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1.
Glucosamine     
We have taken a stepwise approach to improving the dosing of continuous intravenous heparin in patients with acute coronary syndromes. Our primary objective was to use computer modeling to develop a nomogram for managing heparin therapy and to put in place a continuous quality monitoring system to evaluate the nomogram's effectiveness. We prospectively collected data on 41 patients with unstable angina or myocardial infarction who were treated with heparin. Their response to heparin was computer modeled and the dose to achieve an activated partial thromboplastin time (aPTT) ratio of 2.0 was established. This dose was regressed against all demographic characteristics to establish predictors of heparin dose (phase I). The regression formula was used prospectively in 110 patients to initiate the infusion rate of heparin and a bolus dose to achieve an aPTT ratio of 2.5. Subsequent dosage adjustments were achieved by computer modeling the patient's aPTT response (phase II). A nomogram was developed that simulated the decisions achieved using computer-assisted methods. This was retrospectively tested and then prospectively tested in 50 patients using nursing staff (phase IV). The nomogram was then made generally available (phase IV) and has been tested in an additional 310 patients. Phase I: Of the original 41 patients, 32% of the aPTT ratios were in the therapeutic range, 36% were supratherapeutic, and 32% were subtherapeutic after the first 24 hours. Phases II and III resulted in 85% of the aPTT ratios between 1.5 and 2.5 at 24 hours. Phase 4 had similar results in 310 patients. The use of computer-assisted or a computer-generated nomogram to adjust heparin therapy results in better control of heparin therapy than using standard methods.  相似文献   

2.
Summary The relationship thickness and density during the rolling of metal powders is considered. On the basis of relationships established earlier, a formula is derived for the mean radial pressure, and all results obtained are generalized in the form of a nomogram. Experimental data are also presented for the relationship between the maximum and mean rolling pressures, demonstrating that this relationship is represented by a straight line.  相似文献   

3.
This paper describes a formula for estimating patient skin entrance exposures from representative techniques used in radiographic facilities. A flexible nomogram has been formatted to the parameters of patient dimensions and focal film distance. The corresponding exposure rate (mGy/mAs) is expressed for any assumed projection and selected kilovoltages. This measured approach is a valuable tool for exposure assessment and is in compliance with emerging government standards and the pursuit of the ALARA (as low as reasonably achievable) concept.  相似文献   

4.
Studies in the last decade demonstrated that in children tubular maximum phosphate reabsorption per glomerular filtration rate (TmP/GFR) is identical to TP/GFR; TP indicating tubular phosphate reabsorption under basal conditions, without phosphate load. TP/GFR is calculated from the formula TP/GFR = SP-UP x SCr:UCr, based on simultaneous urine and blood creatinine and phosphate concentrations, and is applicable in both the fasting and non-fasting child. These studies also demonstrated that the use of Walton and Bijvoet nomogram in children may result in overestimation of TmP/GFR compared with TP/GFR calculated from the above formula. When using the formula, one should bear in mind that creatinine is used to express GFR and as a result a significant deviation from true GFR may occur in patients with renal failure. Therefore when employing TP/GFR for the investigation of the renal handling of phosphate in children, three factors should be taken into consideration: (1) the formula in reality expresses TP/CCr; (2) only data obtained by exactly the same methodology can be used as reference values; data obtained from studies in which the nomogram was utilized or in which methods other than CCr were used to measure GFR should not be used for reference; (3) in patients with renal failure, TP/CCr will significantly overestimate TP/Cinulin.  相似文献   

5.
Recent developments in measurement of intact parathormone (PTH) has enabled to generate a nomogram for parathyroid function. Blood levels of PTH can thus be interpreted in relation to calcemia. Intact PTH and calcium were assayed in blood from 99 healthy subjects studied under fasting conditions; 26 subjects were also studied during hyper- and hypocalcemia, induced by calcium and EDTA infusions, respectively. Serum levels of intact PTH which had been obtained in 99 patients were then analysed retrospectively by comparison with the nomogram. Patients whose intact PTH levels lie above the normal zone of the nomogram produce too much PTH relative to the blood calcium level (hyperparathyroidism); those falling under the normal zone produce too little (hypoparathyroidism).  相似文献   

6.
OBJECTIVE: To compare a heparin dosing nomogram using an initial infusion rate of 18 units/kg/h with physician-directed heparin prescribing and with a modified version of the nomogram adjusted for institution-specific data. METHODS: During consecutive phases of this cohort study, patients' intravenous heparin therapies were initiated and adjusted by using one of the following three methods: (1) physician-directed dosing, (2) a body weight-based dosing nomogram with an initial infusion rate of 18 units/kg/h, and (3) a body weight-based dosing nomogram with an initial infusion rate determined by the median dose of heparin (in units/kg/h) required to achieve therapeutic activated partial thromboplastin times (aPTTs) during the first two phases. The time required to achieve therapeutic aPTTs as well as the percentage of initial aPTTs in the therapeutic range were compared for the three phases. RESULTS: The heparin dosing nomogram in which the initial infusion rate was adjusted for our individual institution resulted in a statistically shorter median time until aPTTs were in the therapeutic range than did either the physician-directed dosing or unmodified nomogram groups (6.1 h in the modified nomogram group, 10.5 h in the physician-directed group, 21.5 h in the unmodified nomogram group; p < 0.05 for all differences). Use of the institution-specific nomogram resulted in the greatest percentage of initial aPTTs in the therapeutic range (84% in the 13 units/kg/h nomogram group vs. 47% in the physician-directed group and 18% in the 18 units/kg/h nomogram group; p < 0.05 for all differences). CONCLUSIONS: Use of a heparin dosing nomogram with an initial infusion rate of 18 units/kg/h resulted in prolongation of the time to reach therapeutic aPTTs. By modifying the nomogram for use at an individual institution, we reduced the time to achieve therapeutic range of aPTTs while still reducing the likelihood of excessive anticoagulation of patients.  相似文献   

7.
Studies have been made on the effects of the fractional composition in a bidispersed mixture on the porosity in the formation of filters by free pouring. A nomogram has been drawn up for the dependence of the porosity on the component contents and sizes. A method is proposed for forecasting the porosity from the component contents. A rapid computer method has been developed for establishing the porosities of planar items.  相似文献   

8.
The misdiagnosis of pediatric bipolar disorder (PBD) has become a major public health concern. Would available evidence-based assessment (EBA) strategies help improve diagnostic accuracy and are clinicians willing to consider these strategies in practice? The purpose of the present study was to document the extent to which using an EBA decision tool—a probability nomogram—improves the interpretation of family history and test data by clinicians and to examine the acceptability of the nomogram technique to clinicians. Over 600 clinicians across the U.S. and Canada attending continuing education seminars were trained to use the nomogram. Participants estimated the probability that a youth in a clinical vignette had bipolar disorder, first using clinical judgment and then using the nomogram. Brief training of clinicians (less than 30 minutes) in using the nomogram for assessing PBD improved diagnostic accuracy, consistency, and agreement. The majority of clinicians endorsed using the nomogram in practice. EBA decision aids, such as the nomogram, may lead to a significant decrease in overdiagnosis and help clinicians detect true cases of PBD. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   

9.
Phase-sensitive impedance analysis in association with anthropometric parameters provides adequate body composition estimates in nephropathic subjects, with complex three-compartment modelling as a reference. Extracellular fluid shifts can be detected during ultrafiltration by phase sensitive impedance analyzers. Rough impedance parameters such as Reactance and Phase Angle have been normalized with large series of data collected from reference populations and a bioelectric nomogram, termed Biagram, is proposed to assess the normality between Extracellular and Intracellular spaces, without the need of anthropometric parameters such as Height and Weight.  相似文献   

10.
OBJECTIVE: To develop, implement and evaluate an effective and efficient heparin nomogram. DESIGN: Retrospective and prospective data collection. SETTING: Coronary care unit (CCU) of a university-affiliated hospital. PATIENTS: Patients with acute coronary ischemic syndromes requiring intravenous (i.v.) heparin who were not receiving thrombolytic and/or warfarin therapy. INTERVENTIONS: A retrospective chart review of 52 CCU patients receiving iv heparin provided the historical control group. The effectiveness of a heparin nomogram (5000 U bolus followed by an initial weight-based infusion of 15 U/kg/h with subsequent rate adjustments according to activated partial thromboplastin time [aPTT] results) was then prospectively assessed in a further 56 consecutive patients. MAIN RESULTS: The historical control and nomogram groups did not significantly differ with respect to age, weight, duration of therapy or total number of aPTTs drawn. Approximately 79% and 84% of patients in the control and nomogram groups, respectively, achieved an aPTT within the therapeutic range (60 to 90 s, P > 0.05), whereas 89% and 100% of control and nomogram patients, respectively, surpassed the therapeutic threshold (longer than 60 s) at some point during treatment (P = 0.009). Compared with empiric dose adjustment, the nomogram more effectively avoided periods of inadequate anticoagulation. Similarly, the time to achieve the therapeutic threshold was significantly longer in the control than in the nomogram group (8.2 +/- 5.9 versus 6.7 +/- 3.7 h, P = 0.026). No adverse bleeding events were noted in either group. CONCLUSIONS: Compared with conventional approaches, the heparin nomogram successfully achieved and maintained adequate anticoagulation in a greater proportion of patients with acute cardiovascular diseases without the need for additional aPTT measurements.  相似文献   

11.
PURPOSE: To evaluate a commercially available neural network program for calculation of photorefractive keratectomy treatment nomograms. SETTING: University referral refractive surgery clinic. METHODS: PRK/LASIK Brain, a commercial neural network computer program, was trained using the demographics, preoperative clinical data, surgical parameters, and 1 year postoperative clinical data of 44 patients treated with a Summit Technology excimer laser using a 5.0 mm optical zone. The neural-network derived nomogram was compared with the standard treatment nomogram for each patient. The relative contribution of age, sex, keratometry, and intraocular pressure (IOP) to the predicted nomograms was also assessed. RESULTS: Nomograms produced by the neural network were qualitatively similar to the standard nomogram. The sequence of data entry during training affected the network's predictions. Entry ordered by outcome (as opposed to entry by chronological order) yielded a nomogram that was more consistent with the standard nomogram. However, both outcome- and chronologically ordered network-derived nomograms diverged from the standard nomogram in individual patients, including a subset for whom use of the standard nomogram yielded desired refractive results (within 0.25 diopter of emmetropia). Further analysis of the neural-network-derived nomograms revealed marked sensitivity to sex, age, keratometry readings, and IOP. CONCLUSIONS: Neural networks offer a potential means of individualizing treatment nomograms, to account for patient demographics, preoperative examination, surgeon style, and equipment bias. However, a data set of 44 patients was not sufficient to train the PRK/LASIK Brain network to accurately predict treatment parameters in individual cases in the training set. A larger training set or a different learning algorithm may be required to improve the neural network's performance.  相似文献   

12.
Conclusions It has been shown that the specific power (per unit of electrode surface are), which is one of the important criteria, can be conveniently used in making an evaluation of cathode materials for use in thermionic converters.The emission parameters used in an analysis of TC characteristics must obey the fundamental laws of thermodynamics. Such data can be obtained by means of the total current method, or by the method in this paper. In the latter case the emission coefficients A are found to be identical functions of the temperature and to be limited upwards by the inequality (6).A comparative evaluation of cathode materials with respect to the specific TC power can be carried out by means of the nomogram given. Utilization of this nomogram permits an easy orientation with regard to the thermoemission data obtained in the search for new effective materials.  相似文献   

13.
Summary A technique is described for calculating the principal atomization-process parameters — gas velocity and temperature — enabling powder of the required particle size to be produced. The results obtained are presented in the form of a nomogram constructed on the basis of the following dimensionless numbers: Fedorov Number Fe, Reynolds Number Re, and blow-by coefficient k characterizing the conditions of heat exchange between gas and metal. The method of application of the nomogram is described.Translated from Poroshkovaya Metallurgiya, No. 4 (64), pp. 6–9, April, 1968.  相似文献   

14.
From simultaneously determined values of the glomerular filtration rate and the concentration of creatinine in plasma an individual nomogram can be constructed from two scales. From this nomogram the actual glomerular filtration rate of the patient can later be read out solely from a new concentration of plasma creatine.  相似文献   

15.
PURPOSE: To evaluate the effectiveness of limbal relaxing incisions (LRIs) for correcting corneal astigmatism during cataract surgery. SETTING: Cullen Eye Institute, Houston, Texas, USA. METHODS: In 12 eyes of 11 patients, cataract surgery was combined with LRIs. The LRIs were made according to a modified Gills nomogram and were based on preoperative corneal astigmatism determined with standard keratometry and computerized videokeratography (EyeSys Corneal Analysis System Version 3.2). RESULTS: The mean preoperative keratometric cylinder was 2.46 +/- 0.81 diopters (D). At 1 month postoperatively, mean arithmetic reduction in keratometric cylinder was 1.12 +/- 0.74 D, and the with-the-wound (WTW) change (calculated by Holladay, Cravy, Koch vector analysis formula) was -0.70 +/- 0.44. From 1 day to 1 month postoperatively, there was 0.55 D of WTW regression with minimal change in the mean cylindrical axis. There were no overcorrections. CONCLUSION: Limbal relaxing incisions are a practical, simple, and forgiving approach to the correction of astigmatism during cataract surgery.  相似文献   

16.
The urodynamic profiles of 97 patients with benign prostatic hyperplasia undergoing low-energy transurethral microwave thermotherapy (TUMT) for lower urinary tract symptoms were analysed using the Abrams/Griffiths nomogram, the urethral resistance algorithm, the linPURR, Sch?fer nomogram, and the CHESS classification. A significant clinical response was seen for the whole group, as shown by changes in symptom score, free flow rate, and residual urine. The best symptomatic response was identified in patients in whom obstruction was present, whatever the classification used. Only the two-dimensional CHESS classification was found to predict a group of patients with a better response in both symptoms and objective variables. Obviously, a better response from TUMT can only be predicted by a classification system that identifies the independent variables of footpoint and slope of the PURR. The CHESS classification was the only one of those studied that satisfactorily identified these two parameters and could be used as a system of case selection for this minimally invasive treatment.  相似文献   

17.
万飞  王勇勤  金敏 《中国冶金》2011,21(5):40-43
本文针对实际生产中使用的带钢立式连续退火炉,建立了预热段(JPF)带钢温度计算公式。根据冲击射流对流换热原理和预热段的喷孔阵列形式,采用生产实测数据,模拟推导出对流换热努塞尔数计算公式。按照这组公式编制成MATLAB软件,计算结果与52组生产数据相符。该组计算公式和方法,可为带钢连续退火炉工程项目设计与应用提供一定的计算依据。  相似文献   

18.
BACKGROUND: Few published studies have combined clinical prognostic factors into risk profiles that can be used to predict the likelihood of recurrence or metastatic progression in patients following treatment of prostate cancer. We developed a nomogram that allows prediction of disease recurrence through use of preoperative clinical factors for patients with clinically localized prostate cancer who are candidates for treatment with a radical prostatectomy. METHODS: By use of Cox proportional hazards regression analysis, we modeled the clinical data and disease follow-up for 983 men with clinically localized prostate cancer whom we intended to treat with a radical prostatectomy. Clinical data included pretreatment serum prostate-specific antigen levels, biopsy Gleason scores, and clinical stage. Treatment failure was recorded when there was clinical evidence of disease recurrence, a rising serum prostate-specific antigen level (two measurements of 0.4 ng/mL or greater and rising), or initiation of adjuvant therapy. Validation was performed on a separate sample of 168 men, also from our institution. RESULTS: Treatment failure (i.e., cancer recurrence) was noted in 196 of the 983 men, and the patients without failure had a median follow-up of 30 months (range, 1-146 months). The 5-year probability of freedom from failure for the cohort was 73% (95% confidence interval = 69%-76%). The predictions from the nomogram appeared accurate and discriminating, with a validation sample area under the receiver operating characteristic curve (i.e., comparison of the predicted probability with the actual outcome) of 0.79. CONCLUSIONS: A nomogram has been developed that can be used to predict the 5-year probability of treatment failure among men with clinically localized prostate cancer treated with radical prostatectomy.  相似文献   

19.
从能量平衡的角度出发,针对振动磨机的工艺特点,推导出振动磨机功率损耗的计算公式。并利用现场实测数据检验了理论公式的实用性,为振动磨的设计和使用提供了理论依据。  相似文献   

20.
Treatment of an acetaminophen overdose with N-acetyl cysteine usually is based on the position of the 4-h acetaminophen (APAP) level on the Rumack-Matthew nomogram; however, there is disagreement on the level at which clinically relevant hepatotoxicity occurs. A retrospective review of all acute adult formulation APAP exposures reported to our poison center between 1986 and 1993 was performed and cases corresponding to the "possible risk or toxicity" range on the nomogram were identified. Our current poison center protocol for APAP poisoning does not recommend treatment with N-acetylcysteine (NAC) in low-risk patients if the 4-h serum APAP level or the extrapolated equivalent falls within the possible toxicity range on the nomogram. Seventeen cases met the inclusion criteria for the study and received no NAC; six additional patients met inclusion criteria but received one or two doses of NAC before therapy was discontinued. No patients in either group demonstrated clinical evidence of hepatotoxicity. This pilot study suggests that patients with no risk factors and APAP levels in the "possible risk" range may not require NAC therapy.  相似文献   

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