Proximal humerus fractures in the pediatric population: a systematic review

PurposeProximal humerus fractures and epiphyseal separations in skeletally immature children and adolescents are traditionally treated non-operatively. Recently, authors have described the operative fixation of these injuries, particularly in older children and adolescents with displaced fractures. We performed a systematic review of the literature to identify operative indications for proximal humerus fractures in children and to compare the results by age, displacement, and treatment modality.MethodsA systematic review of the literature from January 1960 to April 2010 was performed. All studies with patients under the age of 18 years who were treated for a proximal humerus fracture either operatively or non-operatively were included.ResultsThe available literature is largely composed of uncontrolled case series (Level IV). According to findings, the literature shows that asymptomatic union is the rule in proximal humerus fractures in children and adolescents. Poorer outcomes were noted in operatively treated patients, patients with more displaced fractures, and older patients.ConclusionsThe currently available literature supports a non-operative treatment approach, particularly in younger children with more growth remaining. Older patients (>13 years) with more widely displaced fractures may benefit from anatomic reduction with stabilization, though the data in the literature at this point is too weak to strongly recommend this approach. Further analysis with a more rigorous scientific method is necessary to evaluate the optimum treatment modality in this subgroup

Signatures of fluid–fluid displacement in porous media: wettability, patterns and pressures

We develop a novel ‘moving-capacitor’ dynamic network model to simulate immiscible fluid–fluid displacement in porous media. Traditional network models approximate the pore geometry as a network of fixed resistors, directly analogous to an electrical circuit. Our model additionally captures the motion of individual fluid–fluid interfaces through the pore geometry by completing this analogy, representing interfaces as a set of moving capacitors. By incorporating pore-scale invasion events, the model reproduces, for the first time, both the displacement pattern and the injection-pressure signal under a wide range of capillary numbers and substrate wettabilities. We show that at high capillary numbers the invading patterns advance symmetrically through viscous fingers. In contrast, at low capillary numbers the flow is governed by the wettability-dependent fluid–fluid interactions with the pore structure. The signature of the transition between the two regimes manifests itself in the fluctuations of the injection-pressure signal

de Sitter Supersymmetry Revisited

We present the basic $\mathcal{N} =1$ superconformal field theories in four-dimensional de Sitter space-time, namely the non-abelian super Yang-Mills theory and the chiral multiplet theory with gauge interactions or cubic superpotential. These theories have eight supercharges and are invariant under the full $SO(4,2)$ group of conformal symmetries, which includes the de Sitter isometry group $SO(4,1)$ as a subgroup. The theories are ghost-free and the anti-commutator $\sum_\alpha\{Q_\alpha, Q^{\alpha\dagger}\}$ is positive. SUSY Ward identities uniquely select the Bunch-Davies vacuum state. This vacuum state is invariant under superconformal transformations, despite the fact that de Sitter space has non-zero Hawking temperature. The $\mathcal{N}=1$ theories are classically invariant under the $SU(2,2|1)$ superconformal group, but this symmetry is broken by radiative corrections. However, no such difficulty is expected in the $\mathcal{N}=4$ theory, which is presented in appendix B.Comment: 21 pages, 2 figure

Aalenian to Cenomanian Radiolaria of the Bermeja Complex (Puerto Rico) and Pacific origin of radiolarites on the Caribbean Plate

The study of the radiolarian ribbon chert is a key in determining the origins of associated Mesozoic oceanic terranes and may help to achieve a general agreement regarding the basic principles on the evolution of the Caribbean Plate. The Bermeja Complex of Puerto Rico, which contains serpentinized peridotite, altered basalt, amphibolite, and chert (Mariquita Chert Formation), is one of these crucial oceanic terranes. The radiolarian biochronology presented in this work is mainly based by correlation on the biozonations of Baumgartner et al. (1995) and O'Dogherty (1994) and indicates an early Middle Jurassic to early Late Cretaceous (late Bajocian-early Callovian to late early Albian-early middle Cenomanian) age. The illustrated assemblages contain about 120 species, of which one is new (Pantanellium karinae), and belonging to about 50 genera. A review of the previous radiolarian published works on the Mariquita Chert Formation and the results of this study suggest that this formation ranges in age from Middle Jurassic to early Late Cretaceous (late Aalenian to early-middle Cenomanian) and also reveal a possible feature of the Bermeja Complex, which is the younging of radiolarian cherts from north to south, evoking a polarity of accretion. On the basis of a currently exhaustive inventory of the radiolarite facies s.s. on the Caribbean Plate, a re-examination of the regional distribution of Middle Jurassic sediments associated with oceanic crust, and a paleoceanographic argumentation on the water currents, we come to the conclusion that the radiolarite and associated Mesozoic oceanic terranes of the Caribbean Plate are of Pacific origin. Eventually, a discussion on the origin of the cherts of the Mariquita Formation illustrated by Middle Jurassic to middle Cretaceous geodynamic models of the Pacific and Caribbean realms bring up the possibility that the rocks of the Bermeja Complex are remnants of two different oceans

Application of light microscopical and ultrastructural immunohistochemistry in the study of goblet cell carcinoid in the appendix

<p>Abstract</p> <p>Background</p> <p>Goblet cell carcinoids appear less frequently in the appendix than do other carcinoids. In the presented work a case with a goblet cell carcinoid of the appendix is described.</p> <p>Methods</p> <p>Routine histological and histochemical methods were employed, with a combination of histochemistry and immunohistochemistry on one section and light and electron microscopical immunohistochemisty on paraffin-embedded material, were applied to identify the type of the carcinoid and to reveal the fine structure of cell types in the tumour nests of the appendix.</p> <p>Results</p> <p>During the biopsy of a patient who had undergone appendectomy, an infiltration with clusters of goblet cells in the submucosa of the appendix was found. After a second operation of right-sided hemicolectomy, similar clusters of goblet cells were detected in the muscle layers of the caecum. After 18 months the patient died from cirrhosis and had not developed metastases or any recurrence. Immunohistochemically the serotonin-, somatostatin-, chromogranin A- and synaptophysin-positive endocrine cells were basally attached to mucin-secreting cells. The combined staining revealed simultaneously present endocrine cells (chromogranin-A-positive) and mucin-secreting cells (PAS- or alcian blue-positive). The ultrastructural immunohistochemistry showed that chromogranin A-positive cells had discoid and pleomorphic granules and were located in tumour nests or as single cells in the appendiceal wall.</p> <p>Conclusion</p> <p>The combined histochemical and immunohistochemical procedure and the ultrastructural immunohistochemistry on archival material could contribute in clarifying the diagnosis of goblet cell carcinoid.</p

Energy-efficient vertical handover parameters, classification and solutions over wireless heterogeneous networks: a comprehensive survey

In the last few decades, the popularity of wireless networks has been growing dramatically for both home and business networking. Nowadays, smart mobile devices equipped with various wireless networking interfaces are used to access the Internet, communicate, socialize and handle short or long-term businesses. As these devices rely on their limited batteries, energy-efficiency has become one of the major issues in both academia and industry. Due to terminal mobility, the variety of radio access technologies and the necessity of connecting to the Internet anytime and anywhere, energy-efficient handover process within the wireless heterogeneous networks has sparked remarkable attention in recent years. In this context, this paper first addresses the impact of specific information (local, network-assisted, QoS-related, user preferences, etc.) received remotely or locally on the energy efficiency as well as the impact of vertical handover phases, and methods. It presents energy-centric state-of-the-art vertical handover approaches and their impact on energy efficiency. The paper also discusses the recommendations on possible energy gains at different stages of the vertical handover process

Minimum Energy Broadcast and Disk Cover in Grid Wireless Networks

Abstract. The Minimum Energy Broadcast problem consists in finding the minimum-energy range assignment for a given set S of n stations of an ad hoc wireless network that allows a source station to perform broadcast operations over S. We prove a nearly tight asymptotical bound on the optimal cost for the Minimum Energy Broadcast problem on square grids. We emphasize that finding tight bounds for this problem restriction is far to be easy: it involves the Gauss’s Circle problem and the Apollonian Circle Packing. We also derive near-tight bounds for the Bounded-Hop version of this problem. Our results imply that the best-known heuristic, the MST-based one, for the Minimum Energy Broadcast problem is far to achieve optimal solutions (even) on very regular, well-spread instances: its worst-case approximation ratio is about pi and it yields Ω( n) hops. As a by product, we get nearly tight bounds for the Minimum Disk Cover problem and for its restriction in which the allowed disks must have non-constant radius. Finally, we emphasize that our upper bounds are obtained via polynomial time constructions.