Te Values Research Articles

NAD(P)H-dependent thioredoxin-disulfide reductase TrxR is essential for tellurite and selenite reduction and resistance in Bacillus sp. Y3.

Microbial reduction of selenite [Se(IV)] and tellurite [Te(IV)] to Se(0) and Te(0) can function as a detoxification mechanism and serve in energy conservation. In this study, Bacillus sp. Y3 was isolated and demonstrated to have an ability of simultaneous reduction of Se(IV) and Te(IV) during aerobic cultivation, with reduction efficiencies of 100% and 90%, respectively. Proteomics analysis revealed that the putative thioredoxin disulfide reductase (TrxR) and sulfate and energy metabolic pathway proteins were significantly upregulated after the addition of Se(IV) and Te(IV). qRT-PCR also showed an increased trxR transcription level in the presence of Se(IV) and Te(IV). Compared with a wild-type Escherichia coli strain, the TrxR-overexpressed E. coli strain showed higher Se(IV) and Te(IV) resistance levels and reduction efficiencies. Additionally, the TrxR showed in vitro Se(IV) and Te(IV) reduction activities when NADPH or NADH were present. When NADPH was used as the electron donor, the optimum conditions for enzyme activities were pH 8.0 and 37°C. The Km values of Te(IV) and Se(IV) were 16.31and 2.91mM, and the Vmax values of Te(IV) and Se(IV) were 12.23 and 11.20 µM min-1 mg-1, respectively. The discovery of the new reductive enzyme TrxR enriches the repertoire of the bacterial Se(IV) and Te(IV) resistance and reduction mechanisms. Bacillus sp. Y3 can efficiently reduce Se(IV) and Te(IV) simultaneously. Strain Y3 provides potential applications for selenite and tellurite bioremediation. The TrxR enzyme shows high catalytic activity for reducing Se(IV) and Te(IV). The discovery of TrxR enriches the bacterial Se(IV) and Te(IV) reduction mechanisms.

Crustal architecture and isostatic compensation of the Comorin Ridge, central Indian Ocean: Implications for the breakup of east Gondwana

The Comorin Ridge, located off the southwest margin of Sri Lanka is an important geological feature with significant relevance to understand the breakup of eastern Gondwanaland. Earlier geophysical studies over this ridge provided several contrasting views due to which its origin and nature of emplacement could not be established very well. In this study, an integrated interpretation of bathymetry, gravity, geoid, and ship-borne magnetic data is carried out to bring out a well-constrained evolution model for the ridge. Results of 3-D gravity inversion of Crustal Bouguer anomalies and joint gravity-magnetic modeling indicate that the southern part of the ridge is underlain by 7–12 km thick crust intruded with volcanic rocks and the presence of 13–18 km of anomalously thicker crust below the northern part of the ridge. Further, crustal models, spatial variations in Geoid-Topography Ratio (GTR), and the effective elastic thickness (Te) value obtained in this study suggest a two-stage emplacement model for the evolution of the ridge. The observed lower Te values (7–8 km) in the southern part (0.5°N–3.5°N) and its proximity to the C34ny spreading anomaly suggest its emplacement on the oceanic lithosphere due to Marion plume activity along a fracture zone during ~88–84 Ma. On the other hand, relatively higher Te values (12.5–15 km) in the northern part (3.5°N–6.5°N) with absence seafloor-spreading magnetic anomalies suggests that it could be a marginal basement high formed at the continent-ocean boundary (COB) during the second phase of rifting between India and Sri Lanka (~94 Ma).

Effective elastic thickness of Zealandia and its implications for lithospheric deformation

Zealandia was once located at the active Gondwana margin and experienced complicated tectonic evolution from continental breakup to subduction and oblique slipping along the plate boundary. Here, we investigate the lithospheric thermal and rheological properties via spatial variations in effective elastic thickness (Te). Using the topography, sediment thickness and gravity data, the fan wavelet coherence method is employed to recover Te values. The effects of dynamic topography and gravity in the subduction zone on the estimated Te are considered and removed. The final results reveal that the Te variation pattern generally coincides well with the tectonic regimes. Relatively high Te values up to 22 km are observed in North Island and the southernmost part of South Island, while central and northern South Island are dominated by smaller Te values (~15 km) similar to those of the surrounding submerged plateaus. We interpret the relatively high Te values as indicating the combined lithospheric strength due to the contacting plates in the subduction zone. To the north along the Tonga-Kermadec subduction zone, the lithosphere surprisingly exhibits anomalously high Te values, ranging from 22 to 36 km, which contradicts the geological evidence of normal faults developed in the incoming Pacific Plate and the magmatism in the overlying Australian Plate that generally contribute to low lithospheric strength. We speculate that the high-Te zone is related to the large bathymetry and gravity anomalies in the bending plate and controlled by non-isostatic factors. Finally, we find widespread low Te values covering the entire arcs and oceanic basins in northern Zealandia, which may indicate that regional lithospheric thinning associated with delamination weakened the integrated strength of the lithosphere.

Structural, thermal and optical characterization of co-existing glass and anti-glass phases of xLa2O3-(100-x)TeO2 and 2TiO2-xLa2O3-(98-x)TeO2 systems

Glass-ceramic, anti-glass and crystalline samples of two systems: xLa2O3-(100-x)TeO2 (x = 5, 7, 10, 12.5, 15 and 20 mol%) and 2TiO2-xLa2O3-(98-x)TeO2 (x = 5, 7 and 10 mol%) were prepared by melt quenching. Glass-ceramic samples are transparent and contain co-existing glass and anti-glass inclusions. Samples with La2O3 concentration greater than 10 mol% required more rapid splat quenching to prepare transparent glass-ceramics whereas the sample with 20 mol% La2O3 produces crystalline monoclinic La2Te4O11 by slow melt quenching and disordered anti-glass phase with the structure of cubic La2Te6O15 by splat quenching. The addition of TiO2 in xLa2O3-(100-x)TeO2 system reduces the size of the inclusions, but it enhances their concentration and also increases the optical transparency and thermal stability of the glasses. Micro-Raman studies found that the Te—O coordination number decreases with an increase in La2O3 mol% and the co-existing glass and anti-glass phases have the same value of average Te—O speciation.

1997 JET DT experiments revisited—comparative analysis of DD and DT stationary baseline discharges

This paper compares the stationary ELMy H-mode baseline 50%–50% deuterium-tritium (DT) mixture discharges in the first high -power JET DT experimental campaign in 1997 (JET-DTE1) with the counterpart 100% deuterium (DD) baseline discharges which have the same engineering parameters, i.e. Ip, Bt, q95, NBI power, plasma shape, no gas dosing, divertor structure, and the carbon wall. There is no difference in profile peaking of Te, Ti, and ne between the DT and the counterpart DD baseline discharges, indicating that there was no isotopic effect on the core transport in the stationary baseline DT discharges in the 1997 JET-DTE1. The core values of Te, Ti, and ne are higher in some DT discharges compared to their counterpart DD discharges, but this is attributed to the higher pedestal values, rather than any improvement in the core transport. The interpretive TRANSP simulations also show that the local heat diffusivity is not consistently different between the DT and the counterpart DD baseline discharges.The baseline discharges in the 1997 JET-DTE1 are also compared to the latest high-power ELMy H-mode baseline DD discharges with an ITER-like wall (ILW) in 2016. Despite the similar effective collisionality and ion heat deposition in the core, it was observed that Ti/Te is consistently close to unity in the 1997 JET-DTE1 discharges, while the 2016 JET baseline discharges have high Ti, exceeding Te, which enabled the highest fusion performance in the ITER-Like Wall. The high rotation frequency was the key factor in increasing Ti/Te in the 2016 JET baseline discharges, and it is also the main difference compared to the stationary baseline discharges in the 1997 JET-DTE1. Based on this, it is prospected that higher rotation frequency is the key factor to achieving high fusion power in the stationary baseline discharges in the 2020 JET-DTE2, and the plasma operation with the low gas dosing and increased torque available in the present NBI system would enable such a high rotation frequency.

Digital marketing in Māori higher education: A case study of Te Wānanga o Aotearoa

The shift to neoliberalism in the 1980s meant that higher education in Aotearoa New Zealand became business-orientated—a situation which prevails today (Narayan, 2020; Olssen, 2002). The digitisation of business means that for businesses to remain relevant, they must embrace digital marketing (Herhausen et al., 2020; Makrides et al., 2020). Indeed, in higher education, too, the need for digital marketing is inescapable (Sawlani & Susilo, 2020). This paper will discuss digital marketing in higher education and will look specifically at some aspects of the digital marketing approach of Te Wānanga o Aotearoa. This paper will begin with a very brief history of Māori business during the early colonial period, as well as a short description of contemporary Māori business. This article will discuss the most current understandings of digital marketing in higher education. Importantly, this paper will use the three relationship marketing success factors identified by John (2020)—trust, commitment, and service orientation—and relate these to the four values of Te Wānanga o Aotearoa (2020)—Te Aroha, Te Whakapono, Ngā Ture, and Kotahitanga—as a means of identifying gaps in Te Wānanga o Aotearoa’s current digital marketing approach.

Improved visualization of diffusion-prepared MR neurography (SHINKEI) in the lumbosacral plexus combining high-intensity reduction (HIRE) technique

PurposeThis study attempted to improve visualization of the pelvic nervous system using the high-intensity reduction (HIRE)-nerve-SHeath signal increased with INKed rest-tissue RARE Imaging (SHINKEI) technique that involves subtracting signals of 3D heavily T2W images from SHINKEI images. We identified the optimum TE value for 3D heavily T2W images and assessed the usefulness of the HIRE-SHINKEI technique. Materials and methodsCoronal lumbosacral plexus images were acquired from six healthy volunteers at 3 T. We optimized the TE of the 3D heavily T2-weighted (T2W) images in HIRE-SHINKEI and compared HIRE-SHINKEI images with conventional SHINKEI images with respect to nerve depiction, and vein, bladder, and cerebrospinal fluid (CSF) signal suppression using a 5-point scale. ResultsIn 3D heavily T2W images optimized by HIRE-SHINKEI technique, the signal corresponding to nerves became significantly lower at TE = 400 ms (p < 0.0005), while that of veins occurred at TE = 400 ms and 600 ms (p < 0.05). The suppression of bladder signals was significant at TE = 400, 600, and 800 ms (p < 0.05); however, there was no difference in signal inhibition from CSF at all TEs tested. Based on these results, an optimal TE of 600 ms was identified for 3D heavily T2W images; these images corresponded to the minimal loss of nerve signal and simultaneous maximum subtraction of signals from the bladder, vein, and CSF with dissimilar T2 values. Compared with SHINKEI images, the optimized HIRE-SHINKEI images selectively delineated nerves in greater detail, and along with significant signal suppression of the bladder (p < 0.0001) and veins (p < 0.05). ConclusionHIRE-SHINKEI can be used to better visualize the lumbosacral plexus with higher signal suppression of other pelvic structures. Such detailed Magnetic resonance neurography and selective depiction of nerves are useful for the diagnosis of peripheral nerve disorders.

Advanced single voxel 1 H magnetic resonance spectroscopy techniques in humans: Experts' consensus recommendations.

Conventional proton MRS has been successfully utilized to noninvasively assess tissue biochemistry in conditions that result in large changes in metabolite levels. For more challenging applications, namely, in conditions which result in subtle metabolite changes, the limitations of vendor-provided MRS protocols are increasingly recognized, especially when used at high fields (≥3 T) where chemical shift displacement errors, B0 and B1 inhomogeneities and limitations in the transmit B1 field become prominent. To overcome the limitations of conventional MRS protocols at 3 and 7 T, the use of advanced MRS methodology, including pulse sequences and adjustment procedures, is recommended. Specifically, the semiadiabatic LASER sequence is recommended when TE values of 25-30 ms are acceptable, and the semiadiabatic SPECIAL sequence is suggested as an alternative when shorter TE values are critical. The magnetic field B0 homogeneity should be optimized and RF pulses should be calibrated for each voxel. Unsuppressed water signal should be acquired for eddy current correction and preferably also for metabolite quantification. Metabolite and water data should be saved in single shots to facilitate phase and frequency alignment and to exclude motion-corrupted shots. Final averaged spectra should be evaluated for SNR, linewidth, water suppression efficiency and the presence of unwanted coherences. Spectra that do not fit predefined quality criteria should be excluded from further analysis. Commercially available tools to acquire all data in consistent anatomical locations are recommended for voxel prescriptions, in particular in longitudinal studies. To enable the larger MRS community to take advantage of these advanced methods, a list of resources for these advanced protocols on the major clinical platforms is provided. Finally, a set of recommendations are provided for vendors to enable development of advanced MRS on standard platforms, including implementation of advanced localization sequences, tools for quality assurance on the scanner, and tools for prospective volume tracking and dynamic linear shim corrections.

Plasma diagnostic of gliding arc discharge at atmospheric pressure

A gliding arc discharge (GAD) with a water spray system was constructed. A non-thermal plasma, generated between two V shaped electrodes in an ambient argon driven by 100 Hz AC voltage, was investigated using optical emission spectroscopy (OES) with different gas flow rates (0.5, 1, 1.5, 2 , 2.5 , 3 1/min). Boltzmann plot method was used to calculate electron temperature (Te) and electron density (ne). The electrodes design was spectrally recognized and its Te value was about 0.588-0.863 eV, while the ne value of 6.875×1017-10.938×1017 cm-3. The results of the plasma diagnostics generated by gliding arc showed that increasing gas flow rates was associated with decreased electron temperature (Te), Debye length, and Debye Number, along with decreased electron density (ne) and plasma frequency.

Uncertainty estimates in point-velocity measurements due to exposure time by functions that assimilate ISO-1088 data & statistically based on the time scale of the very-large-scale flow motions

The International Standard Organization Standard ISO 1088 provides a methodology to estimate total uncertainty in measurements of discharge by velocity-area methods. Table G.3 in ISO 1088 lists two sets of uncertainty estimates of point-mean velocity measurements due to time of exposure Te and space resolution based on prior knowledge (Type B uncertainty estimates). The two sets include uncertainty estimates for point-mean velocities measured over times of exposure of 30, 60, 120 and 180 s, one for measurements made at 0.2, 0.4 and 0.6D (D = flow depth) from the free surface, the other for measurements made at 0.8 and 0.9D. Here, we apply an incomplete similarity technique to assimilate the data in Table G.3 to formulae of the form uVm/Vm=a(Te)+b(Te)e−c(Te)Vm, where Vm = measured point-man velocity, uVm = standard uncertainty, and a(Te),b(Te) and c(Te) are parameters that vary with Te. These formulae allow us to estimate uVm/Vm due to Te for values of Vm and Te within the range of values in Table G.3 without the need of interpolation. Hence it simplifies an important step in the computation of the total uncertainty in discharge measurements by the velocity-area methods following the ISO 1088 Standard. In addition to the proposed formulae to assimilate Type B uncertainty estimates in ISO 1088, we present an approach useful to get estimates of uVm/Vm due to Te by statistical methods, based on the period of the very-large-scale flow motions (VLSMs). The period of the VLSMs, Tz, which scales with the flow depth D and the mean-channel velocity U as Tz ≈ (10–20) D/U, provides a plausible time scale to determine the number n of independent samples in point-mean velocity measurements made over a time of exposure Te. We show that determining the number of independent events that contribute to the total variance of point-mean velocity measurements as n ~ Te/Tz can be used to estimate uVm/Vm due to Te by statistical methods (Type A uncertainty estimates). We illustrate the application of this approach to obtain Type A estimates of uVm/Vm for records of point-velocity measurements made in an open-channel with high-frequency, acoustic point-velocity meters and contrast them with Type B estimates.

Small for gestational age birth may increase airflow limitation in bronchopulmonary dysplasia.

To determine significant indices for assessing the pulmonary function of infants according to bronchopulmonary dysplasia (BPD) severity and to evaluate whether small for gestational age (SGA) could affect pulmonary function in BPD. We evaluated 117 preterm infants who had undergone tidal breathing flow-volume loop and multiple-breath washout analyses within 7 months after birth. We categorized preterm infants according to BPD severity into mild/moderate BPD (n = 86), severe BPD (n = 21), and without BPD (n = 10) and the presence of SGA or appropriate gestational age (AGA) using the Fenton growth chart. We evaluated nine healthy term infants as controls. The tidal breathing ratio (time to peak expiratory flow/expiratory time [tPEF /tE ]) was significantly lower in infants with severe BPD than in those with mild/moderate BPD. Lung clearance index (LCI) was not different based on BPD severity. In the correlation analysis after adjusting for gestational age and sex, tPEF /tE was correlated with the duration of mechanical ventilation (r = -0.347, P < .001) and the duration of oxygen supply (r = -0.248, P = .013) in infants with BPD. The proportion of "lower tPEF /tE ," defined as below the cut-off value, was greater in SGA infants (P = .017), while no significant difference was seen in the percentage of "higher LCI," defined as above the cut-off value between SGA and AGA infants. In infants with BPD, tPEF /tE could be a useful pulmonary index which shows lower values in severe BPD. The finding of SGA in infants with BPD could be associated with poor pulmonary function related to the tPEF /tE values.

Sintesis dan Potensi Aktivitas Tabir Surya Senyawa Analog Kalkon Turunan 3’-Hidroksiasetofenon dan 4-Metoksibenzaldehid

Chalcone analogues have attracted the attention of researchers due to their various biological activities. In this study, a chalcone analogue, (E)-1-(3-hydroxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-on has been synthesized under microwave irradiation and its sunscreen activity has been evaluated by in vitro assay using 96-well microplate reader. Based on the in vitro assay, at concentration of 100-500 µg/ml, the compound showed potential sunscreen activity with %Te value of 5.49 – 0.04 % (extra protection – sunblock), %Tp value of 0.51-0.05 % (sunblock) and SPF value of 18.20 – 32.91 (ultra protection). The assay result showed that the (E)-1-(3-hydroxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-on has a potency to be developed as active ingredient in sunscreen product.

Uji Aktivitas Tabir Surya Ekstrak Metanol Kulit Batang Kersen (Muntingia calabura L.) Secara In Vitro

ABSTRACT&#x0D; Kersen (Muntingia calabura L.) is a plant that is usually useful as a shade tree on the side of the road, which is thought to have the potential with sunscreen activity. This study aim to determine sunscreen activity of the bark based on %Te, %Tp and SPF values ??in vitro. The extraction was done by maceration using methanol solvent, and then phytochemical screening by color reaction test that showed the presence of flavonoids, phenolics, tannins, saponins, and terpenoid. Sunscreen activity and SPF values ??were determined by measuring the absorbance of extracts with several variations of concentration, using spectrophotometer. The results showed the best concentration for the sunscreen category was 700 ppm. Based on the value of %Te and %Tp, including standard suntan and sunblock categories. While based on the SPF value &gt;15 shows that methanol extract is included in the category of ultra protection.

Lithospheric strength of the Caroline Islands and its tectonic implications

The Caroline Islands are located in a broad zone near plate boundaries in southwestern Pacific. Accumulating evidence suggests that the hotspot origin alone cannot completely explain the formation of the Caroline Islands. To investigate the tectonic setting of their formation, we calculated the effective elastic thickness (Te) of the lithosphere beneath the Caroline Islands from an analysis of bathymetry and free-air gravity anomaly data by the admittance method. A synthetic model based on the actual bathymetry data of the Caroline Islands was developed for the finite window size biasing correction. The results show that the Te values of the Caroline Islands (4.5–11.5 km) are significantly lower than the Te expected for a normal oceanic lithosphere (23–50 km), and that the Te values can be approximated by the depth to the 150 ± 100°C isotherm. The low Te values indicate that the strength of the lithosphere beneath the Caroline Islands has been weakened by geological process. The thermal anomalies related to the Ontong Java Plateau and the South Pacific Isotopic and Thermal Anomaly, and the lithospheric fractures induced by interaction of plates are probable causes of the lithospheric strength reduction of the Caroline Islands.

Charge transport mechanism and thermoelectric behavior in Te:(PEDOT:PSS) polymer composites

Polymer thermoelectics are an emerging class of materials for realizing flexible thermoelectric devices due to its low cost, solution processability and bio-compatibility. We report a systematic investigation of the charge transport and thermoelectric properties of polymer composites comprising of tellurium (Te) nanorods and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) spanning over a temperature range from 10 K up to 320 K. The temperature dependence of electrical resistivity for Te:(PEDOT:PSS) composites is dominated by the thermal assisted hopping following Mott’s and Efros-Shklovskii (ES) variable range hopping (VRH) mechanism. A cross-over from ES to Mott VRH model is observed near 105 K. The Seebeck coefficient and the electrical resistivity values for Te:(PEDOT:PSS) composites are found to decrease with the increase in PEDOT:PSS concentration at 300 K. Moreover, the thermal conductivity of the polymer composites is found to decrease due to enhanced phonon-phonon scattering ascribed to the acoustical mismatch between the Te-nanorods and PEDOT:PSS interface. The maximum thermoelectric figure of merit, ZT, of the polymer composites is estimated to be 0.013 ± 0.001 for Te:(PEDOT:PSS) (1:5) weight percentage. The bending test done on the polymer composite film and mechanical properties investigated using nanoindentation technique suggest the flexible nature of the composite sample which is promising for room temperature flexible thermoelectric application.

PENENTUAN NILAI SPF EKSTRAK DAN LOSIO TABIR SURYA EKSTRAK ETANOL DAUN KERSEN (Muntingia calabura L.) DENGAN METODE SPEKTROFOTOMETRI UV-VIS

Excessive and prolonged sun exposure can cause erythema and sunburn, premature aging and skin cancer. Kersen leaves contain total flavonoids and phenolics which can be used as active ingredients for making sunscreen lotion. This study was to determine the SPF value, the value of erythema transmission (% Te) and the value of pigmentation Transmission (% Tp) from extracts and lotions of kersen ethanol extract using the Uv-Vis spectrophotometric method. Absorbance increases at wavelengths of 290-400 nm at intervals of 5 nm. The results showed SPF extract values ​​with a composition of 500 ppm, 1000 ppm, and 2000 ppm combined - 12 were 12.15 (maximum ability); 17,29 (ultra protection); and 22.01 (ultra protection). % Te value 0.54; 0.16 and 0.05 all include the total block category,% value Tp 2.50; 1.30 and 0.49 (total blocks). Whereas for losio with a concentration of 0.5%, 1% and 2% respectively the SPF value produced is 3.61 (minimum protection); 8.18 (maximum protection) and 10.13 (maximum protection). % Te value 4.29 (extra protection); 1.58 (extra protection) and 0.99 (maximum protection). % value Tp 9.30; 4.22 and 2.80 are all included in the total block category.&#x0D; Keywords : kersen leaves, sunscreen lotion, SPF, erythema transmission, pigmentation transmission

T2 mapping in orbital masses: preliminary study on differential diagnostic ability of T2 relaxation time.

Background T2 mapping has been proven to be useful in tumor characterization. As to orbital masses, its diagnostic value needs to be investigated. Purpose To evaluate the usefulness of T2 mapping in orbital masses and the ability of T2 relaxation time in differentiating malignant from benign orbital masses. Material and Methods Forty-seven patients with solid orbital masses (33 benign and 14 malignant) who underwent T2 mapping examination for preoperative assessment were enrolled in the current study. T2 mapping was acquired using 16 TE values (range 12–192 ms; delta TE 12 ms). Mean T2 relaxation time was calculated based on the whole mass region of interest and compared between the malignant and benign groups using the unpaired t-test. Receiver operating characteristic curve analysis was adopted to calculate its diagnostic value. Results Malignant orbital masses showed significantly lower T2 relaxation time than benign masses (76.4 ± 13.0 ms vs. 119.1 ± 20.4 ms; P &lt; 0.001). If setting a T2 relaxation time of 89.5 ms as the threshold value, optimal differentiating performance could be achieved (area under the curve 0.936; sensitivity 100.0%; specificity 87.9%; accuracy 91.5%; positive predictive value 77.8%; negative predictive value 100%). Conclusion T2 mapping and its derived T2 relaxation time could provide quantitative information and serve as a supplementary imaging marker for differentiating malignant from benign orbital masses.

Model‐Informed Approach to Assess the Treatment Effect Conditional to the Level of Placebo Response

One of the most important reasons for failure of placebo-controlled randomized controlled clinical trials (RCTs) is the lack of appropriate methodologies for detecting treatment effect (TE; difference between placebo and active treatment response) in the presence of excessively low/high levels of placebo response. Although, the higher the level of placebo response in a trial, the lower the apparent detectable TE. TE is usually estimated in a conventional analysis of an RCT as an "apparent" TE value conditional to the level of placebo response in that RCT. A model-informed methodology is proposed to establish a relationship between level of placebo response and TE. This relationship is used to estimate the "typical" TE associated with a "typical" level of placebo response, irrespective of the level of placebo response observed. The approach can be valuable for providing a reliable estimate of TE, for conducting risk/benefit analysis, and for determining dosage recommendations.

Dual-Echo Arterial Spin Labeling for Brain Perfusion Quantification and Functional Analysis

Arterial Spin Labeling (ASL) is a noninvasive MRI-based method to measure cerebral blood flow (CBF). Recently, the study of ASL as a functional tool has emerged once CBF fluctuation comes from capillaries in brain tissue, giving a more spatially specific response when compared to the standard functional MRI method, based on the blood oxygenation level-dependent (BOLD) contrast. Although the BOLD effect could be desirable to study brain function, if one aims to quantify CBF, such effect is considered contamination that can be more attenuated if short TE value is used in the image acquisition. An approach that provides both CBF and function information in a simultaneous acquisition is the use of a dual-echo ASL (DE-ASL) readout. Our purpose was to evaluate the information provided by DE-ASL regarding CBF quantification and functional connectivity with a motor task. Pseudocontinuous ASL of twenty healthy subjects (age: 32.4 ± 10.2 years, 13 male) was acquired at a 3T scanner. We analyzed the influence of TE on CBF values and brain connectivity provided by CBF and concurrent BOLD (cc-BOLD) time series. Brain networks were obtained by the general linear model and independent component analysis. Connectivity matrices were generated using a bivariate correlation (Fisher Z values). No effect of the sequence readout, but significant effect of the TE value, was observed on gray matter CBF values. Motor networks with reduced extension and more connections with important regions for brain integration were observed for CBF data acquired with short TE, proving its higher spatial specificity. Therefore, it was possible to use a dual-echo readout provided by a standard commercial ASL pulse sequence to obtain reliable quantitative CBF values and functional information simultaneously.

The Gravitational Signature of Martian Volcanoes

AbstractBy modeling the elastic flexure of the Martian lithosphere under imposed loads, we provide a systematic study of the old and low‐relief volcanoes (&gt;3.2 Ga, 0.5 to 7.4 km) and the younger and larger prominent constructs within the Tharsis and Elysium provinces (&lt;3 Ga, 5.8 to 21.9 km). We fit the theoretical gravitational signal to observations in order to place constraints on 18 volcanic structures. Inverted parameters include the bulk density of the load, the elastic thickness required to support the volcanic edifice at the time it was emplaced (Te), the heat flow, the volume of extruded lava, and the ratio of volcanic products that form within (Vi) and above the preexisting surface (Ve). The bulk density of the volcanic structures is found to have a mean value of 3,206±190 kg/m3, which is representative of iron‐rich basalts as sampled by the Martian basaltic meteorites. Te beneath the small volcanoes is found to be small, less than 15 km, which implies that the lithosphere was weak and hot when these volcanoes formed. Conversely, most large volcanoes display higher values of Te, which is consistent with the bulk of their emplacement occurring later in geologic history, when the elastic lithosphere was colder and thicker. Our estimates for the volumes of volcanic edifices are about 10 times larger than those that neglect the flexure of the lithosphere. Constraints on the magnitude of subsurface loads imply that the ratio Vi/Ve is generally 3:5, which is smaller than for the Hawaiian volcanoes on Earth.