Freezing Of Motion Research Articles

Structural and biophysical insights into the interactions of anisotropic gold nanoparticles with human telomeric G-quadruplex DNA: Spectroscopic and calorimetric approach

We are reporting curcumin-induced synthesis of anisotropic citrate capped Gold nanoparticles (ctGNPs). The techniques such as UV–visible spectroscopy, Raman spectroscopy, FT-IR, X-ray diffraction (XRD), and Transmission Electron Microscopy (TEM) were used to characterize the nanoparticles. The synthetic route shows the formation of an anisotropic gold nanostructure consisting of spherical, triangles, hexagonals, and a low-yield rod with an aspect ratio ranging from 4.2 to 8.5. Curcumin-derived ctGNPs shows stability at different physiological conditions and better biocompatibility. Synthesized nanoparticles are found non-toxic towards eukaryotic cells but more effective against the cancer cell lines HeLa and MCF-7. The interaction of these synthesized nanoparticles with human telomeric G-quadruplex (GQ) DNA was studied using different physiochemical methods. The spectroscopic studies show that synthesized nanoparticles have stronger binding affinity towards telomeric GQ as compared to ds DNA through Van der Waals and H-bonding interactions. Thermodynamic interpretation reveals that the formation of the complex between the telomeric GQ and ctGNPs are enthalpy driven and entropy unfavourable process, resulting in motion freezing and, eventually, AuNP aggregation. Thus, our study shows a new approach to understand the interaction of telomeric G-quadruplexes with gold nanoparticles generated via the green route.

DanceAnyWay: Synthesizing Beat-Guided 3D Dances with Randomized Temporal Contrastive Learning

We present DanceAnyWay, a generative learning method to synthesize beat-guided dances of 3D human characters synchronized with music. Our method learns to disentangle the dance movements at the beat frames from the dance movements at all the remaining frames by operating at two hierarchical levels. At the coarser "beat" level, it encodes the rhythm, pitch, and melody information of the input music via dedicated feature representations only at the beat frames. It leverages them to synthesize the beat poses of the target dances using a sequence-to-sequence learning framework. At the finer "repletion" level, our method encodes similar rhythm, pitch, and melody information from all the frames of the input music via dedicated feature representations. It generates the full dance sequences by combining the synthesized beat and repletion poses and enforcing plausibility through an adversarial learning framework. Our training paradigm also enforces fine-grained diversity in the synthesized dances through a randomized temporal contrastive loss, which ensures different segments of the dance sequences have different movements and avoids motion freezing or collapsing to repetitive movements. We evaluate the performance of our approach through extensive experiments on the benchmark AIST++ dataset and observe improvements of about 7%-12% in motion quality metrics and 1.5%-4% in motion diversity metrics over the current baselines, respectively. We also conducted a user study to evaluate the visual quality of our synthesized dances. We noted that, on average, the samples generated by our method were about 9-48% more preferred by the participants and had a 4-27% better five-point Likert-scale score over the best available current baseline in terms of motion quality and synchronization. Our source code and project page are available at https://github.com/aneeshbhattacharya/DanceAnyWay.

Kinetic arrest during the drying of cellulose nanocrystal films from aqueous suspensions analogous to the freezing of thermal motions

A comprehensive understanding of controlling the iridescence of cellulose films by manipulating the alignment and helical pitch of cellulose nanocrystals (CNCs) is required to advance cellulose photonics and its optoelectronic applications. Aqueous suspensions of CNCs exhibit a cholesteric liquid crystal (LC) phase with structural color; however, attaining a uniformly colored film is extremely difficult. Presumably, because multiple interrelated factors influence the CNC molecular alignment and helical pitch, existing models are not necessarily conclusive and remain a subject of debate. To eventually achieve homogeneously colored films, we compare aqueous CNC suspensions as a lyotropic liquid LC with thermotropic ones, and we spectroscopically confirm that the coloration of CNC droplets originates from the periodic CNC structure. The suspension drying process significantly influences the quality of iridescence of CNC films. Rapidly drying a droplet of a CNC suspension forms a concentric rainbow film, with red edges and a blue center, typical of the coffee-ring effect observed in air-dried films. By contrast, slow drying under controlled humidity, which reduces capillary flow, provides higher uniformity and a large blue area. Orbitally shaking films while drying under high humidity further improves the uniformity. Therefore, the evaporation rate significantly influences the thermodynamically stabilized helical pitch of CNCs, which determines the structural color. We qualitatively model the kinetic arrest induced by the rapid evaporation of lyotropic LCs in a manner equivalent to that induced by the rate of temperature change in thermotropic LCs and other materials.

Anomalous Phase Transition, Polarization Switching, and Relaxation in a Novel Composite Consisting of Dimethylammonium Aluminum Sulfate Hexahydrate and Oxidized Multiwalled Carbon Nanotubes

A novel ferroelectric composite consisting of dimethylammonium aluminum sulfate hexahydrate (CH3)2NH2Al(SO4)2·6H2O and oxidized multiwalled carbon nanotubes was developed to investigate its dielectric relaxation, phase transition, and ferroelectric switching behaviors. Experimental methods combined with theoretical analyses were employed. The results showed that the filler of oxidized multiwalled carbon nanotubes caused the freezing of domain-wall motion in (CH3)2NH2Al(SO4)2·6H2O at 98.2 K, leading to a decrease in dielectric constant, dielectric loss, and the polarization. In addition, an increase in dielectric permittivity and dielectric loss was found at higher temperatures. The role of hydroxyl groups incorporated in the carbon nanotubes after its oxidation was responsible for the obtained anomalies.

Study on irradiation effect of insulating materials for fusion superconducting magnets -interlaminar shear strength at liquid helium temperature-

Insulating materials for superconducting magnets of fusion reactors are not only exposed to electromagnetic forces at cryogenic temperatures, but also to neutrons and γ-rays which are secondary radiation generated by nuclear fusion reactions. Hence, insulating materials are required to keep high radiation resistance, high mechanical strength and high insulation performance even at cryogenic temperatures. To evaluate the physical properties of insulating materials at cryogenic temperatures, most of the previous studies have been conducted in liquid nitrogen. However, it has been pointed out that the molecular motion freezing between liquid nitrogen temperature and liquid helium temperature may cause changes in mechanical properties. In this study, the experiments were conducted in liquid helium, which is closer to the actual environment of ITER, to evaluate the temperature dependence of irradiation effects. Interlaminar shear strength (ILSS) was measured at room temperature (RT), liquid nitrogen temperature (LNT), and liquid helium temperature (LHeT) after γ-ray irradiation of glass reinforced plastics (GFRP) made of epoxy resin. As a result, in the unirradiated samples, ILSS was maximum at LNT, whereas in the samples irradiated at 5 and 10 MGy, ILSS was maximum at LHeT. It was considered that the change in molecular structure caused by γ-ray irradiation led to stress relaxation phenomena even at LHeT in the irradiated samples.

Study on Irradiation Effect of Insulating Materials for Fusion Superconducting Magnet: Effect of Low-temperature Irradiation

The purpose of this study is to investigate the change in dielectric performance in the direction of parallel to layers due to the difference in γ-ray irradiation temperature, irradiation atmosphere, and absorbed dose. γ-ray was irradiated using a 60Co source at room temperature, in liquid nitrogen, and in liquid nitrogen temperature gas atmosphere in the absorbed doses of 0, 5, and 10 MGy, respectively, and the dielectric breakdown tests were conducted at room temperature using a high-voltage breakdown tester. To investigate the mechanism of the change in dielectric strength, the density and electron spin resonance (ESR) measurements of the specimens were carried out. After irradiation at room temperature, the dielectric strength increased slightly with the increase in the absorbed dose. The reason for this may be that the molecular density increased due to the promotion of cross-linking reaction by recombination of molecules and reaction of unreacted epoxy groups by γ-ray irradiation. After irradiation in liquid nitrogen, the dielectric strength decreased significantly at 10 MGy, while after irradiation in liquid nitrogen temperature gas atmosphere, the dielectric strength slightly decreased with the increase in absorbed dose. These results suggest that, at low temperature, the freezing of molecular motion limits the movement of radicals generated by irradiation, and that the decomposition reaction is dominant against the crosslinking reaction.

Retrospective Use of Breathing Motion Compensation Technology (MCT) Enhances Vessel Detection Software Performance.

Cone beam CT (CBCT) with planning software is used in intra-arterial liver-directed therapies. Software accuracy relies on high CBCT image quality, which can be impaired by breathing motion. We assessed the impact of a specific MCT on software performance for procedure planning and navigation. Institutional Review Board (IRB)-approved retrospective evaluation of liver-directed therapies from July 2015 to April 2018 was performed. CBCTs with at least one well-defined tumor and noticeable breathing motion were included. Each CBCT was reconstructed with and without breathing MCT (Motion Freeze, GE Healthcare). Automatic tumor-supplying vessel detection was performed on up to 4 tumors in each CBCT reconstruction (Liver ASSIST V.I., GE Healthcare). Vessel detection sensitivity and positive predictive value (PPV) were measured with and without MCT using Digital Subtracted Angiography (DSA) as reference. Preprocedural contrast-enhanced CT was also utilized in some cases to rule out the possibility of extrahepatic supplying vessels. MCT was applied retrospectively to 18 CBCTs with a total of 30 tumors. At least one supplying vessel was detected for 28/30 (93%) tumors with MCT versus 20/30 (66%) without. On the subgroup of 10 CBCTs (22 tumors, 76 feeders) in which the automatic vessel detection initially worked in both reconstructions, the average sensitivity and PPV increased from 63% (48/76) and 57% (48/84) before MCT to 83% (63/76) and 79% (63/80) after (p = 0.002 and p < 0.001). Breathing MCT improves planning software performance in CBCT impaired by breathing motion.

Evaluating Utility of 4D PET-CT Motion Freeze Imaging for Lung SABR

In Lung stereotactic ablative radiotherapy (SABR), 4D PET-CT gives an edge over static 3D PET-CT in target volume delineation given its ability to reduce motion artifacts. Motion Freeze (MF) PET imaging combines the quantitative benefits of 100% counts of 4D phase-matched PET-CT imaging into a single static image by collecting CT & PET data at each phase of the breathing cycle, then matching the data for attenuation consistency. This provides further robustness of biologic target volume delineation with reduced image noise. The authors evaluated the utility of 4D PET-CT MF imaging in lung SABR treatments & the consequent dosimetric impact when either motion inclusive (retrospective imaging) technique or gating technique were to be used. Five patients of lung SABR were included for purpose of this dosimetric study (1 Ca lung and 4 lung oligo-metastasis). All patients underwent 4D CT /PET scan with the RPM system on 16 slice PET-CT scanner. The 4D CT and 4D PET data were binned in 10 phases of respiratory cycle. The Motion match software was utilized to create a MF image of all the 10 PET bins (MF-10) and 3 bins corresponding to end expiratory phase 40%,50%,60% (MF-3) in which tumor position was relatively stable. For study purpose we analyzed 3 clinical scenarios for target delineation (a) target volume generated using 4D CT alone (b) 4D CT all bins deformably registered with MF-10 (c) 4D-CT 3 bins deformably registered with corresponding MF-3, using gradient based intensity based registration algorithm. Three VMAT 6 MV FFF plans were generated for all the above all 3 volumes. The dosimetric parameters analysed included Target volume coverage, dose spillage (high, intermediate and low dose) & OAR doses as per RTOG protocol. Statistical comparison was done using paired sample t test in statistical analysis software. The target volume was reduced using 4D PET MF 10 & MF 3 as compared to 4D CT alone though the values were statistically insignificant [P=0.75(MF10), P=0.68 (MF3)]. There was statistically insignificant difference in target volume coverage parameters i.e. Conformity index, Heterogeneity index, dose spillage (high, intermediate and low dose) among all the plans. However the trend towards reduced OAR doses was seen in MF 10 plan & MF 3 plan as compared to 4D CT plan {Lungs V20 [P=0.06(MF10), P=0.08(MF3)], Heart Dmax [P=0.02(MF10), P=0.03(MF3)], Spinal cord Dmax [P=0.08(MF10), P=0.07(MF3)], Chest wall Dmax [P=0.001(MF10), P=0.037(MF3)], Great Vessel Dmax [P=0.03(MF10), P=0.045 (MF3)]}. Inclusion of 4D PET-CT MF scan 10 bins (non gated delivery) or 3 bins (gated delivery) can improvise the robustness of Lung SABR in terms of better target volume delineation, OAR doses & estimation of SUV values helping in better treatment response evaluation in follow up. While this study, first of its kind for Lung SABR, gives proof-of-concept & integration into workflow, a larger sample size evaluating 4D PET-CT MF would address the target delineation issue.

Thermal &amp; Dielectric Spectroscopic Investigation on Orientationaly Disordered Crystal- Cyclobutanol

Abstract Orientationallydisordered crystals (plastic crystals) maintain translational order along their crystallographic axis while continue to have orientational degrees of freedom. Since freezing of orientational motion of molecule leads to glass transition, these rotationally disordered systems form glassy crystals below their glass transition temperature. Because of the presence of translational order, these kind of materials can easily treated in both mathematical and simulation approaches and are considered as the ideal or model system for studying glass transition phenomena. Here by using differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS), thermal and dielectric behaviour of the orientation ally disordered phases of an organic plastic crystal cyclobutanol have been studied. During quench cooling of the sample below the melting point, three solid-solid phase transitions, one at 180K called phase I, other at 170K called phase II, and another one at 158 K and glass transition (133K) events were observed using the DSC. The dielectric spectra of the cyclobutanol were recorded in a wide frequency range of 10-2 Hz to 107Hz for different temperatures. The dielectric spectra revealed the presence of the three phases, of which phase I was observed below the melting point up to nearly 180 K, the phase II was observed up to nearly 170 K and phase III was observed further up to 158K. In these phases signatures of two structural α relaxations were observed. The secondary relaxation below the glass transition event was also seen, whose strength was found to be very small compared to those observed in other plastic crystals. The α relaxation showed non-Arrhenius temperature dependence depicted by Vogel-Fulcher-Tammann equation,while secondary relaxation mimicked Arrhenius temperature dependence.

Planning Lung Radiotherapy Incorporating Motion Freeze PET/CT Imaging

Motion Freeze (MF), which integrates 100% of the signal of each respiratory phase in four-dimensional positron emission tomography (4D-PET) images and creates the MF-PET, is capable of eliminate the influences induced by respiratory motion and dispersing from three-dimensional PET (3D-PET) and 4D-PET images. In this study, the effectiveness of respiratory gated radiotherapy applying MF-PET (MF-Plan) in lung cancer patient was investigated and compared with three-dimensional intensity modulated radiotherapy (3D-Plan) and routine respiratory gated radiotherapy (4D-Plan) on the impact of target volume and dosimetry. Thirteen lung cancer patients were enrolled. The internal target volumes were generated with 40% of maximum standardized uptake value. The 3D-Plan, 4D-Plan, and MF-Plan were created for each patient to study the radiation to the targets and organs at risk. MF-Plans were associated with significant reductions in lung, heart, and spinal cord doses. The median reductions in lung V20, lung mean, heart mean doses, and spinal cord maximum dose compared with 3D-Plans were improved. When compared with 4D-Plans, the median reductions in lung V20, lung mean dose, heart mean dose, and spinal cord maximum dose were improved. Our results indicate that the MF-Plan may improve critical organ sparing in the lung, heart, and spinal cord, while maintaining high target coverage.

Vibration-induced Behavioral Responses and Response Threshold in Female C57BL/6 Mice.

Despite documented adverse effects, limits for rodent exposure to vibration in the laboratory animal facility have not been established. This study used female C57BL/6 mice to determine the frequencies of vibration at which mice were most sensitive to behavioral changes, the highest magnitude of vibration that would not cause behavioral changes, the behavioral changes that occur in response to vibration, and the extent to which mice habituate to vibration. Mice were exposed to frequencies of vibration between 20 and 190 Hz at accelerations of 0.05 to 1.0 m/s2. Behavioral responses were videorecorded and subsequently scored. Mice showed the most behavioral responses at 1.0 m/s2. At intermediate accelerations of 0.5 and 0.75 m/s2, behavioral responses were most prevalent at frequencies of 70 to 100 Hz. In contrast, at an acceleration of 0.05 m/s2, mice did not show any discernible behavioral response. Behavioral responses induced by the initiation of vibration were transient, generally lasting only 2 to 10 s. Behaviors in awake mice included abrupt freezing of motion, hunched posture, and surveying the cage environment. In mice that were asleep, responses consisted of lifting the head suddenly with or without prior shifting of body position. When exposed to multiple periods of vibration over a short time, responses seemed to decrease. In summary, mice were particularly sensitive to vibration between 70 to 100 Hz, did not respond to the slowest acceleration (0.05 m/s2), and exhibited transient responses at the initiation of vibration.

Cardiac contraction motion compensation in gated myocardial perfusion SPECT: A comparative study

IntroductionCardiac contraction significantly degrades quality and quantitative accuracy of gated myocardial perfusion SPECT (MPS) images. In this study, we aimed to explore different techniques in motion-compensated temporal processing of MPS images and their impact on image quality and quantitative accuracy. Material and method50 patients without known heart condition underwent gated MPS. 3D motion compensation methods using Motion Freezing by Cedars Sinai (MF), Log-domain Diffeomorphic Demons (LDD) and Free-Form Deformation (FFD) were applied to warp all image phases to fit the end-diastolic (ED) phase. Afterwards, myocardial wall thickness, myocardial to blood pool contrast, and image contrast-to noise ratio (CNR) were measured in summed images with no motion compensation (NoMC) and compensated images (MF, LDD and FFD). Total Perfusion Defect (TPD) was derived from Cedars-Sinai software, on the basis of sex-specific normal limits. ResultLeft ventricle (LV) lateral wall thickness was reduced after applying motion compensation (p < 0.05). Myocardial to blood pool contrast and CNR in compensated images were greater than NoMC (p < 0.05). TPD_LDD was in good agreement with the corresponding TPD_MF (p = 0.13). ConclusionAll methods have improved image quality and quantitative performance relative to NoMC. LDD and FFD are fully automatic and do not require any manual intervention, while MF is dependent on contour definition. In terms of diagnostic parameters LDD is in good agreement with MF which is a clinically accepted method. Further investigation along with diagnostic reference standards, in order to specify diagnostic value of each technique is recommended.

Alkylamine-Templated Niccolite Frameworks of [GaIIIMII(HCOO)6]- (M = Fe, Ni): Structure, Magnetism, and Dielectricity.

The five heterometallic formate frameworks [EtA][GaIIIFeII(HCOO)6] (1; EtA = CH3CH2NH3+), [DMA][GaIIIFeII(HCOO)6] (2; DMA = (CH3)2NH2+), [DEtA][GaIIIFeII(HCOO)6] (3; DEtA = (CH3CH2)2NH2+), [MA][GaIIINiII(HCOO)6] (4; MA = CH3NH3+), and [DMA][GaIIINiII(HCOO)6] (5) were synthesized through solvothermal methods. Complexes 1-5 are isotructural, and all crystallize in the trigonal P3̅1 c space group. Each metal center is 6-connected, with each HCOO- bridging ligand in an anti-anti mode to build a three-dimensional niccolite-like architecture. All of the complexes exhibit weak ferromagnetism at low temperature. A variable-temperature (VT) dielectric study indicates that the dielectric anomaly is induced by the freezing of motions from the protonated amines during the freezing process.

On the origin of ferroelectric structural phases in perovskite-like metal–organic formate

The spontaneous electric polarization of methylhydrazinium zinc formate occurs due to freezing of motion around the 2- and 3-axes of the methylhydrazinium cation.

Coronary artery assessment using self-navigated free-breathing radial whole-heart magnetic resonance angiography in patients with congenital heart disease

To evaluate a self-navigated free-breathing three-dimensional (SNFB3D) radial whole-heart MRA technique for assessment of main coronary arteries (CAs) and side branches in patients with congenital heart disease (CHD). SNFB3D-MRA datasets of 109 patients (20.1±11.8 years) were included. Three readers assessed the depiction of CA segments, diagnostic confidence in determining CA dominance, overall image quality and the ability to freeze cardiac and respiratory motion. Vessel sharpness was quantitatively measured. The percentages of cases with excellent CA depiction were as follows (mean score): left main, 92.6 % (1.92); left anterior descending (LAD), 88.3 % (1.88); right (RCA), 87.8 % (1.85); left circumflex, 82.8 % (1.82); posterior descending, 50.2 % (1.50) and first diagonal, 39.8 % (1.39). High diagnostic confidence for the assessment of CA dominance was achieved in 56.2 % of MRA examinations (mean score, 1.56). Cardiac motion freezing (mean score, 2.18; Pearson's r=0.73, P<0.029) affected image quality more than respiratory motion freezing (mean score, 2.20; r=0.58, P<0.029). Mean quantitative vessel sharpness of the internal thoracic artery, RCA and LAD were 53.1, 52.5 and 48.7 %, respectively. Most SNFB3D-MRA examinations allow for excellent depiction of the main CAs in young CHD patients; visualisation of side branches remains limited. • Self-navigated free-breathing three-dimensional magnetic resonance angiography (SNFB3D-MRA) sufficiently visualises coronary arteries (CAs). • Depiction of main CAs in patients with congenital heart disease is excellent. • Visualisation of CA side branches using SNFB3D-MRA is limited. • SNFB3D-MRA image quality is especially correlated to cardiac motion freezing ability.

Photoinduced Enhancement of Anisotropic Charge Correlations on Triangular Lattices with Trimers

To explore nontrivial photoinduced modulations of charge correlations, we theoretically study photoinduced dynamics in quarter-filled extended Hubbard models with competing intersite repulsive interactions on triangular lattices with trimers, where the end points are crystallographically equivalent. The exact diagonalization method is used and the time-dependent Schr\"odinger equation is numerically solved during and after photoexcitation. Time-averaged double occupancy and intersite density-density correlations can be interpreted as due to effective on-site and intersite repulsive interactions, respectively, relative to transfer energies. In the case where the intersite repulsive interactions compete with each other, the anisotropy of their effective interactions can be enhanced with the help of the trimers, irrespective of whether the trimers are linear or bent. In particular, in the case where the arrangement of the trimers is close to that in $\alpha$-(bis[ethylenedithio]-tetrathiafulvalene)$_2$I$_3$ [$\alpha$-(BEDT-TTF)$_2$I$_3$] in the metallic phase, the effective on-site repulsion is enhanced relative to the transfer energies. The relevance of this theoretical finding to the experimentally observed optical freezing of charge motion is discussed.

Optical freezing of charge motion in an organic conductor.

Dynamical localization, that is, reduction of the intersite electronic transfer integral t by an alternating electric field, E(ω), is a promising strategy for controlling strongly correlated systems with a competing energy balance between t and the Coulomb repulsion energy. Here we describe a charge localization induced by the 9.3 MV cm(-1) instantaneous electric field of a 1.5 cycle (7 fs) infrared pulse in an organic conductor α-(bis[ethylenedithio]-tetrathiafulvalene)(2)I(3). A large reflectivity change of >25% and a coherent charge oscillation along the time axis reflect the opening of the charge ordering gap in the metallic phase. This optical freezing of charges, which is the reverse of the photoinduced melting of electronic orders, is attributed to the ~10% reduction of t driven by the strong, high-frequency (ω ≧ t/ħ) electric field.

Raman and IR studies of pressure- and temperature-induced phase transitions in [(CH2)3NH2][Zn(HCOO)3

Temperature- and pressure-dependent studies of Raman and IR spectra have been performed on azetidinium zinc formate, [(CH2)3NH2][Zn(HCOO)3]. Vibrational spectra showed distinct anomalies in mode frequencies and bandwidths near 250 and 300 K, which were attributed to structural phase transitions associated with the gradual freezing of ring-puckering motions of the azetidinium cation. Pressure-dependent studies revealed a pressure-induced transition near 0.4 GPa. Raman spectra indicate that the structure of the room-temperature intermediate phase observed near 0.4 GPa is the same as the monoclinic structure observed at ambient pressure below 250 K. The second phase transition was found near 2.4 GPa. This transition has strong first-order character and is associated with strong distortion of both the zinc formate framework and azetidinium cations. The last phase transition was found near 7.0 GPa. This transition leads to lowering of the symmetry and further distortion of the zinc formate framework, whereas the azetidinium cation structure is weakly affected.

Motion Freeze for Respiration Motion Correction in PET/CT: A Preliminary Investigation With Lung Cancer Patient Data

Purpose. Respiratory motion presents significant challenges for accurate PET/CT. It often introduces apparent increase of lesion size, reduction of measured standardized uptake value (SUV), and the mismatch in PET/CT fusion images. In this study, we developed the motion freeze method to use 100% of the counts collected by recombining the counts acquired from all phases of gated PET data into a single 3D PET data, with correction of respiration by deformable image registration. Methods. Six patients with diagnosis of lung cancer confirmed by oncologists were recruited. PET/CT scans were performed with Discovery STE system. The 4D PET/CT with the Varian real-time position management for respiratory motion tracking was followed by a clinical 3D PET/CT scan procedure in the static mode. Motion freeze applies the deformation matrices calculated by optical flow method to generate a single 3D effective PET image using the data from all the 4D PET phases. Results. The increase in SUV and decrease in tumor size with motion freeze for all lesions compared to the results from 3D and 4D was observed in the preliminary data of lung cancer patients. In addition, motion freeze substantially reduced tumor mismatch between the CT image and the corresponding PET images. Conclusion. Motion freeze integrating 100% of the PET counts has the potential to eliminate the influences induced by respiratory motion in PET data.

Freezing of Molecular Motions Probed by Cryogenic Magic Angle Spinning NMR.

Cryogenic magic angle spinning makes it possible to obtain the NMR spectra of solids at temperatures low enough to freeze out most molecular motions. We have applied cryogenic magic angle spinning NMR to a crystalline small-molecule solid (ibuprofen sodium salt), which displays a variety of molecular dynamics. Magic angle (13)C NMR spectra are shown for a wide range of temperatures, including in the cryogenic regime down to 20 K. The hydrophobic and hydrophilic regions of the molecular structure display different behavior in the cryogenic regime, with the hydrophilic region remaining well-structured, while the hydrophobic region exhibits a broad frozen conformational distribution.