Reproducibility and regional variations of an improved gagCEST protocol for the in vivo evaluation of knee cartilage at 7 T

Objective

The objective was to establish a gagCEST protocol that would enable robust and reproducible assessment of the glycosaminoglycan (GAG) content in knee cartilage at 7 T within a clinically feasible measurement time.

Materials and methods

Ten young healthy volunteers (mean age 26 years, range 24–28, five males, five females) were examined on a 7 T MR system. Informed consent was obtained from all individual participants prior to enrollment into the study. Each volunteer was measured twice for reproducibility assessment. The examined knee was immobilized using a custom-made fixation device. For the gagCEST measurement, a prototype segmented 3-D RF-spoiled gradient-echo sequence with an improved saturation scheme employing adiabatic pulses was used in a scan time of 19 min. The asymmetry of the Z-spectra (MTR_asym) in selected regions of interest in knee cartilage was calculated. Differences in MTR_asym between different regions were evaluated using ANOVA and the Bonferroni corrected post hoc test.

Results

The improvement of the saturation scheme reduced the influence of field inhomogeneities, resulted in more uniform saturation, and allowed for good reproducibility in a reasonable measurement time (19 min), as demonstrated by an intraclass correlation coefficient of 0.77. Improved fixation helped to reduce motion artifacts. Whereas similar MTR_asym values were found for weight-bearing and non-weight-bearing femoral cartilage, lower values were observed in the trochlear groove (p = 0.028), patellar (p = 0.015) and tibial cartilage (p < 0.001) when compared to non-weight-bearing femoral cartilage.

Conclusion

Reasonable reproducibility and sensitivity to regional differences in GAG content suggests that the improved gagCEST protocol might be useful for assessing the biochemical changes in articular cartilage that are associated with early stages of cartilage degeneration.

     

Orientational dependent sensitivities of T2 and T1ρ towards trypsin degradation and Gd-DTPA2? presence in bovine nasal cartilage

Objective

To study the orientational dependencies of T₂ and T_1ρ in native and trypsin-degraded bovine nasal cartilage, with and without the presence of 1?mM Gd-DTPA^2?.

Materials and methods

Sixteen specimens were prepared in two orthogonal fibril directions (parallel and perpendicular), treated using different protocols (native, Gd treated, trypsin-treated, and combination), and imaged using μMRI at 0° and 55° (the magic angle) fibril orientations with respect to the magnetic field B₀. Two-dimensional (2D) T₂ and T_1ρ images were then calculated quantitatively.

Results

Without Gd, native perpendicular tissues demonstrated significant T_1ρ dispersion (including T₂ at the zero spin-lock field) at 0° and less dispersion at 55°, while native parallel specimens exhibited smaller T_1ρ dispersion at both 0° and 55°. Trypsin degradation caused a minimum 50% increase in T_1ρ. With Gd, trypsin degradation caused significant reduction in T_1ρ values up to 60%.

Conclusion

The collagen orientation in nasal cartilage can influence T₂ and T_1ρ MRI of cartilage. Without Gd, T_1ρ was sensitive to the proteoglycan content and its sensitivity was nearly constant regardless of fibril orientation. In comparison, the T₂ sensitivity to proteoglycan was dependant upon fibril orientation, i.e., more sensitive at 55° than 0°. When Gd ions were present, both T₂ and T_1ρ became insensitive to the proteoglycan content.     

Development and Prospect of Installation Technology of Electrical and Mechanical Equipment in Hydropower Construction

The hydropower installed capacity in China exceeded 100GW by the end of 2004. With the development of hydropower construction cause, the contingents of eleetrical and mechanical installation also grew steadily.The installation and debugging techniques made great strides in aspects of different conventional hydrogenerator sets. reversible pumped-storage units and their rotor spiders, runners, bearings, penstocks as well as control equipment, such as computerized governors, intelligent monitoring devices. Major technical innovations were brought about in the electrical and mechanical installation. For an arduous task to construct hydropower projects of over 50 GW confronts hydropower installatinn enterprises at the beginning of 2 I st century, the installation technologies will certainly develop around the projects.     

A Brief Introduction to the Key National Disciplines of College of Electrical and Electronic Engineering of Huazhong University of Science and Technology

The electrical engineering discipline of HUST is amongthe first batch of disciplines approved by the Academic DegreeEvaluating Committee of the State Council of China as entitledto confer the mastership and the doctorate (1981), the firstbatch of postdoctoral programs (1985), and the first batch ofdisciplines entitled to award the doctorate in top level discipline(1996). The electrical machinery and electrical apparatus discipline,and the power system and its automation discipline were elected asthe key national disciplines January 2002. Also, the electrical amchinery discipline is one of the original two key nationaldisciplines, and its Electrical Machinery State SpecializedLaboratory is the only state key laboratory in this field.     

Practice and Development of Environmental Impact Assessment

Environmentalimpactassessment(EIA)ofthermalpowerprojecthasbeencarriedoutfor20yearssinceEIAsystemwassetupin1979inChina.Inthebeginning,theairenvironmentalimpactwastakenastheprincipalitemofEIA.Now,ithasinvolvedtoassesscomprehensivelytheair,water,noise,solidwastematter(ashandslag)environmentalimpactriskanalysis,pollutantsemissionquantitycontrolcleanproduction,waterandsoilpreservation,environmentalmanagementandmonitoringplanpublicparticipationetc.Somenewassessmentfieldsuchastransmissionandsubst…     

Construction and commissioning news of key projects

Ｃｏｎｓｔｒｕｃｔｉｏｎａｎｄｃｏｍｍｉｓｓｉｏｎｉｎｇｎｅｗｓｏｆｋｅｙｐｒｏｊｅｃｔｓ１．Ｃｈｉｎａ＇ｓｓｅｃｏｎｄｌａｒｇｅｓｔｈｙｄｒｏｐｏｗｅｒｐｒｏｊｅｃｔ,ＥｒｔａｎＨｙｄｒｏｐｏｗｅｒＳｔａｔｉｏｎｉｎＳｉｃｈｕａｎＰｒｏｖｉｎｃｅ,...     

Informatization of Power Plant and Its Implementation

This paper presents the working procedure of power generating enterprises and explains the framework of an e-power-plant and its information system, puts forward the guideline and the general goal of informatization construction while focusing on the construction goal in the applied system, the implementing strategy, the project management and organization.     

Reform and Development of China''''s Power Industry

Mr.Chairman,LadiesandGentlemen:ItismygreatpleasuretobeinvitedtoparticipateintheChinaPowerForum's97jointlysponsoredbyChinaElectricityCouncil,PanwellConferences&ExhibitionsandSingaporePublishingGroup.OnbehalfoftheMinistryofElectricPowerofChina,Iampleasedtohavethisopportunitytodiscussthereformanddevelopmentofpowerindustrywithnewfriendsandoldacquaintancesfromtheelectricitycommunityworldwide.IwouldliketobriefyouhereonStatePowerCorporationofChinaandthepolicyonutilizationofforeigncapitalinC…     

Achievements and Prospects of China's Hydropower Generation

<正>Outstanding achievements The scale of hydropower development continuously expanding to a new level As a type of clean and renewable energy     

Practical application of the benchmarking technique to increase reliability and efficiency of power installations and main heat-mechaniс equipment of thermal power plants

Data on the comparative analysis variants of the quality of power installations (benchmarking) applied in the power industry is systematized. It is shown that the most efficient variant of implementation of the benchmarking technique is the analysis of statistical distributions of the indicators in the composed homogenous group of the uniform power installations. The benchmarking technique aimed at revealing the available reserves on improvement of the reliability and heat efficiency indicators of the power installations of the thermal power plants is developed in the furtherance of this approach. The technique provides a possibility of reliable comparison of the quality of the power installations in their homogenous group limited by the number and adoption of the adequate decision on improving some or other technical characteristics of this power installation. The technique provides structuring of the list of the comparison indicators and internal factors affecting them represented according to the requirements of the sectoral standards and taking into account the price formation characteristics in the Russian power industry. The mentioned structuring ensures traceability of the reasons of deviation of the internal influencing factors from the specified values. The starting point for further detail analysis of the delay of the certain power installation indicators from the best practice expressed in the specific money equivalent is positioning of this power installation on distribution of the key indicator being a convolution of the comparison indicators. The distribution of the key indicator is simulated by the Monte-Carlo method after receiving the actual distributions of the comparison indicators: specific lost profit due to the short supply of electric energy and short delivery of power, specific cost of losses due to the nonoptimal expenditures for repairs, and specific cost of excess fuel equivalent consumption. The quality loss indicators are developed facilitating the analysis of the benchmarking results permitting to represent the quality loss of this power installation in the form of the difference between the actual value of the key indicator or comparison indicator and the best quartile of the existing distribution. The uncertainty of the obtained values of the quality loss indicators was evaluated by transforming the standard uncertainties of the input values into the expanded uncertainties of the output values with the confidence level of 95%. The efficiency of the technique is demonstrated in terms of benchmarking of the main thermal and mechanical equipment of the extraction power-generating units T-250 and power installations of the thermal power plants with the main steam pressure 130 atm.     

An investigation of performance limits of conventional and tunneling graphene-based transistors

In this paper we perform a simulation study on the limits of graphene-nanoribbon field-effect transistors (GNR-FETs) for post-CMOS digital applications. Both conventional and tunneling FET architectures are considered. Simulations of conventional narrow GNR-FETs confirm the high potential of these devices, but highlight at the same time OFF-state leakage problems due to various tunneling mechanisms, which become more severe as the width is made larger and require a careful device optimization. Such OFF-state problems are partially solved by the tunneling FETs, which allow subthreshold slopes better than 60 mV/dec, at the price of a reduced ON-current. The importance of a very good control on edge roughness is highlighted by means of a direct simulation of devices with non-ideal edges.     

Current Situation and Development of Cogeneration in China

1. The Power Industry and Cogeneration in China 1.1 The Power Industry in China The power industry has developed rapidly in China in recent decades. In 1994, total electricity generation was 927.8 TWh and the total installed capacity was 199.80 GW. It is broken down as follows: hydropower 49.0 GW. 24.5 %; thermal power 148.73 GW, 74.4c/c: and nuclear power 2.1 GW, 0.7%.     

The Intranet of NARI and Its Application Development

1.IntroductionWiththecobingofinformahontechnologyera,itbecomesanimportantcriterionofevaluatingacountry,abranchandacorPOrahontodevelopandamplementinformahontechniques.NARIgrouP,asatoppingcolorationofscienhficresearchandequipmentmanufactUreofelectricPOwersysteminChina,keepsaheadalltheWhileintheprocesstowardsinformahonnetWorkthroughtheactiVedevelopmentandresearchofcomputernetWorkanditsaPPlicahontechniques.Fromthelaterhalfof1996,thetechniciansofNAKIwereorganizedtobuildtheNARIIntranetandd…     

Past, present and future of fuel cells

Ｉｎ 18 3 9,Ｇｒｏｖｅ[1] ｐｕｂｌｉｓｈｅｄｈｉｓｓｔｕｄｉｅｓｏｎｔｈｅｇｅｎｅｒａｔｉｏｎｏｆｅｌｅｃｔｒｉｃｉｔｙｂｙｃｏｎｎｅｃｔｉｎｇｔｗｏｐａｒｔｉａｌｌｙｉｍｍｅｒｓｅｄｐｌａｔｉｎｕｍｆｏｉｌｓｉｎｓｕｌｐｈｕｒｉｃａｃｉｄａｎｄｆｅｅｄｉｎｇｈｙｄｒｏｇｅｎａｎｄｏｘｙｇｅｎｓｅｐａｒａｔｅｌｙｔｏｔｈｅｅｌｅｃｔｒｏｄｅｓ .Ｔｈｅｂａｓｉｃｅｌｅｃｔｒｏｃｈｅｍｉｃａｌｒｅａｃｔｉｏｎｗａｓｓｉｍｐｌｅ :Ａｎｏｄｉｃｒｅａｃｔｉｏｎ :Ｈ2 2Ｈ+ + 2ｅ-Ｃａｔｈｏｄｉｃｒｅａｃｔ…     

Development and Prospect of China''''s Electric Power Industry

Since the founding of new China, especially sinceimplementing the reform and open policy, China'selectric power industry has witnessed rapid growth, withgigantic achievement of world interest gained. Electric powerinstalled generating capacity grew from 1850MW just afterliberation to l00 GW in 1987. At the end of 1999, the installedgenerating capacity had reached more than 290 GW,approaching 300 GW, increasing by 160 times, with an annualaverage growth of about 11%. In the meantime, yearly…     

Language and Stylistic Analysis of International Sales Contracts

With international trade activities getting more and more frequent, preparing contracts in the language of English has become a common practice for businessmen. Although they may employ preprinted form of contracts, it is inevitable that new clauses should be produced to satisfy the demands of specific transactions. This essay makes a language and stylistic analysis on the international sales contract and illustrates the detailed principles and requirements for the production of such contracts.     

Energy and water saving of thermal power plant

The average coal consumption of thermal power plants inShandong Provincial Grid was reduced from 449 g(standardcoal)/kWh in 1979 to 389 g(standard coal)/kWh in 1989,as inrecent ten years,the thermal power plants of Shandong Provinceadopted the method of constructing large scale generating units andimproving the economic performance of old generation units,mean-while the other technical and economical targets also were improvedsignificantly.For instance,the electric energy consumption rate of     

Status and Functions of Regional Power Grid Corporations

In line with power institutional reform and formation of the state power grid, status and roles of regional power grid corporations experienced several variations and are now being incessantly marginalized and weakened. The reform of turning regional grid corporations into regional headquarters of State Grid Corporation may be a better choice beneficial to group operation, intensive development and precise management. This article can be regarded as the author＇s personal opinion.     

I Ching and Two of Its English Versions

I Ching, the essence of Chinese culture, has a history of three thousand years. It embodies a kind of philosophy, wisdom, even a kind of science, and greatly influences Chinese civilization. However, for its special style and abstract content, I Ching＇s meaning is far to reach, especially for foreigners. This paper is going to compare two well-known English editions t~om the aspects of comprehension, wording and expression. The author attempts to primarily probe into the practice and skills of the translation of I Ching.