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The viscosity of crude oil plays a pivotal role in the exploration and development of oil fields. The predominant reliance on laboratory measurements, which are constrained by manual expertise, represents a significant limitation in terms of efficiency. Two-dimensional nuclear magnetic resonance (NMR) logging offers a number of advantages over traditional methods. It is capable of providing faster measurement rates, as well as insights into fluid properties, which can facilitate timely adjustments in oil and gas development strategies. This study focuses on the loose sandstone reservoirs with high porosity and permeability containing heavy oil in the Huabei oilfield. Two-dimensional nuclear magnetic resonance (NMR) measurements and analyses were conducted on saturated rocks with different-viscosity crude oils and varying oil saturation levels, in both natural and artificial rock samples. This study elucidates the distribution patterns of different-viscosity crude oils within the two-dimensional NMR spectra. Furthermore, the T1 and T2 peak values of the extracted oil signals were employed to establish a model correlating oil viscosity with NMR parameters. Consequently, a criterion for determining oil viscosity based on two-dimensional NMR was formulated, providing a novel approach for estimating oil viscosity. The application of this technique in the BQ well group of the Huabei oilfield region yielded an average relative error of 15% between the actual oil viscosity and the computed results. Furthermore, the consistency between the oil types and the oil discrimination chart confirms the reliability of the method. The final outcomes meet the precision requirements for practical log interpretation and demonstrate the excellent performance of two-dimensional nuclear magnetic resonance (NMR) logging in calculating oil viscosity. The findings of this study have significant implications for subsequent exploration and development endeavors in the research area's oilfields. [ABSTRACT FROM AUTHOR]

Background: Characterisation of the structure and water status of leaf tissues is essential to the understanding of leaf hydraulic functioning under optimal and stressed conditions. Magnetic Resonance Imaging is unique in its capacity to access this information in a spatially resolved, non-invasive and non-destructive way. The purpose of this study was to develop an original approach based on transverse relaxation mapping by Magnetic Resonance Imaging for the detection of changes in water status and distribution at cell and tissue levels in Brassica napus leaves during blade development and dehydration. Results: By combining transverse relaxation maps with a classification scheme, we were able to distinguish specific zones of areoles and veins. The tissue heterogeneity observed in young leaves still occurred in mature and senescent leaves, but with different distributions of T2 values in accordance with the basipetal progression of leaf blade development, revealing changes in tissue structure. When subjected to severe water stress, all blade zones showed similar behaviours. Conclusion: This study demonstrates the great potential of Magnetic Resonance Imaging in assessing information on the structure and water status of leaves. The feasibility of in planta leaf measurements was demonstrated, opening up many opportunities for the investigation of leaf structure and hydraulic functioning during development and/or in response to abiotic stresses. [ABSTRACT FROM AUTHOR]

The method of nuclear magnetic resonance, which is currently the most common in research and control of parameters of condensed matter, and the nuclear magnetic flowmeters and relaxometers that implement this method are described. The features of determining the times of longitudinal and transverse relaxation in nuclear magnetic flowmeters-relaxometers in various modes of medium flow while monitoring its parameters have been established. The advantages of the modulation technique for signal recording in nuclear magnetic flowmeters-relaxometers compared to other recording methods are noted. Using various approximations by the Giulotto method from the Bloch equations, a relation was obtained to determine the longitudinal relaxation time based on the results of measurements of two values of nuclear magnetic resonance signal amplitudes or resonance frequencies at different modulation frequencies. It has been experimentally proven that this relationship has a number of limitations when applied to a flowing liquid. These limitations are associated with the method of recording nuclear magnetic resonance signals and the possibility of their formation at different modulation frequencies of a constant magnetic field, and the amplitudes of the signals differ from each other beyond the measurement error. The reasons that led to such a discrepancy in the ratio of determining the time of longitudinal relaxation have been established. The limits of applicability of the obtained relation are found and it is experimentally proven that within these limits it can be used for reliable measurements of relaxation constants. Based on experimental data, the relationship for determining the longitudinal relaxation time was studied. It has been proven that in a number of cases it is impossible to determine the required time using the specified relationship, although nuclear magnetic resonance signals of the flowing liquid are recorded and it has relaxation times. The results obtained make it possible to eliminate errors when using the nuclear magnetic resonance method to study flowing liquids and solve a number of complex problems in the energy, oil, chemical and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Objectives: Evidence regarding placental function in pregnancies complicated by confined placental mosaicism (CPM) is conflicting. We aimed to compare placental function between CPM and non‐CPM pregnancies prenatally and at birth. A secondary objective was to evaluate the relationship between placental function and chromosomal subtype of CPM. Methods: This was a retrospective study of pregnancies with CPM and control pregnancies delivered at a tertiary hospital in Denmark between 2014 and 2017. Placental volume and placental transverse relaxation time (T2*) were estimated on magnetic resonance imaging (MRI), fetal weight and uterine artery pulsatility index (UtA‐PI) were estimated on ultrasound and fetoplacental ratio was assessed on MRI and at birth. These estimates of placental function were adjusted for gestational age and compared between groups using the Wilcoxon rank‐sum test. Within the group of CPM pregnancies, measures of placental function were compared between those at high risk (chromosome numbers 2, 3, 7, 13 and 16) and those at low risk (chromosome numbers 5, 18 and 45X). Results: A total of 90 pregnancies were included, of which 12 had CPM and 78 were controls. MRI and ultrasound examinations were performed at a median gestational age of 32.6 weeks (interquartile range, 24.7–35.3 weeks). On MRI assessment, CPM placentae were characterized by a lower placental T2* Z‐score (P = 0.004), a lower fetoplacental ratio (P = 0.03) and a higher UtA‐PI Z‐score (P = 0.03), compared with non‐CPM placentae. At birth, the fetoplacental ratio was significantly lower (P = 0.02) and placental weight Z‐score was higher (P = 0.01) in CPM pregnancies compared with non‐CPM pregnancies. High‐risk CPM pregnancies showed a reduced placental T2* Z‐score (P = 0.003), lower birth‐weight Z‐score (P = 0.041), earlier gestational age at delivery (P = 0.019) and higher UtA‐PI Z‐score (P = 0.028) compared with low‐risk CPM pregnancies. Low‐risk CPM pregnancies did not differ in any of these parameters from non‐CPM pregnancies. Conclusions: CPM pregnancies are characterized by an enlarged and dysfunctional placenta. Placental function was highly related to the chromosomal type of CPM; placental dysfunction was seen predominantly in high‐risk CPM pregnancies in which chromosomes 2, 3, 7, 13 or 16 were involved. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance (NMR) characteristic of hydrates is of great significance for offshore hydrate reservoir exploration and stratigraphic description. The low-field NMR experiments were conducted to explore the relaxation response of tetrabutylammonium bromide (TBAB) aqueous solution during the step cooling and heating processes. The transverse relaxation time spectrum is divided into three intervals: small peak interval ( < 4 ms), medium peak interval (4 ~ 100 ms) and large peak interval ( > 100 ms), and their NMR relaxation signals originate from hydrate, TBAB molecules and water, respectively. Evolution of sample temperature and transverse relaxation time distribution can be used to distinguish the substances contained in the sample, that is, solid hydrate, TBAB aqueous solution, water, and ice. The signal of small peak interval is completely generated by TBAB hydrate, and thus the relationship between the hydrate NMR signal (amplitude and T2 ) and temperature is established, which can be used as a temperature calibration basis for quantitative analysis of hydrate content. [ABSTRACT FROM AUTHOR]

• Placental volume and transverse relaxation time (T2*) are predictors of small for gestational age (SGA). • In the multi-variate model, placental T2* was the only independent predictor of SGA. • Placental magnetic resonance imaging may improve the antenatal detection of SGA. Placental magnetic resonance imaging (MRI) may be a valuable tool in the prediction of small for gestational age (SGA) at birth. MRI provides reliable estimates of placental volume and thickness. In addition, placental transverse relaxation time (T2*) may be directly related to placental function. This study aimed to explore and compare the predictive performance of three placental MRI parameters – volume, thickness and T2* – in relation to SGA at birth. A mixed cohort of 85 pregnancies was retrieved from the placental MRI database at the study hospital. MRI was performed in a 1.5 T system at gestational weeks 15–41. In normal birthweight (BW) pregnancies [BW > –22 % of expected for gestational age (GA)], the correlation between each of the MRI parameters and GA was investigated by linear regression. The prediction of SGA was investigated by logistic regression analysis adjusted for GA at MRI. In normal BW pregnancies, a significant linear correlation was found between GA and each of the MRI parameters. Univariate analysis demonstrated that placental volume [odds ratio (OR) 0.97, p = 0.001] and placental T2* (OR 0.79, p = 0.003), but not placental thickness (OR 0.92, p = 0.862) were significant predictors of SGA. A multi-variate model including all three MRI parameters found that placental T2* was the only independent predictor of SGA (OR 0.81, p = 0.04). Among the MRI parameters investigated in this study, placental T2* was the only independent predictor of SGA in a multi-variate model. This finding underlines the strong position of T2*-weighted placental MRI in the prediction of SGA. [ABSTRACT FROM AUTHOR]

Single-sided magnetic resonance (SSMR) offers advantages of portability and noninvasive measurement for water detection, with significant potential applications in groundwater exploration, petroleum well logging, and soil moisture monitoring. However, the inherent highly inhomogeneous static magnetic field and radiofrequency (RF) field in SSMR necessitate the utilization of the Carr–Purcell–Meiboom–Gill (CPMG) sequence measurement scheme. To accelerate forward modeling during pulse excitation, we introduce a Geometric Analysis Method (GAM) and assess T 2 error using its primary parameters. The GAM involves applying spatial geometric rotations on the magnetization vector, leading to an analytical solution to the Bloch equation that disregards relaxation effects. Compared with the rotation matrix (RM) method, the GAM demonstrates high accuracy and reduces computational time by approximately 20.9%. By analyzing the primary parameters governing the magnetization vector in the analytical formula, we evaluated their impact on the transverse relaxation time (T 2) obtained through fitting the SE signal. Ultimately, the forward modeling results of the CPMG sequence within the region of interest (ROI) of a single-sided Halbach magnet array are validated. The T 2 fitting error increases as the primary parameters deviate from the ideal values, highlighting their significant role in the T 2 fitting results. This study provides a theoretical foundation for optimizing the design of SSMR magnets and RF coils. • Geometric analytical method (GAM) is proposed to solve the Bloch equation. • Compared with the rotation matrix (RM) method, the GAM demonstrates high accuracy and reduces computational time by approximately 20.9%. • The primary parameters in GAM can be used to evaluate the T 2 fitting error. • This research provides a theoretical basis for optimizing the design of SSMR magnets and RF coils. [ABSTRACT FROM AUTHOR]

This study aimed to analyze the time-course of the physical properties of the psoas major muscle (PM) before and after exercise using magnetic resonance elastography (MRE). Muscle stiffness is one of the important properties associated with muscle function. However, there was no research on the stiffness of the PM after exercise. In this study, we investigated time-course changes of the shear modulus of the PM after exercise. Furthermore, T2 values and apparent diffusion coefficient (ADC), as the additional information associated with muscular physical properties, were also measured simultaneously. Healthy young male volunteers were recruited in this study (n = 9) and they were required to perform a hand-to-knee isometric and unilateral exercise (left side). At each time-point before and after exercise, a set of 3 types of MR scans to measure multiple physical properties of the PM [shear modulus (MRE), T2 values, and ADC] were repeatedly taken. On day 1, a single set MR scan was taken before exercise (pre-exercise MR scan), and 6 sets MR scans were taken (5.5 to 38.0 min after exercise). After about 10-min rest (46.0 to 56.0 min after exercise), 4 sets MR scans were taken (57.5 to 77.0 min after exercise). About 10-min rest was taken again (85.0–95.0 min after exercise), 4 sets MR scans were taken (96.5 to 116.0 min after exercise). On days 2 and 7, a single set MR scan (MRE, T2 value, and ADC) was taken on each experimental day. The data were analyzed as relative changes (%) of the given parameters to the pre-exercise values. The results indicated significant decreases in PM shear modulus up to about 30 min after exercise. Then, it gradually increased and showed significant increases at about 100 min after exercise compared to that before exercise. T2 values and ADC showed significant increases up to about 65 min after exercise compared to those before exercise, and then returned to the pre-exercise values. On days 2 and 7, all values showed no significant changes compared to the pre-exercise values. This study is the first to report the time-course of the physical properties of the PM after exercise. [ABSTRACT FROM AUTHOR]

The paper justifies the need to improve the primary processing (separation) of oil at a drilling station or on an offshore platform, as well as describing associated problems and determining conditions for increasing the efficiency of the primary oil mixture processing. In order to ascertain the ow rate and control the state of an oil mixture supplied from the well, the authors consider the possibility of using optical instruments and flowmeters of various designs, specifically NMR flowmeter-relaxometers. The design of an industrial M-Phase 5000 NMR flowmeter-relaxometer is described, which is used for monitoring the flow rate and quality of oil and petroleum products; problems that prevent its use at a drilling rig or on an offshore platform are identified. An NMR flowmeter-relaxometer was designed to implement various modulation techniques for measuring the flow rate, as well as longitudinal and transverse relaxation times, of oil mixtures. The application of these techniques and proposed technical solutions allows this instrument to be used at a drilling station and on an offshore platform. The results of studies on various media using the developed instrument are presented. [ABSTRACT FROM AUTHOR]

To detect maize seed vigor under salt-alkaline and drought stress conditions, transverse relaxation time, physiological index, and electron microscopy images of germinating seeds were studied under different stress conditions. The results showed that the water in germinating maize seeds exist in bound water (T 21), semi-bound water (T 22), and free water (T 23), in addition parabolic water (T 24). The Pearson correlation analysis was performed with T 2 relaxation parameters and seed vigor parameters, and this analysis yield nine optimized parameters. To predict vigor levels under different stress conditions, an error backpropagation artificial neural network model was developed, wherein the T 2 chirality parameter was used as the input value, and the seed germination indices of different stress levels were used as the output values. The model could predict the environmental stress level of maize seed growth. The optimized parameter set showed a prediction accuracy of 92.50%, thus outperforming the T 2 relaxation information model without parameter optimization (75.01%). The proposed method can collect data during the germination of maize seeds without any interference and achieve large-scale prediction of seed development status by small sample collection. With the stress environment was aggravated, the physiological structure of seed cells was changed, and the cell structure was destroyed and the ability of water absorption was disappeared. This analysis provides theoretical support and a reference basis for maize planting and production. [Display omitted] • Error backpropagation artificial neural network model (BP-ANN) to predict the vigor level of corn seeds. • The germination of corn seeds is severely affected by salt-alkaline and drought stress. • Nuclear magnetic data of a few corn seeds samples are used to predict the large-scale seed development. [ABSTRACT FROM AUTHOR]

• A paramagnetic Cu2+-induced magnetic resonance tuning (MRET) strategy is proposed. • A Cu–M-MRS immunosensor was constructed for detection of chlorpyrifos and Salmonella. • Fe 3 O 4 @PDA-Ab 2 was used for signal conversion by regulating the amount of Cu2+ ions. • The LOD for chlorpyrifos and Salmonella are 0.05 ng/mL and 50 CFU/mL, respectively. Magnetic relaxation switching (MRS) biosensors have been recognized as useful analytical tools for a range of targets; however, traditional MRS biosensors are limited by the "prozone effect", resulting in a narrow linear range and low sensitivity. Herein, we proposed a paramagnetic Cu2+-induced magnetic resonance tuning (MRET) strategy, based on which Cu2+ ions and magnetic nanoparticles (MNPs) were adopted to construct a Cu–MNP-mediated MRS (Cu–M-MRS) immunosensor with Cu2+ ions acting as a quencher and MNPs as an enhancer. An Fe 3 O 4 @polydopamine-secondary antibody conjugate was prepared and used to correlate the amount of Cu2+ ions to the target concentration through an immunoassay. Based on the immunoreaction, the Cu–M-MRS immunosensor enabled the sensitive detection of chlorpyrifos (0.05 ng/mL, a 77-fold enhancement in sensitivity compared with the traditional MRS immunosensor) and Salmonella (50 CFU/mL). The proposed MRET strategy effectively improved the sensitivity and accuracy of the MRS immunosensor, offering a promising and versatile platform for food safety detection. [ABSTRACT FROM AUTHOR]

The relaxation signal intensity and transverse relaxation time of Portland cement pastes with different dosages of recycled powder at different ages were measured by low-field nuclear magnetic resonance (NMR) technology. Combined with scanning electron microscopy (SEM), the effect of recycled powder on early-age hydration and microstructure of Portland cement was studied. The results show that the hydration process of composite slurry can be divided into four stages, namely, induction period, acceleration period, attenuation period and stable period. As the hydration progressed, the T2 distribution of evaporable water in the composite slurry shifted to short relaxation time, indicating the pores were filled by hydration productions and pore diameter was getting smaller. Recycled powder has high water-adsorption capacity and water slowly-release function, which will lead to the formation of interfacial transition zone (ITZ) and compromise the mechanical property. The transverse relaxation time T2 of samples with higher recycled powder content always maintains obvious bimodal distribution during hydration. [ABSTRACT FROM AUTHOR]

The relaxation signal intensity and transverse relaxation time of Portland cement pastes with different dosages of recycled powder at different ages were measured by low-field nuclear magnetic resonance (NMR) technology. Combined with scanning electron microscopy (SEM), the effect of recycled powder on early-age hydration and microstructure of Portland cement was studied. The results show that the hydration process of composite slurry can be divided into four stages, namely, induction period, acceleration period, attenuation period and stable period. As the hydration progressed, the T2 distribution of evaporable water in the composite slurry shifted to short relaxation time, indicating the pores were filled by hydration productions and pore diameter was getting smaller. Recycled powder has high water-adsorption capacity and water slowly-release function, which will lead to the formation of interfacial transition zone (ITZ) and compromise the mechanical property. The transverse relaxation time T2 of samples with higher recycled powder content always maintains obvious bimodal distribution during hydration. [ABSTRACT FROM AUTHOR]

Specific features of monitoring the state of a flowing medium by method of nuclear magnetic resonance (NMR) are considered. An approach to studying the state of a flowing medium by monitoring variation of the values of longitudinal (T1) and transverse (T2) relaxation times is justified. Optimum relations between parameters of the system of NMR signal registration and magnetic fields are established. Obeying these relations allows the signal to noise ratio level S/N > 5 to be obtained for measuring the T1 and T2 values online at an error not exceeding 1%. Results of experimental investigations are presented. [ABSTRACT FROM AUTHOR]

The associations of 4 proteins—AK4, ITPK1, HSPB2, and IGFBP5—with cognitive function in older adults were largely unexplained by known brain pathologies. We examined the extent to which individual protein associations with cognitive decline were attributable to microstructural changes in the brain. This study included 521 participants (mean age 90.3, 65.9–108.3) with the postmortem reciprocal of transverse relaxation time (R 2) magnetic resonance image. All participants came from one of the 2 ongoing longitudinal cohorts of aging and dementia, the Religious Orders Study and Rush Memory and Aging Project. Higher abundance of AK4, HSPB2, and IGFBP5 was associated with faster cognitive decline and mediated through lower postmortem R 2 in the frontal and temporal white matter regions. In contrast, higher abundance of ITPK1 was associated with slower cognitive decline and mediated through higher postmortem R 2 in the frontal and temporal white matter regions. The associations of 4 proteins—AK4, ITPK1, IGFBP5, and HSPB2—with cognition in late life were explained via microstructural changes in the brain. • Microstructural change in the brain mediates relation of 4 proteins to cognition. • AK4, HSPB2, and IGFBP5 associated with faster cognitive decline via damaged white matter. • ITPK1 associated with slower cognitive decline via healthy state of white matter. [ABSTRACT FROM AUTHOR]

To classify different walnut varieties based on water and oil content of walnut, and determine their storage conditions, the low-field nuclear magnetic resonance (LFNMR) technology was used to obtain the NMR transverse relaxation time (T2) of the samples based on the physical and chemical indicators of the walnut quality. The relationship between the relaxation time and phase state of the internal material of the sample was investigated, and the characteristic parameters of the NMR spectrum signals were statistically analyzed using cluster analysis to determine the different walnut varieties, and three different components, as well as their contents, were detected by a LFNMR spectrometer: firmly bound water, weakly bound water, and weakly bound oil. Test results indicated that the oil peak was dominant in the overall signal intensity compared to the water peaks, in which the firmly bound water phase contributed more to the overall water signal between the water peaks. Using the analytic hierarchy process of cluster analysis, 21 walnut samples were classified into three different classes, based on the characteristic parameters of the water-content and oil-content spectrum signals. The first class contains four walnut varieties characterized by least water and highest oil contents; the third class contains two walnut varieties, with the highest water content and least oil content; whereas, the second class contains 15 walnut varieties, with both water and oil contents at medium levels. The results showed that LFNMR led to a rapid detection of moisture and oil contents in walnuts, while cluster analysis classified different walnuts varieties based on these parameters. This study also provided the basis for optimizing the storage methods and storage conditions of walnuts. [ABSTRACT FROM AUTHOR]

Biofilm and dairy fouling formation is difficult to study non-invasively in closed systems such as flexible tubing. Nuclear magnetic resonance (NMR) is considered as a promising non-invasive detection method for different deposits. This study aimed to investigate three deposit models: (1) Paenibacillus polymyxa biofilm, (2) dairy biofouling, and (3) dairy fouling, in different experimental set-ups by low-field 1H NMR. The transverse relaxation time T2 of each component in samples of experimental set-ups was studied. The results show that low-field NMR offers the possibility of qualitatively measuring the selected deposit models and differentiating non-destructively between the tubing and each deposit. The samples in each experimental set-up showed characteristic relaxation behavior of flexible tubing, deposit, and liquid. For the P. polymyxa biofilm, longer relaxation times T2 of about 100 ms were detected, while relaxation times T2 for dairy biofouling and dairy fouling were in range of 50–60 ms. It was thus concluded that low-field NMR has a great potential for non-invasive detection of deposit formation at practical industrial scales. [ABSTRACT FROM AUTHOR]

The accumulation of unwanted deposits in food-processing equipment may cause significant production downtime, add to expenses for cleaning agents and wastewater disposal, as well as food contamination. Nuclear magnetic resonance (NMR) is considered as a promising non-invasive tool for the monitoring of processes in food industry. In this work, two deposit models and cleaning agents are investigated by low-field 1H NMR: (1) Paenibacillus polymyxa biofilm, (2) dairy biofouling and (3) clean-in-place (CIP) cleaning agents. The transverse relaxation times T2 obtained by inverse Laplace transform as well as diffusion coefficients DS of the samples are studied. The obtained results reveal that low-field NMR can be used for the detection and identification of selected deposit models and CIP-cleaning agents. Transverse relaxation times T2 demonstrate characteristic relaxation behavior of flexible tubing, differently structured deposits, and liquid phases. Moreover, with increasing biofouling thickness (up to 406.2 mg/cm2), transverse relaxation times T2 shift toward slower relaxation rates up to T2 111.9 ms. In addition, significant differences in the diffusion behavior of water are noted in each sample group of the deposit models and CIP-cleaning agents. The diffusion coefficient of water in dairy biofouling and in microbial biofilm matrix corresponds to approximately 65% and 75% of the value in pure water, respectively. In addition to the NMR results, the biofilm and biofouling identification is validated through microbiological methods and by microscope images. [ABSTRACT FROM AUTHOR]

Abstract Identification of pay zones is as a challenging topic in the reservoir characterization. Various methods have been employed to tackle this prominent task. Well logs are one of the most useful means for identifying pay zones, chiefly resistivity logs. However, resistivity measurements in some complex environments such as mixed lithology reservoirs, low resistivity and low contrast pay zones may fail to unveil productive zones. As an essentially lithology-independent tool, nuclear magnetic resonance (NMR) log may be the only approach to deal with detecting such subtleties. Using wavelet analysis technique and the NMR log data, this paper was aimed at identifying hydrocarbon bearing zones in two carbonate reservoirs. Discrete wavelet transform (DWT) was applied to the spin echo train at each depth to extract transverse relaxation time ( T 2 ). By comparing the generated T 2 log and resistivity log, a striking similarity was found between them. The T 2 log manifested strong correlation with porosity log. Therefore, the DWT was repeatedly applied to the T 2 log so as to remove the correlation. Various wavelets were adopted to remove the effect of porosity from the T 2 log, leading to achieve pore fluid transverse relaxation time, referred to as T 2 f . Scrutinizing the T 2 f log demonstrated that this log is not only highly functional in detecting productive zones but also highly capable of highlighting the subtle changes of pay zones. Consequently, the T 2 f log revealed the latent pay zones unseen by resistivity log. Highlights • This paper was aimed to identify pay zones using wavelet analysis on NMR log data. • The DWT was initially utilized to denoise the CPMG spin echo train at each depth. • Transverse relaxation time was obtained from the smoothed CPMG sequence. • The DWT was again conducted to remove the information of porosity. • Pore fluid transverse relaxation time led to distinguishing pay zones. [ABSTRACT FROM AUTHOR]

A new method to predict the seed vigor of rice was developed to control adulteration during the seed trading process and to address the deficiencies of traditional manual detection methods. Low-field nuclear magnetic resonance (LF-NMR) technique was used to detect the vigor of rice seeds. Four varieties (Beijing-1, Qianchonglang-2, Yanfeng-47 and Shennong-265) of rice seeds from the Rice Research Institute of Shenyang Agricultural University were chosen for the experiment. The transverse relaxation time T2, T21 and T22 were observed in the experiment. The peak start time of free water (transverse relaxation time T22), signal amplitude of bound water (transverse relaxation time T21), and moisture content decreased with the decrease in the vigor of the seeds. There were no obvious trends observed for the top of the peak and the end point of the transverse relaxation time T22. In addition, the start, top, and end time of the peak (transverse relaxation time T21), and the signal amplitude of bound water showed no consistent changes. The results indicated that LF-NMR could be used as a method to distinguish the vigor of rice seeds rapidly. This study provided theoretical basis and technical support for the rapid detecting of rice seed vigor. [ABSTRACT FROM AUTHOR]

Abstract Based on the low hydration heat requirement of cement slurry system used in natural gas hydrate formation and the effective utilization of industrial waste materials, the fly ash and slag were introduced into ordinary Portland cement to prepare a low hydration heat cement slurry system. During this study, the influences of fly ash and slag on the heat evaluation of cement slurry system were investigated by temperature profiles and hydration heat, which were tested by using a developed semi-adiabatic test equipment. Currently, the temperature profiles of cement slurry system were studied by the initial temperature (T i), temperature rise (T r), maximum temperature (T m), and the hydration time (t m) corresponding to the maximum temperature, respectively. Moreover, the investigations of the influences of fly ash and slag on the strength property of cement stone were investigated. Then, a novel low hydration heat cement slurry system CFS 1-1 used in natural gas hydrate formation was developed by the mass ratio of 2:1:1 (cement: fly ash: slag). Simultaneously, the initial hydration process of CFS 1-1 was investigated by low field NMR, the rheological and thickening properties of CFS 1-1 were also studied. Besides, some other application performances, such as density, fluidity, stability and consistency, were also studied. As a result, it was found that the application performances of CFS 1-1 meet the cementing requirement of hydrate formation. In addition, the effective and reasonable utilization of industrial waste materials were also realized during this study. Highlights • Hydration heat evaluation was controlled by fly ash and slag. • Semi-adiabatic test equipment was developed. • A novel low hydration heat cement slurry was developed. • A new possibility for cementing of hydrate formation was provided. • The effective utilization of industrial waste materials is also realized. [ABSTRACT FROM AUTHOR]

Emulsions are thermodynamically unstable systems formed through blending of two immiscible fluids. Recent studies have shown that High Hydrostatic Pressure (HHP) can initiate or accelerate lipid crystallization in emulsions. In this study, the effect of HHP on lipid crystallization was examined. Emulsion samples were prepared with palm stearin (PS) as the oil phase and sodium caseinate (SC) as the emulsifier and they were pressurized at 100 and 500 MPa at 10, 20 and 40 °C for 15 min. In order to determine the crystal structure of the emulsions, differential scanning calorimeter (DSC) was used and the change in the crystal morphology during 28 day-storage at 4 °C was observed. Nuclear Magnetic Resonance Relaxometry (NMR) experiments were also conducted and transverse relaxation time (T 2 ) and self-diffusion coefficient (SDC) values showed a trend to follow polymorphic changes of lipid crystals. Results showed that pressure and storage time both had significant effects (p < 0.05) on the crystal structures of emulsions. [ABSTRACT FROM AUTHOR]

Emulsions are thermodynamically unstable systems formed through blending of two immiscible fluids. Recent studies have shown that High Hydrostatic Pressure (HHP) can initiate or accelerate lipid crystallization in emulsions. In this study, the effect of HHP on lipid crystallization was examined. Emulsion samples were prepared with palm stearin (PS) as the oil phase and sodium caseinate (SC) as the emulsifier and they were pressurized at 100 and 500 MPa at 10, 20 and 40 °C for 15 min. In order to determine the crystal structure of the emulsions, differential scanning calorimeter (DSC) was used and the change in the crystal morphology during 28 day-storage at 4 °C was observed. Nuclear Magnetic Resonance Relaxometry (NMR) experiments were also conducted and transverse relaxation time (T 2 ) and self-diffusion coefficient (SDC) values showed a trend to follow polymorphic changes of lipid crystals. Results showed that pressure and storage time both had significant effects (p < 0.05) on the crystal structures of emulsions. [ABSTRACT FROM AUTHOR]

The detection of samples in a microfluidic nuclear magnetic resonance chip is generally performed under flow condition. To study the effect of sample flow on the apparent transverse relaxation time in a microfluidic nuclear magnetic resonance chip, theoretical calculations were performed on three microfluidic samples (including deionized water, absolute ethanol, and copper sulfate pentahydrate) for flow velocities in the range 1.7-25 mm/s. A microfluidic nuclear magnetic resonance device with a low cost microfluidic solenoid coil was fabricated to verify the theoretical calculations by experiments. The results show that the apparent transverse relaxation time of the sample is a monoexponential decay with respect to flow velocity. In addition, it was found that the experimental values and the theoretical values of the apparent transverse relaxation time are identical when the samples are prepolarized completely; but for the samples that are not prepolarized completely, all the experimental values are smaller than the theoretical values and their difference increases with the flow velocity of the sample. After further study, it was discovered that the relative error between the experimental values and the theoretical values is a monoexponential decay to the level of the sample to be prepolarized. This discovery is very useful, because it can be used to modify the theoretical calculation model of the apparent transverse relaxation time for the samples that are prepolarized incompletely, as well as improve the application of microfluidics on nuclear magnetic resonance. [ABSTRACT FROM AUTHOR]

Hydroxypropyl methylcellulose (HPMC) belongs to the cellulose ether family that has hydroxyl groups substituted by hydrophobic methyl groups (DS) and hydrophilic hydroxypropyl groups (MS). Herein, the interactions between water molecules and cryogels prepared with HPMC in the presence and absence of a linear nonionic surfactant, as well as CaO 2 microparticles, which react with water producing O 2 , were systematically investigated by sorption experiments and Time-Domain Nuclear Magnetic Resonance. Regardless of the DS and MS, most water molecules presented transverse relaxation time t2 typical of intermediate water and a small population of more tightly bound water. HPMC cryogels with the highest DS of 1.9 presented the slowest swelling rate of 0.519 ± 0.053 g water /(g.s) and the highest contact angle values 85.250o ± 0.004o, providing the best conditions for a slow reaction between CaO 2 and water. The presence of surfactant favored hydrophobic interactions that allowed the polar head of the surfactant to be exposed to the medium, resulting in a higher swelling rate and lower contact angle values. The HPMC with the highest MS presented the fastest swelling rate and the lowest contact angle. These findings are relevant for the formulations and reactions, where tuning the swelling kinetics is crucial for the final application. [Display omitted] • HPMC cryogels with the highest DS had the lowest wettability and swelling rate. • HPMC hydrogels presented mostly intermediate water and a small fraction of bound water. • Surfactant affected moderately the wettability of HPMC cryogels. • The incorporation of CaO 2 into HPMC cryogels retards its reaction with water. [ABSTRACT FROM AUTHOR]

Food structure affects the breakdown kinetics of food. This has been extensively studied via in vitro digestion models. However, these in vitro findings need to be verified in vivo. Previously, we found that MRI parameters (T 1 and T 2 relaxation times) can serve as markers of protein digestion. Here, we assessed the effect of food hardness and protein content on gastric emptying as well as the application of these MRI parameters to monitor in vivo gastric digestion of solid foods. In a randomized cross-over trial, 18 healthy males (age: 27 ± 5 y; BMI 23 ± 1 kg/m2) ingested three gels: a soft gel with low protein content (Soft-LP), a hard gel with low protein content (Hard-LP), and a hard gel with high protein content (Hard-HP). Before and every 10 min after ingestion till 85 min, abdominal MRI scans were obtained to determine the gastric content volume and T 1 and T 2 of the gastric content. The decrease in gastric content volume differed among gels: Hard-HP < Hard-LP < Soft-LP. For all gels, mean T 1 and T 2 of the measured stomach content decreased directly after ingestion and then after 15 min gradually increased with Hard-HP < Hard-LP < Soft-LP. In conclusion, high protein content and high hardness slowed gastric emptying down. In addition, we show that T 1 and T 2 measurements provide extra information on the dilution and digestion of solid foods in the stomach. This underpins the potential of MRI to provide insights into in vivo protein digestion and link in vitro and in vivo digestion research. [Display omitted] • We studied gastric digestion of protein gels differing in protein content and hardness in a human trial. • High protein content and high hardness reduce gastric emptying. • In vivo MRI T 1 and T 2 measurements can provide extra information on the dilution and digestion. • These in vivo data can serve as input data for tuning and validating in vitro and in silico models. [ABSTRACT FROM AUTHOR]

Background: Metabolic syndrome (MetS) is a highly prevalent condition that identifies individuals at risk for type 2 diabetes mellitus and atherosclerotic cardiovascular disease. Prevention of these diseases relies on early detection and intervention in order to preserve pancreatic β-cells and arterial wall integrity. Yet, the clinical criteria for MetS are insensitive to the early-stage insulin resistance, inflammation, cholesterol and clotting factor abnormalities that characterize the progression toward type 2 diabetes and atherosclerosis. Here we report the discovery and initial characterization of an atypical new biomarker that detects these early conditions with just one measurement.Methods: Water T2, measured in a few minutes using benchtop nuclear magnetic resonance relaxometry, is exquisitely sensitive to metabolic shifts in the blood proteome. In an observational cross-sectional study of 72 non-diabetic human subjects, the association of plasma and serum water T2 values with over 130 blood biomarkers was analyzed using bivariate, multivariate and logistic regression.Results: Plasma and serum water T2 exhibited strong bivariate correlations with markers of insulin, lipids, inflammation, coagulation and electrolyte balance. After correcting for confounders, low water T2 values were independently and additively associated with fasting hyperinsulinemia, dyslipidemia and subclinical inflammation. Plasma water T2 exhibited 100% sensitivity and 87% specificity for detecting early insulin resistance in normoglycemic subjects, as defined by the McAuley Index. Sixteen normoglycemic subjects with early metabolic abnormalities (22% of the study population) were identified by low water T2 values. Thirteen of the 16 did not meet the harmonized clinical criteria for metabolic syndrome and would have been missed by conventional screening for diabetes risk. Low water T2 values were associated with increases in the mean concentrations of 6 of the 16 most abundant acute phase proteins and lipoproteins in plasma.Conclusions: Water T2 detects a constellation of early abnormalities associated with metabolic syndrome, providing a global view of an individual's metabolic health. It circumvents the pitfalls associated with fasting glucose and hemoglobin A1c and the limitations of the current clinical criteria for metabolic syndrome. Water T2 shows promise as an early, global and practical screening tool for the identification of individuals at risk for diabetes and atherosclerosis. [ABSTRACT FROM AUTHOR]

The characteristics of transverse relaxation time (T2) of water in wheat were studied by measuring the relaxation time of low-field nuclear magnetic resonance. Analysis of the exponential distribution ofT2revealed that wheat contains five water components. TheT2relaxation time and distribution significantly changed during drying. The dynamic characteristics of five water components during wheat drying were determined using the signal quantity of their characteristic peaks, which showed different features. Weakly chemically bound water (T22) and water ascribed to cell wall (T23) were the main source of water loss. Moreover, mostT23and extracellular water (T24) were removed during drying. Water migration between strongly chemically bound water (T21) and the other water components was bidirectional. This process was not only affected by temperature but also by wheat moisture content and proportion of the five water components. The start time of water migration advanced and growth rate ofT21at the end of drying to that before drying increased at 60, 70, and 80°C. Drying at varied temperatures should be applied according to the characteristics of five water components during the drying process. In addition, high initial temperature was found to be necessary to achieve high drying rate ofT23,T24, and free water (T25). The use of drying temperature of 80°C at the early stage and then changing to 70°C reduced the heat consumption by 4.81% and increased the drying time by 9.61%. [ABSTRACT FROM PUBLISHER]

The purpose of this study was to examine whether inter- and intramuscular differences in hypertrophy induced by resistance training correspond to differences in muscle activation during the first training session. Eleven young men completed 12 weeks of training intervention for knee extension. Before and after the intervention, T1-weighted magnetic resonance ( MR) images were recorded to determine the volume and anatomical cross-sectional area ( CSA) along the length of the individual muscles of the quadriceps femoris. The T2-weighted MR images were also acquired before and immediately after the first training session. The T2 was calculated for each pixel within the quadriceps femoris, from which the muscle activation was evaluated as %activated volume and area. The results showed that the %activated volume after the first training session was significantly higher in the vastus intermedius than the vastus medialis. However, the relative change in muscle volume after the training intervention was significantly greater in the rectus femoris than the vasti muscles (vastus lateralis, intermedius and medialis). Within the rectus femoris, both the %activated area and relative increase in CSA were significantly greater in the distal region than the proximal region. In contrast, the %activated area and relative increase in CSA of the vasti were nearly uniform along each muscle. These results suggest that the muscle activation during the first training session is associated with the intramuscular difference in hypertrophy induced by training intervention, but not with the intermuscular difference. [ABSTRACT FROM AUTHOR]

The transverse relaxation time of noble-gas atoms in nuclear-magnetic-resonance gyroscopes is a very important indicator for measuring the gyroscope’s performance. In this paper, the optimized free-induction-decay method, together with fitting-ratio method and magnetic-resonance-broadening method in the rotating coordinate system, is analyzed for the first time, in order to accurately measure the transverse relaxation time. An experimental device was designed, and the transverse-relaxation-time measurements were carried out by using these three methods under specific conditions. The advantages of these three methods are analyzed by comparison of experimental process and experimental results. The influence of pump-light intensity on the transverse relaxation time of noble-gas atoms is further studied on this basis, and verified through experiments. [ABSTRACT FROM AUTHOR]

The authors describe a rapid and sensitive magnetic relaxation switch (MRSw) aptasensor for the determination of the food-borne pathogen Pseudomonas aeruginosa. An aptamer against P. aeruginosa is covalently bound to superparamagnetic iron oxide nanoparticles. On incubation with P. aeruginosa bacteria, they will be captured by the aptamer, and this affects the formation of SPIO aggregates. The resulting strong increase in the spin-spin relaxation time (T) is utilized as the analytical information to quantify the bacteria. Under optimized conditions, the assay has a linear range that extends from 100 cfu⋅mL to 10 cfu⋅mL, and a detection limit of 50 cfu⋅mL (at an S/N ratio of 3). The method was applied to the detection of P. aeruginosa in (spiked) real food and drinking water samples and was validated by the established plate counting method. This aptasensor is considered to represent a promising platform for the determination of P. aeruginosa. Conceivably, the method may be extended to other food-borne bacteria or biomolecules for which respective aptamers are available. [ABSTRACT FROM AUTHOR]

Elements of studies of flows of liquid media by a nuclear magnetic spectrometer are considered. Through an assessment of these features in the design of a nuclear magnetic spectrometer the relative concentrations of paramagnetic ions could be determined and the longitudinal and transverse relaxation times measured in flows of liquid media with error not more than 0.5%. A regime for recording the nuclear magnetic resonance signal of a flowing liquid of fluorine, phosphorous, lithium, boron, sodium, chlorine, and mercury nuclei is created. The results of experimental studies of flows of liquid media are presented. [ABSTRACT FROM AUTHOR]

There is a pressing need for biomarkers and outcomes that can be used across disease stages in Duchenne muscular dystrophy (DMD), to facilitate the inclusion of a wider range of participants in clinical trials and to improve our understanding of the natural history of DMD. Quantitative magnetic resonance imaging (qMRI) and spectroscopy (MRS) biomarkers show considerable promise in both the legs and forearms of individuals with DMD, but have not yet been examined in functionally important proximal upper extremity muscles such as the biceps brachii and deltoid. The primary objective of this study was to examine the feasibility of implementing qMRI and MRS biomarkers in the proximal upper extremity musculature, and the secondary objective was to examine the relationship between MR measures of arm muscle pathology and upper extremity functional endpoints. Biomarkers included MRS and MRI measures of fat fraction and transverse relaxation time ( T ). The MR exam was well tolerated in both ambulatory and non-ambulatory boys. qMR biomarkers differentiated affected and unaffected participants and correlated strongly with upper extremity function ( r = 0.91 for biceps brachii T versus performance of upper limb score). These qMR outcome measures could be highly beneficial to the neuromuscular disease community, allowing measurement of the quality of functionally important muscles across disease stages to understand the natural history of DMD and particularly to broaden the opportunity for clinical trial participation. [ABSTRACT FROM AUTHOR]

Purpose: This study compared maximal eccentric (ECC) and concentric (CON) contractions of the elbow flexors for changes in transverse relaxation time (T2) and indirect markers of muscle damage. Methods: Twelve young men performed five sets of six maximal isokinetic (30°/s) ECC with one arm followed by CON with the other arm. Magnetic resonance images to assess T2 and cross-sectional area (CSA) of biceps brachii, brachialis, and brachioradialis, and measurements of maximal voluntary isometric contraction (MVC) torque, range of motion (ROM), and muscle soreness were taken before, immediately after, and 1, 3, and 5 days after each exercise. Results: MVC torque and ROM decreased greater after ECC than CON ( p < 0.05), and muscle soreness developed only after ECC. Biceps brachii and brachialis CSA increased immediately after CON, but delayed increases in brachialis CSA were found only after ECC ( p < 0.05). T2 of the muscles increased greater after CON (27-34 %) than ECC (16-18 %) immediately post-exercise ( p < 0.05), but returned to baseline by 1 day after CON. The biceps brachii and brachialis T2 increased by 9-29 % at 1-5 days after ECC ( p < 0.05). The post-ECC T2 changes showed no significant correlations with the changes in MVC torque, muscle soreness, and CSA, but the T2 increase immediately post-ECC was correlated with the peak T2 in 1-5-day post-ECC ( r = 0.63, p < 0.05). Conclusion: These results suggest that muscle activity during exercise was lower in ECC than CON, and the T2 changes after ECC do not necessarily relate to the changes in other indirect markers of muscle damage. [ABSTRACT FROM AUTHOR]

Transverse spin-spin relaxation of liquids entrapped in nanocavities with different orientational order is theoretically investigated. Based on the bivariate normal distribution of nanocavities directions, we have calculated the anisotropy of the transverse relaxation time for biological systems, such as collagenous tissues, articular cartilage, and tendon. In the framework of the considered model, the dipole-dipole interaction is determined by a single coupling constant. The calculation results for the transverse relaxation time explain the angular dependence observed in MRI experiments with biological objects. The good agreement with the experimental data is obtained by adjustment of only one parameter which characterizes the disorder in fiber orientations. The relaxation time is correlated with the degree of ordering in biological tissues. Thus, microstructure of the tissues can be revealed from the measurement of relaxation time anisotropy. The clinical significance of the correlation, especially in the detection of damage must be evaluated in a large prospective clinical trials. [ABSTRACT FROM AUTHOR]

In this study, changes in the transverse relaxation time (T2), signal intensity (A2), and images of 'Jinxiu' yellow peach fruits were investigated using low-field nuclear magnetic resonance (LF-NMR) and proton magnetic resonance imaging (1H-MRI). The water content, (determined using centrifuging technology), fruit firmness, and ethylene production were evaluated at 4±1°C and 25±2°C. The results showed a signal peak (A2) and T2 at 500-1000 ms. On days 4-6, T2 changed from 796 ms to 861 ms, and decreased with longer time at 25°C. Water content also decreased and high adjusted determination coefficient (adj-R2) values with water content were found for T2 (R2 = 0.95) and A2 (R2 = 0.99), indicating a high degree of ft for the prediction equations. A2 decreased and T2 shortened after prolonged storage at 4°C and high adj-R2 values were found between the water content and T2 (R2 = 0.93) and A2 (R2 = 0.97).Ethylene production and firmness were the same as for T2, A2, and internal breakdown at 25°C for 4-6 days, and 4°C for 16-21 days. Compared with storage at 25°C, low temperature storage inhibited water loss and also prohibited internal breakdown. T2 and A2 can be used to evaluate the storage characteristics of yellow peach fruits, and the internal breakdown of pulp tissue could be clearly observed by 1H-MRI, which is a function of LF-NMR. 1H-MRI can provide high-resolution images showing the internal structure of intact peaches. Thus, LF-NMR is a new technology that could be an effective and simpler method for monitoring and predicting water content, as well as detecting quality issues during peaches storage. [ABSTRACT FROM AUTHOR]

Objectives: The magnetic resonance imaging (MRI) variable transverse relaxation time (T2*) depends on multiple factors, one important one being the presence of deoxyhemoglobin. We aimed to describe placental T2* measurements in normal pregnancies and in those with fetal growth restriction (FGR).Methods: We included 24 normal pregnancies at 24-40 weeks' gestation and four FGR cases with an estimated fetal weight below the 1(st) centile. Prior to MRI, an ultrasound examination, including Doppler flow measurements, was performed. The T2* value was calculated using a gradient echo MRI sequence with readout at 16 different echo times. In normal pregnancies, repeat T2* measurements were performed and interobserver reproducibility was assessed in order to estimate the reproducibility of the method. Placental histological examination was performed in the FGR cases.Results: The method was robust regarding the technical and interobserver reproducibility. However, some slice-to-slice variation existed owing to the heterogeneous nature of the normal placenta. We therefore based T2* estimations on the average of two slices from each placenta. In normal pregnancies, the placental T2* value decreased significantly with increasing gestational age, with mean ± SD values of 120 ± 17 ms at 24 weeks' gestation, 84 ± 16 ms at 32 weeks and 47 ± 17 ms at 40 weeks. Three FGR cases had abnormal Doppler flow, histological signs of maternal hypoperfusion and a reduced T2* value (Z-score < -3.5). In the fourth FGR case, Doppler flow, placental histology and T2* value (Z-score, -0.34) were normal.Conclusions: The established reference values for placental T2* may be clinically useful, as T2* values were significantly lower in FGR cases with histological signs of maternal hypoperfusion. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

In this study, we aimed to elucidate the characteristics of water mobility and distribution in soybean antioxidant peptide powders (SAPPs) using low-field nuclear magnetic resonance (LF-NMR). SAPPs of three different molecular weights (MWs) were exposed to a room temperature environment with a relative humidity of 45%, and the dynamics of water mobility and distribution were monitored by LF-NMR. Results revealed that there were four transverse relaxation time fractions in SAPPs. The major (over 90%) fraction was bound water, and the distribution of water in samples with different MWs was different. The moisture absorption capacity of SAPPs with MWs of less than 1 kDa was the strongest, and all T 2 fractions/water population contents in SAPPs with MWs of 1–3 kDa were the lowest. This study provided an effective real-time monitoring method for water mobility and distribution in SAPPs and may have applications for promoting peptides quality assurance. [ABSTRACT FROM AUTHOR]

For non-invasive stem cells tracking through MRI, it is important to understand the efficiency of in vitro labeling of stem cells with iron oxide with regard to its relaxation behavior. In this study, we have carried out a pilot study of labeling mice mesenchymal stem cells (mMSCs) with ultrasmall superparamagnetic iron oxide (USPIO) entrapped with poly-L-lysine (PLL) in different ratios and incubated with different times. Our results demonstrated that 50:1.5 µg/ml of iron oxide and PLL at an incubation time of 6 h with 10% serum concentration are sufficient enough for effective labeling. Optimized labeling showed that >98% of viability and <3% toxicity were observed at a total iron content of 11.8 pg/cell. In vitro relaxometry study showed that almost a 6.6 fold reduction in transverse relaxation time (T 2 ) was observed after labeling as compared to unlabeled. IO-PLL complex was more effective than iron oxide alone in labeling and a detectable lower limit found to be hundred with optimized concentration. Significant increase in Oct-4 expression on day-3 after labeling was observed, whereas CD146 expression remains unchanged in real time RT-PCR. This optimized labeling method of MSCs may be very useful for cellular MRI and stem cells tracking studies. [ABSTRACT FROM AUTHOR]

BACKGROUND: Eccentric contractions (ECC)-induced muscle damage and activation pattern are not fully understood. OBJECTIVE: To investigate the activation level and damage in each muscle and site after ECC. METHODS: Eleven men performed 30 isokinetic ECC of the elbow flexors. Maximal voluntary isometric contraction (MVC) torque, range of motion of the elbow joint (ROM), delayed onset muscle soreness (DOMS), transverse relaxation time (T2), and cross-sectional area (CSA) were measured immediately before, immediately after, and 1, 3, 5 days after ECC. RESULTS: MVC and ROM significantly decreased while DOMS significantly increased until 3 days after ECC. The CSA of the brachialis significantly increased after ECC. The T2 in biceps brachii and middle and distal brachialis increased significantly at post (p < 0.01) day 1 (middle; p < 0.01, distal; biceps brachii, p < 0.05, brachialis, p < 0.01), and day 3 (middle; p < 0.01, distal; biceps brachii, p < 0.05, brachialis, p < 0.01). In addition, after 5 days only the distal brachialis has shown a significant increase (p < 0.01). CONCLUSIONS: Following maximal ECC the activation pattern and muscle damage differ among the elbow flexors depending upon the individual muscle and site of recording. [ABSTRACT FROM AUTHOR]

Purpose: Neuromuscular electrostimulation (NMES) leads to a spatially fixed, synchronous, and superficial motor unit recruitment, which could induce muscle damage. Therefore, the extent of muscle damage and its spatial occurrence were expected to be heterogeneous across and along the quadriceps femoris (QF) muscles. The aim of the present study was to characterize muscle spatial heterogeneity in QF damage after a single bout of isometric NMES using multimodal magnetic resonance imaging (MRI). Methods: Twenty-five young healthy males participated in this study. MRI investigations consisted of the assessment of muscle volume, transverse relaxation time (T2), and diffusion tensor imaging (DTI) in muscles positioned near the stimulation electrodes (i.e., vastus lateralis (VL) and vastus medialis (VM)) and muscles located outside the stimulated regions (i.e., vastus intermedius and rectus femoris). These measurements were performed 6 d before, and 2 d and 4 d (D4) after the NMES session. Results: For the muscles placed in direct contact with the stimulation electrodes, volume (VL, +8.5%; VM, +3.8%), T2 (VL, +19.5%; VM, +6.7%) and radial diflusivity (λ3) (VL, + 7.3%; VM, +3.7%) significantly increased at D4. Whereas MRI parameter changes were larger for VL as compared with those for other QF muscles at D4, homogeneous alterations were found along all QF muscles. Conclusions: Isometric NMES induced specific and localized alterations in VL and VM, with heterogeneous damage amplitude among them. Potential effects of unaccustomed intermuscle shear stress during electrically evoked isometric contractions could be a key factor in the spatial occurrence and the extent of damage among QF muscles (especially in VL). The kinetics and extent of MRI changes varied between T2 and diffusion tensor imaging metrics, suggesting the involvement of different physiological processes. [ABSTRACT FROM AUTHOR]

Modeling the anisotropic behavior of the nuclear magnetic resonance (NMR) transverse relaxation time (T 2) allows to investigate the fibril nanostructure of biological samples (fresh celery sample in the attached Figure). Sample's nanoarchitecture was modeled as a set of water filled nanocavities (Panel 'a'). θ s is the angle between the external magnetic field and the sample's main axis Z s. θ n denotes the angle between the external magnetic field H 0 and the axis of a n -th nanocavity (Z n). Z 0 axis represents the averaged orientation of the ensemble of all nanocavities. To account for deviations of the nanocavities' orientations from Z 0 we defined the polar ζ and azimuthal ξ angles, reflecting the deviation of the main axis of each specific nanocavity (Z n) from the main Z s axis. Lastly, ζ 0 and ξ 0 are the polar and azimuthal angles which determine the deviation of the Z 0 -axis from the Z s -axis. The presented framework can be utilized explain the anisotropy the T 2 relaxation time, and specifically to determine the degree of orientational ordering of the nanocavities, their characteristic volume, and their average direction with respect to the macroscopic sample. Results show good agreement between theory and experimental data (Panel 'b'), which are, moreover, supported by optical microscopy. The quantitative NMR approach presented herein can be potentially used to determine the internal ordering of biological tissues noninvasively. [Display omitted] • We investigate of the angular dependence of NMR's transverse (T 2) relaxation time. • Used model is a fresh celery stem having ordered nanoscale architecture. • A new theoretical model can extract nanocavities orientational ordering and volume. • Model can be applied for probing nanostructure of biological tissues and materials. This study investigates the fibril nanostructure of fresh celery samples by modeling the anisotropic behavior of the transverse relaxation time (T 2) in nuclear magnetic resonance (NMR). Experimental results are interpreted within the framework of a previously developed theory, which was successfully used to model the nanostructures of several biological tissues as a set of water filled nanocavities, hence explaining the anisotropy the T 2 relaxation time in vivo. An important feature of this theory is to determine the degree of orientational ordering of the nanocavities, their characteristic volume, and their average direction with respect to the macroscopic sample. Results exhibit good agreement between theory and experimental data, which are, moreover, supported by optical microscopic resolution. The quantitative NMR approach presented herein can be potentially used to determine the internal ordering of biological tissues noninvasively. [ABSTRACT FROM AUTHOR]

• Physical improvement of steel slag cement by HEMC is confirmed and analyzed. • Ultra-fine grinding is able to improve reactivity of steel slag remarkably. • Calcium ion complexation enhanced the dissolution of SCMs. • HEMC leads to a new peak in T 2 pattern of 1H NMR. The applications of steel slag (SS) in the cement industry provide a sustainable solution both for construction materials and industrial solid wastes, but the problem of easily bleeding presents a threat to its later performance and utilization efficiency. This work was designed to improve the water retention of SS blended cement by using hydroxyethyl methyl cellulose (HEMC) and evaluate the physio-chemical properties of the modified SS cement. The interaction mechanism between HEMC and SS blended cement was explored via calorimetry, acoustic and electroacoustic spectrometer, low-field NMR relaxometry, XRD, TG-DSC, as well as fluorescent microscopy. Results show that the water retention of SS blended cement mortar is improved both by ultra-fine grinding and incorporating HEMC, while the water retention rates are prominently increased from 84.87% to 94.35% by 0.1% HEMC. Ultra-fine grinding is able to activate SS and improve water retention ability more efficient compared with the application of HEMC. HEMC does not modify the amount of hydration heat but postpones the occurrence of the exothermic peak. A sudden increase in zeta potential demonstrates the Ca2+-adsorption on surfaces of SCM and cement particles. An additional peak commences on the 1H NMR spectrum of HEMC incorporated cement paste, which reflects the water adsorbed by HEMC, starting to submerge after 500 min via the desorption of water. HEMC affects the SS blended mortar via adsorbing on particles in the paste, capturing water and Ca2+ around it, thus improving the water retention and retarding the hydrate-polymerization. [ABSTRACT FROM AUTHOR]

Traditional magnetic relaxation switching (MRS) biosensors suffer from poor sensitivity and unsatisfactory stability. In this study, a polydopamine (PDA) nanoparticles (NPs)-Cu2+ chelate complex mediated signal conversion system and a Cu+-catalyzed click chemistry triggered magnetic signal amplification system were evaluated and dynamically integrated into an MRS biosensor. Owing to abundant functional groups and a large surface area, PDA NPs enabled the absorption of a large amount of Cu2+ ions by chelation. The residual Cu2+ ions can be reduced with sodium ascorbate to Cu+, which could initiate the click reaction between azide-functionalized magnetic NPs (MNPs) and alkyne-functionalized MNPs that resulted in the production of aggregated nanoclusters. The transverse relaxation time (T 2) depends on the degree of aggregation of MNPs; T 2 is expressed as the magnetic signal readout. In addition, PDA NPs can be easily conjugated with antibodies by mixing, thus providing a straightforward bridge that integrates the immunoassay and magnetic signal readout. Combined with the high capacity of PDA NPs for chelating Cu2+ and high efficiency of click reaction for changing the T 2 signals, the PDA-MRS biosensor enables the detection of chlorpyrifos with a limit of detection of 0.084 ng/mL, providing 22-fold enhancement than traditional enzyme-linked immunosorbent assay (1.86 ng/mL). This demonstrates its great potential for the detection of hazardous chemical molecules in a complex sample matrix. • PDA NP mediated click chemistry is an efficient magnetic relaxation sensing strategy. • PDA NP can absorb Cu2+ ions by chelation and can be covalently attached to antibody. • CuCC-triggered aggregation of MNPs is used to generate and amplify magnetic signals. • The magnetic biosensor detects chlorpyrifos with high sensitivity and good stability. [ABSTRACT FROM AUTHOR]

Purpose: Existing studies have failed to provide evidence of a positive effect on exercise performance by wearing compression short tights covering only both thighs. This could be due to an inadequate pressure intensity that otherwise has a significant effect if applied on the crucial point in the thigh. This study aimed to examine the effect of pressure intensity of elastic compression short-tights on the metabolic state of thigh muscles during submaximal running. Methods: Two groups of 11 male subjects performed treadmill running at 12 km•h1 in three conditions in each of experiment 1 (short-tights with a compression intensity at the thigh of 8 mm Hg (LOW) and 15 mm Hg (MID) and noncompression shorts as control (CON1)) and experiment 2 (short-tights with 20 mm Hg (MID-HIGH) and 25 mm Hg (HIGH) and CON2). Before and immediately after the running exercises, T2-weighted magnetic resonance images of the right thigh were obtained without testing garments. From the images, skeletal muscle proton transverse relaxation time (T2) of each muscle in the thigh was calculated. Results: T2 was significantly increased after the treadmill running in all conditions in the hamstring and adductor muscles. In experiment 1, after the running, T2 elevation was significantly smaller in MID than that in CON1 for the biceps femoris, semimembranosus, adductor longus, and adductor magnus muscles. In experiment 2, after the running, T2 elevation was significantly lower in MID-HIGH than that in CON2 and HIGH for the biceps femoris, semimembranosus, and adductor longus. Conclusions: The findings suggest that wearing compression short tights with a pressure intensity of 15-20 mm Hg at the thigh can reduce development of fatigue of exercising muscles during submaximal running exercise in healthy adult males. [ABSTRACT FROM AUTHOR]

Purpose: During constant work rate exercise above the lactate threshold (LT), the initial rapid phase of pulmonary oxygen uptake ( $$\dot{V}$$ O) kinetics is supplemented by an additional $$\dot{V}$$ O slow component ( $$\dot{V}$$ O) which reduces the efficiency of muscular work. The $$\dot{V}$$ O amplitude has been shown to increase with maturation but the mechanisms are poorly understood. We utilized the transverse relaxation time ( T) of muscle protons from magnetic resonance imaging (MRI) to test the hypothesis that a lower $$\dot{V}$$ O slow component ( $$\dot{V}$$ O) amplitude in children would be associated with a reduced muscle recruitment compared to adults. Methods: Eight boys (mean age 11.4 ± 0.4) and eight men (mean age 25.3 ± 3.3 years) completed repeated step transitions of unloaded-to-very heavy-intensity (U → VH) exercise on a cycle ergometer. MRI scans of the thigh region were acquired at rest and after VH exercise up to the $$\dot{V}$$ O time delay (ScTD) and after 6 min. T for each of eight muscles was adjusted in relation to cross-sectional area and then summed to provide the area-weighted Σ T as an index of thigh recruitment. Results: There were no child/adult differences in the relative $$\dot{V}$$ O amplitude [Boys 14 ± 7 vs. Men 18 ± 3 %, P = 0.15, effect size (ES) = 0.8] during which the change (∆) in area-weighted Σ T between the ScTD and 6 min was not different between groups (Boys 1.6 ± 1.2 vs. Men 2.3 ± 1.1 ms, P = 0.27, ES = 0.6). A positive and strong correlation was found between the relative $$\dot{V}$$ O amplitude and the magnitude of the area-weighted ∆Σ T in men ( r = 0.92, P = 0.001) but not in boys ( r = 0.09, P = 0.84). Conclusions: This study provides evidence to show that progressive muscle recruitment (as inferred from T changes) contributes to the development of the $$\dot{V}$$ O during intense submaximal exercise independent of age. [ABSTRACT FROM AUTHOR]

Objective: To evaluate gestational age-dependent changes in the T2 relaxation time in normal murine placentas in vivo. The role of susceptibility-weighted imaging (SWI) in visualization of the murine fetal anatomy was also elucidated. Methods: Timed-pregnant CD-1 mice at gestational day (GD) 12 and GD17 underwent magnetic resonance imaging. Multi-echo spin echo and SWI data were acquired. The placental T2 values on GD12 and GD17 were quantified. To account for the influence of systemic maternal physiological factors on placental perfusion, maternal muscle was used as a reference for T2 normalization. A linear mixed-effects model was used to fit the normalized T2 values, and the significance of the coefficients was tested. Fetal SWI images were processed and reviewed for venous vasculature and skeletal structures. Results: The average placental T2 value decreased significantly on GD17 (40.17 ± 4.10 ms) compared to the value on GD12 (55.78 ± 8.13 ms). The difference in normalized T2 values also remained significant (p = 0.001). Using SWI, major fetal venous structures like the cardinal vein, the subcardinal vein, and the portal vein were visualized on GD12. In addition, fetal skeletal structures could also be discerned on GD17. Conclusion: The T2 value of a normal murine placenta decreases with advancing gestation. SWI provided clear visualization of the fetal venous vasculature and bony structures. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: Duchenne muscular dystrophy (DMD) is characterized by an increased muscle damage and progressive replacement of muscle by noncontractile tissue. Both of these pathological changes can lengthen the MRI transverse proton relaxation time (T2). The current study measured longitudinal changes in T2 and its distribution in the lower leg of 16 boys with DMD (5–13years, 15 ambulatory) and 15 healthy controls (5–13years). These muscles were chosen to allow extended longitudinal monitoring, due to their slow progression compared with proximal muscles in DMD. In the soleus muscle of boys with DMD, T2 and the percentage of pixels with an elevated T2 (⩾2SD above control mean T2) increased significantly over 1year and 2years, while the width of the T2 histogram increased over 2years. Changes in soleus T2 variables were significantly greater in 9–13years old compared with 5–8years old boys with DMD. Significant correlations between the change in all soleus T2 variables over 2years and the change in functional measures over 2years were found. MRI measurement of muscle T2 in boys with DMD is sensitive to disease progression and shows promise as a clinical outcome measure. [Copyright &y& Elsevier]

The purpose of this study was to examine the changes in the metabolic state of quadriceps femoris muscles using transverse relaxation time (T2), measured by muscle functional magnetic resonance (MR) imaging, after inactive or active recovery exercises with different intensities following high-intensity knee-extension exercise. Eight healthy men performed recovery sessions with four different conditions for 20 min after high-intensity knee-extension exercise on separate days. During the recovery session, the participants conducted a light cycle exercise for 20 min using a cycle (50%, 70% and 100% of the lactate threshold (LT), respectively: active recovery), and inactive recovery. The MR images of quadriceps femoris muscles were taken before the trial and after the recovery session every 30 min for 120 min. The percentage changes in T2 for the rectus femoris and vastus medialis muscles after the recovery session in 50%LT and 70%LT were significantly lower than those in either inactive recovery or 100%LT. There were no significant differences in those for vastus lateralis and vastus intermedius muscles among the four trials. The percentage changes in T2 of rectus femoris and vastus medialis muscles after the recovery session in 50%LT and 70%LT decreased to the values before the trial faster than those in either inactive recovery or 100%LT. Those of vastus lateralis and vastus intermedius muscles after the recovery session in 50%LT and 70%LT decreased to the values before the trial faster than those in 100%LT. Although the changes in T2 after active recovery exercises were not uniform in exercised muscles, the results of this study suggest that active recovery exercise with the intensities below LT are more effective to recover the metabolic state of quadriceps femoris muscles after intense exercise than with either intensity at LT or inactive recovery. [ABSTRACT FROM PUBLISHER]

PURPOSE: Muscle hypertrophy in response to resistance training has been reported to occur nonuniformly along the length of the muscle. The purpose of the present study was to examine whether the regional difference in muscle hypertrophy induced by a training intervention corresponds to the regional difference in muscle activation in the training session. METHODS: Twelve young men participated in a training intervention program for the elbow extensors with a multijoint resistance exercise for 12 wk (3 d·wk). Before and after the intervention, cross-sectional areas of the triceps brachii along its length were measured with magnetic resonance images. A series of transverse relaxation time (T2)-weighted magnetic resonance images was recorded before and immediately after the first session of training intervention. The T2 was calculated for each pixel within the triceps brachii. In the images recorded after the session, the number of pixels with a T2 greater than the threshold (mean + 1 SD of T2 before the session) was expressed as the ratio to the whole number of pixels within the muscle and used as an index of muscle activation (percent activated area). RESULTS: The percent activated area of the triceps brachii in the first session was significantly higher in the middle regions than that in the most proximal region. Similarly, the relative change in cross-sectional area induced by the training intervention was also significantly greater in the middle regions than the most proximal region. CONCLUSION: The results suggest that nonuniform muscle hypertrophy after training intervention is due to the region-specific muscle activation during the training session. [ABSTRACT FROM AUTHOR]