewer number of CMOS IC`s having SIC. The SIC board described here takes care of this dynamic user interface issue.

  6. Rethinking Coercive Control.

    PubMed

    Stark, Evan

    2009-12-01

    The critical appraisals of Coercive Control focus largely on what my analysis implies for intervention, a matter to which the book devotes only limited space. In this reply, I reiterate core concepts in the book and acknowledge that much more work is needed to translate the realities of coercive control into practical legal and advocacy strategies. I review how coercive control differs from partner assaults and so why it merits a distinct response; the extent to which coercive control targets gender identity; the wisdom of complementing the focus on violence with an emphasis on male domination, sexual inequality and personal liberty; what this implies for shelters and the law; why sexual inequality differentiates coercive control from female partner abuse of men; how sexual equality can be both cause and antidote for coercive control; why I think an affirmative concept of freedom is essential to grasp the human rights violations inflicted by coercive control; and what it means to "story" coercive control by integrating women into the larger liberty narrative on which our national identity rests.

  7. Command and Control.

    ERIC Educational Resources Information Center

    Thwaites, Donald

    1992-01-01

    Provides background information as an introduction to three articles on command and control simulations that involve police and fire departments. Elements of command and control situations are discussed, including leadership, management of people and resources, communication, and coordination; the effectiveness of simulations is considered; and…

  8. Control-structure interaction

    NASA Technical Reports Server (NTRS)

    Cheng, Joseph K.; Ianculescu, George D.; Kenney, Charles S.; Laub, Alan J.; Ly, Jason H. Q.; Papadopoulos, Philip M.

    1992-01-01

    The feasibility of using conventional proportional-integral-derivative (PID) control and an alternative optimal control to perform the pointing and tracking functions of the Space Station solar dynamic power module is investigated. A very large state model of 6 rigid body modes and 272 flexible modes is used in conjunction with classical linear-quadratic-Gaussian (LQG) optimal control to produce a full-order controller that satisfies the requirements. The results are compared with a classically designed PID controller that was implemented for a much smaller (6 rigid body, 40 flexible modes) model. The conventional control design approach is shown to be very much influenced by the order reduction of the plant model, i.e., the number of retained elastic modes from the full-order model, suggesting that for a complex, large space structure, such as the Space Station Freedom solar dynamic module, application of conventional control system design methods may not be adequate. The use of LQG control is recommended, and method for solving the large matrix. Riccati equation that arises from the optimal formulation is provided.

  9. Aircraft thrust control

    NASA Technical Reports Server (NTRS)

    Bennett, George W. (Inventor); Walker, Neil (Inventor)

    1988-01-01

    An integrated control system for coaxial counterrotating aircraft propulsors driven by a common gas turbine engine. The system establishes an engine pressure ratio by control of fuel flow and uses the established pressure ratio to set propulsor speed. Propulsor speed is set by adjustment of blade pitch.

  10. Programmable Logic Controllers.

    ERIC Educational Resources Information Center

    Insolia, Gerard; Anderson, Kathleen

    This document contains a 40-hour course in programmable logic controllers (PLC), developed for a business-industry technology resource center for firms in eastern Pennsylvania by Northampton Community College. The 10 units of the course cover the following: (1) introduction to programmable logic controllers; (2) DOS primer; (3) prerequisite…

  11. Pattern Recognition Control Design

    NASA Technical Reports Server (NTRS)

    Gambone, Elisabeth

    2016-01-01

    Spacecraft control algorithms must know the expected spacecraft response to any command to the available control effectors, such as reaction thrusters or torque devices. Spacecraft control system design approaches have traditionally relied on the estimated vehicle mass properties to determine the desired force and moment, as well as knowledge of the effector performance to efficiently control the spacecraft. A pattern recognition approach can be used to investigate the relationship between the control effector commands and the spacecraft responses. Instead of supplying the approximated vehicle properties and the effector performance characteristics, a database of information relating the effector commands and the desired vehicle response can be used for closed-loop control. A Monte Carlo simulation data set of the spacecraft dynamic response to effector commands can be analyzed to establish the influence a command has on the behavior of the spacecraft. A tool developed at NASA Johnson Space Center (Ref. 1) to analyze flight dynamics Monte Carlo data sets through pattern recognition methods can be used to perform this analysis. Once a comprehensive data set relating spacecraft responses with commands is established, it can be used in place of traditional control laws and gains set. This pattern recognition approach can be compared with traditional control algorithms to determine the potential benefits and uses.

  12. Contamination Control Techniques

    SciTech Connect

    EBY, J.L.

    2000-05-16

    Welcome to a workshop on contamination Control techniques. This work shop is designed for about two hours. Attendee participation is encouraged during the workshop. We will address different topics within contamination control techniques; present processes, products and equipment used here at Hanford and then open the floor to you, the attendees for your input on the topics.

  13. Multipath star switch controller

    NASA Technical Reports Server (NTRS)

    Anderson, T. O.

    1980-01-01

    Device concept permits parallel computers to scan several commonnetwork-connected data stations at maximum rate. Sequencers leap-frog to bypass ports already being serviced by another computer. Two-path system for 16-port star switch controller is cost effective if added bandwidth or increased reliability is desired. Triple-path system would be cost effective for 32-port controller.

  14. Readings in program control

    NASA Technical Reports Server (NTRS)

    Hoban, Francis T. (Editor); Lawbaugh, William M. (Editor); Hoffman, Edward J. (Editor)

    1994-01-01

    Under the heading of Program Control, a number of related topics are discussed: cost estimating methods; planning and scheduling; cost overruns in the defense industry; the history of estimating; the advantages of cost plus award fee contracts; and how program control techniques led to the success of a NASA development project.

  15. QUALITY CONTROLS FOR PCR

    EPA Science Inventory

    The purpose of this presentation is to present an overview of the quality control (QC) sections of a draft EPA document entitled, "Quality Assurance/Quality Control Guidance for Laboratories Performing PCR Analyses on Environmental Samples." This document has been prepared by th...

  16. Robust Control Systems.

    DTIC Science & Technology

    1981-12-01

    Controller ................... 38 Sampled-Data Performance Analysis ............. 44 Doyle and Stein Technique in Discrete-Time Systems - 1...48 Doyle and Stein Technique in Discretd-Time System.s - 2 ................................. 50 Enhancing Robustness of... Technique Extended to Sampled-Data Controllers ................ 73 G715 Robustness Enhancement by Directly D"?C TAB E

  17. Systems Modelling and Control.

    ERIC Educational Resources Information Center

    Kershenbaum, L. S.; And Others

    1980-01-01

    Describes aims, objectives content, and instructional strategies of a course in systems modelling and control at Imperial College, England. Major problem areas include multivariable control system design, estimation and filtering, and the design and use of adaptive "self-tuning" regulators. (Author/JN)

  18. Demand-controlled lighting

    NASA Technical Reports Server (NTRS)

    Owens, L. J.

    1977-01-01

    Automatic lighting is controlled by photocell that measures intensity of available light. Photocell drives motor which operates mercury switches controlling indoor illumination sources. Device effects increase in indoor illumination intensity when illumination input to cell is insufficient. Reverse is true if input is too great.

  19. Police Robbery Control Manual.

    ERIC Educational Resources Information Center

    Ward, Richard H.; And Others

    The manual was designed as a practical guide for police department personnel in developing robbery control programs. An introductory chapter defines types of robberies and suggests administrative and operational uses of the manual. Research and control strategies are reported according to five robbery types: street (visible and non-visible),…

  20. Control without Wires.

    ERIC Educational Resources Information Center

    Hobart, Jordan

    2002-01-01

    Describes how modern lighting systems, such as wireless lighting, which come complete with user-friendly controls and audio/video interfaces, enhance the educational process and cut costs. Discusses evaluating a building's lighting situation, lighting controls, and such systems' flexibility for future needs. (EV)