首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   11篇
  免费   0篇
教育   4篇
科学研究   7篇
  2024年   1篇
  2021年   1篇
  2015年   3篇
  2013年   3篇
  2012年   1篇
  2007年   1篇
  2005年   1篇
排序方式: 共有11条查询结果,搜索用时 15 毫秒
1.
Since it was first recognized in bacteria and archaea as a mechanism for innate viral immunity in the early 2010 s,clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein(Cas) has rapidly been developed into a robust, multifunctional genome editing tool with many uses. Following the discovery of the initial CRISPR/Cas-based system, the technology has been advanced to facilitate a multitude of different functions. These include development as a base editor, prime editor, epigenetic editor, and CRISPR interference(CRISPRi) and CRISPR activator(CRISPRa) gene regulators. It can also be used for chromatin and RNA targeting and imaging. Its applications have proved revolutionary across numerous biological fields, especially in biomedical and agricultural improvement. As a diagnostic tool, CRISPR has been developed to aid the detection and screening of both human and plant diseases, and has even been applied during the current coronavirus disease 2019(COVID-19) pandemic. CRISPR/Cas is also being trialed as a new form of gene therapy for treating various human diseases, including cancers, and has aided drug development. In terms of agricultural breeding, precise targeting of biological pathways via CRISPR/Cas has been key to regulating molecular biosynthesis and allowing modification of proteins, starch, oil, and other functional components for crop improvement. Adding to this, CRISPR/Cas has been shown capable of significantly enhancing both plant tolerance to environmental stresses and overall crop yield via the targeting of various agronomically important gene regulators. Looking to the future, increasing the efficiency and precision of CRISPR/Cas delivery systems and limiting off-target activity are two major challenges for wider application of the technology. This review provides an in-depth overview of current CRISPR development, including the advantages and disadvantages of the technology,recent applications, and future considerations.  相似文献   
2.

Introduction:

Today, the pneumatic tube transport system (PTS) is used frequently because of its advantages related to timing and speed. However, the impact of various types of PTS on blood components is unknown. The aim of this study was to examine the influence of PTS on the quality of routine blood cell counts, erythrocyte sedimentation, and certain blood coagulation tests.

Materials and methods:

Paired blood samples were obtained from each of 45 human volunteers and evaluated by blood cell count, erythrocyte sedimentation, and several coagulation tests, including prothrombin time (PT) and activated partial thromboplastin time (aPTT). Blood samples were divided into 2 groups: Samples from group 1 were transported to the laboratory via the PTS, and samples from group 2 were transported to the laboratory manually. Both groups were evaluated immediately by the tests listed above.

Results:

The blood sample test results from groups 1 and 2 were evaluated and compared. No statistically significant differences were observed (P = 0.069–0.977).

Conclusion:

The PTS yielded no observable effects on blood cell counts, erythrocyte sedimentation, or PT and aPTT test results. We concluded that the PTS can be used to transport blood samples and yield reliable results for blood cell counts, erythrocyte sedimentation, and several coagulation tests.  相似文献   
3.
In this study, we consider the potential of multimedia cases as tools for teacher professional development. Specifically, we examined online and face-to-face discussions that occurred within groups composed of pre-service mathematics teachers, in-service mathematics teachers, mathematicians, and mathematics teacher educators. Discussions within these heterogeneous groups tended to focus on issues of classroom implementation of the tasks shown in the multimedia case. Secondary foci of discussion included task characteristics and appropriateness of tasks for engaging students in thinking about mathematical concepts and processes. Analysis of contributions to discussions across group member type revealed differences that suggest that the variety of backgrounds and experiences of group members can blend in ways that support rich and critical discussions of mathematics, teaching, and learning.  相似文献   
4.

Introduction

Glycosylated hemoglobin (HbA1c) concentrations measured in clinical chemistry laboratories show large differences between their interlaboratory reported values. Laboratory measurements of quality performance should be based on quantitative data. The sigma metrics model provides an objective method for the assessment of current HbA1c assays and is useful in quality management planning. The aim of our study was to evaluate the analytical performance of the MQ-2000 PT HbA1c analyzer test results in the context of our operating conditions on the sigma scale.

Materials and methods

The coefficient of variation was determined from the calculated mean and standard deviation evaluated from internal quality control (QC) (N = 168 days) (Shanghai Huachen Biological Reagent Co. Ltd, China) data, and records of external quality data (KBUDEK, İstanbul, Turkey) measured in the period from May to November 2013 were used to determine the bias. The resulting data and total allowable error rate (TEA = 10%) from the Clinical Laboratory Improvement Amendments of 1988 (CLIA’88) were used to calculate the sigma level.

Results

The calculated coefficient of variations (CVs) at the two levels, normal (QC1 = 36.6 ± 2.38 mmol/mol) and pathological (QC2 = 84.7 ± 2.68 mmol/mol), were 6.5% and 3.1%, respectively. The average bias between the external QC and MQ-2000 PT during the study period was 4.3%. The calculated average sigma value was 1.19.

Conclusions

The MQ-2000 PT HbA1c is a new analyser in the market; there is need for improvement and the method should be controlled with greater attention to ensure quality.Key words: diabetes mellitus, hemoglobin A1c protein, human, chromatography, high pressure liquid chromatography  相似文献   
5.

Background

In heart failure patients, mean platelet volume (MPV) may reflect increased platelet activation or increased numbers of large, hyper-aggregable platelets. B-type natriuretic peptide (BNP) concentration in blood is a sensitive and specific marker of heart failure, correlating with the severity and prognosis of illness, in patients presenting with acute dyspnea to the emergency department. This study evaluated the correlation between BNP concentration and MPV.

Material and methods

Data were collected from 319 patients admitted to the emergency department of a cardiology hospital from January–July 2014. EDTA blood samples drawn at admission were analyzed using automated hematology system, and BNP concentration was measured using a fluorescence immunoassay.

Results

The study included 190 patients with and 129 without acute heart failure (AHF). These groups had BNP concentration of 200-5000 ng/L and 5-98 ng/L, respectively. MPV levels were significantly higher in the AHF group (P < 0.001). BNP concentrations were positively correlated with MPV (r = 0.41, P < 0.001) and neutrophil / lymphocyte ratio (r = 0.38, P < 0.001).

Conclusion

Increased MPV values correlate with BNP concentration, an indicator of HF severity and clinical status, in patients with AHF admitted to the emergency department.Key words: natriuretic peptide, brain; heart failure; platelet; mean platelet volume  相似文献   
6.

Introduction

The aim of the present study was to validate prothrombin time (PT) international normalized ratio (INR) results obtained using Steelex test reagents and a Steelex coagulometer (Steelex Scientific Instrument Company, Beijing, China), in comparison with use of a well-established standard test employing Pacific Hemostasis reagents (Fisher Diagnostics, Middletown, VA, USA) and Teco Coatron A4 coagulometer (Teco Medical Instruments GmbH, Neufahrn, Germany).

Materials and methods:

Between- and within-day coefficients of variation (CVs) of both assays were calculated using control samples provided by the test manufacturers. Samples from 90 subjects were collected and INR values were determined in a double-blind parallel manner employing both systems.

Results:

The within-day coefficients of variation (CVs) in INR estimates ranged from 2.6% (INR = 1.12) to 3.1% (INR = 2.51) for the Steelex system and from 2.1% (INR = 1.09) to 1.8% (INR = 2.8) for the Pacific test; the between-day values ran from 3.4% (INR = 1.16) to 7.9% (INR = 2.64) and from 3.3% (INR = 1.1) to 2.3% (INR = 2.7), respectively. Passing-Bablok fit of the of the Steelex and Pacific methods yielded the equation: Steelex INR = 0.85 (0.79–0.91) × Pacific INR + 0.12 (−0.02–0.21), whereas the CUSUM linearity P value was < 0.01. The mean bias as determined by the Bland-Altman test was −0.156 (−0.912–0.600).

Conclusion:

The results obtained using Steelex reagents and the M600H coagulometer are not equivalent to those obtained using Pacific Hemostasis reagents and a Teco Coatron A4 coagulometer, at least in the therapeutic range.  相似文献   
7.
The purpose of this study is to introduce and evaluate a method for generating reading comprehension items using template-based automatic item generation. To begin, we describe a new model for generating reading comprehension items called the text analysis cognitive model assessing inferential skills across different reading passages. Next, the text analysis cognitive model is used to generate reading comprehension items where examinees are required to read a passage and identify the irrelevant sentence. The sentences for the generated passages were created using OpenAI GPT-3.5. Finally, the quality of the generated items was evaluated. The generated items were reviewed by three subject-matter experts. The generated items were also administered to a sample of 1,607 Grade-8 students. The correct options for the generated items produced a similar level of difficulty and yielded strong discrimination power while the incorrect options served as effective distractors. Implications of augmented intelligence for item development are discussed.  相似文献   
8.
The teachers of living languages play an intercultural role. In order to perform their task fully, it is necessary that their process of instruction be planned in the light of the pedagogical sciences. These sciences suggest the concept of a curriculum which contains interdependent elements. Therefore, a programme aimed at training teachers of foreign languages should not be regarded as a simple instrument and should not be reduced to a list of subject matter to be taught. It must be designed in such a way as to satisfy the professional needs of teachers of foreign languages in the future. Thus, one must replace the concept of a programme by that of a curriculum comprising a systematic construction.

Les enseignants de langues vivantes jouent un rôle interculturel. Pour qu'ils remplissent pleinement leur tâche, il faut planifier leur formation sous la lumière des sciences pédagogiques. Elles nous suggèrent le concept de curriculum qui contient certains éléments interdépendants. De ce fait, un programme tendant à former les enseignants des langues vivantes ne doit pas être considéré comme un instrument si simple et réduit en une liste de matière à enseigner. Il doit être conçue de manière à satisfaire les besoins professionnels et éducatifs des futurs enseignants des langues vivantes.

Die Fremdsprachenlehrer spielen in der Schulpraxis eine interculturelle rolle. Daher muß die Lehrerausbildung unter Berücksichtigung der Erziehungswissenschaften dermaßen geplant sein, dass die Fremdsprachenlehrer dieser Aufgabe nachkommen können. Nach Erkenntnissen der Erziehungswissenschaften ist die Entwicklung eines Studienplans, der aus in einem Zusammenhang stehenden Komponenten besteht, unerlablässlich. Aus diesem Grund darf der Studienplan nicht als ein einfaches Medium und als eine bloße Themenlist betrachtet werden. Der Studienplan ist dermaßen zu entwerfen, dass er den beruflichen Bedürfnissen der Fremdsprachenlehrer entspricht.

Los profesores de idiomas extranjeros juegan un rol intercultural. Para llevar a cabo esta tarea completamente, su educación debe ser planificada bajo la luz de las ciencias pedagógicas. Las Ciencias Pedagógicas nos sugieren el concepto de programa educacional que contiene elementos interdependientes. Por esta razón, un programa guiado a educar a los profesores de idiomas extranjeros no puede considerarse como un simple instrumento y no puede ser reducido a una lista de materias a enseñar. Entonces el programa debe ser diseñado para satisfacer las necesidades profesionales y educativas de los profesores de idiomas extranjeros.  相似文献   

9.

Introduction

Measurements of blood ethanol concentrations must be accurate and reliable. The most important factors affecting blood ethanol stability are temperature and storage time. In this study, we aimed to compare ethanol stability in plasma samples at -20 °C for the different storage periods.

Materials and methods

Blood samples were collected from intoxicated drivers (N = 80) and initial plasma ethanol concentrations were measured immediately. Plasma samples were then stored at -20 °C and re-assessed after 2, 3, 4, or 5 months of storage. Differences between the initial and stored ethanol concentrations in each group (N = 20) were analyzed using Wilcoxon matched-pairs test. The deviation from the initial concentration was calculated and compared with Clinical Laboratory Improvement Amendments (CLIA’88) Proficiency Testing Limits. Relationships between the initial concentrations and deviations from initial concentrations were analyzed by Spearman’s correlation analysis. For all statistical tests, differences with P values of less than 0.05 were considered statistically significant.

Results

Statistically significant differences were observed between the initial and poststorage ethanol concentrations in the overall sample group (P < 0.001). However, for the individual storage duration groups, analytically significant decreases were observed only for samples stored for 5 months, deviations from the initial concentrations exceeded the allowable total error (TEa). Ethanol decreases in the other groups did not exceed the TEa.

Conclusion

According to our results, plasma ethanol samples can be kept at -20 °C for up to 3-4 months until re-analysis. However, each laboratory should also establish its own work-flow rules and criterion for reliable ethanol measurement in forensic cases.Key words: preanalytical phase, ethanol, stability, storage temperature  相似文献   
10.

Introduction

Urinary tract infection (UTI) is one of the most common types of infection. Currently, diagnosis is primarily based on microbiologic culture, which is time- and labor-consuming. The aim of this study was to assess the diagnostic accuracy of urinalysis results from UriSed (77 Electronica, Budapest, Hungary), an automated microscopic image-based sediment analyzer, in predicting positive urine cultures.

Materials and methods:

We examined a total of 384 urine specimens from hospitalized patients and outpatients attending our hospital on the same day for urinalysis, dipstick tests and semi-quantitative urine culture. The urinalysis results were compared with those of conventional semi-quantitative urine culture.

Results:

Of 384 urinary specimens, 68 were positive for bacteriuria by culture, and were thus considered true positives. Comparison of these results with those obtained from the UriSed analyzer indicated that the analyzer had a specificity of 91.1%, a sensitivity of 47.0%, a positive predictive value (PPV) of 53.3% (95% confidence interval (CI) = 40.8–65.3), and a negative predictive value (NPV) of 88.8% (95% Cl = 85.0–91.8%). The accuracy was 83.3% when the urine leukocyte parameter was used, 76.8% when bacteriuria analysis of urinary sediment was used, and 85.1% when the bacteriuria and leukocyturia parameters were combined. The presence of nitrite was the best indicator of culture positivity (99.3% specificity) but had a negative likelihood ratio of 0.7, indicating that it was not a reliable clinical test.

Conclusions:

Although the specificity of the UriSed analyzer was within acceptable limits, the sensitivity value was low. Thus, UriSed urinalysis results do not accurately predict the outcome of culture.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号