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We demonstrate a method to enhance the atom loading rate of a ytterbium (Yb) magneto-optic trap (MOT) operating on the 556 nm ${^1S}_0 \rightarrow {^3P}_1$ intercombination transition (narrow linewidth $\Gamma_g = 2\pi \times 182$ kHz). Following traditional Zeeman slowing of an atomic beam near the 399 nm ${^1S}_0 \rightarrow {^1P}_1$ transition (broad linewidth $\Gamma_p = 2\pi \times 29 $ MHz), two laser beams in a crossed-beam geometry, frequency tuned near the same transition, provide additional slowing immediately prior to the MOT. Using this technique, we observe an improvement by a factor of 6 in the atom loading rate of a narrow-line Yb MOT. The relative simplicity and generality of this approach make it readily adoptable to other experiments involving narrow-line MOTs. We also present a numerical simulation of this two-stage slowing process which shows good agreement with the observed dependence on experimental parameters, and use it to assess potential improvements to the method.

We characterize a hybrid pixel direct detector and demonstrate its suitability for electron energy loss spectroscopy (EELS). The detector has a large dynamic range, narrow point spread function, detective quantum efficiency ≥ 0.8 even without single electron arrival discrimination, and it is resilient to radiation damage. It is capable of detecting ~5 × 106 electrons/pixel/second, allowing it to accommodate up to 0.8 pA per pixel and hence >100 pA EELS zero-loss peak (ZLP) without saturation, if the ZLP is spread over >125 pixels (in the non-dispersion direction). At the same time, it can reliably detect isolated single electrons in the high loss region of the spectrum. The detector uses a selectable threshold to exclude low energy events, and this results in essentially zero dark current and readout noise. Its maximum frame readout rate at 16-bit digitization is 2250 full frames per second, allowing for fast spectrum imaging. We show applications including EELS of boron nitride in which an unsaturated zero loss peak is recorded at the same time as inner shell loss edges, elemental mapping of an STO/BTO/LMSO multilayer, and efficient parallel acquisition of angle-resolved EEL spectra (S(q, ω)) of boron nitride.

Total elbow arthroplasty is currently an established surgical treatment for several pathologies of the elbow. Although initially used primarily in the treatment of rheumatoid arthritis, indications for total elbow arthroplasty have expanded and now include trauma, primary and secondary osteoarthritis, fracture nonunion, and following neoplasm resection. Desired outcomes of elbow arthroplasty include decreasing patient pain, restoration of function and mobility, and prevention of or treatment for instability. In comparison with total elbow arthroplasty, radial head replacements are most commonly performed following trauma. An additional technique, capitellar resurfacing arthroplasty, was developed in an effort to prevent early-onset osteoarthritis secondary to altered elbow biomechanics following radial head replacement. Complications of these surgeries include loosening, fracture, instability and dissociation, bushing wear, and particle disease.

Arthroscopy for acetabular labral tears has minimal impact on pain and function in older patients, especially in the setting of concomitant osteoarthritis. Still, many physicians seek this diagnosis with MR arthrography. Our purpose is to assess the frequency of acetabular labral tears in older patients with hip pain and correlate likelihood of labral pathology with severity of osteoarthritis as visualized on conventional radiograph. From 2004 to 2013, 208 hip MRI arthrograms and corresponding radiographs on patients aged 50 years and older were identified. Age, gender, grade and location of labral tear, alpha angle, Tonnis grade, and joint space width were documented. Labral tears and alpha angle were identified and measured on MR arthrogram. Tonnis grade and joint space width were measured on radiographs. On MR arthrography, true labral tearing was identified in 73 % of patients. There was some degree of labral pathology in 93.3 % of patients, and this increased to 100 % in patients with moderate to severe osteoarthritis, as defined by Tonnis grade 2–3 or joint space width ≤ 2 mm. There were no statistically significant correlations between labral tear grade and Tonnis grade or joint space width. Given the high frequency of labral pathology and the questionable efficacy of arthroscopic surgical intervention in older patients, MR arthrography should be primarily for those with minimal arthritis on radiograph and potential to benefit from surgery. If further imaging beyond radiographs is necessary in these patients, standard MRI may be a more appropriate imaging tool.

Electron energy loss spectroscopy (EELS) in the electron microscope has progressed remarkably in the last five years. Advances in monochromator and spectrometer design have improved the energy resolution attainable in a scanning transmission electron microscope (STEM) to 4.2 meV, and new applications of ultrahigh energy resolution EELS have not lagged behind. They include vibrational spectroscopy in the electron microscope, a field that did not exist 5 years ago but has now grown very substantially. Notable examples include vibrational mapping with about 1 nm spatial resolution, analyzing the momentum dependence of vibrational states in very small volumes, determining the local temperature of the sample from the ratio of energy gains to energy losses, detecting hydrogen and analyzing its bonding, probing radiation-sensitive materials with minimized damage by aloof spectroscopy and leap-frog scanning, and identifying biological molecules with different isotopic substitutions. We review the instrumentation advances, provide a summary of key applications, and chart likely future directions.

We demonstrate the scale up of a symmetric three-path contrast interferometer to large momentum separation. The observed phase stability at separation of 112 photon recoil momenta exceeds the performance of earlier free-space interferometers. In addition to the symmetric interferometer geometry and Bose-Einstein condensate source, the robust scalability of our approach relies on the suppression of undesired diffraction phases through a careful choice of atom optics parameters. The interferometer phase evolution is quadratic with number of recoils, reaching a rate as high as $7\ifmmode\times\else\texttimes\fi{}{10}^{7}\text{ }\text{ }\mathrm{rad}/\mathrm{s}$. We discuss the applicability of our method towards a new measurement of the fine-structure constant and a test of QED.

Background Multiple studies have demonstrated that a significant amount of variability exists in various demineralized bone matrix (DBM) formulations, which casts doubts on its reliability in consistently promoting fusion. Bone marrow aspirate (BMA) is a cellular based graft that contains mesenchymal stem cells (MSCs) and growth factors can confer osteogenic and osteoinductive potential to DBM. The goal of this study was to describe the outcome of DBM enriched with concentrated BMA in patients undergoing combined lumbar interbody and posterolateral fusion. Methods Eighty patients with a minimum of 12 months of follow-up were evaluated. Fusion and rates of complication were evaluated. Functional outcomes were assessed based on the modified Odom’s criteria. Multiple logistic regression analysis was used to examine the effects of independent variables on fusion outcome. Results The overall rate of solid fusion (i.e patients with both solid posterolateral and interbody fusion) was 81.3% (65/80). Specifically, the radiographic evidence of solid posterolateral and interbody fusions were 81.3% (65/80) and 92.5% (74/80), respectively. Seven (8.75%) patients developed hardware-related complications, 2 (2.5%) patients developed a postoperative infection and 2 (2.5%) patients developed clinical pseudarthrosis. Charlson comorbidity index (CCI) scores of 3 and 4 were associated with non-solid unions (CCI-3, p = 0.048; CCI-4, p = 0.03). Excellent or good outcomes were achieved in 58 (72.5%) patients. Conclusions Patients undergoing lumbar fusion using an enriched bone graft containing concentrated BMA added to DBM can achieve successful fusion with relatively low complications and good functional outcomes. Despite these findings, more studies with higher level of evidence are needed to better understand the efficacy of this promising graft option.

Ultrasound is a frontline tool for evaluating, diagnosing, and monitoring rheumatoid arthritis. This article looks at the typical manifestations of rheumatoid arthritis on ultrasound, and why ultrasound is a useful tool in evaluating patients with rheumatoid arthritis. The sonographic manifestations of rheumatoid arthritis are seen much earlier than those on radiographs. Recent scoring systems by the American College of Rheumatology and the European League Against Rheumatism have provided a standardized system of grading and diagnosing rheumatoid arthritis based on ultrasound findings. These scoring systems are useful in aiding treatment decisions to improve diagnosis in cases of clinical uncertainty. Rheumatoid arthritis is a debilitating disease, which should be diagnosed and treated early to prevent permanent disabling arthritis. Ultrasound is a useful and relatively inexpensive tool that aids in the diagnosis and evaluation of the disease. Ultrasound is very sensitive for detecting the early manifestations of synovitis and erosion, which will be occult on radiographs. It is important to recognize the imaging manifestations of the disease to diagnosis, grade, and guide treatment.

The etiology of Kienbock disease, or avascular necrosis of the lunate, is controversial, and there are a myriad of treatments aimed at correcting the various hypothesized pathologies. Interventions to reduce mechanical stress on the lunate have been used for decades, including radial osteotomy with or without radial shortening, ulnar lengthening and metaphyseal core decompression procedures. However, these procedures require preservation of lunate architecture. Newer procedures to revascularize the lunate bone have emerged in the last 10 years, such as pedicled corticoperiosteal vascularized bone grafting. Once there is collapse of the radiocarpal joint or midcarpal arthrosis, the conventional treatments have included proximal row carpectomy and complete or partial wrist joint arthrodesis. Newer salvage procedures such as lunate excision with autologous or synthetic interposition grafts are now being used when possible. As this disease is relatively rare, radiologists may not be familiar with the expected post-operative radiologic findings and complications, especially of the newer treatments. The goals of this paper are to review the available treatment options and their expected appearance on postoperative imaging, with discussion of possible complications when appropriate.

This article will demonstrate a variety of diagnostic entities and categories of muscle disease that can be assessed using ultrasound. Illustrative examples based on four general categories of muscle pathology (trauma, edema, fluid collections, and mass) will be presented with pertinent findings highlighted and discussed. Multiple distinct advantages of ultrasound compared to other imaging modalities will be emphasized through these examples. Normal appearance and architecture of muscle on ultrasound will be reviewed with discussion of the specific ultrasound techniques that yield images of greatest diagnostic utility.

Using a three-path contrast interferometer (CI) geometry and laser-pulse diffraction gratings, we create the first matter-wave interferometer with ytterbium (Yb) atoms. We present advances in contrast interferometry relevant to high-precision measurements. By comparing to a traditional atom interferometer, we demonstrate the immunity of the CI to vibrations for long interaction times (> 20 ms). We characterize and demonstrate control over the two largest systematic effects for a high-precision measurement of the fine structure constant via photon recoil with our interferometer: diffraction phases and atomic interactions. Diffraction phases are an important systematic for most interferometers using large-momentum transfer beam splitters; atomic interactions are a key concern for any BEC interferometer. Finally, we consider the prospects for a future sub-part per billion photon recoil measurement using a Yb CI., 7 pages -- Reorganized and edited in response to review

Quantum degenerate mixtures of alkali and spin-singlet atoms form the starting point for studying few- and many-body physics of mass-imbalanced pairs as well as the production of paramagnetic polar molecules. We recently reported the achievement of dual-species quantum degeneracy of a mixture of lithium and ytterbium atoms. Here we present details of the key experimental steps for the all-optical preparation of these mixtures. Further we demonstrate the use of the magnetic field gradient tool to compensate for the differential gravitational sag of the two species and control their spatial overlap., 8 pages, 6 figures

We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser's transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudden failures such as temporary occlusion of the injection beam. We demonstrate the successful performance of our stabilization method in a diode laser setup at 399 nm used for laser cooling of Yb atoms. The device eases the requirements on passive stabilization and can benefit any diode laser injection lock application, particularly those where several such locks are employed., Comment: 5 pages, 7 figures

We present a case of solitary fibrous tumor of pleura (SFTP) in a 63-year-old male. Clinical manifestations of this entity, including paraneoplastic syndromes, are discussed, albeit absent in our presented case. Furthermore radiographic findings and pathologic correlations are provided. SFTP remains a rare neoplasm for which radiographic features are suggestive yet nonspecific, and immunohistochemistry remains as the diagnostic method of choice.

Background: The presence of two rather than three phalanges involving a lateral toe is a common variant. This is most often seen at the fifth toe. A fracture through the expected location of the distal interphalangeal joint can mimic a normal triphalangeal toe, leading to a delayed diagnosis. Methods: Over a thirty-four month period, records of fractures through a fused biphalangeal joint were kept by all members of the musculoskeletal imaging section of a large university. Results: Thirty-three patients with fractures through biphalangeal toes found on routine clinical examinations were included in the study. Demographic information, mechanism of fracture, and digit involved were recorded. Conclusions: Fractures occurring at the level of an expected interphalangeal joint are easily overlooked. Prompt diagnosis can improve patient outcomes.

We present a case of lipoma arborescens of the knee in a 17-year-old man, discuss its characteristic imaging findings, and review the relevant differential diagnoses.