Detecting deteriorated vigilance using percentage of eyelid closure time during behavioral maintenance of wakefulness tests

2011 ◽  
Vol 82 (3) ◽  
pp. 269-274 ◽  
Author(s):  
Takashi Abe ◽  
Tomohide Nonomura ◽  
Yoko Komada ◽  
Shoichi Asaoka ◽  
Taeko Sasai ◽  
...  
Keyword(s):  
Eyelid Closure ◽  
Closure Time ◽  
Behavioral Maintenance

scholarly journals CO<sub>2</sub> flux determination by closed-chamber methods can be seriously biased by inappropriate application of linear regression

2007 ◽  
Vol 4 (6) ◽  
pp. 1005-1025 ◽  
Author(s):  
L. Kutzbach ◽  
J. Schneider ◽  
T. Sachs ◽  
M. Giebels ◽  
H. Nykänen ◽  
...  
Keyword(s):  
Linear Regression ◽  
Nonlinear Regression ◽  
Co2 Flux ◽  
Exponential Model ◽  
Co2 Uptake ◽  
Co2 Fluxes ◽  
Closed Chamber ◽  
Exponential Regression ◽  
Closure Time ◽  
Over Time

Abstract. Closed (non-steady state) chambers are widely used for quantifying carbon dioxide (CO2) fluxes between soils or low-stature canopies and the atmosphere. It is well recognised that covering a soil or vegetation by a closed chamber inherently disturbs the natural CO2 fluxes by altering the concentration gradients between the soil, the vegetation and the overlying air. Thus, the driving factors of CO2 fluxes are not constant during the closed chamber experiment, and no linear increase or decrease of CO2 concentration over time within the chamber headspace can be expected. Nevertheless, linear regression has been applied for calculating CO2 fluxes in many recent, partly influential, studies. This approach has been justified by keeping the closure time short and assuming the concentration change over time to be in the linear range. Here, we test if the application of linear regression is really appropriate for estimating CO2 fluxes using closed chambers over short closure times and if the application of nonlinear regression is necessary. We developed a nonlinear exponential regression model from diffusion and photosynthesis theory. This exponential model was tested with four different datasets of CO2 flux measurements (total number: 1764) conducted at three peatlands sites in Finland and a tundra site in Siberia. Thorough analyses of residuals demonstrated that linear regression was frequently not appropriate for the determination of CO2 fluxes by closed-chamber methods, even if closure times were kept short. The developed exponential model was well suited for nonlinear regression of the concentration over time c(t) evolution in the chamber headspace and estimation of the initial CO2 fluxes at closure time for the majority of experiments. However, a rather large percentage of the exponential regression functions showed curvatures not consistent with the theoretical model which is considered to be caused by violations of the underlying model assumptions. Especially the effects of turbulence and pressure disturbances by the chamber deployment are suspected to have caused unexplainable curvatures. CO2 flux estimates by linear regression can be as low as 40% of the flux estimates of exponential regression for closure times of only two minutes. The degree of underestimation increased with increasing CO2 flux strength and was dependent on soil and vegetation conditions which can disturb not only the quantitative but also the qualitative evaluation of CO2 flux dynamics. The underestimation effect by linear regression was observed to be different for CO2 uptake and release situations which can lead to stronger bias in the daily, seasonal and annual CO2 balances than in the individual fluxes. To avoid serious bias of CO2 flux estimates based on closed chamber experiments, we suggest further tests using published datasets and recommend the use of nonlinear regression models for future closed chamber studies.

Customised gold weight eyelid implantation in paralytic lagophthalmos

2008 ◽  
Vol 122 (10) ◽  
pp. 1088-1091 ◽  
Author(s):  
N Jayashankar ◽  
K P Morwani ◽  
M J Shaan ◽  
S R Bhatia ◽  
K T Patil
Keyword(s):  
Visual Acuity ◽  
Prospective Study ◽  
Study Design ◽  
Study Group ◽  
Upper Eyelid ◽  
Eyelid Closure ◽  
Gold Weight ◽  
One Year ◽  
A Prospective Study

AbstractGold eyelid implantation is widely considered the procedure of choice to reanimate the upper eyelid in paralytic lagophthalmos. Commercially supplied implants are not readily available in all places and are sometimes cumbersome to import.Objective:We aimed to devise a method whereby every surgeon performing gold eyelid implantation could have easy and quick access to the implant. Furthermore, we aimed to develop a means of creating an implant of the exact weight required for complete eyelid closure.Study design and setting:A prospective study was performed from 1997 to 2005 in a tertiary research hospital, involving 50 subjects requiring gold upper eyelid implantation and using the technique in question.Results:Only patients with a minimum follow up of one year were included in the study group. Symptoms improved in 96 per cent of subjects, who were able to dispense with eyedrops and eye ointments. Visual acuity improved in 92 per cent of patients. There were two extrusions amongst the early cases.Conclusion and significance:Customised gold eyelid implantation offers an alternative in regions where commercial implants are not easily obtained.

Attempted eyelid closure affects intraocular pressure measurement in open-angle glaucoma patients

2002 ◽  
Vol 134 (2) ◽  
pp. 186-189 ◽  
Author(s):  
Karim N Jamal ◽  
Rabİa Gürses-Özden ◽  
Jeffrey M Liebmann ◽  
Robert Ritch
Keyword(s):  
Intraocular Pressure ◽  
Pressure Measurement ◽  
Open Angle Glaucoma ◽  
Open Angle ◽  
Eyelid Closure

Intraoperative computed tomography registration and electromagnetic neuronavigation for transsphenoidal pituitary surgery: accuracy and time effectiveness

2011 ◽  
Vol 114 (2) ◽  
pp. 329-335 ◽  
Author(s):  
Paula Eboli ◽  
Bob Shafa ◽  
Marc Mayberg
Keyword(s):  
Mr Imaging ◽  
Operating Room ◽  
Navigation System ◽  
Surgical Techniques ◽  
Imaging Data ◽  
3D Navigation ◽  
Closure Time ◽  
Bony Landmarks ◽  
Room Time ◽  
Operating Room Time

Object The authors assessed the feasibility, anatomical accuracy, and cost effectiveness of frameless electromagnetic (EM) neuronavigation in conjunction with portable intraoperative CT (iCT) registration for transsphenoidal adenomectomy (TSA). Methods A prospective database was established for data obtained in 208 consecutive patients who underwent TSA in which the iCT/EM navigation technique was used. Data were compared with those acquired in a retrospective cohort of 65 consecutive patients in whom fluoroscope-assisted TSA had been performed by the same surgeon. All patients in both groups underwent transnasal removal of pituitary adenomas or neuroepithelial cysts, using identical surgical techniques with an operating microscope. In the iCT/EM technique–treated cases, a portable iCT scan was obtained immediately prior to surgery for registration to the EM navigation system, which did not require rigid head fixation. Preexisting (nonnavigation protocol) MR imaging studies were fused with the iCT scans to enable 3D navigation based on MR imaging data. The accuracy of the navigation system was determined in the first 50 iCT/EM cases by visual concordance of the navigation probe location to 5 preselected bony landmarks. For all patients in both cohorts, total operating room time, incision-to-closure time, and relative costs of imaging and surgical procedures were determined from hospital records. Results In every case, iCT registration was successful and preoperative MR images were fused to iCT scans without affecting navigation accuracy. There was 100% concordance between probe tip location and predetermined bony loci in the first 50 cases involving the iCT/EM technique. Total operating room time was significantly less in the iCT/EM cases (mean 108.9 ± 24.3 minutes [208 patients]) compared with the fluoroscopy group (mean 121.1 ± 30.7 minutes [65 patients]; p < 0.001). Similarly, incision-to-closure time was significantly less for the iCT/EM cases (mean 61.3 ± 18.2 minutes) than for the fluoroscopy cases (mean 71.75 ± 19.0 minutes; p < 0.001). Relative overall costs for iCT/EM technique and intraoperative C-arm fluoroscopy were comparable; increased costs for navigation equipment were offset by savings in operating room costs for shorter procedures. Conclusions The use of iCT/MR imaging–guided neuronavigation for transsphenoidal surgery is a time-effective, cost-efficient, safe, and technically beneficial technique.

scholarly journals Grainyhead-like factor Get1/Grhl3 regulates formation of the epidermal leading edge during eyelid closure

2008 ◽  
Vol 319 (1) ◽  
pp. 56-67 ◽  
Author(s):  
Zhengquan Yu ◽  
Ambica Bhandari ◽  
Jaana Mannik ◽  
Thu Pham ◽  
Xiaoman Xu ◽  
...  
Keyword(s):  
Leading Edge ◽  
Eyelid Closure

Charts for water hammer in pipelines resulting from valve closure from full opening only

1985 ◽  
Vol 12 (2) ◽  
pp. 241-264 ◽  
Author(s):  
Bryan W. Karney ◽  
Eugen Ruus
Keyword(s):  
Good Accuracy ◽  
Pipe Wall ◽  
Pressure Head ◽  
Wall Friction ◽  
Maximum Pressure ◽  
Valve Closure ◽  
Closure Time ◽  
Basic Parameters ◽  
Valve Opening ◽  
Open Position

Maximum pressure head rises, which result from total closure of the valve from an initially fully open position, are calculated and plotted for the valve end and for the midpoint of a simple pipeline. Uniform, equal-percentage, optimum, and parabolic closure arrangements are analysed. Basic parameters such as pipeline constant, relative closure time, and pipe wall friction are considered with closures from full valve opening only. The results of this paper can be used to draw the maximum hydraulic grade line along the pipe with good accuracy for the closure arrangements considered. It is found that the equal-percentage closure arrangement yields consistently less pressure head rise than does the parabolic closure arrangement. Further, the optimum closure arrangement yields consistently less head rise than the equal-percentage one. Uniform closure produces pressure head rise that usually lies between those produced by the parabolic and the equal-percentage closure arrangements, except for the range of low pressure head rise combined with low or zero friction, where the rise due to uniform closure approaches that produced by optimum closure.

scholarly journals Tyrosine kinase inhibitor–induced platelet dysfunction in patients with chronic myeloid leukemia

Blood ◽  
2009 ◽  
Vol 114 (2) ◽  
pp. 261-263 ◽  
Author(s):  
Alfonso Quintás-Cardama ◽  
Xin Han ◽  
Hagop Kantarjian ◽  
Jorge Cortes
Keyword(s):  
Platelet Aggregation ◽  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Chronic Phase ◽  
Platelet Dysfunction ◽  
Normal Platelet ◽  
Closure Time ◽  
Platelet Aggregometry ◽  
Increased Risk

Abstract Dasatinib is associated with increased risk of bleeding among patients with chronic myeloid leukemia, even in the absence of thrombocytopenia, suggesting the presence of a hemostatic defect. We tested platelet aggregation in 91 patients with chronic myeloid leukemia in chronic phase either off-therapy (n = 4) or receiving dasatinib (n = 27), bosutinib (n = 32), imatinib (n = 19), or nilotinib (n = 9). All but 3 patients simultaneously receiving imatinib and warfarin had normal coagulation studies. All 4 patients off therapy had normal platelet aggregation. Impaired platelet aggregation on stimulation with arachidonic acid, epinephrine, or both was observed in 70%, 85%, and 59% of patients on dasatinib, respectively. Eighty-five percent of patients on bosutinib, 100% on nilotinib, and 33% on imatinib had normal platelet aggregation. Dasatinib 400 nM induced rapid and marked prolongation of closure time to collagen/epinephrine in normal whole blood on the PFA-100 system. In conclusion, dasatinib and, to some extent, imatinib produce abnormalities in platelet aggregometry testing.

scholarly journals Epidemiology and outcome of patients with postoperative abdominal fistula

2016 ◽  
Vol 43 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Janaina Wercka ◽  
Patricia Paola Cagol ◽  
André Luiz Parizi Melo ◽  
Giovani de Figueiredo Locks ◽  
Orli Franzon ◽  
...  
Keyword(s):  
Biliary Fistula ◽  
Spontaneous Closure ◽  
Significant Morbidity ◽  
Fistula Closure ◽  
Cross Sectional ◽  
Predictors Of Mortality ◽  
Closure Time ◽  
Epidemiological Profile ◽  
Time To Onset ◽  
Age Over 60

ABSTRACT Objective: to present the epidemiological profile, incidence and outcome of patients who developing postoperative abdominal fistula. Methods: This observational, cross-sectional, prospective study evaluated patients undergoing abdominal surgery. We studied the epidemiological profile, the incidence of postoperative fistulas and their characteristics, the outcome of this complication and the predictors of mortality. Results: The sample consisted of 1,148 patients. The incidence of fistula was 5.5%. There was predominance of biliary fistula (26%), followed by colonic fistulas (22%) and stomach (15%). The average time to onset of fistula was 6.3 days. For closure, the average was 25.6 days. The mortality rate of patients with fistula was 25.4%. Predictors of mortality in patients who developed fistula were age over 60 years, presence of comorbidities, fistula closure time more than 19 days, no spontaneous closure of the fistula, malnutrition, sepsis and need for admission to the Intensive Care Unit Conclusion: abdominal postoperative fistulas are still relatively frequent and associated with significant morbidity and mortality.

The influence of the haematocrit on primary haemostasis in vitro

2005 ◽  
Vol 94 (12) ◽  
pp. 1213-1218 ◽  
Author(s):  
Marco Eugster ◽  
Walter H. Reinhart
Keyword(s):  
Platelet Function ◽  
Type I Collagen ◽  
Inverse Correlation ◽  
Type I ◽  
Membrane Pore ◽  
Closure Time ◽  
Function Analyzer ◽  
Platelet Function Analyzer

SummaryPrimary haemostasis consists of platelet adhesion to subendothelial collagen, their activation and aggregation and finally the formation of a platelet plug. Erythrocytes are involved in this process because they flow in the center of the vessel and push platelets towards the site of action on the vessel wall and enhance shear forces, which activate platelets. In the platelet function analyzer PFA-100® (Dade Behring, Düdingen, Switzerland), the in vivo situation is simulated in vitro with blood being aspirated at high shear rates (5000s-1) through a capillary into a membrane pore with a diameter of 150 μm coated with type I collagen and either epinephrine or adenosine diphosphate. Aggregating platelets plug the pore and stop the flow, which is measured as the closure time. We analysed the influence of erythrocytes on platelet function analyzer measurements by systematic variation of the haematocrit (20,30,40,and 50%) at constant platelet counts of 289±61 ×103/μl plasma, or 152±30 ×103/μl blood, 96±9 ×103/μl blood and 54±5 ×103/μl blood, respectively. An inverse correlation was found between haematocrit and closure time under all circumstances. A decrease of the platelet count by 50 ×103 /μl could be compensated for by a 10% increase in haematocrit. The haematocrit must, therefore, be taken into consideration for the correct interpretation of PFA-100® measurements. Our data also provide a pathophysiological rationale to reduce the risk of bleeding in patients with thrombocytopenia and anaemia by normalizing the haematocrit with erythrocyte transfusions.

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