Retrograde fixation of the lesser trochanter in the adolescent: new surgical technique and clinical results of two cases.

INTRODUCTION: Avulsions of the lesser femoral trochanter are rare injuries in the adolescent population. An acute avulsion causes severe functional impairment with compromised hip flexion. Recent literature reports the superiority of surgical treatment for apophyseal avulsion fractures of the pelvis in adolescents. Unfortunately, there are no guidelines for an evidence-based treatment of lesser trochanter avulsions established. We present the cases of two adolescent athletes treated operatively. MATERIALS AND METHODS: Two adolescent males, 12 and 16 years old, suffered an avulsion of the lesser trochanter during soccer. They reported immobilizing groin pain with subjective impairment in daily activities and inability to perform sports. Surgical treatment with a new retrograde technique by applying an adapted mini-open anterior approach was performed. Intraoperatively, both cases showed an intact musculo-tendinous unit attached to the avulsed fragment. RESULTS: Both patients showed excellent postoperative results and were satisfied with the clinical outcome. In the postoperative follow-up an adequate consolidation of the lesser trochanter was visible. No complications were postoperatively reported at final follow-up. CONCLUSIONS: The retrograde fixation technique has led to an excellent outcome without complications in two adolescents with acute lesser trochanter apophyseal avulsions. Further clinical use may support the value of this new surgical technique.

[Osteoarthritis of the shoulder: pathogenesis, diagnostics and conservative treatment options]. / Omarthrose: Pathogenese, Diagnostik und konservative Therapieoptionen.

PATHOGENESIS: Osteoarthritis of the shoulder is characterized by a progressive degenerative process, which is based on chronic inflammation with intra-articular release of different cytokines and proteolytic enzymes. The main predisposing factors are a history of trauma or surgery, as well as chronic overuse or instability of the glenohumeral joint. Affected patients especially suffer from impaired joint function and pain, which are often associated with cognitive and psychosocial restrictions. DIAGNOSTICS: Possible co-pathologies have to be evaluated carefully both clinically and radiologically as they must be taken into account in the therapeutic procedure. If arthroplasty of the shoulder is planned, a pre-operative CT scan is mandatory in order to evaluate the bone stock of the glenoid, which has a decisive influence on the choice of implant. TREATMENT: Conservative treatment options are oral pain medication, physical therapy, and intra-articular injections, whereby, in comparison to corticosteroids, hyaluronic acid seems to be advantageous especially with respect to the duration of a positive clinical effect.

[Distal femoral osteotomy using a lateral opening wedge technique]. / Distale Femurosteotomie in lateraler Open-wedge-Technik.

OBJECTIVE: To shift the weight-bearing axis of the lower limb medially by opening a lateral-based metaphyseal osteotomy at the distal femur. INDICATIONS: Femoral-based valgus malalignment and symptomatic lateral unicompartimental osteoarthritis, lateral hyperpression syndrome, cartilage therapy of the lateral compartment, lateral meniscal replacement/transplantation, medial instability with valgus thrust, reconstruction of the medial collateral ligament, patellar instability and/or maltracking. CONTRAINDICATIONS: Advanced cartilage damage (>grade 2) or subtotal meniscal loss of the medial compartment, age >65 years (relative), nicotine abuse, body mass index >30, flexion contracture >25°, corrections with a wedge base >10 mm in case of congenital deformities, inflammatory or septic arthritis, severe osteoporosis. SURGICAL TECHNIQUE: Lateral approach to the distal femur; biplanar osteotomy (frontal + axial osteotomy), gradual opening of the osteotomy, osteotomy fixation with a locking plate. POSTOPERATIVE MANAGEMENT: Free range of motion. Partial weight bearing with 20 kg for 2 weeks, followed by progressive weight bearing thereafter. RESULTS: Mean improvement of knee scores from 20-30 points and mean 10-year survival rate of 80% in patients with lateral unicompartimental osteoarthritis. Mean complication rate of 9%.

Determination of the Boltzmann constant with cylindrical acoustic gas thermometry: new and previous results combined.

We report a new determination of the Boltzmann constant kB using a cylindrical acoustic gas thermometer. We determined the length of the copper cavity from measurements of its microwave resonance frequencies. This contrasts with our previous work (Zhang et al 2011 Int. J. Thermophys.32 1297, Lin et al 2013 Metrologia50 417, Feng et al 2015 Metrologia52 S343) that determined the length of a different cavity using two-color optical interferometry. In this new study, the half-widths of the acoustic resonances are closer to their theoretical values than in our previous work. Despite significant changes in resonator design and the way in which the cylinder length is determined, the value of kB is substantially unchanged. We combined this result with our four previous results to calculate a global weighted mean of our kB determinations. The calculation follows CODATA's method (Mohr and Taylor 2000 Rev. Mod. Phys. 72 351) for obtaining the weighted mean value of kB that accounts for the correlations among the measured quantities in this work and in our four previous determinations of kB. The weighted mean k̂B is 1.380 6484(28) × 10-23 J K-1 with the relative standard uncertainty of 2.0 × 10-6. The corresponding value of the universal gas constant is 8.314 459(17) J K-1 mol-1 with the relative standard uncertainty of 2.0 × 10-6.

Detecting leaks in gas-filled pressure vessels using acoustic resonances.

We demonstrate that a leak from a large, unthermostatted pressure vessel into ambient air can be detected an order of magnitude more effectively by measuring the time dependence of the ratio p/f(2) than by measuring the ratio p/T. Here f is the resonance frequency of an acoustic mode of the gas inside the pressure vessel, p is the pressure of the gas, and T is the kelvin temperature measured at one point in the gas. In general, the resonance frequencies are determined by a mode-dependent, weighted average of the square of the speed-of-sound throughout the volume of the gas. However, the weighting usually has a weak dependence on likely temperature gradients in the gas inside a large pressure vessel. Using the ratio p/f(2), we measured a gas leak (dM/dt)/M ≈ - 1.3 × 10(-5) h(-1) = - 0.11 yr(-1) from a 300-liter pressure vessel filled with argon at 450 kPa that was exposed to sunshine-driven temperature and pressure fluctuations as large as (dT/dt)/T ≈ (dp/dt)/p ≈ 5 × 10(-2) h(-1) using a 24-hour data record. This leak could not be detected in a 72-hour record of p/T. (Here M is the mass of the gas in the vessel and t is the time.).

Electrical detection of liquid lithium leaks from pipe joints.

A test stand for flowing liquid lithium is under construction at Princeton Plasma Physics Laboratory. As liquid lithium reacts with atmospheric gases and water, an electrical interlock system for detecting leaks and safely shutting down the apparatus has been constructed. A defense in depth strategy is taken to minimize the risk and impact of potential leaks. Each demountable joint is diagnosed with a cylindrical copper shell electrically isolated from the loop. By monitoring the electrical resistance between the pipe and the copper shell, a leak of (conductive) liquid lithium can be detected. Any resistance of less than 2 kΩ trips a relay, shutting off power to the heaters and pump. The system has been successfully tested with liquid gallium as a surrogate liquid metal. The circuit features an extensible number of channels to allow for future expansion of the loop. To ease diagnosis of faults, the status of each channel is shown with an analog front panel LED, and monitored and logged digitally by LabVIEW.

[Combination of ACL-replacement and high tibial osteotomy]. / Kombination von VKB-Ersatzplastik und hoher tibialer Umstellungsosteotomie.

OBJECTIVE: Replacement of the anterior cruciate ligament (ACL) with an autologous tendon together with a high tibial osteotomy (HTO) in one operation. INDICATION: Simultaneous symptomatic ACL insufficiency and symptomatic varus osteoarthritis. CONTRAINDICATIONS: Risk of a higher complication rate for a one-stage procedure, e.g., in loss of motion due to soft tissue contracture, loss of motion due to insufficiency of a existent ACL replacement with tunnel malplacement, tunnel widening of an existent ACL replacement with the risk of tunnel confluence, infection in a former operation. Varus osteoarthritis with a hollow posteromedial tibial plateau (knee abuser). Exclusion criteria include PLC insufficiency, lateral or posterolateral instability, lateral arthritis. SURGICAL TECHNIQUE: Osteotomy: placement of the two K-wires from the medial tibia about 4-5 cm below the medial tibial plateau towards the lateral hinge about 2 cm below the lateral tibial plateau. Mobilization of the long fibers of the medial collateral ligament distal of the osteotomy, mobilization of the pes anserinus tendons. Frontal and axial osteotomy with an oscillating saw. Completion and opening of the osteotomy with chisels. Opening of the osteotomy with a spreader according to the new leg axis of the preoperative planning. Fixation of the osteotomy with an angle stable plate (PPP Arthrex, Tomofix Synthes). In case of a distal osteotomy of the hiberosity fixation with 2 screws. Arthroscopy: positioning of a 2.4 mm K-wire in the center of the remnant femoral ACL insertion, cannulated drilling according to the graft diameter. Positioning of a 2.4 mm K-wire in the center of the remnant tibial ACL insertion, cannulated drilling. In the case of interference of the tibial tunnel with one of the osteotomy screws, removal of the screw and finishing of the tunnel preparation. Measurement of the length and insertion of the respective osteotomy screw. Insertion of the graft and fixation with a button-wire construct at the femur and with a bioabsorbable interference screw and a lag screw at the tibia. POSTOPERATIVE MANAGEMENT: Postoperative management relating to weight bearing rehabilitation follows osteotomy rules, while range of motion rehabilitation follows the ACL protocol.

Confronting the constraints of morphological taxonomy in the Botryosphaeriales.

Identification of fungi and the International Code of Nomenclature underpinning this process, rests strongly on the characterisation of morphological structures. Yet, the value of these characters to define species in many groups has become questionable or even superfluous. This has emerged as DNA-based techniques have increasingly revealed cryptic species and species complexes. This problem is vividly illustrated in the present study where 105 isolates of the Botryosphaeriales were recovered from both healthy and diseased woody tissues of native Acacia spp. in Namibia and South Africa. Thirteen phylogenetically distinct groups were identified based on Internal Transcribed Spacer (ITS) rDNA PCR-RFLP and translation elongation factor 1-α (TEF1-α) sequence data, two loci that are known to be reliable markers to distinguish species in the Botryosphaeriales. Four of these groups could be linked reliably to sequence data for formerly described species, including Botryosphaeria dothidea, Dothiorella dulcispinae, Lasiodiplodia pseudotheobromae and Spencermartinsia viticola. Nine groups, however, could not be linked to any other species known from culture and for which sequence data are available. These groups are, therefore, described as Aplosporella africana, A. papillata, Botryosphaeria auasmontanum, Dothiorella capri-amissi, Do. oblonga, Lasiodiplodia pyriformis, Spencermartinsia rosulata, Sphaeropsis variabilis and an undescribed Neofusicoccum sp. The species described here could not be reliably compared with the thousands of taxa described in these genera from other hosts and regions, where only morphological data are available. Such comparison would be possible only if all previously described taxa are epitypified, which is not a viable objective for the two families, Botryosphaeriaceae and Aplosporellaceae, in the Botryosphaeriales identified here. The extent of diversity of the Botryosphaeriales revealed in this and other recent studies is expected to reflect that of other undersampled regions and hosts, and illustrates the urgency to find more effective ways to describe species in this, and indeed other, groups of fungi.

Detection of B-mode polarization in the cosmic microwave background with data from the South Pole Telescope.

Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This "B-mode" signal provides a measure of the projected mass distribution over the entire observable Universe and also acts as a contaminant for the measurement of primordial gravity-wave signals. In this Letter we present the first detection of gravitational lensing B modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing B-mode signal by combining E-mode polarization measured by SPTpol with estimates of the lensing potential from a Herschel-SPIRE map of the cosmic infrared background. We compare this template to the B modes measured directly by SPTpol, finding a nonzero correlation at 7.7σ significance. The correlation has an amplitude and scale dependence consistent with theoretical expectations, is robust with respect to analysis choices, and constitutes the first measurement of a powerful cosmological observable.

Dusty starburst galaxies in the early Universe as revealed by gravitational lensing.

In the past decade, our understanding of galaxy evolution has been revolutionized by the discovery that luminous, dusty starburst galaxies were 1,000 times more abundant in the early Universe than at present. It has, however, been difficult to measure the complete redshift distribution of these objects, especially at the highest redshifts (z > 4). Here we report a redshift survey at a wavelength of three millimetres, targeting carbon monoxide line emission from the star-forming molecular gas in the direction of extraordinarily bright millimetre-wave-selected sources. High-resolution imaging demonstrates that these sources are strongly gravitationally lensed by foreground galaxies. We detect spectral lines in 23 out of 26 sources and multiple lines in 12 of those 23 sources, from which we obtain robust, unambiguous redshifts. At least 10 of the sources are found to lie at z > 4, indicating that the fraction of dusty starburst galaxies at high redshifts is greater than previously thought. Models of lens geometries in the sample indicate that the background objects are ultra-luminous infrared galaxies, powered by extreme bursts of star formation.

Noninvasive measurement of dissipation in colloidal systems.

According to Harada and Sasa [Phys. Rev. Lett. 95, 130602 (2005)], heat production generated in a nonequilibrium steady state can be inferred from measuring response and correlation functions. In many colloidal systems, however, it is a nontrivial task to determine response functions, whereas details about spatial steady state trajectories are easily accessible. Using a simple conditional averaging procedure, we show how this fact can be exploited to reliably evaluate average heat production. We test this method using Brownian dynamics simulations, and apply it to experimental data of an interacting driven colloidal system.

Role of hidden slow degrees of freedom in the fluctuation theorem.

The validity of the fluctuation theorem for entropy production as deduced from the observation of trajectories implicitly requires that all slow degrees of freedom are accessible. We experimentally investigate the role of hidden slow degrees of freedom in a system of two magnetically coupled driven colloidal particles. The apparent entropy production based on the observation of just one particle obeys a fluctuation theorem-like symmetry with a slope of 1 in the short time limit. For longer times, we find a constant slope, but different from 1. We present theoretical arguments for a generic linear behavior both for small and large apparent entropy production but not necessarily throughout. By fine-tuning experimental parameters, such an intermediate nonlinear behavior can indeed be recovered in our system as well.

Frequency multiplexed superconducting quantum interference device readout of large bolometer arrays for cosmic microwave background measurements.

A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ∼MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4 K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors.

A massive, cooling-flow-induced starburst in the core of a luminous cluster of galaxies.

In the cores of some clusters of galaxies the hot intracluster plasma is dense enough that it should cool radiatively in the cluster's lifetime, leading to continuous 'cooling flows' of gas sinking towards the cluster centre, yet no such cooling flow has been observed. The low observed star-formation rates and cool gas masses for these 'cool-core' clusters suggest that much of the cooling must be offset by feedback to prevent the formation of a runaway cooling flow. Here we report X-ray, optical and infrared observations of the galaxy cluster SPT-CLJ2344-4243 (ref. 11) at redshift z = 0.596. These observations reveal an exceptionally luminous (8.2 × 10(45) erg s(-1)) galaxy cluster that hosts an extremely strong cooling flow (around 3,820 solar masses a year). Further, the central galaxy in this cluster appears to be experiencing a massive starburst (formation of around 740 solar masses a year), which suggests that the feedback source responsible for preventing runaway cooling in nearby cool-core clusters may not yet be fully established in SPT-CLJ2344-4243. This large star-formation rate implies that a significant fraction of the stars in the central galaxy of this cluster may form through accretion of the intracluster medium, rather than (as is currently thought) assembling entirely via mergers.

Invited article: millimeter-wave bolometer array receiver for the Atacama pathfinder experiment Sunyaev-Zel'dovich (APEX-SZ) instrument.

The Atacama pathfinder experiment Sunyaev-Zel'dovich (APEX-SZ) instrument is a millimeter-wave cryogenic receiver designed to observe galaxy clusters via the Sunyaev-Zel'dovich effect from the 12 m APEX telescope on the Atacama plateau in Chile. The receiver contains a focal plane of 280 superconducting transition-edge sensor (TES) bolometers instrumented with a frequency-domain multiplexed readout system. The bolometers are cooled to 280 mK via a three-stage helium sorption refrigerator and a mechanical pulse-tube cooler. Three warm mirrors, two 4 K lenses, and a horn array couple the TES bolometers to the telescope. APEX-SZ observes in a single frequency band at 150 GHz with 1' angular resolution and a 22' field-of-view, all well suited for cluster mapping. The APEX-SZ receiver has played a key role in the introduction of several new technologies including TES bolometers, the frequency-domain multiplexed readout, and the use of a pulse-tube cooler with bolometers. As a result of these new technologies, the instrument has a higher instantaneous sensitivity and covers a larger field-of-view than earlier generations of Sunyaev-Zel'dovich instruments. The TES bolometers have a median sensitivity of 890 µK(CMB)√s (NEy of 3.5 × 10(-4) √s). We have also demonstrated upgraded detectors with improved sensitivity of 530 µK(CMB)√s (NEy of 2.2 × 10(-4) √s). Since its commissioning in April 2007, APEX-SZ has been used to map 48 clusters. We describe the design of the receiver and its performance when installed on the APEX telescope.

Experimental model for study of anorectal sphincter musculature by manometry and computerized tomography in piglets.

There seems to be controversy on the anorectal sphincter presentation and anatomical division, as well as on its functional representation. Evaluation of the anorectal sphincter musculature has been achieved through several methods, including anorectal manometry and computerized tomography, but to date there is no experimental model allowing a detailed manometric study of this muscle complex. In this work, we have developed such a model, which should enable the manometric and radiographic study of the anatomical features and functional mechanisms of sphincteric injuries, as well as the assessment of drug effects on the anorectal musculature upon incontinence and constipation. Twenty-two piglets (aged 25-30 days, weighing 5-7 kg) were studied by anorectal manometry (rectoanal inhibitory reflex and vector volume) and computerized tomography (anorectal angle and anal canal length). The data obtained for the rectoanal inhibitory reflex, represented here as the average and standard deviation, were the following: relaxation duration = 14.75 +/- 3.62 s, sphincter basal pressure = 41.58 +/- 8.20 mmHg, relaxation index = 87.26 +/- 11.52%, speed of relaxation = 5.90 +/- 2.10 mm/s, and speed of relaxation recovery = 4.03 +/- 1.78 mm/s. As for the vector volume, results were as follows: vector volume = 2692.32 +/- 1298.12 mm Hg2 cm, sphincter length = 11.82 +/- 2.74 mm, high pressure zone length = 5.09 +/- 1.34 mm, maximum pressure = 61.50 +/- 20.58 mmHg, and asymmetry index = 43.50 +/- 10.03%. Radiographic evaluation led to the following results: anal canal length = 9.61 +/- 2.14 mm and anorectal angle = 137.91 +/- 7.75 degrees . The experimental model designed here allows both anorectal manometry and computerized tomography to be carried out in the same way it is performed in human beings, as long as animal sedation is strictly controlled.

Direct TLC-MALDI coupling using a hybrid plate.

A new TLC-MALDI direct coupling method which recovers approximately 100% of the analyte is presented. The method makes use of a hybrid TLC-MALDI plate in which a silica layer and a MALDI layer are configured adjacently on a common backing. After TLC separation, the plate is rotated 90 degrees and the separated analyte spots are eluted from the silica layer to the MALDI layer via capillary action of the MALDI layer. Signal-to-noise ratios are significantly improved over previously reported coupling methods. Low-femtomole detection limits have been demonstrated for small cyclic peptides, which are comparable to detection limits for standard MALDI measurements.

Emergent saphenous vein graft stenting for acute occlusion during percutaneous transluminal coronary angioplasty.

This report describes the initial use in the United States of emergency intravascular stenting for the treatment of acute coronary occlusion complicating elective saphenous vein graft angioplasty. This case adds further support to the role of the balloon expandable stent as an effective "bail out" device for failed angioplasty.

Antimicrobial activity of synthetic bactenecin.

Bactenecin is an antimicrobial peptide isolated from bovine neutrophils. Bactenecin was synthesized by solid-phase peptide synthesis and renatured to a fully disulfide bonded form. The peptide inhibits the growth of Escherichia coli and Staphylococcus aureus at the same concentration reported for the peptide purified from bovine neutrophils. Bactenecin inhibits the growth of other medically important bacteria and yeast, and it kills the fungus Trichophyton rubrum. Acetylation and amidation of the amino- and carboxy-termini of bactenecin do not change its potency, while replacement of its two cysteine residues with serine decreases the potency.