Search

The New Advanced Telescope for High ENergy Astrophysics (NewAthena) will be the largest space-based X-ray observatory ever built. It will have an effective area above 1.1 m2 at 1 keV, which corresponds to a polished mirror surface of about 300 m2 due to the grazing incidence. As such a mirror area is not achievable with an acceptable mass even with nested shells, silicon pore optics (SPO) technology will be utilized. In the PTB laboratory at BESSY II, two dedicated beamlines are in use for their characterization with monochromatic radiation at 1 keV and a low divergence well below 2 arcsec: the X-ray Pencil Beam Facility (XPBF 1) and the X-ray Parallel Beam Facility (XPBF 2.0), where beam sizes up to 8 mm × 8 mm are available while maintaining low beam divergence. This beamline is used for characterizing mirror stacks and controlling the focusing properties of mirror modules (MMs) – consisting of four mirror stacks – during their assembly at the beamline. A movable CCD based camera system 12 m from the MM registers the direct and the reflected beams. The positioning of the detector is verified by a laser tracker. The energy-dependent reflectance in double reflection through the pores of an MM with an Ir coating was measured at the PTB four-crystal monochromator beamline in the photon energy range 1.75 keV to 10 keV, revealing the effects of the Ir M edges. The measured reflectance properties are in agreement with the design values to achieve the envisaged effective area.

Human adipose-derived mesenchymal stem cells (ASCs) transduced with a lentiviral vector system to express bone morphogenetic protein 2 (LV-BMP-2) have been shown to reliably heal bone defects in animal models. However, the influence of donor characteristics such as age, sex, race, and medical co-morbidities on ASC yield, growth and bone regenerative capacity, while critical to the successful clinical translation of stem cell-based therapies, are not well understood. Human ASCs isolated from the infrapatellar fat pads in 122 ASC donors were evaluated for cell growth characteristics; 44 underwent additional analyses to evaluate in vitro osteogenic potential, with and without LV-BMP-2 transduction. We found that while female donors demonstrated significantly higher cell yield and ASC growth rates, age, race, and the presence of co-morbid conditions were not associated with differences in proliferation. Donor demographics or the presence of comorbidities were not associated with differences in in vitro osteogenic potential or stem cell differentiation, except that transduced ASCs from healthy donors produced more BMP-2 at day 2. Overall, donor age, sex, race, and the presence of co-morbid conditions had a limited influence on cell yield, proliferation, self-renewal capacity, and osteogenic potential for non-transduced and transduced (LV-BMP-2) ASCs. These results suggest that ASCs are a promising resource for both autologous and allogeneic cell-based gene therapy applications.

Lentiviral transduction of human mesenchymal stem cells (MSCs) induces long-term transgene expression and holds great promise for multiple gene therapy applications. Polybrene is the most commonly used reagent to improve viral gene transfer efficiency in laboratory research; however, it is not approved for human use and has also been shown to impair MSC proliferation and differentiation. Therefore, there is a need for optimized transduction protocols that can also be adapted to clinical settings. LentiBOOST (LB) and protamine sulfate are alternative transduction enhancers (TEs) that can be manufactured to current Good Manufacturing Practice standards, are easily applied to existing protocols, and have been previously studied for the transduction of human CD34+ hematopoietic stem cells. In this study, we investigated these reagents for the enhancement of lentiviral transduction of adipose-derived MSCs. We found that the combination of LB and protamine sulfate could yield comparable or even superior transduction efficiency to polybrene, with no dose-dependent adverse effects on cell viability or stem cell characteristics. This combination of TEs represents a valuable clinically compatible alternative to polybrene with the potential to significantly improve the efficiency of lentiviral transduction of MSCs for gene therapy applications.

Karst systems are hierarchically spatially organized three-dimensional (3D) networks of conduits behaving as drains for groundwater flow. Recently, geostatistical approaches proposed to generate karst networks from data and parameters stemming from analogous observed karst features. Other studies have qualitatively highlighted relationships between speleogenetic processes and cave patterns. However, few studies have been performed to quantitatively define these relationships. This paper reports a quantitative study of cave geometries and topologies that takes the underlying speleogenetic processes into account. In order to study the spatial organization of caves, a 3D numerical database was built from 26 caves, corresponding to 621 km of cumulative cave passages representative of the variety of karst network patterns. The database includes 3D speleological surveys for which the speleogenetic context is known, allowing the polygenic karst networks to be divided into 48 monogenic cave samples and classified into four cave patterns: vadose branchwork (VB), water-table cave (WTC), looping cave (LC), and angular maze (AM). Eight morphometric cave descriptors were calculated, four geometrical parameters (width-height ratio, tortuosity, curvature, and vertical index) and four topological ones (degree of node connectivity, α and γ graph indices, and ramification index) respectively. The results were validated by statistical analyses (Kruskal-Wallis test and PCA). The VB patterns are clearly distinct from AM ones and from a third group including WTC and LC. A quantitative database of cave morphology characteristics is provided, depending on their speleogenetic processes. These characteristics can be used to constrain and/or validate 3D geostatistical simulations. This study shows how important it is to relate the geometry and connectivity of cave networks to recharge and flow processes. Conversely, the approach developed here provides proxies to estimate the evolution of the vadose zone to epiphreatic and phreatic zones in limestones from the quantitative analysis of existing cave patterns.

Karst systems are hierarchically spatially organized three-dimensional (3D) networks of conduits behaving as drains for groundwater flow. Recently, geostatistical approaches proposed to generate karst networks from data and parameters stemming from analogous observed karst features. Other studies have qualitatively highlighted relationships between speleogenetic processes and cave patterns. However, few studies have been performed to quantitatively define these relationships. This paper reports a quantitative study of cave geometries and topologies that takes the underlying speleogenetic processes into account. In order to study the spatial organization of caves, a 3D numerical database was built from 26 caves, corresponding to 621 km of cumulative cave passages representative of the variety of karst network patterns. The database includes 3D speleological surveys for which the speleogenetic context is known, allowing the polygenic karst networks to be divided into 48 monogenic cave samples and classified into four cave patterns: vadose branchwork (VB), water-table cave (WTC), looping cave (LC), and angular maze (AM). Eight morphometric cave descriptors were calculated, four geometrical parameters (width-height ratio, tortuosity, curvature, and vertical index) and four topological ones (degree of node connectivity, α and γ graph indices, and ramification index) respectively. The results were validated by statistical analyses (Kruskal-Wallis test and PCA). The VB patterns are clearly distinct from AM ones and from a third group including WTC and LC. A quantitative database of cave morphology characteristics is provided, depending on their speleogenetic processes. These characteristics can be used to constrain and/or validate 3D geostatistical simulations. This study shows how important it is to relate the geometry and connectivity of cave networks to recharge and flow processes. Conversely, the approach developed here provides proxies to estimate the evolution of the vadose zone to epiphreatic and phreatic zones in limestones from the quantitative analysis of existing cave patterns.

Ioanna K Bolia, Kevin Collon, Jacob Bogdanov, Rae Lan, Frank A Petrigliano USC Epstein Family Center for Sports Medicine at Keck Medicine of USC, Los Angeles, CA, USACorrespondence: Frank A PetriglianoUSC Epstein Family Center for Sports Medicine at Keck Medicine of USC, 1520 San Pablo Street Suite 2000, Los Angeles, CA, 90033, USATel +1 9703432813Fax +1 818-658-5925Email frank.petrigliano@med.usc.eduAbstract: Athletes participating in overhead sports are at particularly high risk of shoulder impingement syndrome. Subcoracoid impingement is defined as impingement of the anterior soft tissues of the shoulder between the coracoid process and the lesser tuberosity. Subacromial impingement syndrome (SIS) occurs due to extrinsic compression of the rotator cuff between the humeral head and coracoacromial structures or intrinsic degeneration of the supraspinatus tendon and subsequent superior migration of the humerus. Internal impingement is a major cause of shoulder pain in overhead athletes, and it occurs due to repetitive impingement of the articular surface of the rotator cuff with the glenoid during maximum abduction and external rotation of the arm. When examining athletes with suspected impingement of the shoulder, it is important to discuss the sport-specific motion that regenerates the symptoms and perform a combination of physical examination tests to improve the diagnostic accuracy. Radiographic evaluation is recommended, and the extent of soft tissue abnormalities can be assessed on ultrasound or magnetic resonance imaging of the shoulder. Management of shoulder impingement syndrome can be conservative or operative, based on the severity and chronicity of symptoms and the associated structural abnormalities. This review provides an update on the management of SIS, subcoracoid impingement, and internal impingement in the athletic population.Keywords: impingement syndromes, shoulder, subacromial impingement syndrome, joint, subcoracoid, internal, athletes

Background: Lateral meniscus deficiency in young patients typically results from irreparable lateral meniscus tears, often associated with discoid meniscus. Such cases present a challenging clinical scenario given the known natural history of meniscus deficiency leading to degenerative lateral knee compartment changes. Managing this problem in a skeletally immature patient presents additional clinical and surgical considerations. Indications: Lateral meniscus allograft transplantation (LMAT) is indicated in patients with prior total or subtotal lateral meniscectomy resulting from irreparable lateral meniscus tears, with the goal of providing chondroprotection to the lateral compartment of the knee. Patients are assessed preoperatively for ligamentous stability of the knee, mechanical alignment, and associated chondral injuries to determine whether secondary procedures may be indicated. Technique Description: We present an all-arthroscopic technique for LMAT using small bone plugs in the anterior and posterior meniscus roots secured through 2 separate anatomic root drill tunnels tied over a bone bridge. The meniscus allograft is further secured using an outside-in suture repair technique. Special attention is given to meniscus allograft preparation, anatomic meniscus root identification, and drilling using a minimally disruptive transphyseal technique. Graft passage, suture management, and meniscus fixation and repair are also highlighted. Results: Anticipated outcomes from LMAT in skeletally mature patients are excellent, particularly if preexisting chondral degenerative changes are not present. Prior studies with greater than 7-year follow-up in adolescent patients undergoing meniscus allograft transplantation have shown reoperation rates of less than 6% with no growth disturbances noted, with most patients able to return to their prior level of sport. Computed tomography modeling data using this technique shows a proximal tibial physeal surface area disruption of less than 2.5%; therefore, the risk of growth disturbance is very low. Discussion/Conclusion: The surgical technique demonstrated here offers a safe and effective approach for the management of lateral meniscus deficiency after subtotal lateral meniscectomy for irreparable meniscus tears in skeletally immature patients. The chondroprotective effect of the lateral meniscus can be restored with an anatomically placed lateral meniscus allograft with minimal disruption to the proximal tibial physis.

The cross-section of the thermal neutron capture 41Ar(n,γ)42Ar(t1/2=32.9 y) reaction was measured by irradiating a 40Ar sample at the high-flux reactor of Institut Laue-Langevin (ILL) Grenoble, France. The signature of the two-neutron capture has been observed by measuring the growth curve and identifying the 1524.6 keV γ-lines of the shorter-lived 42K(12.4 h) β− daughter of 42Ar. Our preliminary value of the 41Ar(n,γ)42Ar thermal cross section is 240(80) mb at 25.3 meV. For the first time, direct counting of 42Ar was performed using the ultra-high sensitivity technique of noble gas accelerator mass spectrometry (NOGAMS) at Argonne National Laboratory, USA.

The thermodynamical conditions and the neutron density produced in a laser-induced implosion of a deuterium-tritium (DT) filled capsule at the National Ignition Facility (NIF) are the closest laboratory analog of stellar conditions. We plan to investigate neutron-induced reactions on 40Ar, namely the 40Ar(n, 2n)39Ar(t1/2 =268 y), the 40Ar(n, γ)41Ar(110 min) and the potential rapid two-neutron capture reaction 40Ar(2n, γ)42Ar(33 y) in an Ar-loaded DT capsule. The chemical inertness of noble gas Ar enables reliable collection of the reaction products.

In adults, mallet finger is a traumatic zone I lesion of the extensor tendon with either tendon rupture or bony avulsion at the base of the distal phalanx. High-energy mechanisms of injury generally occur in young men, whereas lower energy mechanisms are observed in elderly women. The mechanism of injury is an axial load applied to a straight digit tip, which is then followed by passive extreme distal interphalangeal joint (DIPJ) hyperextension or hyperflexion. Mallet finger is diagnosed clinically, but an X-ray should always be performed. Tubiana's classification takes into account the size of the bony articular fragment and DIPJ subluxation. We propose to stage subluxated fractures as stage III if the subluxation is reducible with a splint and as stage IV if not. Left untreated, mallet finger becomes chronic and leads to a swan-neck deformity and DIPJ osteoarthritis. The goal of treatment is to restore active DIPJ extension. The results of a six- to eight-week conservative course of treatment with a DIPJ splint in slight hyperextension for tendon lesions or straight for bony avulsions depends on patient compliance. Surgical treatments vary in terms of the approach, the reduction technique, and the means of fixation. The risks involved are stiffness, septic arthritis, and osteoarthritis. Given the lack of consensus regarding indications for treatment, we propose to treat all cases of mallet finger with a dorsal glued splint except for stage IV mallet finger, which we treat with extra-articular pinning.