183 research outputs found
Surface directed electrokinetic flows in microfluidic devices:
No full textElectroosmotic flow control in microfluidic devices is an important and challenging problem, as electroosmosis directly influences separation efficiencies in lab-on-chip applications. In this study, a non-mechanical passive flow directing method is presented for electrokinetically driven flow. Due to the high surface-area-to-volume (SA/V) ratio, surface properties dominate the flow in microfluidic channels. For electrokinetically driven flows, the main surface property affecting electroosmotic flows is the surface ζ potential, which is related to the effective surface charge density. By changing the effective surface charge density, the electroosmotic flow rates of charged species can be controlled in microfluidic channels. In this work, to change the effective surface charge density, surfaces were chemically modified with –Br, –NH2 and –CH3 functional groups by ‘click’ chemistry. Since these functional surface layers are integrated within model glass microfluidic devices prepared by standard microfabrication procedures, the first step was to investigate the stability of the adherent surface layers to a variety of microfabrication conditions. A model “Y” shaped glass microfluidic device was developed. One leg of this model microfluidic device was selectively chemically modified to alter the ζ potential and thereby increase or decrease the electroosmotic flow with respect to rest of the device. Electroosmotic flow is visualized by using marker dyes under a fluorescent microscope. In addition, experiments were validated by using the CFD code in COMSOL. The experiments concluded that the surface layers are stable to a variety of conditions including a wide pH range (pH 3 – pH 11), solvent exposure, acid and base exposure, and UV light. Extreme conditions such as a piranha solution or oxidative plasma degrade the surface layers. Electrokinetic flow experiments show that depending on the charge of a species the electroosmotic flow is preferentially directed as a function of the ζ potential in the microfluidic channels.M.S.Includes bibliographical references (p. 78-81)by Mehmet Basar Karaco
The prognostic value of the Glasgow coma scale, serum acetylcholinesterase and leukocyte levels in acute organophosphorus poisoning
No full textBackground and Objectives: Organophosphate poisoning (OP) is a serious clinical condition that may sometimes be fatal. The aim of this study was to determine whether the Glasgow coma scale (GCS), and serum acetylcholinesterase and leukocyte levels have prognostic value in acute OP poisoning. Design and Setting: Retrospective review of records of patients admitted to the intensive care unit of Selcuk University, Meram Medical Faculty, Emergency Department, Konya, Turkey, between January 2006 and January 2009. Methods: We studied acutely OP-poisoned patients admitted within 24 hours after OP exposure. Results: The mean age of the 25 patients was 37 years (range, 20-80 years). Three (12%) of the 25 patients (male-female ratio, 12:13) died. The mean GCS values of the patients who died were significantly lower compared to those of the group that survived (4 vs 11.7, respectively P<.05). While the mean serum acetylcholinesterase levels were lower in the patients who died, the difference in the mean serum acetylcholinesterase levels between the patients who died and the ones who survived was not statistically significant (3841 IU/L vs. 1768 IU/L, respectively). Conclusion: Although serum cholinesterase values can be used in the quick diagnosis, their efficiency at predicting outcome in patients with OP poisoning has not been established. It has also been determined that serum leukocyte values have no prognostic value in OP poisoning, but GCS values have been found to be effective in predicting the outcome
Kronik Obstrüktif Akciğer Hastalığı Alevlenmesinde Eozinofil Sayısı ve Yüzdesinin Rolü: Bir Gözlemsel Retrospektif Çalışma
No full textAim: To reveal the role of eosinophil count and percentage evaluated at the time of presentation in patients hospitalized with the exacerbation of chronic obstructive pulmonary disease (COPD). Material and Methods: In this study, the data of patients with a diagnosis of the exacerbation of COPD, who presented to the emergency department, and admitted to the general internal medicine ward, were retrospectively analyzed. The relationship of eosinophil count and ratios with the length of hospital stay and intensive care requirement was investigated.The Spearman correlation analysis was used for investigating correlation between parameters and outcome. Results: Of the study population, 39.7% were female and 60.3% were male. The ages of the participants ranged from 25 to 94 years, with a median value of 76 years. There was no significant correlation between the length of stay in ward and eosinophil count and percentage (rho=-0.148, p=0.066 and p=0.074, rho=-0.143, respectively) (Spearman correlation test). The group admitted to the intensive care unit had a significantly higher eosinophil count and percentage of eosinophils than the group that did not require intensive care (0.81(Inter Quarter Range (IQR):0.41-1.31) versus 1.32 (IQR:0.83-1.43) p=0.042 and 1.0 (IQR:0.81-1.21) versus 1.42 (IQR:1.02-1.64), p=0.018, respectively) (Mann Whitney U test). Conclusion: There was no correlation between a high eosinophil count and percentage and the length of hospital stay. However, the number and percentage of eosinophils were significantly higher among the patients requiring intensive care
Thrombolysis in STEMI at Prehospital Settings
Get PDFThrombolysis is a rapidly available but semi-effective treatment, whereas percutaneous coronary intervention is a potentially delayed but highly effective therapy. What about thrombolysis in the prehospital setting for ST-elevated myocardial infarction? Does scientific evidence support or oppose? Which patient group is more eligible for prehospital thrombolysis? Is there any skirmish between emergency medicine and cardiovascular professionals? You can find a history of prehospital thrombolysis on the basis of scientific evidence in this writing
Prognostic factors in mechanically ventilated patients
No full textAim: In this study, we aimed to investigate the prognostic values of respiratory parameters recorded within the first 48 hours in patients connected to mechanical ventilation in the intensive care unit (ICU), in terms of 30-day mortality. Material and Method: This prospective study included patients who received mechanical ventilation due to acute respiratory failure between 2011 and 2013. The demographic characteristics of the patients, Glasgow Coma Score (GCS) scores, Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) values, vital signs, the results of complete blood count, biochemistry parameters and blood gas analyses were recorded. Patients were divided into two groups as survivors and non-survivors, and the differences in the parameters between the groups were analysed. Results: The study included 99 mechanically ventilated patients with the mean age 71.73 (18-105) years. Of the patients, 56 (56.6%) were male and 43 (43.4%) were female. Comparison of the survivors (n=37) with the non-survivors (n=62) indicated that the non-survivors had no statistical differences in terms of age, gender, or concomitant diseases. The values of GCS, APACHE II, and SOFA were significantly different between survivors and non-survivors (for all, p<0.001). Significant differences were also noted in FiO2 (p<0.001), pH (p=0.001), PO2 (p=0.044), PCO2 (p=0.046), A-a Gradient (p<0.001) and the expected increase of O2 gradient (p=0.026) between two groups. Discussion: Our findings indicate that, during the follow-up of the mechanically ventilated patients, respiratory parameters measured within the first 48 hours are cheap and easy-to-use parameters to predict the prognosis
Morphologic and quantitative analyses of leukocytes in patients with multiple system trauma
No full textMultiple system trauma can occur in accidents, natural disasters, and deliberate attacks, and vital areas of the body, such as the head, chest, and abdomen, may be affected. Investigators in the present study sought to examine morphologic and morphometric alterations of leukocyte responses in patients with multiple trauma during the first 4 h after a traumatic event. Venous blood samples were drawn from 51 patients, 30 male and 21 female, aged 16 to 59 y. The number of leukocytes increased significantly in all patients, but no significant differences were noted between the male and female groups. Complete blood counts revealed normal ratios of leukocyte types. It is suggested that in patients who have experienced multiple trauma, aggressive antibiotic therapy should be initiated to prevent posttraumatic infection and to protect against secondary organ failure
Prognostic value of serum zinc levels in critically ill patients
No full textPurpose: We investigated the hypothesis that a decline in serum zinc concentrations among critically ill patients is related to mortality, length of stay in the intensive care unit, and Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment (SOFA) scores. Materials and Methods: All the patients (>= 18 years old) presenting to the intensive care unit from September 2009 through November 2009 were enrolled the study. Patients' demographic characteristics and Acute Physiology and Chronic Health Evaluation and SOFA scores were recorded. Blood samples were collected within 24 hours after admission and analyzed for serum zinc, copper, C-reactive protein, and albumin levels. Patients were followed up for mortality and length of stay in the intensive care unit for 28 days. Results: A total of 36 patients, with a median age of 70.5 years (range, 18-87 years), were enrolled during the study period. Serum zinc levels were found to be inversely correlated with SOFA scores (r = -0.41, P < .01). Patients with SOFA scores of 8 or higher had significantly lower serum zinc levels compared with patients with SOFA scores lower than 8 (6.74 +/- 1.63 and 9.17 +/- 2.76 mu mol/L, respectively; P < .01). Conclusion: The result of this study supports the fact that organ failure and critical illness lead to a decline in serum zinc concentrations and that administration of zinc may be beneficial for critically ill patients. (C) 2011 Elsevier Inc. All rights reserved
Topics in decentralized detection
No full textIn this thesis we obtain several new results in the areas of decentralized sequential detection and robust decentralized detection.In the area of decentralized sequential detection, we first consider the case in which each sensor performs a sequential test on its observations and arrives at a local decision about the true hypothesis; subsequently, the local decisions of all of the sensors are used for a common purpose. Here we assume that decision errors at the sensors are penalized through a common cost function and that each time step taken by the detectors as a team is assigned a positive cost. We show that optimal sensor decision functions can be found in the class of generalized sequential probability ratio tests with monotonically convergent thresholds. We present a technique for obtaining optimal thresholds.We also consider the case in which each sensor sends a sequence of summary messages to a fusion center in which a sequential test is carried out to determine the true hypothesis. Here we assume that decision errors at the fusion center are penalized through a cost function and that each time step taken to arrive at the final decision costs a positive amount. We show that the problem is tractable when the information structure in the system is quasiclassical. In particular, we show that an optimal fusion center policy has a simple structure resembling a sequential probability ratio test and that a stationary set of monotone likelihood ratio tests is optimal at the sensors. Finally, we compute the optimal decision functions for some representative examples.In the area of robust decentralized detection, we consider the case in which the sensor distributions are assumed to belong to known uncertainty classes. We show for a broad class of such decentralized detection problems that a set of least favorable distributions exists for minimax robust testing between the hypotheses. We thus establish that minimax robust tests are obtained as solutions to simple decentralized detection problems in which the sensor distributions are specified to be the least favorable distributions.Made available in DSpace on 2011-05-07T12:48:37Z (GMT). No. of bitstreams: 2
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