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1.
PURPOSE: Dynamic natural-abundance 13C MR spectroscopy (MRS) studies without proton decoupling were performed in the human liver using commercial 1.5 T MR equipment. MATERIAL AND METHODS: A single tuned custom-made circular surface coil with an OD of 20 cm operating at 16.04 MHz was used for the 13C study. Seventy-five grams of glucose dissolved in water was administered for the natural-abundance 13C-MRS dynamic study which lasted for approximately 40 to 60 min. Data acquisition was broken into 20-min and 1.7-min blocks. Localized proton shimming with a whole-body coil was performed with sufficient volume to include the observing area of the surface coil; the line width of the water signal was less than 20 Hz. RESULTS AND CONCLUSION: The glucose and glycogen spectra were clearly visible at 80 to 120 ppm after oral administration of the glucose solution. These data demonstrate that dynamic hepatic carbohydrate metabolism can be observed with commercially available MR equipment. Given that the human hepatic glycogen pool reaches maximum level within less than 10 min, this technique should provide a direct diagnosis of hepatic carbohydrate metabolic disorders.  相似文献   

2.
In general, one cannot use algebraic or enumerative methods to optimize a quality-control (QC) procedure for detecting the total allowable analytical error with a stated probability with the minimum probability for false rejection. Genetic algorithms (GAs) offer an alternative, as they do not require knowledge of the objective function to be optimized and can search through large parameter spaces quickly. To explore the application of GAs in statistical QC, I developed two interactive computer programs based on the deterministic crowding genetic algorithm. Given an analytical process, the program "Optimize" optimizes a user-defined QC procedure, whereas the program "Design" designs a novel optimized QC procedure. The programs search through the parameter space and find the optimal or near-optimal solution. The possible solutions of the optimization problem are evaluated with computer simulation.  相似文献   

3.
A problem became apparent while analyzing intensive conversation between very "competent" elderly that a) were eye-witnesses of National Socialism in Germany as well as of wartime including the bombardment of larger cities, and b) volunteered to participate in the project as such witnesses. This problem seems worthy of being scrutinized in a sophisticated and systematic fashion: It is methodologically difficult to assess divergent--or even contradictory--information pertaining to the specific subjective foundations of an individual's competence and there are problems with integrating this information to a plausible and tenable statement about their action orientations. This holds especially for the assumptions related to the concept of "locus of control," since this concept could prove itself relevant in regard to a differential intervention strategy as well as for basic research on aging, in which the concept's potential for explaining aspects of the aging process remains to be further clarified. Finally, a possible solution to this assessment problem is presented.  相似文献   

4.
The beta recombinase encoded by the streptococcal plasmid pSM19035, which shows 28 to 34% identity with DNA resolvases and DNA invertases, can catalyze formation of deletions or inversions between properly oriented target sites. We have constructed a number of site-directed mutations at residues that are conserved between the beta protein and other DNA recombinases of the resolvase/invertase family. The analysis of the recombination and DNA-binding ability of each mutant protein shows that the mutations affect the catalytic activity and, in two cases, the dimerization of the protein. The results suggest that the beta protein probably mediates recombination by a catalytic mechanism similar to that proposed for the resolvase/invertase family. Since the beta recombinase differs from DNA resolvases and DNA invertases in its lack of bias towards either of these reactions, the results presented support the hypothesis that its unique properties might depend on details of the architecture or assembly of the recombination complex. In addition, two beta protein mutants that can no longer form dimers in solution have provided new insights into the way the protein binds to DNA.  相似文献   

5.
American College of Surgeons triage guidelines recommend rapid identification and transfer of seriously injured patients to regional trauma centers, bypassing local hospitals if necessary. This approach raises concerns about the potential negative financial impact of implementing such triage strategies on already strained rural hospitals. OBJECTIVE: The purpose of this study was to determine the association between injury severity and reimbursement for trauma care in rural hospitals. It was our hypothesis that the seriously injured would be high cost and relatively low reimbursement patients, and thus be a significant financial liability to the rural hospital. This would imply that concerns by the rural hospital about triage of such patients to trauma centers would be unfounded. METHODS: Data on every injured patient seen in the emergency department during two 3-month periods were obtained from three rural hospitals in the state using the American College of Surgeons Trauma Registry data base. RESULTS: One thousand six hundred thirty patients had complete data available for analysis. The analyses demonstrated that as the injury severity increased, there was an increase in hospital charges, length of stay, and risk of dying. In contrast, the reimbursement changed little as the charges and severity increased. Thus, hospital losses increased in an exponential fashion as injury severity increased above 15. CONCLUSION: The study demonstrates that as injury severity increases, costs and charges increase, but reimbursement does not keep pace with these increased charges. The rural hospital was projected to lose an average of $25,000 for each patient with an Injury Severity Score over 15. This study supports the rapid triage and transport of the seriously injured patient from the rural hospital to the regional trauma center both for improved patient outcome and for the hospital's best interest. The potential impact of such a system on the trauma center also needs to be addressed.  相似文献   

6.
OBJECTIVES: We sought to determine whether a natural disaster affected total cardiovascular mortality and coronary mortality in an entire population. BACKGROUND: The effect of the January 17, 1994 Northridge Earthquake (NEQ) on all deaths and causes of deaths within the entire population of Los Angeles County is unknown. The purposes of our study were to analyze all deaths in this entire population before, during and after the NEQ and to determine whether the NEQ temporally and spatially altered death due to cardiovascular disease. METHODS: We analyzed all death certificate data (n = 19,617) from Los Angeles County during January of 1992, 1993 (control periods) and 1994, using International Classification of Diseases, 9th Revision codes for ischemic heart disease (IHD) and atherosclerotic cardiovascular disease (ASCVD), as well as other causes of death. RESULTS: There was an average of 73 deaths per day due to IHD and ASCVD during January 1 to 16, 1994; this increased to 125 on the day of the NEQ, and then decreased to 57 deaths per day from January 18 to 31 (p < 0.00001, before NEQ vs. day of NEQ; after NEQ vs. day of NEQ; and before NEQ vs. after NEQ). The NEQ was associated with an increase in deaths due to myocardial infarction and trauma but not cardiomyopathy, hypertensive heart disease, valvular heart disease, cerebrovascular disease or noncardiovascular causes. Based on plots of daily deaths due to IHD and ASCVD, the decrease in deaths during the 14 days after the NEQ (-144) overcompensated for the increase on the day of the NEQ (+55). Geographic analysis revealed a redistribution of deaths due to IHD and ASCVD toward the epicenter on the day of the NEQ. CONCLUSIONS: When an entire population simultaneously experiences a major environmental stress, there is an increase in death due to coronary artery disease (but not other cardiac causes), followed by a decrease that overcompensates for the excess of death. The overcompensation may represent a residual population that is more resistant to stress or a possible preconditioning effect of the stress, or both. This study supports the concept that cardiovascular events within an entire population can be triggered by a shared stress.  相似文献   

7.
This paper describes the development of the protocol for the International Programme on Chemical Safety (IPCS)-sponsored Collaborative Study on Neurobehavioral Screening Methods, including background on the methods and chemicals selected, as well as details concerning the conduct of the collaborative study, including proficiency testing, range-finding and main study. Participating laboratories in the collaborative study received training in the conduct and scoring of the behavioral tests and each laboratory received a video training film to train additional personnel as needed. Each of the eight laboratories that chose to participate in the study completed proficiency testing and assessed seven representative chemicals using a functional observational battery and automated motor activity assessment. The seven chemicals studied were acrylamide, bis-acrylamide, p,p'-DDT, lead acetate, parathion, toluene, and triethyl tin. Participants received coded samples of the chemicals from a common source. Each laboratory derived doses for single and repeated administration based on the determination of a within-laboratory acute "top dose." Animal strains were not standardized and laboratory conditions were standardized to a limited degree in order to judge the general utility and robustness of these procedures in a diversity of testing situations.  相似文献   

8.
OBJECTIVES: 1. To design a device that would reduce contamination of staff during obstetric procedures. 2. To undertake clinical trials to assess the effectiveness and acceptability of such a device. DESIGN: A prospective study. The arm sleeve is made of a nonwoven material laminated on polyethylene film making it waterproof. It has an elastomeric cuff with adhesive that ensures a watertight seal between it and the glove. SETTING: Delivery suite in a teaching hospital. METHODS: Doctors and midwives were requested to wear the sleeve on top of the standard gown and gloves. Each user was assessed for blood contamination at the end of the procedure and a questionnaire detailing the extent of contamination and the views of the user was completed. RESULTS: Eighty questionnaires were completed. The contamination of arms and hands was 3.8% and 5%, respectively. Eighty-nine percent thought the sleeve had served its purpose and 76% said they would use it regularly. CONCLUSIONS: The sleeve is an effective protective device which complements the glove and gown. We recommend that it should be used during all obstetric procedures.  相似文献   

9.
In mid-January 1993, an outbreak of Escherichia coli O157:H7 infections associated with eating hamburger patties at a fast-food restaurant chain (chain A) was reported in Washington State. From mid-December to mid-January, 9 cases of E coli O157:H7-associated bloody diarrhea and the hemolytic-uremic syndrome had been reported in San Diego County, California. A total of 34 persons had bloody diarrhea, the hemolytic-uremic syndrome, or E coli O157:H7 organisms isolated from stool during the period November 15, 1992, through January 31, 1993. Organisms of E coli O157:H7 identified from 6 persons were indistinguishable from those of the Washington outbreak strain. Illness was associated with eating at chain A restaurants in San Diego (odds ratio, 13; 95% confidence interval, 1.7, 99) and with eating regular-sized hamburgers (odds ratio, undefined; lower-limit 95% confidence interval, 1.3). Improved surveillance by mandating laboratory- and physician-based reporting of cases of E coli O157:H7 infection and the hemolytic-uremic syndrome might have alerted health officials to this outbreak sooner, which could have resulted in earlier investigation and the institution of measures to prevent more cases.  相似文献   

10.
11.
曹金荣 《黄金》1996,17(1):18-21
本文对黄金矿山总图设计中要充分利用地形自然坡度,减少土石方工程量,减少生产期间的经营费,使矿山达到最佳经济效益进行了探讨。  相似文献   

12.
Contrasted completed suicides in a state hospital with natural deaths and inpatients. No significant differences were found among the groups on patterns of admission complaints. For all 3 groups (Ns = 27, 173, 109), depression was found to be the most frequent admission complaint. Neither MMPI profiles nor a recently developed suicide threat scale served to discriminate suicides from the comparison groups. Highly significant differences were found on social competence variables, with suicides tending to be younger, more intelligent, and better educated than comparison groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

13.
The design and conduct of a 9-month multi-center clinical trial to evaluate the safety and efficacy of subgingivally delivered 5% sanguinarium chloride (SC) and 10% doxycycline hyclate (DH) from a biodegradable drug delivery system in the treatment of adult periodontitis is described. The 3-group randomized study of 180 adults with moderate to severe periodontitis was a modified double-blind parallel design. One group received DH, one group received SC, and the other group received the vehicle control (VC). Patients selected had two quadrants with a minimum of four periodontal pockets > or = 5 mm in depth with two sites > or = 7 mm. All qualifying sites exhibited bleeding on gentle probing. Qualifying sites were treated at baseline and again at 4 months. Clinical response was assessed by measuring attachment level, probing depth, and bleeding on probing at monthly examinations at qualifying sites and the entire dentition. The plaque index was measured monthly to verify oral hygiene status. The parallel design afforded the opportunity to distinguish between treatment effectiveness of SC, DH, and VC independent of possible crossover effects. Also the effectiveness of oral hygiene in untreated sites of the mouth could be evaluated. Finally, treatment effects in moderate (5 to 6 mm) and deep (> or = 7 mm) pockets in both treated and untreated sites could be compared. The design was capable of simulating a periodontal practice maintenance program and assessing the response according to maintenance and treatment history. Study management procedures that emphasized center examiner and therapist training and adherence to protocol and procedures to reduce variability are described.  相似文献   

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