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Hydrogel‐based actuators are innovative materials that exhibit responsive and dynamic behavior in response to external stimuli, making them promising candidates for a wide range of applications in fields such as soft robotics. We employ 3D printing to create layered rectangles, using a passive ink composed of gelatin methacryloyl (GelMA) and an active ink consisting of GelMA and poly(N‐isopropylacrylamide) (PNIPAM). Our aim is to assess and compare the bending capabilities of these structures based on their layer arrangements in a buffer above the lower critical solution temperature. Therefore, an asymmetric rectangular structure is selected as the shape‐changing component in the tail of a 3D printed fish‐shaped hydrogel actuator. We show that gold nanostars integrated into the actuators serve as photothermal elements, enabling the fish tail to repeatedly bend when near infrared light is turned on and off. Our effort illustrates the potential of combining 3D printing, responsive hydrogels and photothermal elements with near infrared light towards soft robotic applications. This combination yields actuators capable of shape‐shifting without requiring localized light or transitioning between environments with varying temperatures. [ABSTRACT FROM AUTHOR]

Purpose: A novel dissolution dynamic nuclear polarization (dDNP) polarizer platform is presented. The polarizer meets a number of key requirements for in vitro, preclinical, and clinical applications. Method: It uses no liquid cryogens, operates in continuous mode, accommodates a wide range of sample sizes up to and including those required for human studies, and is fully automated. Results: It offers a wide operational window both in terms of magnetic field, up to 10.1 T, and temperature, from room temperature down to 1.3 K. The polarizer delivers a 13C liquid state polarization for [1‐13C]pyruvate of 70%. The build‐up time constant in the solid state is approximately 1200 s (20 minutes), allowing a sample throughput of at least one sample per hour including sample loading and dissolution. Conclusion: We confirm the previously reported strong field dependence in the range 3.35 to 6.7 T, but see no further increase in polarization when increasing the magnetic field strength to 10.1 T for [1‐13C]pyruvate and trityl. Using a custom dry magnet, cold head and recondensing, closed‐cycle cooling system, combined with a modular DNP probe, and automation and fluid handling systems, we have designed a unique dDNP system with unrivalled flexibility and performance. [ABSTRACT FROM AUTHOR]

Purpose To present a constrained optimal-control (OC) framework for designing large-flip-angle parallel-transmit (pTx) pulses satisfying hardware peak-power as well as regulatory local and global specific-absorption-rate (SAR) limits. The application is 2D and 3D spatial-selective 90° and 180° pulses. Theory and Methods The OC gradient-ascent-pulse-engineering method with exact gradients and the limited-memory Broyden-Fletcher-Goldfarb-Shanno method is proposed. Local SAR is constrained by the virtual-observation-points method. Two numerical models facilitated the optimizations, a torso at 3 T and a head at 7 T, both in eight-channel pTx coils and acceleration-factors up to 4. Results The proposed approach yielded excellent flip-angle distributions. Enforcing the local-SAR constraint, as opposed to peak power alone, reduced the local SAR 7 and 5-fold with the 2D torso excitation and inversion pulse, respectively. The root-mean-square errors of the magnetization profiles increased less than 5% with the acceleration factor of 4. Conclusion A local and global SAR, and peak-power constrained OC large-flip-angle pTx pulse design was presented, and numerically validated for 2D and 3D spatial-selective 90° and 180° pulses at 3 T and 7 T. Magn Reson Med 77:374-384, 2017. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Oligomeric and protofibrillar aggregates formed by the amyloid-β peptide (Aβ) are believed to be involved in the pathology of Alzheimer's disease. Central to Alzheimer pathology is also the fact that the longer Aβ42 peptide is more prone to aggregation than the more prevalent Aβ40. Detailed structural studies of Aβ oligomers and protofibrils have been impeded by aggregate heterogeneity and instability. We previously engineered a variant of Aβ that forms stable protofibrils and here we use solid-state NMR spectroscopy and molecular modeling to derive a structural model of these. NMR data are consistent with packing of residues 16 to 42 of Aβ protomers into hexameric barrel-like oligomers within the protofibril. The core of the oligomers consists of all residues of the central and C-terminal hydrophobic regions of Aβ, and hairpin loops extend from the core. The model accounts for why Aβ42 forms oligomers and protofibrils more easily than Aβ40. [ABSTRACT FROM AUTHOR]

Purpose The use of hyperpolarization to enhance the sensitivity of MRI has so far been limited by the decay of the polarization through T1 relaxation. Recently, methods have been proposed that extend the lifetime of the hyperpolarization by storing the spin order in slowly relaxing singlet states. Methods With this aim, optimal control theory was applied to create pulses that for near-equivalent spins accomplish transfers in and out of the singlet state with maximum efficiency while ensuring robustness toward variations in the nuclear spin system Hamiltonian (chemical shift, J-couplings, B1 and B0 magnetic field inhomogeneity). Results The pulses are designed to accomplish efficient transfer with low B1 amplitude, essential for applications on preclinical and clinical MR scanners. Conclusion It is demonstrated that significantly improved efficiency and robustness can be obtained within the limitations of typical MR scanner performance. Magn Reson Med 71:921-926, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

1H-detected magic-angle spinning NMR experiments facilitate structural biology of solid proteins, which requires using deuterated proteins. However, often amide protons cannot be back-exchanged sufficiently, because of a possible lack of solvent exposure. For such systems, using 2H excitation instead of 1H excitation can be beneficial because of the larger abundance and shorter longitudinal relaxation time, T1, of deuterium. A new structure determination approach, 'quadruple-resonance NMR spectroscopy', is presented which relies on an efficient 2H-excitation and 2H-13C cross-polarization (CP) step, combined with 1H detection. We show that by using 2H-excited experiments better sensitivity is possible on an SH3 sample recrystallized from 30 % H2O. For a membrane protein, the ABC transporter ArtMP in native lipid bilayers, different sets of signals can be observed from different initial polarization pathways, which can be evaluated further to extract structural properties. [ABSTRACT FROM AUTHOR]

Purpose: To be able to screen and identify potential candidate agents for noninvasive imaging of diseases involving angiogenesis, a standardized in vivo angiogenesis model is needed. Angiogenesis is a common feature of many pathological conditions and has become an important target for diagnosis and treatment, with many noninvasive imaging agents emerging. Materials and Methods: Uniform scaffolds consisting of porous and flexible polycaprolactone were implanted subcutaneously in mice and studied after 1 to 6 weeks to describe the time course of angiogenesis. The model was characterized by histology and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Results: Microscopic examination revealed progressive ingrowth of new vessels from the periphery, leading to a fully vascularized scaffold within 6 weeks. Blood flow through the new vessels, assessed by DCE-MRI, revealed peripheral vascularization corresponding to 12.3% (SD 6.1%) of scaffold area at week 1 and a more uniform and complete distribution of vessels corresponding to 84.1% (SD 16.2%) of scaffold area at week 4. Conclusion: In agreement with microscopic examination, noninvasive DCE-MRI visualized progressive development of new vessels in a novel and standardized murine angiogenesis model, making this model suitable for screening angiogenesis-related drugs and contrast agents. J. Magn. Reson. Imaging 2012;35:703-710. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

We present mobile, low-field 17O NMR as a means for monitoring oxygen in liquids. Whereas oxygen is one of the most important elements, oxygen NMR is limited by a poor sensitivity related to low natural abundance and gyro-magnetic ratio of the NMR active 17O isotope. Here, we demonstrate 17O NMR detection at a Larmor frequency of 8.74 MHz in a 1.5-T Halbach neodymium magnet with a home-built digital NMR instrument suitable for large-scale production and in-line monitoring applications. The proposed 17O NMR sensor may be applied for direct, noninvasive measurements of water content in, for example, oil, manure, or food in automated quality or process control. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Transforming growth factor β-induced protein (TGFBIp) has been linked to several corneal dystrophies as certain point mutations in the protein may give rise to a progressive accumulation of insoluble protein material in the human cornea. Little is known about the biological functions of this extracellular protein, which is expressed in various tissues throughout the human body. However, it has been found to interact with a number of extracellular matrix macromolecules such as collagens and proteoglycans. Structural information about TGFBIp might prove to be a valuable tool in the elucidation of its function and its role in corneal dystrophies caused by mutations in the TGFBI gene. A simple method for the purification of wild-type and mutant forms of recombinant human TGFBIp from human cells under native conditions is presented here. Moreover, the crystallization and preliminary X-ray analysis of TGFBIp are reported. [ABSTRACT FROM AUTHOR]

Abstract: The structure of the chlorosome baseplate protein CsmA from Chlorobium tepidum in a 1:1 chloroform:methanol solution was determined using liquid-state NMR spectroscopy. The data reveal that the 59-residue protein is predominantly α-helical with a long helical domain extending from residues V6 to L36, containing a putative bacteriochlorophyll a binding domain, and a short helix in the C-terminal part extending from residues M41 to G49. These elements are compatible with a model of CsmA having the long N-terminal α-helical stretch immersed into the lipid monolayer confining the chlorosome and the short C-terminal helix protruding outwards, thus available for interaction with the Fenna–Matthews–Olson antenna protein. [Copyright &y& Elsevier]

Abstract: The structure of a synthetic peptide corresponding to the fifth membrane-spanning segment (M5) in Na+,K+-ATPase in sodium dodecyl sulfate (SDS) micelles was determined using liquid-state nuclear magnetic resonance (NMR) spectroscopy. The spectra reveal that this peptide is substantially less α-helical than the corresponding M5 peptide of Ca2+-ATPase. A well-defined α-helix is shown in the C-terminal half of the peptide. Apart from a short helical stretch at the N-terminus, the N-terminal half contains a non-helical region with two proline residues and sequence similarity to a non-structured transmembrane element of the Ca2+-ATPase. Furthermore, this region spans the residues implicated in Na+ and K+ transport, where they are likely to offer the flexibility needed to coordinate Na+ as well as K+ during active transport. [Copyright &y& Elsevier]

Two recent X-ray structures have tremendously increased the understanding of the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and related proteins. Both structures show the fifth transmembrane span (M5) as a single continuous α-helix. The inherent structural and dynamic features of this span (Lys758–Glu785) were studied in isolation in sodium dodecyl sulfate (SDS) micelles using liquid-state nuclear magnetic resonance (NMR) spectroscopy. We find that a flexible region (Ile765–Asn768) is interrupting the α-helix. The location of the flexible region near the Ca2+ binding residues Asn768 and Glu771 suggests that together with a similar region in M6 it has a hinge function that may be important for cooperative Ca2+ binding and occlusion. [Copyright &y& Elsevier]

. A comparative study of the factors concerned with coagulation and fibrinolysis in newborn infants with erythroblastosis-( a) at the time of birth, ( b) before, and ( c) after exchange transfusion-showed the following significant changes: A. During the period from birth until the start of the exchange transfusion (an average of approximately 5 hours): A decrease in PP and factor V simultaneously with a markedly decreasing fibrinolytic activity. B. During the period from before until after the exchange transfusion: A marked fall in the platelet count, an increase in the PP, but a prolonged Quick time. In addition, a slight fall in the fibrinogen content simultaneously with a slight, but not significant, increase in fibrinolytic activity. Moreover, a pronounced increase in plasminogen content. The cause of these changes is discussed, with particular reference to the levels of factors, in the donor blood, concerned with coagulation and fibrinolysis. [ABSTRACT FROM AUTHOR]

. Investigation of the parameters of coagulation and fibrinolysis in mothers with premature separation of the placenta (P.S.P.) and their newborn infants, compared with normal prematurely delivered women and their normal premature infants, showed the following: A. In the mothers: With increasing severity of the premature separation also increasing alteration in the parameters of coagulation i.e. decreasing platelet count, factor V, prothrombin-proconvertin, fibrinogen content, and prolonged partial thromboplastin time. In severe cases the TAT three-stage indicated a slightly increased content of coagulation-activating components in the plasma. No definite effect upon fibrinolytic activity of premature separation of the placenta. B. In the infants: In premature separation of the placenta, the infants also exhibited changes in their coagulation status, most distinct in the most severe cases. These changes consisted of decreasing platelet counts, factor V, prothrombin-proconvertin, fibrinogen content, and prolonged partial thromboplastin time. For platelet count and fibrinogen the changes were not significant. As for the mothers the TAT three-stage showed an increased content of clot-promoting components in the plasma in the most severe cases. No definite effect of premature separation of the placenta upon fibrinolytic activity could be shown. The cause of the demonstrated changes is discussed and therapeutic possibilities mentioned. [ABSTRACT FROM AUTHOR]

. A study of the parameters of coagulation and fibrinolysis in Rhesus D immunized mothers and their erythroblastotic infants gave the following results, on comparison with normal women delivered at term and their newborn infants and with prematurely delivered women and their newborn infants: A. Mothers: No influence of the Rhesus immunization upon the parameters of coagulation or fibrinolysis. B. Newborn infants: With increasing severity of erythroblastosis a decreasing platelet count and at the same time an increasing content of clot-promoting components in the plasma. In addition, a reduced content of PP and factor V, but unchanged fibrinogen. Fibrinolytic activity was also reduced in erythroblastotic newborn infants. The causes of these changes are discussed. [ABSTRACT FROM AUTHOR]

. The microscopic appearances of vulval hidroadenoma are described. Differential diagnostic problems are discussed, emphasizing in particular the possibility of confusing this tumour with epidermoid carcinoma. One such case is reported. It is stressed that hidroadenoma is a benign tumour to be treated by wide local excision, unlike the malignant tumours which require total vulvectomy with dissection of the lymph nodes. [ABSTRACT FROM AUTHOR]

Transforming growth factor beta-induced protein (TGFBIp) has been linked to several corneal dystrophies as certain point mutations in the protein may give rise to a progressive accumulation of insoluble protein material in the human cornea. Little is known about the biological functions of this extracellular protein, which is expressed in various tissues throughout the human body. However, it has been found to interact with a number of extracellular matrix macromolecules such as collagens and proteoglycans. Structural information about TGFBIp might prove to be a valuable tool in the elucidation of its function and its role in corneal dystrophies caused by mutations in the TGFBI gene. A simple method for the purification of wild-type and mutant forms of recombinant human TGFBIp from human cells under native conditions is presented here. Moreover, the crystallization and preliminary X-ray analysis of TGFBIp are reported.