1,721,121 research outputs found
Single- and multi-population kinetic models for vehicular traffic reproducing fundamental diagrams and with low computational complexity.
Full text linkIn this work, we focus on kinetic theory of vehicular traffic. We introduce (Boltzmann and Fokker-Planck) models having the following properties: they are amenable for computations and analytical investigations, but at the same time they are able to characterize and to explain the features of experimental diagrams.
The scattering observed in experimental data is reproduced by a multi-population model. We propose a new interpretation of the dispersion of data since it can be attributed to the heterogeneous composition of the flow. In fact, the scattering is obtained by treating traffic as a mixture of vehicles with different physical and kinematic characteristics.
The multi-population model is built as generalization of a new single-population model for which the analytical expression of the steady state can be computed explicitly. This is possible thanks to the particular choice of the microscopic interactions. These models are able to catch the macroscopic properties of the flow at equilibrium, as the phase transition, the capacity drop and the scattering of data.
The proposed models are endowed with a robust mathematical structure. We study the mathematical properties which induce the structure of diagrams, the well posedness with the existence and uniqueness proof of the solution of the kinetic equations.
A further result of this thesis is the analysis of the effects of the microscopic interactions on the macroscopic dynamics. This purely multiscale issue which is tackled by an asymptotic study of the model in the Fokker-Planck limit
The role of sacrolumbar fat grafting in the treatment of spinal fusion instrumentation-related chronic low back pain: a preliminary report
No full textA report of 2 cases
Anteromedial thigh perforator-assisted closure of the anterolateral thigh free flap donor site
No full textPrimary closure of the anterolateral thigh free flap donor site is advisable as skin grafting can be associated with higher morbidity. However, this is not possible when anterolateral thigh free flap width is over 8-9 cm with a corresponding flap width-to-thigh circumference ratio over 16%. The authors report their experience and technique with the anteromedial thigh perforator dissection during anterolateral thigh free flap donor-site closure that, on demand, can be used to design a local perforator flap to achieve primary closure of the donor site. Between July and December 2012, 20 consecutive patients underwent elective anterolateral thigh free flap reconstruction for head and neck oncologic surgery. Attempts to close directly the anterolateral thigh free flap donor site failed in two patients with large flaps and V-Y anteromedial thigh perforator flaps were advanced to close the defect. Flaps healed uneventfully. Except two patients, at least one >1-mm perforator was found in all the remaining thighs. Further investigation is needed to establish the maximum anterolateral thigh free flap donor-site width that can be served by this reconstruction. This represents an ideal model for residents to start training on perforator dissection
The divine proportion ace of spades umbilicoplasty a new method of navel positioning and plasty in abdominoplasty
No full textBackground: Achievement of a well-balanced positioned navel along the longitudinal axiswith a pleasing shape and hidden scarring will have a tremendous impact on the overall cosmetic outcome of an abdominoplasty. In this era of navel display, piercing, and tattooing, an increasing attention is paid by people toward navel shape and position. However, in plastic surgery, there is no standardization regarding navel repositioning and plasty during abdominoplasty. The aim of this article is to describe the clinical translation of our observational study on navel surface anatomy by reporting our experience with a new umbilicoplasty technique. Materials and Methods: Between July 2013 and March 2014, 23 consecutive patients underwent elective deep inferior epigastric perforator free flap breast reconstruction. Patients'mean agewas 45.5 years (range, 36-68 years). Ten patients were normal weight, 11 were overweight, and 2 were class-1 obese. All 23 patients underwent the divine proportion ace of spade umbilicoplasty. Results: Pleasant looking, depressed, and oval navels with superior hooding were successfully achieved. No infection or necrosis of the navel skin or abdominal skin flaps was experienced. Additionally, no scar constriction, navel distortion, or stenosis occurred. Postoperative results were graded as excellent in 8 cases (36%), very good in 12 (55%), and good in the 2 cases (9%) with mildly hypertrophic scars. Patient satisfaction was high to very high. Conclusions: A Fibonacci caliper might aid in the proper positioning of the umbilicus on the abdominal wall avoiding an undesirable high-or low-riding navel. The "ace of spades" umbilicoplasty restores a natural-looking depressed navel with an oval shape and superior hooding
Transaxillary totally subfascial breast augmentation with anatomical breast implants: review of 27 cases
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Ultrasound-Assisted Lymphaticovenular Anastomosis for the Treatment of Peripheral Lymphedema
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Nipple-sparing mastectomy with immediate implant reconstruction: cosmetic outcomes and technical refinements
No full textNipple-sparing mastectomy is gaining widespread popularity, as it could allow improved aesthetic outcome without increasing oncologic risk. To investigate the reconstructive issues experienced with immediate implant reconstruction, the authors reviewed the cosmetic outcomes of their series
The Recipient Venule in Supermicrosurgical Lymphaticovenular Anastomosis: Flow Dynamic Classification and Correlation with Surgical Outcomes
No full textBackground Venules have been usually neglected in the literature on lymphaticovenular anastomosis (LVA). The aim of this study was to analyze the flow dynamic of recipient venules in LVA and their impact on the surgical outcomes. Patients and Methods Data from 128 patients affected by extremity lymphedema, who underwent LVA, were collected in two institutions from August 2014 to May 2016. Recipient venules were classified according to their flow dynamic into backflow, slack, and outlet (BSO classification). Quantitative (lower extremity lymphedema/upper extremity lymphedema index) and qualitative outcomes (needing of compression garment and compression garment class) were evaluated. Chi-square test or Fisher's exact test was used for categorical variables and independent-samples t -test for continuous variables. The association between lymphatic collector degeneration status (normal, ectasis, contractile, sclerotic type [NECST]) and BSO classification with the outcomes was analyzed by the Mantel–Haenszel test. Results On a total of 128 patients, 37 suffered from upper and 91 from lower limb lymphedema. An average number of four LVA were performed for each patient (range: 2–8). A significant association was observed between NECST and BSO categories and the outcomes were evaluated. Patients with contractile and sclerotic collectors had 2.24 times the odd of having poor composite outcome compared with those with normal-to-ectasis collectors ( p < 0.05). Patients with backflow venules had 3.32 times the odd of having poor composite outcome compared with those without outlet or slack pattern ( p < 0.05). Conclusion The subtype of recipient venule flow dynamic has a significant impact on the surgical outcome of patients undergoing LVA for the treatment of lymphedema, regardless of the lymphatic collector degeneration status. Locating favorable venules in the preoperative mapping might enhance the surgical outcomes
Ultra-high frequency ultrasound in planning capillary perforator flaps: Preliminary experience☆
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