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Detailed understanding of ionic behavior in the region near a charged surface is important for the enhancement of water filtration mechanisms. In this study, a highly charged membrane is hypothesized to form an ion depletion zone (IDZ) without an external power supply. The formation of IDZ was experimentally investigated using membranes with varying surface zeta potential (SZP) values to confirm the hypothesis. The surface zeta potential of the charged membrane was controlled by layer-by-layer deposition method. Our results indicate that indicated that the fluorescent intensity near the charged surface becomes weaker with an increased absolute magnitude of SZP. Ionic surfactants enhance the formation of IDZ by increasing SZP magnitude, and by forming a secondary filtration layer. These findings provide information that is helpful in understanding the ionic behavior near the highly charged surface. In addition, the information provided by the findings would be helpful in fabricating a small-scale water filtration device. [ABSTRACT FROM AUTHOR]

Many precision magnetic measurements can benefit significantly from or even require strong prepolarization fields (Bp) and magnetically shielded environments. We describe here in detail a cancellation coil (CC) which can neutralize the Bp on the electrically conductive shield walls that may otherwise induce currents on the walls to produce a lingering transient residual field (Btr) inside the shielded environment and disrupt the measurement operations. The CC was designed using the inverse problem method to effectively neutralize magnetic fields generated on the shield walls by the Bp coil. The implemented CC was evaluated by measuring Btr using a fluxgate magnetometer at different magnetometer positions and cancellation coil currents (ICC). Multi-mode component analysis on the Btr measurements revealed two dominant components, where the component with shorter time constant comes from the current induced around the shield side walls and the other with longer time constant from the current induced on the ceiling and floor of the magnetically shielded room. The analysis also revealed the optimal ICC for each of the top, side, and bottom sections of the CC, which enables significantly easier fine-tuning of individual sections of the CC to enhance CC performance. [ABSTRACT FROM AUTHOR]

We developed an ultra-low field (ULF)-nuclear magnetic resonance (NMR) measurement system capable of working with a measurement field (Bm) of several micro-tesla and performed basic NMR studies with a double relaxation oscillation superconducting quantum interference device (DROS) instead of conventional dc-SQUIDs. DROS is a SQUID sensor utilizing a relaxation oscillation between a dc-SQUID and a relaxation circuit; the new unit consists of an inductor and a resistor, and is connected in parallel with the SQUID. DROS has a 10 times larger flux-to-voltage transfer coefficient (∼mV/[lowercase_phi_synonym]0) than that of the dc-SQUID, and this large transfer coefficient enables the acquisition of the SQUID signal with a simple flux-locked-loop (FLL) circuit using room temperature pre-amplifiers. The DROS second-order gradiometer showed average field noise of 9.2 μ[lowercase_phi_synonym]0/[Square_Root]Hz in a magnetically shielded room (MSR). In addition, a current limiter formed of a Josephson junction array was put in a flux-transformer of DROS to prevent excessive currents that can be generated from the high pre-polarization field (Bp). Using this system, we measured an 1H NMR signal in water under 2.8 μT Bm field and reconstructed a one-dimensional MR image from the 1H NMR signal under a gradient field BG of 4.09 nT/mm. In addition, we confirmed that the ULF-NMR system can measure the NMR signal in the presence of metal without any distortion by measuring the NMR signal of a sample wrapped with metal. Lastly, we have measured the scalar J-coupling of trimethylphosphate and were able to confirm a clear doublet NMR signal with the coupling strength J3[P,H] = 10.4 ± 0.8 Hz. Finally, because the existing ULF-NMR/MRI studies were almost all performed with dc-SQUID based systems, we constructed a dc-SQUID-based ULF-NMR system in addition to the DROS based system and compared the characteristics of the two different systems by operating the two systems under identical experimental conditions. [ABSTRACT FROM AUTHOR]

We developed a technique to excite the self-oscillation of a commercially available metal-coated cantilever and detect the deflection simultaneously with only a single optical fiber. The technique is based on the fact that the light transmitted to a cantilever in the fiber-optic interferometer induces the photothermal positive feedback to the cantilever oscillation. The model analysis on the cantilever oscillation shows that the product of the slope of an intensity curve and the thermal coefficient of deflection of the cantilever should be greater than the product of the damping parameter and the dynamic heat capacity to excite the self-oscillation, which was confirmed by experiment. It can be used either to excite the self-oscillation in the frequency modulation atomic force microscopy or to avoid it in normal force microscopy. [ABSTRACT FROM AUTHOR]

Spontaneous filtration without a power supply was investigated using highly charged precursor mixtures instead of recognized microfluidic desalination techniques. The proposed filtration method consisted of a main channel (depth: 1 mm) and shallow channels (depth: 400 μm) in which the precursor mixture was injected. The filtration performance of the proposed device was evaluated by injecting a fluorescent dye that moved toward the centerline of the main channel. The respective rejection rates of CaCl 2 , NaCl, CaSO 4 , and Na 2 SO 4 were 3.16%, 30.13%, 43.74%, and 36.32%, respectively. This trend can be explained by the mechanism of Donnan exclusion theory. The focusing of charged species toward the centerline of the main channel was caused by highly charged surfaces. The proposed filtration method exhibited a migration of charged microparticles toward a certain direction. This particle migration behavior was consistent with the simulation data. These results suggested that the proposed filtration method had strong potential for desalinating brackish water or salty surface water without an external power supply. • A spontaneous filtration of ions and charged particles without an external electrical power supply. • Crossly charged channel surfaces had the same surface charge between diagonal-directional shallow channels. • The proposed method exhibited a noticeable filtration performance by focusing charged materials toward a certain direction. • This work can be considered a promising paradigm of nature-inspired desalination technology. [ABSTRACT FROM AUTHOR]

Abstract Bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI) has been popularly employed as an efficient p-dopant that increases the conductivity of a hole transport layer (HTL) in perovskite solar cells and dye-sensitized solar cells. However, the working mechanism of the Li-TFSI dopant is a long-standing question. The hygroscopicity of Li-TFSI makes it difficult to isolate the exact doping mechanism. In this study, we unveil the role of Li-TFSI in the p-doping to the N , N ′-di(1-naphthyl)- N , N ′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) HTL. A series of systematic in situ measurements using ultraviolet and inverse photoelectron spectroscopy reveal that electron transfer from NPB to Li-TFSI occurs due to the lower-lying negative polaronic level of Li-TFSI rather than the positive polaronic level of NPB. The hole injection barrier between NPB and indium tin oxide is significantly reduced with Li-TFSI doping, enhancing the device performance of hole-only devices and organic light-emitting diodes dramatically. With excessive dopants, however, the agglomerative property of Li-TFSI became dominant, decreasing the doping efficiency. These results provide robust guidelines for developing an efficient doping method for a molecular system with high conductivity. Graphical abstract Unlabelled Image Highlights • Electronic structure of Li-TFSI and NPB was investigated using in situ UPS and IPES. • Electron transfer occurred from NPB to Li-TFSI through their polaronic levels. • Hole injection barrier was reduced by 0.70 eV with Li-TFSI doping. • Device performance of OLEDs was significantly enhanced with Li-TFSI doping. • With excessive dopants, agglomeration of Li-TFSI decreased doping efficiency. [ABSTRACT FROM AUTHOR]

Highlights • Lithium is adsorbed by carboxylic acid and phosphonate groups in brown algae. • Brown algae-inspired pMOF@Alg were fabricated. • pMOF@Alg(Cu) exhibits relatively high Li selectivity by size exclusion. • pMOF@Alg(Al) exhibits relatively high Mg selectivity by partial dehydration. • Fabricated alginate hydrogels were reusable by washing with using ethanol/DI water. Abstract With increasing global demands for lithium resources, the separation of lithium from seawater-based resources has been widely explored. Herein, we propose phosphonate metal organic framework (MOF)-incorporated alginate hydrogels inspired by brown algae. The analysis of Li+ adsorption characteristics of brown algae revealed that carboxylic acid and phosphonate groups were the dominant functional groups for Li+ adsorption. Biomimetic phosphonate MOF-incorporated alginate hydrogels (pMOF@Alg) were fabricated on the basis of the Li+ adsorption characteristics of brown algae. Their adsorption behaviors indirectly evaluated by conductivities showed that the growth of phosphonate MOF in Cu2+-based alginate hydrogel enhances Li+ adsorption but inhibits Mg2+ adsorption with a small difference, which might be attributed to size confinement effect by heterogeneously distributed phosphonate MOF. By contrast, the growth of phosphonate MOF homogeneously distributed in Al3+-based alginate hydrogel greatly enhances Mg2+ adsorption while rejecting Li+ adsorption. This reverse adsorption behavior of pMOF@Alg(Al) seems to be attributed to partial dehydration, depending on the dehydration energy of hydrated metal ions. The adsorbed ions are easily removable by using ethanol/DI water because of the weak electrostatic interaction with negatively charged groups. This study would provide novel selective adsorption methodology for the separation of Li+ and Mg2+ and an effective lithium recovery technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • Degradation of blue PhOLEDs consisting of a cohost-dopant type emissive layer (EML) is investigated. • XPS and UPS depth profile technique with Ar gas cluster reveals the changes in chemical states and energy level alignments inside the blue PhOLEDs. • Most molecules are chemically stable upon device operation, and only molecular aggregation of blue dopant is observed. • The energy level mismatch near the EML is observed after the degradation, regardless of the blue dopant doping. Phosphorescent organic light-emitting diodes (PhOLEDs) have been considered potential candidates for high-efficiency blue emission. However, their short lifetime has been an issue, and much effort has been put into resolving this. Among such efforts, understanding energy level alignments (ELA) is one of the essential factors in understanding the degradation. However, ELA inside the actual PhOLED is rarely studied due to technical limitations. Here, we comprehensively investigate the degradation mechanism of blue PhOLEDs consisting of a cohost-dopant type emissive layer (EML). The blue PhOLEDs are aged with typical operating conditions until the luminance performance degrades. Ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS) combined with a damage-free gas cluster ion beam (GCIB) etching and transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDX) unveil the buried interfaces inside the PhOLEDs. XPS and TEM-EDX measurements show that the dopant is unlikely to be the primary origin of the device degradation. Instead, UPS measurements show that the ELAs at the interfaces facing the EML are significantly altered unfavorably after device aging. This implies that the changes in the ELA are the leading cause of PhOLED degradation. Our results highlight the importance of retaining the ELAs during device operation to achieve long-lifetime blue PhOLEDs. [ABSTRACT FROM AUTHOR]

A 3-D cardiac visualization is significantly helpful toward clinical applications of magnetocardiography (MCG), but the cardiac reconstruction requires a segmentation process using additional image modalities. This paper proposes a 3-D cardiac outline reconstruction method using only MCG measurement data without further imaging techniques. The cardiac outline was reconstructed by a combination of both spatial filtering and coherence mapping method. The strength of cardiac activities was first estimated by the array-gain constraint minimum-norm spatial filter with recursively updated gram matrix (AGMN-RUG). Then, waveforms were reconstructed at whole source grids, and the maximum source points of an atrium and ventricle were selected as a reference, respectively. Next, the coherence between each maximum source point and whole source points was compared by the coherence mapping method. A reconstructed cardiac outline was validated by comparing with an overlapped volume ratio when the reconstructed volume was identically matched with the original volume. The results obtained by the AGMN-RUG were compared to the results by other spatial filters. The accuracy of numerical simulation and phantom experiment by the AGMN-RUG was superior 10% and 8%, respectively, than the accuracy by the standardized low-resolution electromagnetic tomography. This accuracy demonstrated the efficacy of the proposed 3-D cardiac reconstruction method. [ABSTRACT FROM PUBLISHER]

Superhydrophobic surfaces (SHS) are attracting attention in many fields owing to their excellent advantages such as anti-freezing, corrosion prevention, and self-cleaning. However, to modify the surface structure, environmental pollution caused by complex processes and chemical treatment must be considered. In this study, the surface of polytetrafluoroethylene (PTFE) was plasma-treated using oxygen and argon plasma to change the surface structure without a complicated process. The PTFE surface was treated in two ways: plasma etching (PE) and reactive ion etching (RIE). The contact angle of the conventional PTFE surface was 113.8 ± 1.4°, but the contact angle of the manufactured surface was 152.3 ± 1.7° and 172.5 ± 1.2°. The chemical composition and physical structure of the samples produced were compared. The treated specimens had the same chemical composition as the specimen before treatment and exhibited differences in their surface structures. Therefore, it was determined that the change in the water repellency was due to the surface structure. After PE treatment, the specimen surface had a mountain range-like structure, and the RIE specimen had a more detailed structure than the PE specimen. The contact rate of water droplets decreased due to the difference in the structure of the specimen before and after treatment, and the increase in the surface contact angle was manifested. In order to confirm that the plasma treatment reduces surface energy, the shape of the liquid collision was observed using a high-speed camera, and the contact time was calculated to confirm water repellency. The contact time of the PE and RIE specimen was 24 milli-second (ms) and 18 ms, respectively. The high contact angle and low sliding angle of the RIE specimen made it easy to restore surface cleanliness in a self-cleaning experiment using graphite. [ABSTRACT FROM AUTHOR]

Abstract: Matching the proton-magnetic-resonance frequency to the frequency of a periodic neural oscillation (e.g., alpha or gamma band waves) by magnetic resonance imaging techniques, enables direct visualization of brain functional connectivity. Functional connectivity has been studied by analyzing the correlation between coherent neural oscillations in different areas of the brain. In electro- or magneto-encephalography, coherent source reconstruction in a source-space is very tricky due to power leaking from the correlation among the sources. For this reason, most studies have been limited to sensor-space analyses, which give doubtful results because of volume current mixing. The direct visualization of coherent brain oscillations can circumvent this problem. The feasibility of this idea was demonstrated by conducting phantom experiments with a SQUID-based, micro-Tesla NMR/MRI system. We introduce an experimental trick, an effective step-up of the measurement B-field in a pulse sequence, to decouple the magnetic resonance signal from the strong magneto-encephalographic signal at the same frequency. [Copyright &y& Elsevier]

Abstract: Atomic magnetometers are emerging as an alternative to SQUID magnetometers for detection of biological magnetic fields. They have been used to measure both the magnetocardiography (MCG) and magnetoencephalography (MEG) signals. One of the virtues of the atomic magnetometers is their ability to operate as a multi-channel detector while using many common elements. Here we study two configurations of such a multi-channel atomic magnetometer optimized for MEG detection. We describe measurements of auditory evoked fields (AEF) from a human brain as well as localization of dipolar phantoms and auditory evoked fields. A clear N100m peak in AEF was observed with a signal-to-noise ratio of higher than 10 after averaging of 250 stimuli. Currently the intrinsic magnetic noise level is 4fTHz−1/2 at 10Hz. We compare the performance of the two systems in regards to current source localization and discuss future development of atomic MEG systems. [Copyright &y& Elsevier]

Microplastics (MPs) and nanoplastics (NPs) have attracted worldwide attention as potential environmental pollutants. However, toxic effects of exposure to MPs and NPs on organisms at developmental stages have not been elucidated yet. In this study, zebrafish embryos at early stage were used to evaluate potential toxic effects of exposure to MPs with diameter of 1 μm and NPs with diameter of 0.4 μm. Solution containing NPs was optically more transparent than solution containing MPs at the same mass concentration. However, exposure to NPs induced significantly higher mortality rate of zebrafish embryos than exposure to MPs. Exposure to MPs or NPs caused pathological changes of caudal vein plexus. In addition, caudal tissues were impaired with inhibition of intact growth of zebrafish embryos. Peripheral microcirculation at caudal region was significantly deteriorated by exposure to MPs or NPs. However, systematic perfusion was still maintained with preservation of RBC velocity profiles regardless of exposure to MPs or NPs. This study provides a new insight to the use of plastics, demonstrating that exposure to MPs or NPs can lead to developmental disorder with significant impairment of growth and peripheral microcirculation dysfunction. • MPs and NPs exposure have toxic effect at developmental stage of zebrafish embryos. • The mortality rate is more affected by NPs exposure compared to MPs exposure. • Pathological angiogenesis of caudal vein plexus is developed with prematurity. • Caudal tissues are impaired with reduced growth. • Peripheral microcirculation dysfunction at caudal region is evolved. [ABSTRACT FROM AUTHOR]

Abstract: A bi-level optimizing control scheme originally proposed for a simulated moving bed (SMB) with linear isotherms has been extended to an SMB with nonlinear isotherms. Cyclic steady state optimization is performed in the upper level to determine the optimum switching period and time-varying feed/desorbent flow rates, and repetitive model predictive control is run in the lower level for purity regulation, taking the decision variables from the upper level as feed-forward information. Experimental as well as numerical study for an SMB process separating a high-concentration mixture of aqueous l-ribose and l-arabinose solutions showed that the proposed scheme performs satisfactorily against various disturbances. In contrast, an alternative scheme based on an SMB model with linear isotherms showed a limitation in the control performance; this scheme was apt to fail in purity regulation. [Copyright &y& Elsevier]

Abstract: Half-metallic Heusler material Co2FeAl0.5Si0.5 (CFAS) nano-particles (NPs) embedded in metal-oxide-semiconductor (MOS) structures with thin HfO2 tunneling and MgO control oxides were investigated. The CFAS NPs were prepared by rapid thermal annealing. The formation of well-controlled CFAS NPs on thin HfO2 tunneling oxide was confirmed by atomic force microscopy (AFM). Memory characteristics of CFAS NPs in MOS devices exhibited a large memory window of 4.65V, as well as good retention and endurance times of 105 cycles and 109 s, respectively, demonstrating the potential of CFAS NPs as promising candidates for use in charge storage. [Copyright &y& Elsevier]

In two-channel microarray experiments, the image analysis extracts red and green fluorescence intensities. The ratio of the two fluorescence intensities represents the relative abundance of the corresponding DNA sequence. The subsequent analysis is performed by taking a log-transformation of this ratio. Therefore, the statistical analyses depend on accuracy of the ratios calculated from the image analysis. However, not many studies have been proposed for developing more reliable ratio statistics. In this paper, we consider a new type of log-transformed ratio statistic. We compare the new ratio statistic with the conventional ratio statistic commonly used in two-channel microarray experiments. First, under the specific log-normal distributional assumption, we compare analytically the new statistics with the conventional ratio statistic. Second, we compare those ratio statistics using a two-channel microarray data obtained by hybridizing a mixture of mouse RNA and yeast in vitro transcript (IVT). Both comparisons show that the proposed ratio statistic performs better than the conventional one. [ABSTRACT FROM AUTHOR]

Abstract: We propose independent component analysis (ICA) as a pre-process for synthetic aperture magnetometry (SAM) in magnetocardiogram. SAM is a very useful method for source current imaging. However, SAM cannot separate one source from the others when there are time-correlated multi-sources, especially for successively active sources. The proposed method compensates the intrinsic drawback of SAM with ICA, which is feasible for 3-D imaging of the myocardial current distribution of specific temporal features. By using our method, we successfully localized an accessory pathway of a patient suffering from the WPW syndrome. [Copyright &y& Elsevier]

Using the method of inverse problem, we designed a cancellation coil that prevents a strong pulsed magnetic field inside a magnetically shielded room (MSR) from magnetizing and inducing large-scale eddy currents around the shielding materials. We implemented this coil with discrete current loops and evaluated it numerically and experimentally. Without the cancellation coil, the transient residual magnetic field in the middle of the MSR was greater than 0.1 μT for 63.5 ms, while the cancellation coil reduced it to less than 0.1 μT after 10.8 ms, shortening the decay time by 83.0%. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy) is a promising conductive polymer (CP) with electrical versatility, easy synthesis and functionalization, stability, and biocompatibility. Diverse architectures have been adopted to improve PPy performance, but the direct and precise patterning of various architectures remains challenging. Here, the unique formation of a PPy membrane on the air/water interface of a droplet solution containing ammonium persulfate and phytic acid is investigated. When a PPy thin film forms on the air/water interface, the top of the droplet rapidly flattens. The formation procedure and final structure of the PPy thin film are visualized and quantitatively investigated. Unlike the typical globular structure of PPy, the self‐assembled PPy film surface fabricated in this study is very organized and regularly shaped. This well‐ordered membrane may have a very high buckling strength greater than the surface tension of the solution. The proposed precise fabrication method is simple and inexpensive for fabricating patterned functional membranes. These results provide new insight into the fabrication of CP and their applications in various practical electromaterial engineering fields. The unique formation of polypyrrole (PPy) thin film on the air/water interface of a droplet solution containing ammonium persulfate and phytic acid is investigated. The self‐assembled PPy film surface is very organized and regularly shaped. Considering that the precise patterning of various architectures hinders the design of conductive polymers, the proposed method is inexpensive and simple for fabricating patterned functional membranes. [ABSTRACT FROM AUTHOR]

Front Cover: The unique formation of a poly(pyrrole) (PPy) membrane, on the air/water interface of a droplet solution containing ammonium persulfate and phytic acid, is investigated in article number 1800707 by Sang Joon Lee and co‐workers. As polymerization occurs at the air/water interface, a blue‐black PPy clearly forms, and the top of the droplet becomes rapidly flattened. The surface of the fabricated PPy thin film has a well‐organized structure of a pretzel shape. [ABSTRACT FROM AUTHOR]

In this study, the spontaneous ion concentration polarization phenomenon induced by pressure via a cation-selective membrane was theoretically and experimentally investigated. Unlike conventional electrokinetic ion concentration polarization, which uses electric current as a driving flux of cations through the membrane, advection caused by pressure is used as a transmembrane driving flux of cations to spontaneously and stably form an ion depletion zone in the present ion concentration polarization technique. The ion depletion zone produced in a simple experimental setup was used to filter electrolyte and preconcentrate ions and microparticles. Different from the general assumption of the negligible thickness of the electric double layer in microchannels, the low concentration in the ion depletion zone considerably increased the length of the electric double layer. This enhanced the formation of the ion depletion zone. The present results can improve the understanding on ion transport in the ion concentration polarization system and can be utilized to develop a portable water desalination device for rural/remote areas and for preconcentrating biomolecules. [ABSTRACT FROM AUTHOR]

Leaf mustard ( Brassica juncea), the main ingredient of leaf mustard kimchi, has a variety of biologically active secondary metabolites such as glucosinolates (GSLs), flavonoids, and polyphenols. In this study, the changes in GSL content and antioxidant properties during the storage of Dolsan leaf mustard kimchi (DLMK) for 35 days were examined by separation and purification of DLMK extracts using high-performance liquid chromatography (HPLC) and preparative octadecylsilane-HPLC. The total GSL content and antioxidant activity of the DLMK extracts had significantly lower values on day 21 of storage ( p <.05). GSLs were detected in a single extract of DLMK using liquid chromatography-tandem mass spectrometry. The GSLs detected throughout most of the storage period (sinigrin, gluconapin, and glucotropaeplin) were different from those detected on day 21 of storage (glucobrassicin and progoitrin), when the antioxidant activity was low. Thus, GSLs may contribute to the antioxidant activity of DLMK. Practical applications Dolsan leaf mustard kimchi (DLMK) is expected to have biological effects owing to the properties of its various ingredients, but the effects of fermentation and the overall composition of DLMK on physiological activity have not been determined. On the basis of this study, DLMK has high value as a natural antioxidant, but the antioxidant activity varies with fermentation time, which is lowest on day 21. Thus, these results can be used to establish appropriate preparation conditions for DLMK as a functional food. [ABSTRACT FROM AUTHOR]

Eye blinks are one of the most influential artifact sources in electroencephalogram (EEG) recorded from frontal channels, and thereby detecting and rejecting eye blink artifacts is regarded as an essential procedure for improving the quality of EEG data. In this paper, a novel method to detect eye blink artifacts from a single-channel frontal EEG signal was proposed by combining digital filters with a rule-based decision system, and its performance was validated using an EEG dataset recorded from 24 healthy participants. The proposed method has two main advantages over the conventional methods. First, it uses single-channel EEG data without the need for electrooculogram references. Therefore, this method could be particularly useful in brain–computer interface applications using headband-type wearable EEG devices with a few frontal EEG channels. Second, this method could estimate the ranges of eye blink artifacts accurately. Our experimental results demonstrated that the artifact range estimated using our method was more accurate than that from the conventional methods, and thus, the overall accuracy of detecting epochs contaminated by eye blink artifacts was markedly increased as compared to conventional methods. The MATLAB package of our library source codes and sample data, named Eyeblink Master, is open for free download. [ABSTRACT FROM AUTHOR]

Dynamic nuclear polarization (DNP) allows measuring enhanced nuclear magnetic resonance (NMR) signals. Though the efficiency of DNP has been known to increase at low fields, the usefulness of DNP has not been throughly investigated yet. Here, using a superconducting quantum interference device-based NMR system, we performed a series of DNP experiments with a nitroxide radical and measured DNP spectra at several magnetic fields down to sub-microtesla. In the DNP spectra, the large overlap of two peaks having opposite signs results in net enhancement factors, which are significantly lower than theoretical expectations [30] and nearly invariant with respect to magnetic fields below the Earth’s field. The numerical analysis based on the radical’s Hamiltonian provides qualitative explanations of such features. The net enhancement factor reached 325 at maximum experimentally, but our analysis reveals that the local enhancement factor at the center of the rf coil is 575, which is unaffected by detection schemes. We conclude that DNP in the hyperfine-field-dominant region yields sufficiently enhanced NMR signals at magnetic fields above 1 μ T. [ABSTRACT FROM AUTHOR]

We investigated T1 relaxations of ex-vivo cancer tissues at low magnetic fields in order to check the possibility of achieving a T1 contrast higher than those obtained at high fields. The T1 relaxations of fifteen pairs (normal and cancerous) of breast tissue samples were measured at three magnetic fields, 37, 62, and 122 μT, using our superconducting quantum interference device-based ultralow field nuclear magnetic resonance setup, optimally developed for ex-vivo tissue studies. A signal reconstruction based on Bayesian statistics for noise reduction was exploited to overcome the low signal-to-noise ratio. The ductal and lobular-type tissues did not exhibit meaningful T1 contrast values between normal and cancerous tissues at the three different fields. On the other hand, an enhanced T1 contrast was obtained for the mucinous cancer tissue. [ABSTRACT FROM AUTHOR]

Via temperature swing adsorption, a dual circulating fluidized bed reactor can capture CO 2 through a continuous process, but controlling the temperature of the reactor at a large scale is difficult due to the non-linearity hydrodynamics and heat transfer in the scaled-up two-phase flow. In the present study, an energy-efficient design of a circulating fluidized bed reactor was investigated. A preliminary design based on numerical simulation was associated with poor heat transfer of single- and multi-tube reactors. To enhance the heat transfer performance, an innovative multi-tube reactor with junctions was proposed. The junctions improved mixing among the tubes and resolved the heat transfer imbalance between the tubes. The heat transfer coefficient of the multi-tube reactor with junctions was about 12 times larger than that of the multi-tube reactor without junctions. An experimental facility was constructed, and the reactor design was verified. Finally, thermal design analysis is performed to evaluate the design effectiveness in terms of the thermal performance of the reactor capable of continuous CO 2 capture. The results showed that the multi-tube reactor with junctions has a large thermal margin and is thus a robust and flexible design applicable to thermochemical process. [Display omitted] • Energy-efficient design of multi-tube configuration with junctions was proposed. • Heat transfer and gas-solid flow depending on the reactor configuration were analyzed. • Experimental verifications for the hydrodynamic of the reactor were conducted. • 100 Nm3/h scale dual circulating fluidized bed system for CO 2 capture was investigated. • Evaluation method for thermally robust design for continuous CO 2 capture was proposed. [ABSTRACT FROM AUTHOR]

Simultaneous magnetoencephalography (MEG) and electroencephalography (EEG) analysis is known generally to yield better localization performance than a single modality only. For simultaneous analysis, MEG and EEG data should be combined to maximize synergistic effects. Recently, beamformer for simultaneous MEG/EEG analysis was proposed to localize both radial and tangential components well, while single modality analyses could not detect them, or had relatively higher location bias. In practice, most interesting brain sources are likely to be activated coherently; however, conventional beamformer may not work properly for such coherent sources. To overcome this difficulty, a linearly constrained minimum variance (LCMV) beamformer may be used with a source suppression strategy. In this work, simultaneous MEG/EEG LCMV beamformer using source suppression was formulated firstly to investigate its capability over various suppression strategies. The localization performance of our proposed approach was examined mainly for coherent sources and compared thoroughly with the conventional simultaneous and single modality approaches, over various suppression strategies. For this purpose, we used numerous simulated data, as well as empirical auditory stimulation data. In addition, some strategic issues of simultaneous MEG/EEG analysis were discussed. Overall, we found that our simultaneous MEG/EEG LCMV beamformer using a source suppression strategy is greatly beneficial in localizing coherent sources. [ABSTRACT FROM AUTHOR]

Abstract: Since the Superconducting Quantum Interference Device (SQUID) is the most sensitive magnetic field detector, it is widely used for measuring very weak biomagnetic signals, such as a Magnetocardiography (MCG). However, because the SQUID is easily affected by environmental magnetic noises, it is often used as a form of gradiometer suppressing spatially homogeneous field noises. The characteristic of the SQUID gradiometer mainly depends on the distance between the connected coils, that is, a baseline. Accordingly, in order to fabricate a gradiometer, the investigation of a proper baseline for the MCG signal is necessary. For the investigation, however, various gradiometers having different baselines have to be fabricated and tested, which required too much cost and effort. In this study, we suggest a simple simulation method to investigate the performance of a SQUID gradiometer depending on the baseline. In addition, in order to verify the reliability of our simulation, we fabricated wire wound axial first-order gradiometers (50 mm, 70 mm, and 100 mm baseline) and a second-order gradiometer (50 mm baseline) and compared the characteristics of the measured gradiometer signal with the simulated signal. [Copyright &y& Elsevier]

Abstract: We present a computational study of reentry wave propagation using electrophysiological models of human cardiac cells and the associated magnetic field map of a human heart. We examined the details of magnetic field variation and related physiological parameters for reentry waves in two-dimensional (2-D) human atrial tissue and a three-dimensional (3-D) human ventricle model. A 3-D mesh system representing the human ventricle was reconstructed from the surface geometry of a human heart. We used existing human cardiac cell models to simulate action potential (AP) propagation in atrial tissue and 3-D ventricular geometry, and a finite element method and the Galerkin approximation to discretize the 3-D domain spatially. The reentry wave was generated using an S1-S2 protocol. The calculations of the magnetic field pattern assumed a horizontally layered conductor for reentry wave propagation in the 3-D ventricle. We also compared the AP and magnetocardiograph (MCG) magnitudes during reentry wave propagation to those during normal wave propagation. The temporal changes in the reentry wave motion and magnetic field map patterns were also analyzed using two well-known MCG parameters: the current dipole direction and strength. The current vector in a reentry wave forms a rotating spiral. We delineated the magnetic field using the changes in the vector angle during a reentry wave, demonstrating that the MCG pattern can be helpful for theoretical analysis of reentry waves. [Copyright &y& Elsevier]

We present a 62-channel double relaxation oscillation SQUID (DROS) planar gradiometer system to measure magnetocardiogram (MCG) signals tangential to the chest surface. The DROSs were fabricated using Nb/Al-oxide/Nb junctions, and provided flux-to-voltage transfers of larger than 1 mV /Φ0 typically, which is large enough for direct readout by room-temperature flux- locked loop (FLL) circuits. The analog FLL circuits and digital control circuits are made in a single printed circuit board. The planar gradiometers are integrated, series-connected first-order pickup coils with a baseline of 4 cm. White noise level of the planar gradiometer is about 1.5 (fT/cm)/√HZ or 6 fT/ √Hz, operated inside a magnetically shielded room. The planar gradiometers were arranged to measure dBx / dz and dBy/dz simultaneously. The covering area of the 62 channel system is 162 mm × 162 mm, which is smaller than the sensor coverage area of vertical measurement systems, but large enough to measure the essential MCG field distribution in a single position measurement. [ABSTRACT FROM AUTHOR]

Compact and low-cost SQUID electronics to operate double relaxation oscillation SQUIDs (DROSs) has been constructed for detecting magnetocardiogram (MCG) fields. SQUID electronics consists of low-noise preamplifier with a white noise of 0.6 nV/√Hz, flux-locked loop (FLL) circuit with auto-reset, and interface circuit to control FLL using 3 digital lines from a computer. The automatic control software adjusts SQUID parameters to the optimum operating condition within 15 seconds for 62 channels. Outputs of FLL circuits are passed through the hardware filter box to the 64-channel data acquisition board. Each SQUID electronics for FLL and digital control is built together on a printed circuit board of 45 mm × 95 mm. When SQUID electronics is connected to DROS gradiometer with typical flux-to-voltage transfers of 1 mV / Φ0, the noise contribution of FLL circuit is about 0.6 μΦ0/√Hz or 0.6 fT/√Hz at 100 Hz, low enough to measure MCG fields. [ABSTRACT FROM AUTHOR]

Despite the exceptional efficiency of perovskite solar cells (PSCs), further improvements can be made to bring their power conversion efficiencies (PCE) closer to the Shockley‐Queisser limit, while the development of cost‐effective strategies to produce high‐performance devices are needed for them to reach their potential as a widespread energy source. In this context, there is a need to improve existing charge transport layers (CTLs) or introduce new CTLs. In this contribution, we introduced a new polyelectrolyte (lithium poly(styrene sulfonate (PSS))) (Li:PSS) polyelectrolyte as an HTL in inverted PSCs, where Li+ can act as a counter ion for the PSS backbone. The negative charge on the PSS backbone can stabilize the presence of p‐type carriers and p‐doping at the anode. Simple Li:PSS performed poorly due to poor surface coverage and voids existence in perovskite film as well as low conductivity. PEDOT:PSS was added to increase the conductivity to the simple Li:PSS solution before its use which also resulted in lower performance. Furthermore, a bilayer of PEDOT:PSS and Li:PSS was employed, which outperformed simple PEDOT:PSS due to high quality of perovskite film with large grain size also the large electron injection barrier (ϕe) impeded back diffusion of electrons towards anode. As a consequence, devices employing PEDOT:PSS / Li:PSS bilayers gave the highest PCE of 18.64%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon molecular sieve membrane supported on alumina hollow fiber for C3 separation. • Selectivity of 28 and permeance of 20 GPU according to long-term stabilization test. • 25.3% and 14.4% total cost saving from typical distillation and heat-pump assisted process. • Techno-economic analysis and sensitivity study according to membrane performance. • Development of correlation contours between membrane performance and cost savings. The conceptual designs of a carbon molecular sieve (CMS) membrane and a distillation process with heat pump integration were used to evaluate propylene/propane separation system economics. A CMS membrane prepared on a porous alumina hollow fiber was employed to establish the conceptual design of the integrated system. The technologies were evaluated in terms of capital and operating costs and compared to a conventional C3-splitter to elicit the one that minimizes total costs. Different configurations are suggested to satisfy the design specifications of 99.6 wt% product purity and 99% propylene recovery rate. When the heat pump with membrane system was applied in condition of stage cut 0.5, pressure ratio 3, propylene/propane selectivity 28, and propylene permeance 20 GPU, the capital and operating costs decreased by 2.3% and 68.7% compared to distillation only process, respectively. The cost saving variation of the hybrid system was confirmed with membrane specifications such as selectivity and permeance. The simulation results indicated that the heat pump with membrane process is advantageous in terms of both energy and economic savings. A correlation contour between membrane permeance/selectivity and cost saving was developed for the hybrid systems. The findings provide a helpful guide to more economically separate gas mixtures. [ABSTRACT FROM AUTHOR]

Signal amplification by reversible exchange (SABRE) is an effective NMR hyperpolarization technique for signal enhancement using para-hydrogen on iridium catalysts. To date, monodentate chelating nitrogen analogs have been predominantly used as substrates for SABRE because of the limited chelating sites of the Ir-catalyst with different molecular orientations. Herein, for the first time, the use of a tridentate chelating ligand (BPEA) containing pyridine moieties and a secondary amine as a SABRE substrate is demonstrated. For the optimization of the tridentate chelating ligand, alkyl chain lengths were varied with the optimization of the external magnetic field and concentrations of three different ligands. Because many chemically multidentate complexes present in nature have scarcely been studied as SABRE substrates, this optimized tridentate chelating ligand structure with the SABRE catalyst and its polarization transfer from para-hydrogen will broaden the scope of hyperpolarizable substrates and help in the investigation of chelating structures for future applications. [ABSTRACT FROM AUTHOR]

Catalytic conversion of naphtha has attracted attention as an alternative method to the conventional thermal cracking to produce light olefins in an environment-friendly and energy-efficient way. In this work, a reaction mechanism study of light straight run naphtha cracking over micro-spherical catalyst containing HZSM-5 was systematically investigated using single hydrocarbon feeds, and the straight run naphtha itself. The identified reaction pathways from the single feeds along with the naphtha experimental data have been utilized to investigate reaction pathways of the naphtha conversion reactions. The experimental tests were carried out in the temperature ranges of 450–650 ℃ and space-times of 0.3–1.5 min using a fixed bed micro-reactor in isothermal and isobaric conditions. The product distribution for the naphtha feed shows that light paraffins and light olefins are the primary products, which are products of monomolecular protolytic cracking of the paraffin components of the naphtha feed. The olefin interconversion reactions illustrated that oligomerization and cracking by β-scission dominate the secondary reactions of naphtha catalytic cracking conversions. The experiments conducted on cyclohexane, cyclohexene and n -hexane single feeds revealed that BTX formation proceeds through the formation of C 6 -C 8 naphthenes, and C 6 -C 8 cyclo-olefinic intermediates. Low temperatures and space times promote the selectivity to propylene while the selectivity of ethylene increases with temperature. The degree of thermal cracking (DTC) illustrated that thermal cracking is considerable only for temperatures of higher than 550 ℃. [Display omitted] • Reaction mechanism for catalytic conversion of naphtha was studied using single hydrocarbon and LSR naphtha feeds. • Blank experiments were conducted to investigate the contribution of thermal cracking to the overall product distribution. • Olefin interconversion reactions proceed via oligomerization and cracking by β-scission. • The formation of BTX proceeds by the formation of naphthenic and cyclo-olefin intermediates. • Propylene to ethylene yield ratio at 600 ºC increased from 0.85 to 1.15 by shifting from thermal to catalytic cracking. [ABSTRACT FROM AUTHOR]

• Cu(Qc) 2 MOF was synthesized and granulated for ethane/ethylene separation. • Adsorption equilibrium and breakthrough using Cu(Qc) 2 were measured up to 5 bar. • Adsorption model was developed and Q-L/LDF model predicted the experimental data. • Nominal VPSA process was synthesized with 99.68% of purity and 65.28% of recovery. • After PSO, recovery and productivity increased to 76.57% with 1.98 mol/kg/hr. The separation of ethylene from ethane/ethylene mixtures is of prime significance, and replacing the energy-intensive cryogenic distillation used in the petrochemical industry is challenging. The aim of this study is to separate ethane and ethylene using a vacuum pressure swing adsorption (VPSA) process on a Cu(Qc) 2 metal–organic framework (MOF) synthesized as a spheroidal adsorbent. To quantify the adsorption equilibrium, single isotherms of ethane and ethylene were measured at 283 and 298 K up to 5 bar. A Quadratic Langmuir adsorption model was employed to predict equilibrium adsorption. Dynamic adsorption experiments were conducted for a single-component and a binary mixture of different feed compositions and flow rates. The mass-transfer coefficients of ethane and ethylene were estimated to be 0.1 sec−1 and 1.0 sec−1, respectively. Based on these parameters, a two-bed, five-step VPSA mathematical model was developed, and the nominal operating conditions were determined from the length of the unused bed. It showed ethylene purity, recovery, and productivity of 99.68 mol%, 65.28%, and 1.84 mol/kg/hr. Sensitivity analyses of purity and recovery were performed using six critical operating variables. The time and rate of the rinse step had the most significant influence on the results, followed by those of the PU, AD and BLW steps. The particle swarm optimization methodology was applied to optimize the operating variables to maximize ethylene recovery. After optimization, the ethylene purity, recovery, and productivity were attained at 99.60 mol%, 76.57%, and 1.98 mol/kg/hr. [ABSTRACT FROM AUTHOR]

Electroencephalography (EEG) has relatively poor spatial resolution and may yield incorrect brain dynamics and distort topography; thus, high-density EEG systems are necessary for better analysis. Conventional methods have been proposed to solve these problems, however, they depend on parameters or brain models that are not simple to address. Therefore, new approaches are necessary to enhance EEG spatial resolution while maintaining its data properties. In this work, we investigated the super-resolution (SR) technique using deep convolutional neural networks (CNN) with simulated EEG data with white Gaussian and real brain noises, and experimental EEG data obtained during an auditory evoked potential task. SR EEG simulated data with white Gaussian noise or brain noise demonstrated a lower mean squared error and higher correlations with sensor information, and detected sources even more clearly than did low resolution (LR) EEG. In addition, experimental SR data also demonstrated far smaller errors for N1 and P2 components, and yielded reasonable localized sources, while LR data did not. We verified our proposed approach's feasibility and efficacy, and conclude that it may be possible to explore various brain dynamics even with a small number of sensors. [ABSTRACT FROM AUTHOR]

Oxo‐bridged trimeric chromium acetate clusters [Cr3O(OOCCH3)6(H2O)3]NO3 have been encapsulated for the first time in the mesoporous cages of the chromium terephthalate MIL‐101(Cr). The isolated clusters in MIL‐101(Cr) have increased affinity towards propylene compared to propane, due to generation of a new kind of pocket‐based propylene‐binding site, as supported by DFT calculations. [ABSTRACT FROM AUTHOR]

• Circularly polarised RF selectively induces either positive or negative enhancements. • O-DNP with circularly polarised RF renders an enhancement factor of around 150,000 at 1.2 μT. • Images with resolution of close to 1 mm were obtained using O-DNP in microtesla fields. Magnetic resonance imaging in ultra-low fields is often limited by mediocre signal-to-noise ratio hindering a higher resolution. Overhauser dynamic nuclear polarisation (O-DNP) using nitroxide radicals has been an efficient solution for enhancing the thermal nuclear polarisation. However, the concurrence of positive and negative polarisation enhancements arises in ultra-low fields resulting in a significantly reduced net enhancement, making O-DNP far less attractive. Here, we address this issue by applying circularly polarised RF. O-DNP with circularly polarised RF renders a considerably improved enhancement factor of around 150,000 at 1.2 μ T. A birdcage coil was adopted into an ultra-low field MRI system to generate the circularly polarised RF field homogeneously over a large volume. We acquired an MR image of a nitroxide radical solution with an average in-plane resolution of 1 mm. De-noising through compressive sensing further improved the image quality. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The first in-situ Overhauser-enhanced nuclear magnetic resonance experiment using an atomic magnetometer at ultra-low field. • Signal-to-noise ratio was 32 after sixteen averages. • On the Larmor precession of 1 H spins, a decaying oscillation was superimposed. • We attribute it to a transient 87 Rb spin precession in response to a non-adiabatic field variation. • Atomic magnetometry technique shows a new capability of zero and ultralow-field NMR. Abstract The development of atomic magnetometers has led to nuclear magnetic resonance (NMR) in zero and ultralow magnetic fields without using cryogenic sensors. However, in-situ detection, meaning that a sample locates in the detection space beside a vapor cell, has been conducted only with parahydrogen-induced polarization. Other hyperpolarization techniques remain unexplored yet. In this work, we demonstrate that Overhauser dynamic nuclear polarization allows in-situ NMR detection with an atomic magnetometer at less than 1 μ T. The 1 H NMR signal of a nitroxide radical solution was observed at 13.83 Hz, which corresponds to 325 nT. Signal-to-noise ratio was 32 after sixteen averages. On the Larmor precession of 1 H spins, a decaying oscillation was superimposed. We attribute it to a transient 87 Rb spin precession in response to a non-adiabatic field variation. This work shows a new capability of zero- and ultralow-field NMR. [ABSTRACT FROM AUTHOR]

Abstract: Thermoreception is an important cutaneous sense, which plays a role in the maintenance of our body temperature and in the detection of potential noxious heat stimulation. In this study, we investigated event‐related fields (ERFs) and neural oscillatory activities, which were modulated by warmth stimulation. We developed a warmth stimulator that could elicit a warmth sensation, without pain or tactile sensation, by using a deep‐penetrating 980‐nm diode laser. The index finger of each participant (n = 24) was irradiated with the laser warmth stimulus, and the cortical responses were measured using magnetoencephalography (MEG). The ERFs and oscillatory responses had late latencies (∼1.3 s and 1.0–1.5 s for ERFs and oscillatory responses, respectively), which could be explained by a slow conduction velocity of warmth‐specific C‐fibers. Cortical sources of warmth‐related ERFs were seen in the bilateral primary and secondary somatosensory cortices (SI and SII), posterior part of the anterior cingulate cortex (pACC), ipsilateral primary motor, and premotor cortex. Thus, we suggested that SI, SII, and pACC play a role in processing the warmth sensation. Time–frequency analysis demonstrated the suppression of the alpha (8–13 Hz) and beta (18–23 Hz) band power in the bilateral sensorimotor cortex. We proposed that the suppressions in alpha and beta band power are involved in the automatic response to the input of warmth stimulation and sensorimotor interactions. The delta band power (1–4 Hz) increased in the frontal, temporal, and cingulate cortices. The power changes in delta band might be related with the attentional processes during the warmth stimulation. [ABSTRACT FROM AUTHOR]

Measuring the electrical impedance of biological tissues in a low frequency range is challenging. Here, we have conducted a superconducting quantum interference device-based microtesla magnetic resonance (MR) imaging study. To obtain an MR image caused by an injected alternating current (ac), we utilized the direct resonance method in which the nuclear spins resonate with the ac magnetic field generated by the external ac current. This method requires an adiabatic pulse and non-adiabatic step-down pulse techniques. The experimental and simulation results agree well with each other and show the feasibility of low-frequency magnetic resonance electrical impedance tomography in the kHz range. [ABSTRACT FROM AUTHOR]

Recently, neurophysiological findings about social interaction have been investigated widely, and hardware has been developed that can measure multiple subjects' brain activities simultaneously. These hyperscanning studies have enabled us to discover new and important evidences of interbrain interactions. Yet, very little is known about verbal interaction without any visual input. Therefore, we conducted a new hyperscanning study based on verbal, interbrain turn-taking interaction using simultaneous EEG/MEG, which measures rapidly changing brain activities. To establish turn-taking verbal interactions between a pair of subjects, we set up two EEG/MEG systems (19 and 146 channels of EEG and MEG, respectively) located ∼100 miles apart. Subjects engaged in verbal communication via condenser microphones and magnetic-compatible earphones, and a network time protocol synchronized the two systems. Ten subjects participated in this experiment and performed verbal interaction and noninteraction tasks separately. We found significant oscillations in EEG alpha and MEG alpha/gamma bands in several brain regions for all subjects. Furthermore, we estimated phase synchronization between two brains using the weighted phase lag index and found statistically significant synchronization in EEG and MEG data. Our novel paradigm and neurophysiological findings may foster a basic understanding of the functional mechanisms involved in human social interactions. Hum Brain Mapp 39:171-188, 2018. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Background Connectivity analysis in magnetoencephalography (MEG) sensor space is commonly used for the preliminary estimation of the functional relationship between cortical areas, but the results are difficult to interpret due to the field spread effect. To improve the interpretability of sensor-level connectivity analysis, we introduce and test a new connectivity measure based on imaginary coherence in this study. New method MEG signals from axial gradiometers are subjected to a wavelet transform at a frequency of interest, and are used to reconstruct 2D tangential magnetometer signals. The Euclidean norm of imaginary coherence values obtained from four available pairs between 2D tangential components at two locations is then used to estimate functional connectivity between sensor locations. The use of this new connectivity measure can be extended to 2D planar gradiometer signals or 3D source signals, where the functional relationship between multi-dimensional signals at different locations needs to be quantified as scalar variables. Results The proposed method was applied to measured and simulated auditory evoked MEG data. The Euclidean norm of imaginary coherence reliably eliminated the field spread effect and showed increased inter-hemispheric coherence between sensors above the left and the right auditory cortex. The significance of the results was tested by introducing variability in spontaneous brain activities in multi-trial evoked data simulations. Comparison with existing method The distribution of imaginary coherence among axial gradiometer signals shows peaks not at the sensors directly above the neuronal current sources, but at sensors with field extreme. [ABSTRACT FROM AUTHOR]

Pine cones fold their scales when it rains to prevent seeds from short-distance dispersal. Given that the scales of pine cones consist of nothing but dead cells, this folding motion is evidently related to structural changes. In this study, the structural characteristics of pine cones are studied on micro-/macro-scale using various imaging instruments. Raindrops fall along the outer scales to the three layers (bract scales, fibers and innermost lignified structure) of inner pine cones. However, not all the layers but only the bract scales get wet and then, most raindrops move to the inner scales. These systems reduce the amount of water used and minimize the time spent on structural changes. The result shows that the pine cones have structural advantages that could influence the efficient motion of pine cones. This study provides new insights to understand the motion of pine cones and would be used to design a novel water transport system. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) spectroscopy is one of the most significant applications of nuclear magnetic resonance (NMR). Here, we demonstrate that the 2D NMR can be performed even at a low magnetic field of less than 5 μT, which is ten times less than the Earth’s magnetic field. The pulses used in the experiment were composed of circularly polarized fields for coherent as well as wideband excitations. Since the excitation band covers the entire spectral range, the simplest two-pulse sequence delivered the full 2D spectrum. At 5 μT, methanol with 13 C enriched up to 99% belongs to a strongly coupled regime, and thus its 2D spectrum exhibits complicated spectral correlations, which can be exploited as a fingerprint in chemical analysis. In addition, we show that, with compressive sensing, the acquisition of the 2D spectrum can be accelerated to take only 45% of the overall duration. [ABSTRACT FROM AUTHOR]

Highlights: [•] The relationship between conduction current and the behavioral outcomes after tDCS was studied. [•] The current density at DLPFC was related with working memory performance after tDCS. [•] Inconsistent outcomes of tDCS may originate from anatomical differences among individuals. [Copyright &y& Elsevier]

Highlights: [•] A pulse of circular polarization can rapidly and precisely drive nuclear spins, even in the regime beyond the rotating wave approximation. [ABSTRACT FROM AUTHOR]