Boundary State for Magnetized D9 Branes and One-Loop Calculation

We construct the boundary state describing magnetized D9 branes in R^{3,1} x T^6 and we use it to compute the annulus and Moebius amplitudes. We derive from them, by using open/closed string duality, the number of Landau levels on the torus T^d.Comment: 12 pages,in honor of Adriano Di Giacomo on his 70th birthday, contribution to the Festschrif

On off-shell bosonic string amplitudes

We give a simple prescription for computing, in the framework of the bosonic string theory, off-shell one-loop amplitudes with any number of external massless particles, both for the open and for the closed string. We discuss their properties and, in particular, for the two-string one-loop amplitudes we show their being transverse.Comment: 12 pages, Latex. One reference added. Introduction and conclusions expanded. Some other minor changes in the tex

The treatment of intertrochanteric fracture: a survey on the preferred treatment used by orthopedic surgeons in Campania

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TIBIO-FIBULAR BONE TRANSPOSITION FOR THE TREATMENT OF ONCOLOGICAL PERIPROSTHETIC INFECTION OF THE KNEE WITH MASSIVE BONE LOSS

Chronic periprosthetic joint infection (PJI) is one of the most relevant complications in orthopaedic surgery, especially in the case of limb reconstruction with megaprostheses after malignant tumoral resection. This is the report of a case of a 35-year-old patient, affected by a chronic PJI around a knee megaprosthesis implanted after the resection of an osteosarcoma of the distal femur. “En bloc” resection and limb reconstruction with an expandable megaprothesis of the knee were performed at the age of 5 years old (1989). PJI occurred after the definitive megaprosthesis implantation (2002), and became chronic over the years. In 2019, due to a massive recrudescence of the infection and the severe femoral bone loss, the patient underwent a wide intercalary resection and a thigh stump reconstruction by transposition of the fibula and the distal third of the tibia in order to avoid a hip disarticulation. Although complex, the proposed treatment allowed improved outcomes in a young patient with high function requests, justifying the global surgical invasiveness

Fragility Fractures of the Acetabulum: Current Concepts for Improving Patients’ Outcomes

The incidence of fragility fractures of the acetabulum (FFA) is constantly increasing. Generally, these fractures are related to a fall on the greater trochanter involving the anterior column. The management of FFA is extremely difficult considering both patients’ comorbidities and poor bone quality. Both non-operative and several operative treatment protocols are available, and the choice among them is still ambiguous. The proposed surgical techniques for FFA [namely open reduction and internal fixation (ORIF), percutaneous fixation and total hip arthroplasty (THA)] are associated with a high complication rate. The treatment with the higher early mortality is the ORIF + THA, while the one with the lowest is the non-operative. However, at longer follow-up, this difference dreadfully change is becoming the opposite. Frequently ORIF, percutaneous fixation, and non-operative treatment need a subsequent re-operation through a THA. This latter could be extremely difficult, because of poor bone quality, acetabular mal union/non-union, bone gaps and hardware retention. However, the outcomes of each of the proposed treatment are mostly poor and controverted; therefore, a comprehensive patient evaluation and an accurate fracture description are required to appropriately manage acetabular fracture in the elderly

N=1 Matter from Fractional Branes

We study a bound state of fractional D3-branes localized inside the world-volume of fractional D7-branes on the orbifold C^3/Z_2 x Z_2. We determine the open string spectrum that leads to N=1 U(N1)xU(N2)xU(N3)xU(N4) gauge theory with matter having the number of D7-branes as a flavor index. We derive the linearized boundary action of the D7-brane on this orbifold using the boundary state formalism and we discuss the tadpole cancellation. After computing the asymptotic expression of the supergravity solution the anomalies of the gauge theory are reproduced.Comment: LaTeX 20 pages, 1 figure, small changes and references adde

Extracapsular femoral neck fractures treated with total hip arthroplasty: identification of a population with better outcomes

BACKGROUND: Femoral neck fractures (FNF) are associated to patient’s disability, reduced quality of life and mortality. None of the fixation devices commonly used for extracapsular (EC) FNF (i.e., dynamic hip screws (DHS) and intramedullary nails (IN)) is clearly superior to the other, especially in case of unstable fractures (31.A2 and 31.A3 according to AO/OTA classification). The aim of our study was to identify a sub-population of patients with EC fractures in which better outcomes could be obtainable using total hip arthroplasty (THA). METHODS: All patients with EC unstable fractures treated with THA were included in the present study. Demographic data, American Society of Anesthesiologists (ASA) score, hospitalization length, transfusion rate, implant-related complications and mortality rate were collected. Clinical outcomes were evaluated using the Oxford Hip Score (OHS), while patients’ general health status through the 12 Item Short Form questionnaires (SF-12). RESULTS: 30 patients (7 male; 23 female) with a mean age of 78.8 years were included. The 1-year mortality rate was 13.3%. The mean OHS was 27.5, while the mean SF-12 were 45.84 for the mental item and 41.6 for the physical one. Age was the only factor associated with the OHS and patients older than 75 years presented a 12- fold higher risk of developing bad outcomes. CONCLUSIONS: THA seems to be a viable option for unstable EC fractures, with good clinical outcomes, especially in patients younger than 75 years of age. The mortality rate associated with THA in EC fractures is low and anyway comparable with IN

Anomalies and Tadpoles in Open/Closed String Duality

We discuss the role played by the divergences appearing in the interaction between a fractional D3 brane dressed with an SU(N) gauge field and a stack of N fractional D3 branes on the orbifolds C^2/Z_2 and C^3/(Z_2 x Z_2). In particular we show that the logarithmic divergences in the closed string channel, interpreted as due to twisted massless tadpoles, are mapped, under open/closed string duality, in the logarithmic ones in the open string channel, due to the massless states circulating in the annulus diagram and corresponding to the one-loop divergences that one finds in the gauge theory living in the world volume of the brane. This result provides a quantitative evidence of why the chiral and scale anomalies of the supersymmetric and non conformal gauge theories supported by the world volume of the branes can be inferred from supergravity calculations.Comment: LaTeX, 8 pages. Contribution to the proceedings of the workshop of the RTN Network "The quantum structure of space-time and the geometric nature of fundamental interactions", Copenhagen, September 200