High resolution solid-state NMR on the desktop.

High-resolution low-field nuclear magnetic resonance (NMR) spectroscopy has found wide application for characterization of liquid compounds because of the low maintenance cost of modern permanent magnets. Solid-state NMR so far is limited to low-resolution measurements of static powders, because of the limited space available in this type of magnet. Magic-angle sample spinning and low-magnetic fields are an attractive combination to achieve high spectral resolution especially for paramagnetic solids. Here we show that magic angle spinning modules can be miniaturized using 3D printing techniques so that high-resolution solid-state NMR in permanent magnets becomes possible. The suggested conical rotor design was developed using finite element calculations and provides sample spinning frequencies higher than 20 kHz. The setup was tested on various diamagnetic and paramagnetic compounds including paramagnetic battery materials. The only comparable experiments in low-cost magnets known so far, had been done in the early times of magic angle spinning using electromagnets at much lower sample spinning frequency. Our results demonstrate that high-resolution low-field magic-angle-spinning NMR does not require expensive superconducting magnets and that high-resolution solid-state NMR spectra of paramagnetic compounds are feasible. Generally, this could introduce low-field solid-state NMR for abundant nuclei standard as a routine analytical tool.

Anteromedial meniscofemoral ligament-A rare finding.

We report a case of a 49-year-old patient presenting an anteromedial meniscofemoral ligament (AMMFL) on both knees with a tear of this ligament in the left knee associated to a normal anterior cruciate ligament (ACL). The AMMFL is a relatively rare anatomic structure that may correspond to a variant of the ACL type anterior root insertion of the medial meniscus. The findings reported in the literature were in most part results of incidental situations. AMMFL can be visualized through magnetic resonance imaging (MRI) and arthroscopy.

Single Molecules Trapped by Dynamic Inhomogeneous Temperature Fields.

We demonstrate a single molecule trapping concept that modulates the actual driving force of Brownian motion--the temperature. By spatially and temporally varying the temperature at a plasmonic nanostructure, thermodiffusive drifts are induced that are used to trap single nano-objects. A feedback controlled switching of local temperature fields allows us to confine the motion of a single DNA molecule for minutes and tailoring complex effective trapping potentials. This new type of thermophoretic microbeaker even provides control over a well-defined number of single molecules and is scalable to large arrays of trapping structures.

Trapping of single nano-objects in dynamic temperature fields.

In this article we explore the dynamics of a Brownian particle in a feedback-free dynamic thermophoretic trap. The trap contains a focused laser beam heating a circular gold structure locally and creating a repulsive thermal potential for a Brownian particle. In order to confine a particle the heating beam is steered along the circumference of the gold structure leading to a non-trivial motion of the particle. We theoretically find a stability condition by switching to a rotating frame, where the laser beam is at rest. Particle trajectories and stable points are calculated as a function of the laser rotation frequency and are experimentally confirmed. Additionally, the effect of Brownian motion is considered. The present study complements the dynamic thermophoretic trapping with a theoretical basis and will enhance the applicability in micro- and nanofluidic devices.

An ensemble of bias-adjusted CMIP6 climate simulations based on a high-resolution North American reanalysis.

ESPO-G6-R2 v1.0 is a set of statistically downscaled and bias-adjusted climate simulations based on the Coupled Model Intercomparison Project 6 (CMIP6) models. The dataset is composed of daily timeseries of three variables: daily maximum temperature, daily minimum temperature and daily precipitation. Data are available from 1950 to 2100 over North America. The simulation ensemble is comprised of 14 models driven by two emissions scenarios (SSP2-4.5 and SSP3-7.0). In this paper, we describe the workflow used for the bias-adjustment, which relies on the detrended quantile mapping method and the Regional Deterministic Reforecast System (RDRS) v2.1 reference dataset. Using the framework defined in the VALUE project, we show the improvements made by the bias-adjustment on marginal, temporal and multivariate aspects of the data. We also verify that the bias-adjusted climate data have similar climate change signal to the original climate model simulations. Finally, we provide guidance to users on how to use this dataset.

Photothermal signal distribution analysis (PhoSDA).

Photothermal correlation spectroscopy (PhoCS) is a powerful counterpart to fluorescence correlation spectroscopy (FCS). Using PhoCS it is possible to probe the dynamics of non-fluorescent and non-bleaching ultra-stable metal-nanoparticles in solution and biological specimen, where they can be used as tracers and markers. This paper complements the absorption correlation method by a histogram analysis framework, the photothermal signal distribution analysis (PhoSDA). It is hereby possible to extract individual absorbent tracer concentrations, size dispersions, heterogeneous populations and focal geometry parameters which are otherwise inaccessible by correlation analysis.

Nano-lens diffraction around a single heated nano particle.

The action of a nanoscopic spherically symmetric refractive index profile on a focused Gaussian beam may easily be envisaged as the action of a phase-modifying element, i.e. a lens: Rays traversing the inhomogeneous refractive index field n(r) collect an additional phase along their trajectory which advances or retards their phase with respect to the unperturbed ray. This lens-like action has long been understood as being the mechanism behind the signal of thin sample photothermal absorption measurements [Appl. Opt. 34, 41-50 (1995)], [Jpn. J. Appl. Phys. 45, 7141-7151 (2006)], where a cylindrical symmetry and a different lengthscale is present. In photothermal single (nano-)particle microscopy, however, a complicated, though prediction-wise limited, electrodynamic scattering treatment was established [Phys. Rev. B 73, 045424 (2006)] during the emergence of this new technique. Our recent study [ACS Nano, DOI: 10.1021/nn300181h] extended this approach into a full ab-initio model and showed for the first time that the mechanism behind the signal, despite its nanoscopic origin, is also the lens-like action of the induced refractive index profile only hidden in the complicated guise of the theoretical generalized Mie-like framework. The diffraction model proposed here yields succinct analytical expressions for the axial photothermal signal shape and magnitude and its angular distribution, all showing the clear lens-signature. It is further demonstrated, that the Gouy-phase of a Gaussian beam does not contribute to the relative photothermal signal in forward direction, a fact which is not easily evident from the more rigorous EM treatment. The presented model may thus be used to estimate the signal shape and magnitude in photothermal single particle microscopy.

Gaussian beam photothermal single particle microscopy.

We explore the intuitive lensing picture of laser-heated nanoparticles occurring in single particle photothermal (PT) microscopy. The effective focal length of the thermal lens (TL) is derived from a ray-optics treatment and used to transform the probing focused Gaussian beam with ABCD Gaussian matrix optics. The relative PT signal is obtained from the relative beam-waist change far from the TL. The analytical expression is semiquantitative, capable of describing the entire phenomenology of single particle PT microscopy, and shows that the signal is the product of the point-spread functions of the involved lasers times a linear function of the axial coordinate. The presented particularly simple and intuitive Gaussian beam lensing picture compares favorably to the experimental results for 60 nm gold nanoparticles and provides the prescription for optimum setup calibration.

Stable magic angle spinning with Low-Cost 3D-Printed parts.

A 3D-printed double-bearing magic angle spinning (MAS) system was developed with a home-built 4.0 mm MAS nuclear magnetic resonance (NMR) probe at 7 T. Various fused deposition modelling 3D printers were used to produce spinning modules of ignorable materials costs for rotors with a diameter of 7.0, 4.0, and 3.5 mm. High-performance MAS experiments on the 4.0 mm-diameter model using a pencil-type ceramic rotor and 3D-printed drive cap resulted in a high-resolution 1H NMR signal of silicone grease. The 3.5 mm-diameter MAS system reached a spinning frequency of 23 kHz. Furthermore, 3D-printed inserts were designed for various rotor sizes which can isolate the sample from humidity for a duration of more than a week. Single crystal inserts for MAS rotors of commercial probes can readily be printed using two-color printers. Those developments enable customized low-cost MAS NMR for both adapting existing and manufacturing new probes, respectively.

Electrooxidative generation of polymer films from rigid tricarbazole monomers.

In this report, syntheses and subsequent electropolymerization of a series of five rigid tricarbazole monomers are described. The monomers involve three planar triphenylene-cored tricarbazole-benzenes (with the carbazole units connected via their a- or b-planes) and two triptycene-cored derivatives. Oxidative electropolymerization of these monomers leads to a continuous growth of smooth and freestanding thin films. Moreover, one type of polymer film, based on a poly-a-tricarbazole network (paTC), shows the occurrence of intrinsic microporosity properties, with a specific BET surface area of 260 m2 g-1.

Enhanced efficiency of solid-state NMR investigations of energy materials using an external automatic tuning/matching (eATM) robot.

We have developed and explored an external automatic tuning/matching (eATM) robot that can be attached to commercial and/or home-built magic angle spinning (MAS) or static nuclear magnetic resonance (NMR) probeheads. Complete synchronization and automation with Bruker and Tecmag spectrometers is ensured via transistor-transistor-logic (TTL) signals. The eATM robot enables an automated "on-the-fly" re-calibration of the radio frequency (rf) carrier frequency, which is beneficial whenever tuning/matching of the resonance circuit is required, e.g. variable temperature (VT) NMR, spin-echo mapping (variable offset cumulative spectroscopy, VOCS) and/or in situ NMR experiments of batteries. This allows a significant increase in efficiency for NMR experiments outside regular working hours (e.g. overnight) and, furthermore, enables measurements of quadrupolar nuclei which would not be possible in reasonable timeframes due to excessively large spectral widths. Additionally, different tuning/matching capacitor (and/or coil) settings for desired frequencies (e.g.7Li and 31P at 117 and 122MHz, respectively, at 7.05 T) can be saved and made directly accessible before automatic tuning/matching, thus enabling automated measurements of multiple nuclei for one sample with no manual adjustment required by the user. We have applied this new eATM approach in static and MAS spin-echo mapping NMR experiments in different magnetic fields on four energy storage materials, namely: (1) paramagnetic 7Li and 31P MAS NMR (without manual recalibration) of the Li-ion battery cathode material LiFePO4; (2) paramagnetic 17O VT-NMR of the solid oxide fuel cell cathode material La2NiO4+δ; (3) broadband 93Nb static NMR of the Li-ion battery material BNb2O5; and (4) broadband static 127I NMR of a potential Li-air battery product LiIO3. In each case, insight into local atomic structure and dynamics arises primarily from the highly broadened (1-25MHz) NMR lineshapes that the eATM robot is uniquely suited to collect. These new developments in automation of NMR experiments are likely to advance the application of in and ex situ NMR investigations to an ever-increasing range of energy storage materials and systems.

Avulsão do tendão reto femoral em atleta amador: relato de caso diagnosticado pela ressonância magnética / Rectus femoris tendon avulsion in an amateur athlete: case report diagnosed by magnetic resonance

Introdução: o músculo reto femoral é o músculo mais frequentemente lesado do grupo quadríceps durante chutes e corridas repetitivas, apesar de suas avulsões serem raras. A dor localizada na coxa proximal e a incapacidade de flexionar o quadril e/ou estender o joelho associado à história do paciente de contração violenta ou alongamento forçado do grupo muscular do quadríceps femoral podem indicar uma avulsão do reto femoral. Objetivo: relatar um caso e revisar a literatura acerca desta lesão incomum. Materiais e Métodos: revisão do prontuário, registro fotográfico do método diagnóstico e revisão da literatura. Resultados: homem de 46 anos com dor localizada no quadril esquerdo com irradiação para a coxa por três meses após cair no chão com a região dolorida em um jogo de futebol. A dor começou subitamente uma semana após a queda. A ressonância magnética do quadril apresentava avulsão completa do reto femoral esquerdo, distando 2 cm da espinha ilíaca anterior inferior com efusão líquida adjacente. Conclusão: este relato demonstra a dificuldade de diagnosticar essa lesão, pois o seu exame físico é inespecífico, podendo simular patologias mais complexas, necessitando de exames complementares para seu correto diagnóstico.

Introduction: the rectus femoris muscle is the most frequently injured muscle of the quadriceps group during repetitive kicking and sprinting. Avulsions of the rectus femoris are rare injuries. Pain located at the proximal thigh and disability in flexing the hip and/or extending the knee associated with a patient history of a violent contraction or forceful stretching of the quadriceps femoris muscle group can indicate an avulsion of rectus femoris. Objective: report a case and review the literature about this uncommon lesion. Materials and Methods: we reviewed medical records, photographic records of diagnostic methods, and reviews from the literature. Results: a 46-year-old man with pain located at the left anterior hip with irradiation to the thigh for three months after falling to the ground with the sore region in a soccer game. The pain started suddenly one week after the fall. The MRI of the hip featured complete avulsion of the left rectus femoris, being 2 cm distal from the anterior inferior iliac spine with adjacent liquid effusion. Conclusion: this report demonstrates the difficulty of diagnosing this lesion, since its physical examination is non-specific, and it can simulate more complex pathologies, requiring complementary tests for its correct diagnosis.

Variz Intra-Óssea ­ um achado raro diagnosticado pela ressonância magnética / Intraosseous Varicose Vein ­ A rare finding diagnosed by magnetic resonance imaging

Introdução: As varizes são veias que após submetidas a períodos de pressão aumentada no sistema venoso periférico se tornam dilatadas, tortuosas e alongadas. Pacientes acometidos irão referir dor no membro, além de sinais de insuficiência venosa. O exame de imagem comumente utilizado é o ultrassom com Doppler, no entanto, na presença de anomalias de drenagem venosa intraóssea, deve-se preferir a ressonância magnética. Objetivo: Relatar um caso e revisar a literatura acerca desta lesão incomum. Materiais e Métodos: Revisão do prontuário do paciente no Hospital América, registro fotográfico do método diagnóstico e revisão da literatura. Resultados: Homem de 46 anos com dor e queimação constantes, além de edema na perna e no pé esquerdos há dois meses Ao exame físico apresenta edema da perna, tornozelo e pé esquerdos, com discreto aumento de temperatura ao toque, sem alteração da coloração da pele. A ressonância magnética demonstra varicosidades das veias tibiais posteriores com comunicação através de veia perfurante com varicosidade da veia intraóssea posterior da tíbia ­ variz intraóssea. Conclusão: Este relato demonstra a dificuldade de diagnosticar a variz intra-óssea que, além de ser uma lesão rara, é diagnosticada apenas pela ressonância magnética.

Introduction: Varicose veins are veins that after being submitted to high pressure on the peripheral venous system become dilated, tortuous and elongated. Patients affected will report pain and venous insufficiency signs in the area. The imaging exam commonly used is the Doppler ultrasound, however, when in front of an intraosseous venous drainage anomaly ­ intraosseous varix, magnetic resonance should be preferred. Objective: Report a case and review the literature about this uncommon lesion. Materials and Methods: We carried out a review of medical records at Hospital América, a photographic record of diagnostic methods, and a review from the literature. Results: A 46-year-old man with constant pain and burning, as well as edema in his left leg and foot for two months. On physical examination, he had edema in his left leg, ankle, and foot, with a slight increase in temperature at the touch, without changing the skin color. Magnetic resonance imaging shows varicosities of the posterior tibial veins with communication through a perforating vein with varicosity of the posterior tibial intraosseous vein - intraosseous varicose vein. Conclusion: This report demonstrates the difficulty of diagnosing intraosseous varices, which, in addition to being a rare lesion, are diagnosed only by magnetic resonance imaging.

Fratura por estresse do cuboide e do cuneiforme lateral ­ uma associação rara / Cuboid and lateral cuneiform stress fractures ­ a rare association

Fraturas por estresse são lesões que ocorrem devido a uma força de baixa intensidade, porém repetida sobre o osso por um longo período de tempo. Esta acomete mais militares e alguns atletas, porém sua incidência vem aumentando na população. Com exceção do calcâneo, estas lesões raramente acometem os ossos do tarso. Cuboide e cuneiforme lateral são dois ossos dessa região do mediopé com poucos relatos na literatura relativos à fratura por estresse. Estes apresentam uma sintomatologia em comum, com dor local, sensibilidade à palpação, possível edema e alterações de pele. Atualmente o melhor método diagnóstico é a ressonância magnética. São fraturas classificadas como de baixo risco e o tratamento é conservador aliado à terapia farmacológica.

Stress fractures are injuries that happen due to a low but repetitive force over the bone during a long period. It is more common in military personnel and in some athletes; however, its incidence has been rising among the population. With exception to the calcaneum, these injuries rarely happen in the tarsal bones. Cuboid and lateral cuneiform are two bones of the midfoot with few literature reports of a stress fracture. These present a common symptomatology with local pain, tenderness to palpation, possible edema and skin changes. Currently, the best diagnostic method is the magnetic resonance imaging. These fractures are classified as low risk and its treatment is conservative, allied to pharmacologic therapy.

Optically controlled thermophoretic trapping of single nano-objects.

Brownian motion is driven by thermal fluctuations and becoming more efficient for decreasing size and elevated temperatures. Here, we show that despite the increased fluctuations local temperature fields can be used to localize and control single nano-objects in solution. By creating strong local temperature gradients in a liquid using optically heated gold nanostructures, we are able to trap single colloidal particles. The trapping is thermophoretic in nature, and thus no restoring body force is involved. The simplicity of the setup allows for an easy integration and scalability to large arrays of traps.

Photothermal single-particle microscopy: detection of a nanolens.

Combining quantitative photothermal microscopy and light scattering microscopy as well as accurate MIE scattering calculations on single gold nanoparticles, we reveal that the mechanism of photothermal single-molecule/particle detection is quantitatively explained by a nanolensing effect. The lensing action is the result of the long-range character of the refractive index profile. It splits the focal detection volume into two regions. Our results lay the foundation for future developments and quantitative applications of single-molecule absorption microscopy.

Nuclear magnetic resonance apparatus for pulsed high magnetic fields.

A nuclear magnetic resonance apparatus for experiments in pulsed high magnetic fields is described. The magnetic field pulses created together with various magnet coils determine the requirements such an apparatus has to fulfill to be operated successfully in pulsed fields. Independent of the chosen coil it is desirable to operate the entire experiment at the highest possible bandwidth such that a correspondingly large temporal fraction of the magnetic field pulse can be used to probe a given sample. Our apparatus offers a bandwidth of up to 20 MHz and has been tested successfully at the Hochfeld-Magnetlabor Dresden, even in a very fast dual coil magnet that has produced a peak field of 94.2 T. Using a medium-sized single coil with a significantly slower dependence, it is possible to perform advanced multi-pulse nuclear magnetic resonance experiments. As an example we discuss a Carr-Purcell spin echo sequence at a field of 62 T.